Quantification of pathophysiological alterations in venous oxygen saturation: A comparison of global MR susceptometry techniques

Publication date: Available online 11 January 2019

Source: Magnetic Resonance Imaging

Author(s): Paula L. Croal, Jackie Leung, Charly L. Phillips, Malambing G. Serafin, Andrea Kassner

Abstract

The purpose of this study was to compare the Infinite Cylinder and Forward Field methods of quantifying global venous oxygen saturation (Y_v) in the superior sagittal sinus (SSS) from MRI phase data, and assess their applicability in systemic cerebrovascular disease.15 children with sickle cell disease (SCD) and 10 healthy age-matched controls were imaged on a 3.0 T MRI system. Anatomical and phase data around the superior sagittal sinus were acquired from a clinically available susceptibility weighted imaging sequence and converted to Y_v using the Infinite Cylinder and Forward Field methods. Y_v was significantly higher when calculated using the Infinite Cylinder method compared to the Forward Field method in both patients (p = 0.003) and controls (p < 0.001). A significant difference in Y_v was observed between patients and controls for the Forward Field method only (p = 0.006). While various implementations of Y_v quantification can be used in practice, the results can differ significantly. Simplistic models such as the Infinite Cylinder method may be easier to implement, but their dependence on broad assumptions can lead to an overestimation of Y_v, and may reduce the sensitivity to pathophysiological changes in Y_v.

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The use of a binary chelate formulation: Could gadolinium based linear contrast agents be rescued by the addition of zinc selective chelates?

Publication date: Available online 10 January 2019

Source: Magnetic Resonance Imaging

Author(s): Wendell Gibby, Wes Parish, Ray M. Merrill, Diego Fernandez, Christopher R. Anderson, Eric Merchel, Ryan Parr

Abstract

Tissue and bone retention of gadolinium based contrast agents (GBCAs) has become a clinical concern because of the potential short and long term toxic effects of free gadolinium. This is a critical problem for most open-chain agents that more readily transmetallate in vivo, in comparison to macrocyclic compounds. Gadoliniumdiethylene tri-aminepentaacetic acid bis-glucosamide (Gd-DTPA-BIGA) is an experimental, open-chain contrast agent which has a significantly increased relaxivity coefficient in comparison to other GBCAs. This results in greater signal intensity and improved contrast enhancement. These superior imaging qualities initiated a search for a solution to the transmettalation of this agent. Plasma zinc is a well-known GBCA transmettalation agent. Since the base chelate of Gadodiamide (Gd-DPTA-Bis-Methylamide or Omniscan), DTPA-Bis-Methylamide (DTPA-BMA), readily transmettalates with and binds serum zinc, we hypothesized that a plasma "zinc sink," may significantly reduce transmettalation of linear agents. 5% DTPA-BMA was added to a formulation of Gd-DTPA-BIGA, which was tested against the original formulation of Gd-DTPA-BIGA with 0.2% of the base chelate DTPA-BIGA. These formulations, including gadodiamide, were labeled with ¹⁵³GdCl₃ followed by infusion into cohorts of Sprague Dawley rats which were sacrificed at 1, 30 and 60 days. Internal organs were harvested, along with blood, skin and femur, and analyzed for residual gadolinium. A subset of tissues were also interrogated with ICP-MS. Labeled Gadodiamide and saline where used as controls.

Conclusion: The addition of 5% DTPA-BMA, as a zinc binding agent, reduced the transmetallation of the linear agent Gd-DTPA-BIGA, in comparison to its original formulation supplemented with 0.2% BIGA. This result indicates that supplementing linear GBCAs with ancillary chelates may hold promise for reducing, or eliminating the biological archiving of gadolinium in tissues. In addition, this paper provides valuable animal data on the long term retention of gadolinium from linear based contrast agents.

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Reduced scan range abdominopelvic CT in patients with suspected acute appendicitis - impact on diagnostic accuracy and effective radiation dose

Abstract

Background

To evaluate a reduced range CT protocol in patients with suspected acute appendicitis as compared to standard abdominal CT regarding diagnostic performance, effective radiation dose and organ doses.

Methods

In this study, we retrospectively included 90 patients (43 female, mean age 56.7 ± 17 years) with suspected acute appendicitis who underwent CT of abdomen and pelvis. From those CTs, we reconstructed images with a reduced scan range from L1 to the the pubic symphysis. Full range and reduced range datasets were assessed by two radiologists for i) coverage of the Appendix, ii) presence/absence of appendicitis and iii) presence of differential diagnoses. Furthermore, effective radiation doses as well as organ doses were calculated using a commercially available dose management platform (Radimetrics, Bayer HealthCare).

Results

The Appendix was covered by the reduced range CT in all cases. In 66 patients CT confirmed the presence of appendicitis. In 14 patients, other relevant differential diagnoses were identified by CT, whereas in 10 patients no relevant findings were detected. Both readers identified all patients with appendicitis on both full and reduced range CT.

For reduced range CT, total effective dose was 39% lower than for full range CT (reduced range: 4.5 [1.9–11.2] vs. full range: 7.4 [3.3–18.8] mSv; p ≤ 0.001). Notably, a remarkable reduction of organ dose in the female breasts by 97% (0.1 [0.1–0.6] vs. 3.8 [0.5–18.8] mSv; p ≤ 0.001) and in the testicles in males by 81% (3.4 [0.7–32.7] vs. 17.6 [5.4–52.9] mSv; p ≤ 0.001) was observed for reduced range CT compared to full range CT.

Conclusions

In patients with suspected acute appendicitis, reduced range abdominopelvic CT results in a comparable diagnostic performance with a remarkable reduction of total effective radiation dose and organ doses (especially breast dose in female and testicle dose in male patients) as compared to full range CT.

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Reduced scan range abdominopelvic CT in patients with suspected acute appendicitis - impact on diagnostic accuracy and effective radiation dose

Abstract

Background

To evaluate a reduced range CT protocol in patients with suspected acute appendicitis as compared to standard abdominal CT regarding diagnostic performance, effective radiation dose and organ doses.

Methods

In this study, we retrospectively included 90 patients (43 female, mean age 56.7 ± 17 years) with suspected acute appendicitis who underwent CT of abdomen and pelvis. From those CTs, we reconstructed images with a reduced scan range from L1 to the the pubic symphysis. Full range and reduced range datasets were assessed by two radiologists for i) coverage of the Appendix, ii) presence/absence of appendicitis and iii) presence of differential diagnoses. Furthermore, effective radiation doses as well as organ doses were calculated using a commercially available dose management platform (Radimetrics, Bayer HealthCare).

Results

The Appendix was covered by the reduced range CT in all cases. In 66 patients CT confirmed the presence of appendicitis. In 14 patients, other relevant differential diagnoses were identified by CT, whereas in 10 patients no relevant findings were detected. Both readers identified all patients with appendicitis on both full and reduced range CT.

For reduced range CT, total effective dose was 39% lower than for full range CT (reduced range: 4.5 [1.9–11.2] vs. full range: 7.4 [3.3–18.8] mSv; p ≤ 0.001). Notably, a remarkable reduction of organ dose in the female breasts by 97% (0.1 [0.1–0.6] vs. 3.8 [0.5–18.8] mSv; p ≤ 0.001) and in the testicles in males by 81% (3.4 [0.7–32.7] vs. 17.6 [5.4–52.9] mSv; p ≤ 0.001) was observed for reduced range CT compared to full range CT.

Conclusions

In patients with suspected acute appendicitis, reduced range abdominopelvic CT results in a comparable diagnostic performance with a remarkable reduction of total effective radiation dose and organ doses (especially breast dose in female and testicle dose in male patients) as compared to full range CT.

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Burnout in Chairs of Academic Radiology Departments in the United States

Publication date: Available online 11 January 2019

Source: Academic Radiology

Author(s): Dhakshinamoorthy Ganeshan, Wei Wei, Wei Yang

Objective

We aimed to estimate the self-reported prevalence of burnout in chairs of academic radiology departments in the United States and identify factors associated with high burnout in chairs.

Materials and Methods

An anonymous cross-sectional online survey was conducted of members of the Society of Chairs of Academic Radiology Departments. Burnout was measured using the abbreviated Maslach Burnout Inventory Human Services Survey. Associations between survey participants' characteristics and burnout were tested using Fisher's exact test and Wilcoxon rank sum test.

Results

Of the 123 chairs invited to complete the survey, 87 responded (response rate, 71%). The mean age of the participants was 58 years. The survey respondents had an average of 9 years of experience as department chair. The average number of work hours per week was 62 hours. Four participants (5%) of the academic chairs met all three criteria for high burnout including high emotional exhaustion, high depersonalization, and low personal accomplishment. Thirty-three participants (38%) had high emotional exhaustion and/or high depersonalization score. Low professional satisfaction score, low work-life balance satisfaction score, and low chair effectiveness score were significantly associated with high burnout. High emotional exhaustion and/or high depersonalization were significantly associated with numerous professional stressors. Lack of an institutional support group for chairs and lower number of faculty members in the department were significantly associated with burnout.

Conclusion

A significant proportion of chairs of academic radiology departments are experiencing 1 or more symptoms of burnout. Efforts to address burnout in radiology chairs should be initiated promptly at the national, institutional, and departmental levels.

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Antifungal activities against Candida albicans, of cell-free supernatants obtained from probiotic Pediococcus acidilactici HW01

Publication date: Available online 11 January 2019

Source: Archives of Oral Biology

Author(s): Hyunjin Kim, Seok-Seong Kang

Abstract

Objective

The aim of this study was to investigate the antifungal activities of cell-free supernatants of a probiotic strain,Pediococcus acidilactici HW01, against Candida albicans.

Design

C. albicans was cultured in the presence of different concentration of cell-free supernatants obtained from P. acidilactici HW01 (HW01 CFS) and the growth of C. albicans was determined. C. albicans was incubated with HW01 CFS for 24 h and the biofilm formation of C. albicans was determined by staining crystal violet and by using a scanning electron microscope. Biofilm quantification was determined by 2, 3-Bis (2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide (XTT) assay.

Results

HW01 CFS inhibitedC. albicans growth, whereas bacteriocin, which is a well-known antimicrobial peptide of lactic acid bacteria, failed to inhibit C. albicans growth. Pre-treatment and simultaneous treatment with HW01 CFS exhibited a significant inhibition of C. albicans biofilm. Although post-treatment with HW01 CFS did not disrupt the established biofilm of C. albicans at 3 h-incubation, significant reduced C. albicans biofilm was observed after 6 h-incubation in the presence of HW01 CFS.

Conclusion

These results suggested that the CFS fromP. acidilactici HW01 was revealed as an effective antifungal agent against C. albicans by reducing the growth and biofilm formation.

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Down-regulation of mitochondrial NADH and cytochrome b gene associated with high tumor stages in head and neck squamous cell carcinoma

Publication date: Available online 10 January 2019

Source: Archives of Oral Biology

Author(s): Pitsapaporn Wangpermtam, Songsak Petmitr, Phaibul Punyarit, Boworn Klongnoi, Sirima Sanguansin

Abstract

Objective

This study aimed to determine mitochondrial mRNA expression levels and the relationships between these expression levels and various adverse clinicopathological characteristics.

Methods

The mRNA expression levels of all 12 genes encoded protein, located on the heavy-strand of mitochondrial DNA including cytochrome b, NADH1, NADH2, NADH3, NADH4, NADH4L, NADH5, ATPase6, ATPase8, cytochrome c oxidase subunit 1, cytochrome c oxidase subunit 2, cytochrome c oxidase subunit 3 were analyzed in 30 head and neck squamous cell carcinoma (HNSCC) and the corresponding normal tissues using reverse transcriptase quantitative real time PCR. Pearson Chi-square test was used to determine the relationships between these expression levels and categorical parameters.

Results

The expression levels of 12 mitochondrial mRNAs were observed in all 30 HNSCC patients with down-regulation, ranging from 43.3% - 76.7% and up-regulation, ranging from 10.0% – 36.7%. Furthermore, the number of cases with down-regulations in all 6 NADH and cytochrome b mRNA with TMN stages III and IV were significantly higher than that in stages I and II (p=0.049 and 0.007, respectively).

Conclusion

Down-regulation of all mitochondrial NADH mRNA as well as mitochondrial cytochrome b mRNA was associated with high tumor stage among HNSCC patients.

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Burnout in Chairs of Academic Radiology Departments in the United States

Publication date: Available online 11 January 2019

Source: Academic Radiology

Author(s): Dhakshinamoorthy Ganeshan, Wei Wei, Wei Yang

Objective

We aimed to estimate the self-reported prevalence of burnout in chairs of academic radiology departments in the United States and identify factors associated with high burnout in chairs.

Materials and Methods

An anonymous cross-sectional online survey was conducted of members of the Society of Chairs of Academic Radiology Departments. Burnout was measured using the abbreviated Maslach Burnout Inventory Human Services Survey. Associations between survey participants' characteristics and burnout were tested using Fisher's exact test and Wilcoxon rank sum test.

Results

Of the 123 chairs invited to complete the survey, 87 responded (response rate, 71%). The mean age of the participants was 58 years. The survey respondents had an average of 9 years of experience as department chair. The average number of work hours per week was 62 hours. Four participants (5%) of the academic chairs met all three criteria for high burnout including high emotional exhaustion, high depersonalization, and low personal accomplishment. Thirty-three participants (38%) had high emotional exhaustion and/or high depersonalization score. Low professional satisfaction score, low work-life balance satisfaction score, and low chair effectiveness score were significantly associated with high burnout. High emotional exhaustion and/or high depersonalization were significantly associated with numerous professional stressors. Lack of an institutional support group for chairs and lower number of faculty members in the department were significantly associated with burnout.

Conclusion

A significant proportion of chairs of academic radiology departments are experiencing 1 or more symptoms of burnout. Efforts to address burnout in radiology chairs should be initiated promptly at the national, institutional, and departmental levels.

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Antifungal activities against Candida albicans, of cell-free supernatants obtained from probiotic Pediococcus acidilactici HW01

Publication date: Available online 11 January 2019

Source: Archives of Oral Biology

Author(s): Hyunjin Kim, Seok-Seong Kang

Abstract

Objective

The aim of this study was to investigate the antifungal activities of cell-free supernatants of a probiotic strain,Pediococcus acidilactici HW01, against Candida albicans.

Design

C. albicans was cultured in the presence of different concentration of cell-free supernatants obtained from P. acidilactici HW01 (HW01 CFS) and the growth of C. albicans was determined. C. albicans was incubated with HW01 CFS for 24 h and the biofilm formation of C. albicans was determined by staining crystal violet and by using a scanning electron microscope. Biofilm quantification was determined by 2, 3-Bis (2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide (XTT) assay.

Results

HW01 CFS inhibitedC. albicans growth, whereas bacteriocin, which is a well-known antimicrobial peptide of lactic acid bacteria, failed to inhibit C. albicans growth. Pre-treatment and simultaneous treatment with HW01 CFS exhibited a significant inhibition of C. albicans biofilm. Although post-treatment with HW01 CFS did not disrupt the established biofilm of C. albicans at 3 h-incubation, significant reduced C. albicans biofilm was observed after 6 h-incubation in the presence of HW01 CFS.

Conclusion

These results suggested that the CFS fromP. acidilactici HW01 was revealed as an effective antifungal agent against C. albicans by reducing the growth and biofilm formation.

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Down-regulation of mitochondrial NADH and cytochrome b gene associated with high tumor stages in head and neck squamous cell carcinoma

Publication date: Available online 10 January 2019

Source: Archives of Oral Biology

Author(s): Pitsapaporn Wangpermtam, Songsak Petmitr, Phaibul Punyarit, Boworn Klongnoi, Sirima Sanguansin

Abstract

Objective

This study aimed to determine mitochondrial mRNA expression levels and the relationships between these expression levels and various adverse clinicopathological characteristics.

Methods

The mRNA expression levels of all 12 genes encoded protein, located on the heavy-strand of mitochondrial DNA including cytochrome b, NADH1, NADH2, NADH3, NADH4, NADH4L, NADH5, ATPase6, ATPase8, cytochrome c oxidase subunit 1, cytochrome c oxidase subunit 2, cytochrome c oxidase subunit 3 were analyzed in 30 head and neck squamous cell carcinoma (HNSCC) and the corresponding normal tissues using reverse transcriptase quantitative real time PCR. Pearson Chi-square test was used to determine the relationships between these expression levels and categorical parameters.

Results

The expression levels of 12 mitochondrial mRNAs were observed in all 30 HNSCC patients with down-regulation, ranging from 43.3% - 76.7% and up-regulation, ranging from 10.0% – 36.7%. Furthermore, the number of cases with down-regulations in all 6 NADH and cytochrome b mRNA with TMN stages III and IV were significantly higher than that in stages I and II (p=0.049 and 0.007, respectively).

Conclusion

Down-regulation of all mitochondrial NADH mRNA as well as mitochondrial cytochrome b mRNA was associated with high tumor stage among HNSCC patients.

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Improving health providers smoking cessation care in pregnancy: A systematic review and meta-analysis

Publication date: Available online 10 January 2019

Source: Addictive Behaviors

Author(s): Bar-Zeev Yael, Bonevski Billie, Lim Ling Li, Twyman Laura, Skelton Eliza, Gruppetta Maree, Palazzi Kerrin, Oldmeadow Christopher, Gould S. Gillian

Abstract

Introduction

Health providers are lacking in their provision of smoking cessation care during pregnancy. The aim of this study was to systematically review all available global studies on the effectiveness of interventions in improving health providers' provision of smoking cessation care during pregnancy.

Methods

Five databases were searched, Inclusion criteria included all intervention study types. Two reviewers screened abstracts and full texts independently. Interventions were characterized according to the Effective Practice Of Care taxonomy. Random-effects meta-analyses examined intervention effects on smoking cessation care components based on the 5As. Estimates were number of participants reporting each outcome, or mean score, transformed into Cohen's d. Crude meta-regressions, and meta-analysis subgrouping, were performed to examine whether intervention effects for 'Ask', 'Advise' and 'Assist' differed by intervention components.

Results

Of 3165 manuscripts, 16 fulfilled inclusion criteria. Pooled analysis showed significant small to large intervention effects on the different care components (Cohen's d ranging from 0.47 for 'Ask' (95%CI 0.13–0.81) to 1.12 (95%CI 0.45–1.79) for 'Setting a quit date'). Crude meta-regression suggested that for 'Ask', having a theoretical basis may improve effectiveness (Cohen's d difference 0.62, 95% CI 0.12–1.1). Subgrouping the meta-analysis suggested that audit and feedback possibly increases intervention effectiveness for 'Advise' and 'Assist'.

Conclusion

Interventions designed to improve provision of smoking cessation care during pregnancy show a small increase in care components. Studies vary substantially in design, intervention components, and outcome measurement, impacting ability to synthesize available data. Audit and feedback and enhancing intervention design by using behaviour change theories may improve effectiveness.

Registration

PROSPERO CRD42016030143.

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Improving health providers smoking cessation care in pregnancy: A systematic review and meta-analysis

Publication date: Available online 10 January 2019

Source: Addictive Behaviors

Author(s): Bar-Zeev Yael, Bonevski Billie, Lim Ling Li, Twyman Laura, Skelton Eliza, Gruppetta Maree, Palazzi Kerrin, Oldmeadow Christopher, Gould S. Gillian

Abstract

Introduction

Health providers are lacking in their provision of smoking cessation care during pregnancy. The aim of this study was to systematically review all available global studies on the effectiveness of interventions in improving health providers' provision of smoking cessation care during pregnancy.

Methods

Five databases were searched, Inclusion criteria included all intervention study types. Two reviewers screened abstracts and full texts independently. Interventions were characterized according to the Effective Practice Of Care taxonomy. Random-effects meta-analyses examined intervention effects on smoking cessation care components based on the 5As. Estimates were number of participants reporting each outcome, or mean score, transformed into Cohen's d. Crude meta-regressions, and meta-analysis subgrouping, were performed to examine whether intervention effects for 'Ask', 'Advise' and 'Assist' differed by intervention components.

Results

Of 3165 manuscripts, 16 fulfilled inclusion criteria. Pooled analysis showed significant small to large intervention effects on the different care components (Cohen's d ranging from 0.47 for 'Ask' (95%CI 0.13–0.81) to 1.12 (95%CI 0.45–1.79) for 'Setting a quit date'). Crude meta-regression suggested that for 'Ask', having a theoretical basis may improve effectiveness (Cohen's d difference 0.62, 95% CI 0.12–1.1). Subgrouping the meta-analysis suggested that audit and feedback possibly increases intervention effectiveness for 'Advise' and 'Assist'.

Conclusion

Interventions designed to improve provision of smoking cessation care during pregnancy show a small increase in care components. Studies vary substantially in design, intervention components, and outcome measurement, impacting ability to synthesize available data. Audit and feedback and enhancing intervention design by using behaviour change theories may improve effectiveness.

Registration

PROSPERO CRD42016030143.

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Influence of angular positioning of the prosthesis in stapes surgeries with a NiTiBond prosthesis: Investigation in cadaveric temporal bones

Publication date: Available online 10 January 2019

Source: Hearing Research

Author(s): P. Cuny, N.J. Alsolami, I. Dobrev, B. Warnholtz, C. Röösli, J.H. Sim

Abstract

In incus stapedotomy surgeries, the longitudinal direction of the piston prosthesis should ideally be perpendicular to the stapes footplate. However, in reality, some amounts of angular deviation of the prosthesis from the ideal angular position is unavoidable due to anatomical constraints and surgical conditions. This study aims to evaluate the influence of angular positioning of the prosthesis on surgical outcomes in incus stapedotomy and to provide surgical guidelines related to practical tolerance of the angular positioning. In this study, this influence was assessed with a Kurz NiTiBond prosthesis (0.4-mm diameter) and fenestra sizes of 0.5- and 0.6-mm diameter in cadaveric temporal bones (n = 7 including 2 preliminary tests). Angular position of the prosthesis relative to the footplate was modulated by rotating the stapes about the long and short axes of the footplate. At each angular position, the tympanic membrane was acoustically stimulated in the frequency range of 0.2-10 kHz, and motion of the prosthesis was measured using a Laser Doppler vibrometer (LDV). Furthermore, micro-computed tomography (micro-CT) data of the middle-ear ossicles were used for anatomical analysis of angular positioning of the prosthesis. The results showed that changes of angular position of the prosthesis relative to the stapes footplate do not cause significant changes of prosthesis motion until a certain angular position threshold, and sharply attenuate prosthesis motion when the angular position reaches the threshold. The threshold of the angular position, as the tilting angle of the prosthesis from the direction normal to the stapes footplate, was 26.9 ± 2.5 degrees with the fenestration hole of 0.5-mm diameter and 30.6 ± 3.0 degrees with the fenestration hole of 0.6-mm diameter (n = 5, p < 0.01 for difference between the two fenestra sizes). Analysis of the middle-ear anatomy in this study revealed that the tolerances of the angular positions of the prosthesis does not always cover possible positions of prosthesis crimping. This study suggests that if an anterior offset of the stapes head and/or the thickened footplate is suspected, efforts to locate prosthesis crimping closer to the tip of the incus and/or to make a sufficiently large fenestration hole are favorable.

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Hereditary hearing loss; about the known and the unknown

Publication date: Available online 10 January 2019

Source: Hearing Research

Author(s): Hannie Kremer

Abstract

Hereditary hearing loss is both clinically and genetically very heterogeneous. Despite the large number of genes that have been associated with the condition, many cases remain unexplained. Novel gene associations with hearing loss are to be expected but also are defects of regulatory regions of the genome which are currently not routinely addressed in molecular genetic testing and research. Inheritance patterns other than monogenic might be more common than assumed in isolated cases and diagnoses might have been missed because of misinterpretation of identified DNA variants. This review summarizes current insights in the genetics of hearing loss, the next steps that are being taken in research, and their challenges. Furthermore, genotype-phenotype correlations and modifying factors are discussed as these are instrumental in counselling hearing impaired individuals and/or their family members.

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Influence of angular positioning of the prosthesis in stapes surgeries with a NiTiBond prosthesis: Investigation in cadaveric temporal bones

Publication date: Available online 10 January 2019

Source: Hearing Research

Author(s): P. Cuny, N.J. Alsolami, I. Dobrev, B. Warnholtz, C. Röösli, J.H. Sim

Abstract

In incus stapedotomy surgeries, the longitudinal direction of the piston prosthesis should ideally be perpendicular to the stapes footplate. However, in reality, some amounts of angular deviation of the prosthesis from the ideal angular position is unavoidable due to anatomical constraints and surgical conditions. This study aims to evaluate the influence of angular positioning of the prosthesis on surgical outcomes in incus stapedotomy and to provide surgical guidelines related to practical tolerance of the angular positioning. In this study, this influence was assessed with a Kurz NiTiBond prosthesis (0.4-mm diameter) and fenestra sizes of 0.5- and 0.6-mm diameter in cadaveric temporal bones (n = 7 including 2 preliminary tests). Angular position of the prosthesis relative to the footplate was modulated by rotating the stapes about the long and short axes of the footplate. At each angular position, the tympanic membrane was acoustically stimulated in the frequency range of 0.2-10 kHz, and motion of the prosthesis was measured using a Laser Doppler vibrometer (LDV). Furthermore, micro-computed tomography (micro-CT) data of the middle-ear ossicles were used for anatomical analysis of angular positioning of the prosthesis. The results showed that changes of angular position of the prosthesis relative to the stapes footplate do not cause significant changes of prosthesis motion until a certain angular position threshold, and sharply attenuate prosthesis motion when the angular position reaches the threshold. The threshold of the angular position, as the tilting angle of the prosthesis from the direction normal to the stapes footplate, was 26.9 ± 2.5 degrees with the fenestration hole of 0.5-mm diameter and 30.6 ± 3.0 degrees with the fenestration hole of 0.6-mm diameter (n = 5, p < 0.01 for difference between the two fenestra sizes). Analysis of the middle-ear anatomy in this study revealed that the tolerances of the angular positions of the prosthesis does not always cover possible positions of prosthesis crimping. This study suggests that if an anterior offset of the stapes head and/or the thickened footplate is suspected, efforts to locate prosthesis crimping closer to the tip of the incus and/or to make a sufficiently large fenestration hole are favorable.

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Hereditary hearing loss; about the known and the unknown

Publication date: Available online 10 January 2019

Source: Hearing Research

Author(s): Hannie Kremer

Abstract

Hereditary hearing loss is both clinically and genetically very heterogeneous. Despite the large number of genes that have been associated with the condition, many cases remain unexplained. Novel gene associations with hearing loss are to be expected but also are defects of regulatory regions of the genome which are currently not routinely addressed in molecular genetic testing and research. Inheritance patterns other than monogenic might be more common than assumed in isolated cases and diagnoses might have been missed because of misinterpretation of identified DNA variants. This review summarizes current insights in the genetics of hearing loss, the next steps that are being taken in research, and their challenges. Furthermore, genotype-phenotype correlations and modifying factors are discussed as these are instrumental in counselling hearing impaired individuals and/or their family members.

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Univariate and multivariate analyses of functional networks in absolute pitch

Publication date: Available online 11 January 2019

Source: NeuroImage

Author(s): Christian Brauchli, Simon Leipold, Lutz Jäncke

Abstract

Absolute pitch (AP) refers to the rare ability to identify the pitch of any given tone without an external reference tone. Previous studies have shown that during auditory processing, AP musicians activate the auditory cortex (AC), the prefrontal cortex (PFC), and parietal areas of the brain. Therefore, it has been hypothesized that AP is sustained by a widespread functional network. In the present functional magnetic resonance imaging (fMRI) study, we tested this hypothesis by employing a mass-univariate analysis of resting-state functional connectivity within the AC, the PFC, and parietal areas in a large sample of musicians with and without AP (N = 100). AP musicians showed increased functional connectivity in the left middle frontal gyrus (MFG), left intraparietal sulcus (IPS), and right superior parietal lobule (SPL). These results provide the first evidence for an AP-specific network characterized by increased functional connections in higher-order cognitive areas. Interestingly, AP was not associated with increases in functional connectivity of the AC, but AP was successfully decoded from functional connectivity patterns in the left AC using multi-voxel pattern analysis (MVPA), with group classification accuracy being highest for the left Heschl's gyrus (HG). MVPA can capture fine-grained patterns in the brain connectivity profile of AP musicians, whilst a mass-univariate analysis is sensitive to macroscopic trends in the data. The successful differentiation of AP musicians by MVPA but not by a mass-univariate analysis of connectivity in the AC thus indicates that AP musicians differ in the fine-grained rather than the macroscopic AC function. Based on our findings, and in light of current literature, we propose pitch-label associations, tonal working memory, pitch categorization, and multimodal integration as potential mechanisms underlying the AP ability. This set of psychological functions is controlled by a distributed functional network and a particular AC connectivity pattern only present in AP musicians.

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Patch-based super-resolution of arterial spin labeling magnetic resonance images

Publication date: Available online 10 January 2019

Source: NeuroImage

Author(s): Cédric Meurée, Pierre Maurel, Jean-Christophe Ferré, Christian Barillot

Abstract

Arterial spin labeling is a magnetic resonance perfusion imaging technique that, while providing results comparable to methods currently considered as more standard concerning the quantification of the cerebral blood flow, is subject to limitations related to its low signal-to-noise ratio and low resolution. In this work, we investigate the relevance of using a non-local patch-based super-resolution method driven by a high resolution structural image to increase the level of details in arterial spin labeling images. This method is evaluated by comparison with other image dimension increasing techniques on a simulated dataset, on images of healthy subjects and on images of subjects scanned for brain tumors, who had a dynamic susceptibility contrast acquisition. The influence of an increase of ASL images resolution on partial volume effects is also investigated in this work.

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Frontal theta predicts specific cognitive control-induced behavioural changes beyond general reaction time slowing

Publication date: Available online 10 January 2019

Source: NeuroImage

Author(s): Patrick S. Cooper, Frini Karayanidis, Montana McKewen, Samuel McLellan-Hall, Aaron S.W. Wong, Patrick Skippen, James F. Cavanagh

Abstract

Investigations into the neurophysiological underpinnings of control suggest that frontal theta activity is increased with the need for control. However, these studies typically show this link by reporting associations between increased theta and RT slowing – a process that is contemporaneous with cognitive control but does not strictly reflect the specific use of control. In this study, we assessed frontal theta responses that underpinned the switch cost in task switching – a specific index of cognitive control that does not rely exclusively on RT slowing. Here, we utilised a single-trial regression approach to assess 1) how cognitive control demands beyond simple RT slowing were linked to midfrontal theta and 2) whether midfrontal theta effects remained stable over time. In a large cohort that included a longitudinal subsample, we found that midfrontal theta was modulated by switch costs, with enhanced theta power when preparing to switch vs. repeating a task. These effects were reliable after a two-year interval (Cronbach's α.39-0.74). In contrast, we found that trial-by-trial modulations of midfrontal theta power predicted the size of the switch cost – so that switch trials with increased theta produced smaller switch costs. Interestingly, these relationships between theta and behaviour were less stable over time (Cronbach's α 0-0.61), with participants first using both delta and theta bands to influence behaviour whereas after two years only theta associations with behaviour remained. Together, these findings suggest midfrontal theta supports the need for control beyond simple RT slowing and reveal that midfrontal theta effects remain relatively stable over time.

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Imaging human cortical responses to intraneural microstimulation using magnetoencephalography

Publication date: Available online 9 January 2019

Source: NeuroImage

Author(s): George C. O'Neill, Roger H. Watkins, Rochelle Ackerley, Eleanor L. Barratt, Ayan Sengupta, Michael Asghar, Rosa Maria Sanchez Panchuelo, Matthew J. Brookes, Paul M. Glover, Johan Wessberg, Susan T. Francis

Abstract

The sensation of touch in the glabrous skin of the human hand is conveyed by thousands of fast-conducting mechanoreceptive afferents, which can be categorised into four distinct types. The spiking properties of these afferents in the periphery in response to varied tactile stimuli are well-characterised, but relatively little is known about the spatiotemporal properties of the neural representations of these different receptor types in the human cortex. Here, we use the novel methodological combination of single-unit intraneural microstimulation (INMS) with magnetoencephalography (MEG) to localise cortical representations of individual touch afferents in humans, by measuring the extracranial magnetic fields from neural currents. We found that by assessing the modulation of the beta (13–30 Hz) rhythm during single-unit INMS, significant changes in oscillatory amplitude occur in the contralateral primary somatosensory cortex within and across a group of fast adapting type I mechanoreceptive afferents, which corresponded well to the induced response from matched vibrotactile stimulation. Combining the spatiotemporal specificity of MEG with the selective single-unit stimulation of INMS enables the interrogation of the central representations of different aspects of tactile afferent signalling within the human cortices. The fundamental finding that single-unit INMS ERD responses are robust and consistent with natural somatosensory stimuli will permit us to more dynamically probe the central nervous system responses in humans, to address questions about the processing of touch from the different classes of mechanoreceptive afferents and the effects of varying the stimulus frequency and patterning.

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A hierarchical independent component analysis model for longitudinal neuroimaging studies

Publication date: Available online 9 January 2019

Source: NeuroImage

Author(s): Yikai Wang, Ying Guo

Abstract

In recent years, longitudinal neuroimaging study has become increasingly popular in neuroscience research to investigate disease-related changes in brain functions, to study neurodevelopment or to evaluate treatment effects on neural processing. One of the important goals in longitudinal imaging analysis is to study changes in brain functional networks across time and how the changes are modulated by subjects' clinical or demographic variables. In current neuroscience literature, one of the most commonly used tools to extract and characterize brain functional networks is independent component analysis (ICA), which separates multivariate signals into linear mixture of independent components. However, existing ICA methods are only applicable to cross-sectional studies and not suited for modeling repeatedly measured imaging data. In this paper, we propose a novel longitudinal independent component model (L-ICA) which provides a formal modeling framework for extending ICA to longitudinal studies. By incorporating subject-specific random effects and visit-specific covariate effects, L-ICA is able to provide more accurate estimates of changes in brain functional networks on both the population- and individual-level, borrow information across repeated scans within the same subject to increase statistical power in detecting covariate effects on the networks, and allow for model-based prediction for brain networks changes caused by disease progression, treatment or neurodevelopment. We develop a fully traceable exact EM algorithm to obtain maximum likelihood estimates of L-ICA. We further develop a subspace-based approximate EM algorithm which greatly reduce the computation time while still retaining high accuracy. Moreover, we present a statistical testing procedure for examining covariate effects on brain network changes. Simulation results demonstrate the advantages of our proposed methods. We apply L-ICA to ADNI2 study to investigate changes in brain functional networks in Alzheimer disease. Results from the L-ICA provide biologically insightful findings which are not revealed using existing methods.

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Customized head molds reduce motion during resting state fMRI scans

Publication date: Available online 9 January 2019

Source: NeuroImage

Author(s): Jonathan D. Power, Benjamin M. Silver, Melanie R. Silverman, Eliana L. Ajodan, Dienke J. Bos, Rebecca M. Jones

Abstract

Head motion causes artifacts in functional magnetic resonance imaging (fMRI) scans, a problem especially relevant for task-free resting state paradigms and for developmental, aging, and clinical populations. In a cohort spanning 7–28 years old (mean age 15) we produced customized head-anatomy-specific Styrofoam molds for each subject that inserted into an MRI head coil. We scanned these subjects under two conditions: using our standard procedure of packing the head coil with foam padding about the head to reduce head motion, and using the customized molds to reduce head motion. Here we report the effects found in our first 13 subjects. In 12 of 13 subjects, the molds reduced head motion throughout the scan, and reduced the fraction of a scan with substantial motion (i.e., volumes with motion notably above baseline levels of motion). Motion was reduced in all 6 head position estimates, especially in rotational, left-right, and superior-inferior directions. Motion was reduced throughout the full age range studied, including children, adolescents, and young adults. In terms of the fMRI data itself, quality indices improved with the head mold on, scrubbing analyses detected less distance-dependent artifact in scans with the head mold on, and distant-dependent artifact was less evident in both the entire scan and also during only low-motion volumes. Subjects found the molds comfortable. Head molds are thus effective tools for reducing head motion, and motion artifacts, during fMRI scans.

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Differential impact of reward and punishment on functional connectivity after skill learning

Publication date: Available online 8 January 2019

Source: NeuroImage

Author(s): Adam Steel, Edward H. Silson, Charlotte J. Stagg, Chris I. Baker

Abstract

Reward and punishment shape behavior, but the mechanisms underlying their effect on skill learning are not well understood. Here, we tested whether the functional connectivity of premotor cortex (PMC), a region known to be critical for learning of sequencing skills, is altered after training by reward or punishment given during training. Resting-state fMRI was collected in two experiments before and after participants trained on either a serial reaction time task (SRTT; n = 36) or force-tracking task (FTT; n = 36) with reward, punishment, or control feedback. In each experiment, training-related change in PMC functional connectivity was compared across feedback groups. In both tasks, reward and punishment differentially affected PMC functional connectivity. On the SRTT, participants trained with reward showed an increase in functional connectivity between PMC and cerebellum as well as PMC and striatum, while participants trained with punishment showed an increase in functional connectivity between PMC and medial temporal lobe connectivity. After training on the FTT, subjects trained with control and reward showed increases in PMC connectivity with parietal and temporal cortices after training, while subjects trained with punishment showed increased PMC connectivity with ventral striatum. While the results from the two experiments overlapped in some areas, including ventral pallidum, temporal lobe, and cerebellum, these regions showed diverging patterns of results across the two tasks for the different feedback conditions. These findings suggest that reward and punishment strongly influence spontaneous brain activity after training, and that the regions implicated depend on the task learned.

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Amyloid-beta induced retrograde axonal degeneration in a mouse tauopathy model

Publication date: Available online 7 January 2019

Source: NeuroImage

Author(s): Christopher Nishioka, Hsiao-Fang Liang, Barsam Barsamian, Shu-Wei Sun

Abstract

White matter abnormalities, revealed by Diffusion Tensor Imaging (DTI), are observed in patients with Alzheimer's Disease (AD), representing neural network deficits that underlie gradual cognitive decline in patients with AD. However, how DTI changes are related to the development of Amyloid beta (Aβ) and tau pathology, two key hallmarks of AD, remains elusive. We hypothesized that tauopathy induced by Aβ could initiate an axonal degeneration process, leading to DTI-detectable white matter abnormalities. We utilized the visual system of the transgenic p301L tau mice as a model system. Aβ was injected in Lateral Geniculate Nucleus (LGN), where the Retinal Ganglion Cell (RGC) axons terminate, and longitudinal DTI was conducted to detect changes in the optic tract (OT, containing the distal segment of RGC axons) and optic nerve (ON, containing the proximal segment of RGC axons). Our results showed early DTI changes in OT (significant 13.2% reduction in axial diffusion, AxD vs. vehicle controls) followed by later significant alterations in ON AxD and fractional anisotropy, FA. Histology data revealed loss of synapses, RGC axons and cell bodies resulting from the Aβ injection. We further tested whether microtubule-stabilizing compound Epothilone D (EpoD) could ameliorate the damage. EpoD co-treatment with Aβ was sufficient to prevent Aβ-induced axon and cell loss. Using an acute injection paradigm, our data suggest that EpoD may mediate its protective effect by blocking localized, acute Aβ-induced tau phosphorylation. This study demonstrates white matter disruption resulting from localized Aβ, the importance of tau pathology induction to changes in white matter connectivity, and the use of EpoD as a potential therapeutic avenue to block axon loss during disease.

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Unbiased age-specific structural brain atlases for Chinese pediatric population

Publication date: Available online 6 January 2019

Source: NeuroImage

Author(s): Tengda Zhao, Xuhong Liao, Vladimir S. Fonov, Qiushi Wang, Weiwei Men, Yanpei Wang, Shaozheng Qin, Shuping Tan, Jia-Hong Gao, Alan Evans, Sha Tao, Qi Dong, Yong He

Abstract

In magnetic resonance (MR) imaging studies of child brain development, structural brain atlases usually serve as important references for the pediatric population, in which individual images are spatially normalized into a common or standard stereotactic space. However, the popular existing pediatric brain atlases (e.g., National Institutes of Health pediatric atlases, NIH-PD) are mostly based on MR images obtained from Caucasian populations and thus are not ideal for the characterization of the brains of Chinese children due to neuroanatomical differences related to genetic and environmental factors. Here, we use an unbiased template construction algorithm to create a set of age-specific Chinese pediatric (CHN-PD) atlases based on high-quality T1-and T2-weighted MR images from 328 cognitively normal Chinese children aged 6–12 years. The CHN-PD brain atlases include asymmetric and symmetric templates, sex-specific templates and tissue probability templates, and contain multiple age-specific templates at one-year intervals. A direct comparison of the CHN-PD and NIH-PD atlases reveals dramatic anatomical differences mainly in the bilateral frontal and parietal regions. After applying the CHN-PD and NIH-PD atlases to two independent Chinese pediatric datasets (N = 114 and N = 71), we find that the CHN-PD atlases result in significantly higher accuracy than the NIH-PD atlases in both predicting "brain age" and guiding brain tissue segmentation. These results suggest that the CHN-PD brain atlases are necessary for studies of the typical and atypical development of the Chinese pediatric population. These CHN-PD atlases have been released on the Neuroimaging Informatics Tools and Resources Clearinghouse (NITRC) website (http://bit.ly/2QBMr8d).

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A distinct cortical network for mathematical knowledge in the human brain

Publication date: 1 April 2019

Source: NeuroImage, Volume 189

Author(s): Marie Amalric, Stanislas Dehaene

Abstract

How does the brain represent and manipulate abstract mathematical concepts? Recent evidence suggests that mathematical processing relies on specific brain areas and dissociates from language. Here, we investigate this dissociation in two fMRI experiments in which professional mathematicians had to judge the truth value of mathematical and nonmathematical spoken statements. Sentences with mathematical content systematically activated bilateral intraparietal sulci and inferior temporal regions, regardless of math domain, problem difficulty, and strategy for judging truth value (memory retrieval, calculation or mental imagery). Second, classical language areas were only involved in the parsing of both nonmathematical and mathematical statements, and their activation correlated with syntactic complexity, not mathematical content. Third, the mere presence, within a sentence, of elementary logical operators such as quantifiers or negation did not suffice to activate math-responsive areas. Instead, quantifiers and negation impacted on activity in right angular gyrus and left inferior frontal gyrus, respectively. Overall, these results support the existence of a distinct, non-linguistic cortical network for mathematical knowledge in the human brain.

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A registration method for improving quantitative assessment in probabilistic diffusion tractography

Publication date: Available online 3 January 2019

Source: NeuroImage

Author(s): J.L. Waugh, J.K. Kuster, M.L. Makhlouf, J.M. Levenstein, T.J. Multhaupt-Buell, S.K. Warfield, N. Sharma, A.J. Blood

Abstract

Diffusion MRI-based probabilistic tractography is a powerful tool for non-invasively investigating normal brain architecture and alterations in structural connectivity associated with disease states. Both voxelwise and region-of-interest methods of analysis are capable of integrating population differences in tract amplitude (streamline count or density), given proper alignment of the tracts of interest. However, quantification of tract differences (between groups, or longitudinally within individuals) has been hampered by two related features of white matter. First, it is unknown to what extent healthy individuals differ in the precise location of white matter tracts, and to what extent experimental factors influence perceived tract location. Second, white matter lacks the gross neuroanatomical features (e.g., gyri, histological subtyping) that make parcellation of grey matter plausible – determining where tracts "should" lie within larger white matter structures is difficult. Accurately quantifying tractographic connectivity between individuals is thus inherently linked to the difficulty of identifying and aligning precise tract location. Tractography is often utilized to study neurological diseases in which the precise structural and connectivity abnormalities are unknown, underscoring the importance of accounting for individual differences in tract location when evaluating the strength of structural connectivity.

We set out to quantify spatial variance in tracts aligned through a standard, whole-brain registration method, and to assess the impact of location mismatch on groupwise assessments of tract amplitude. We then developed a method for tract alignment that enhances the existing standard whole brain registration, and then tested whether this method improved the reliability of groupwise contrasts. Specifically, we conducted seed-based probabilistic diffusion tractography from primary motor, supplementary motor, and visual cortices, projecting through the corpus callosum. Streamline counts decreased rapidly with movement from the tract center (−35% per millimeter); tract misalignment of a few millimeters caused substantial compromise of amplitude comparisons. Alignment of tracts "peak-to-peak" is essential for accurate amplitude comparisons. However, for all transcallosal tracts registered through the whole-brain method, the mean separation distance between an individual subject's tract and the average tract (3.2 mm) precluded accurate comparison: at this separation, tract amplitudes were reduced by 74% from peak value. In contrast, alignment of subcortical tracts (thalamo-putaminal, pallido-rubral) was substantially better than alignment for cortical tracts; whole-brain registration was sufficient for these subcortical tracts.

We demonstrated that location mismatches in cortical tractography were sufficient to produce false positive and false negative amplitude estimates in both groupwise and longitudinal comparisons. We then showed that our new tract alignment method substantially reduced location mismatch and improved both reliability and statistical power of subsequent quantitative comparisons.

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Task activations produce spurious but systematic inflation of task functional connectivity estimates

Publication date: 1 April 2019

Source: NeuroImage, Volume 189

Author(s): Michael W. Cole, Takuya Ito, Douglas Schultz, Ravi Mill, Richard Chen, Carrisa Cocuzza

Abstract

Most neuroscientific studies have focused on task-evoked activations (activity amplitudes at specific brain locations), providing limited insight into the functional relationships between separate brain locations. Task-state functional connectivity (FC) – statistical association between brain activity time series during task performance – moves beyond task-evoked activations by quantifying functional interactions during tasks. However, many task-state FC studies do not remove the first-order effect of task-evoked activations prior to estimating task-state FC. It has been argued that this results in the ambiguous inference "likely active or interacting during the task", rather than the intended inference "likely interacting during the task". Utilizing a neural mass computational model, we verified that task-evoked activations substantially and inappropriately inflate task-state FC estimates, especially in functional MRI (fMRI) data. Various methods attempting to address this problem have been developed, yet the efficacies of these approaches have not been systematically assessed. We found that most standard approaches for fitting and removing mean task-evoked activations were unable to correct these inflated correlations. In contrast, methods that flexibly fit mean task-evoked response shapes effectively corrected the inflated correlations without reducing effects of interest. Results with empirical fMRI data confirmed the model's predictions, revealing activation-induced task-state FC inflation for both Pearson correlation and psychophysiological interaction (PPI) approaches. These results demonstrate that removal of mean task-evoked activations using an approach that flexibly models task-evoked response shape is an important preprocessing step for valid estimation of task-state FC.

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Neural histology and neurogenesis of the human fetal and infant brain

Publication date: Available online 27 December 2018

Source: NeuroImage

Author(s): I. Kostović, G. Sedmak, M. Judaš

Abstract

The human brain develops slowly and over a long period of time which lasts for almost three decades. This enables good spatio-temporal resolution of histogenetic and neurogenetic events as well as an appropriate and clinically relevant timing of these events. In order to successfully apply in vivo neuroimaging data, in analyzing both the normal brain development and the neurodevelopmental origin of major neurological and mental disorders, it is important to correlate these neuroimaging data with the existing data on morphogenetic, histogenetic and neurogenetic events. Furthermore, when performing such correlation, the genetic, genomic, and molecular biology data on phenotypic specification of developing brain regions, areas and neurons should also be included. In this review, we focus on early developmental periods (form 8 postconceptional weeks to the second postnatal year) and describe the microstructural organization and neural circuitry elements of the fetal and early postnatal human cerebrum.

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Imaging human cortical responses to intraneural microstimulation using magnetoencephalography

Publication date: Available online 9 January 2019

Source: NeuroImage

Author(s): George C. O'Neill, Roger H. Watkins, Rochelle Ackerley, Eleanor L. Barratt, Ayan Sengupta, Michael Asghar, Rosa Maria Sanchez Panchuelo, Matthew J. Brookes, Paul M. Glover, Johan Wessberg, Susan T. Francis

Abstract

The sensation of touch in the glabrous skin of the human hand is conveyed by thousands of fast-conducting mechanoreceptive afferents, which can be categorised into four distinct types. The spiking properties of these afferents in the periphery in response to varied tactile stimuli are well-characterised, but relatively little is known about the spatiotemporal properties of the neural representations of these different receptor types in the human cortex. Here, we use the novel methodological combination of single-unit intraneural microstimulation (INMS) with magnetoencephalography (MEG) to localise cortical representations of individual touch afferents in humans, by measuring the extracranial magnetic fields from neural currents. We found that by assessing the modulation of the beta (13–30 Hz) rhythm during single-unit INMS, significant changes in oscillatory amplitude occur in the contralateral primary somatosensory cortex within and across a group of fast adapting type I mechanoreceptive afferents, which corresponded well to the induced response from matched vibrotactile stimulation. Combining the spatiotemporal specificity of MEG with the selective single-unit stimulation of INMS enables the interrogation of the central representations of different aspects of tactile afferent signalling within the human cortices. The fundamental finding that single-unit INMS ERD responses are robust and consistent with natural somatosensory stimuli will permit us to more dynamically probe the central nervous system responses in humans, to address questions about the processing of touch from the different classes of mechanoreceptive afferents and the effects of varying the stimulus frequency and patterning.

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Slow spindles are associated with cortical high frequency activity

Publication date: Available online 9 January 2019

Source: NeuroImage

Author(s): Nasrin Sadat Hashemi, Fereshteh Dehnavi, Sahar Moghimi, Maryam Ghorbani

Abstract

Thalamocortical network shows self-sustained oscillations in a broad frequency range especially during slow wave sleep when cortical neurons show synchronized transitions between a quiescent down state and an active up state with beta and gamma oscillations. Inconsistent with previous models, thalamocortical spindles are separated into slow spindles (8_12 Hz) and fast spindles (13_17 Hz) with differential properties. We proposed that cortical high frequency (∼ 25 Hz) activity during up states is the key ingredient for the generation of slow spindles. In fact, the nonlinear interaction between cortical high frequency and thalamic oscillations at fast spindle frequency reproduces oscillations in the range of the difference between the two frequencies that lies into the range of slow spindle. The developed simple deterministic thalamocortical model is able to reproduce up and down states with stochastic high-frequency up-state activity as well as both fast and slow spindles. In agreement with the previous experimental observations, the fast and slow spindles are generated at opposing phases of the up state. To further confirm the causal relationship between slow spindles and cortical high frequency oscillations, we next showed that externally applied high frequency stimulation enhanced the slow spindle activity. Moreover, the prediction of the model was validated experimentally by recording EEG from subjects during nap. Both model and experimental results show increase in high frequency activity before slow spindles. Our findings suggest the important role of cortical high frequency activity in the generation of slow spindles.

Graphical abstract

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Customized head molds reduce motion during resting state fMRI scans

Publication date: Available online 9 January 2019

Source: NeuroImage

Author(s): Jonathan D. Power, Benjamin M. Silver, Melanie R. Silverman, Eliana L. Ajodan, Dienke J. Bos, Rebecca M. Jones

Abstract

Head motion causes artifacts in functional magnetic resonance imaging (fMRI) scans, a problem especially relevant for task-free resting state paradigms and for developmental, aging, and clinical populations. In a cohort spanning 7–28 years old (mean age 15) we produced customized head-anatomy-specific Styrofoam molds for each subject that inserted into an MRI head coil. We scanned these subjects under two conditions: using our standard procedure of packing the head coil with foam padding about the head to reduce head motion, and using the customized molds to reduce head motion. Here we report the effects found in our first 13 subjects. In 12 of 13 subjects, the molds reduced head motion throughout the scan, and reduced the fraction of a scan with substantial motion (i.e., volumes with motion notably above baseline levels of motion). Motion was reduced in all 6 head position estimates, especially in rotational, left-right, and superior-inferior directions. Motion was reduced throughout the full age range studied, including children, adolescents, and young adults. In terms of the fMRI data itself, quality indices improved with the head mold on, scrubbing analyses detected less distance-dependent artifact in scans with the head mold on, and distant-dependent artifact was less evident in both the entire scan and also during only low-motion volumes. Subjects found the molds comfortable. Head molds are thus effective tools for reducing head motion, and motion artifacts, during fMRI scans.

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Qoala-T: A supervised-learning tool for quality control of FreeSurfer segmented MRI data

Publication date: Available online 8 January 2019

Source: NeuroImage

Author(s): Eduard T. Klapwijk, Ferdi van de Kamp, Mara van der Meulen, Sabine Peters, Lara M. Wierenga

Abstract

Performing quality control to detect image artifacts and data-processing errors is crucial in structural magnetic resonance imaging, especially in developmental studies. Currently, many studies rely on visual inspection by trained raters for quality control. The subjectivity of these manual procedures lessens comparability between studies, and with growing study sizes quality control is increasingly time consuming. In addition, both inter-rater as well as intra-rater variability of manual quality control is high and may lead to inclusion of poor quality scans and exclusion of scans of usable quality. In the current study we present the Qoala-T tool, which is an easy and free to use supervised-learning model to reduce rater bias and misclassification in manual quality control procedures using FreeSurfer-processed scans. First, we manually rated quality of N = 784 FreeSurfer-processed T1-weighted scans acquired in three different waves in a longitudinal study. Different supervised-learning models were then compared to predict manual quality ratings using FreeSurfer segmented output data. Results show that the Qoala-T tool using random forests is able to predict scan quality with both high sensitivity and specificity (mean area under the curve (AUC) = 0.98). In addition, the Qoala-T tool was also able to adequately predict the quality of two novel unseen datasets (total N = 872). Finally, analyses of age effects showed that younger participants were more likely to have lower scan quality, underlining that scan quality might confound findings attributed to age effects. These outcomes indicate that this procedure could further help to reduce variability related to manual quality control, thereby benefiting the comparability of data quality between studies.

Graphical abstract

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Individual variation in brain network topology is linked to emotional intelligence

Publication date: Available online 8 January 2019

Source: NeuroImage

Author(s): George Ling, Ivy Lee, Synthia Guimond, Olivia Lutz, Neeraj Tandon, Uzma Nawaz, Dost Öngür, Shaun Eack, Kathryn Lewandowski, Matcheri Keshavan, Roscoe Brady

Abstract

Background

Social cognitive ability is a significant determinant of functional outcome, and deficits in social cognition are a disabling symptom of psychotic disorders. The neurobiological underpinnings of social cognition are not well understood, hampering our ability to ameliorate these deficits.

Objective

Using 'resting state' functional magnetic resonance imaging (rsfMRI) and a trans-diagnostic, data-driven analytic strategy, we sought to identify the brain network basis of emotional intelligence, a key domain of social cognition.

Methods

The study included 60 participants with a diagnosis of schizophrenia or schizoaffective disorder and 45 healthy controls. All participants underwent a rsfMRI scan. Emotional Intelligence was measured using the Mayer-Salovey-Caruso Emotional Intelligence Test (MSCEIT). A connectome-wide analysis examined how each individual brain voxel's connectivity correlated with emotional intelligence using multivariate distance matrix regression (MDMR).

Results

We identified a region in the left superior parietal lobule (SPL) where individual network topology is linked to emotional intelligence. Specifically, in high scoring individuals, this region is a node of the Default Mode Network and in low scoring individuals, it is a node of the Dorsal Attention Network. This relationship was observed in both schizophrenia and healthy comparison participants.

Conclusion

Prior studies have demonstrated individual variance in the topology of canonical resting state networks but the cognitive or behavioral relevance of these differences has largely been undetermined. We observe that the left SPL, a region of high individual variance at the cytoarchitectonic level, also demonstrates individual variance in its association with large scale resting-state networks and that network topology is linked to emotional intelligence.

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Amyloid-beta induced retrograde axonal degeneration in a mouse tauopathy model

Publication date: Available online 7 January 2019

Source: NeuroImage

Author(s): Christopher Nishioka, Hsiao-Fang Liang, Barsam Barsamian, Shu-Wei Sun

Abstract

White matter abnormalities, revealed by Diffusion Tensor Imaging (DTI), are observed in patients with Alzheimer's Disease (AD), representing neural network deficits that underlie gradual cognitive decline in patients with AD. However, how DTI changes are related to the development of Amyloid beta (Aβ) and tau pathology, two key hallmarks of AD, remains elusive. We hypothesized that tauopathy induced by Aβ could initiate an axonal degeneration process, leading to DTI-detectable white matter abnormalities. We utilized the visual system of the transgenic p301L tau mice as a model system. Aβ was injected in Lateral Geniculate Nucleus (LGN), where the Retinal Ganglion Cell (RGC) axons terminate, and longitudinal DTI was conducted to detect changes in the optic tract (OT, containing the distal segment of RGC axons) and optic nerve (ON, containing the proximal segment of RGC axons). Our results showed early DTI changes in OT (significant 13.2% reduction in axial diffusion, AxD vs. vehicle controls) followed by later significant alterations in ON AxD and fractional anisotropy, FA. Histology data revealed loss of synapses, RGC axons and cell bodies resulting from the Aβ injection. We further tested whether microtubule-stabilizing compound Epothilone D (EpoD) could ameliorate the damage. EpoD co-treatment with Aβ was sufficient to prevent Aβ-induced axon and cell loss. Using an acute injection paradigm, our data suggest that EpoD may mediate its protective effect by blocking localized, acute Aβ-induced tau phosphorylation. This study demonstrates white matter disruption resulting from localized Aβ, the importance of tau pathology induction to changes in white matter connectivity, and the use of EpoD as a potential therapeutic avenue to block axon loss during disease.

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Simultaneous task-based BOLD-fMRI and [18-F] FDG functional PET for measurement of neuronal metabolism in the human visual cortex

Publication date: Available online 4 January 2019

Source: NeuroImage

Author(s): Sharna D. Jamadar, Phillip GD. Ward, Shenpeng Li, Francesco Sforazzini, Jakub Baran, Zhaolin Chen, Gary F. Egan

Abstract

Studies of task-evoked brain activity are the cornerstone of cognitive neuroscience, and unravel the spatial and temporal brain dynamics of cognition in health and disease. Blood oxygenation level dependent functional magnetic resonance imaging (BOLD-fMRI) is one of the most common methods of studying brain function in humans. BOLD-fMRI indirectly infers neuronal activity from regional changes in blood oxygenation and is not a quantitative metric of brain function. Regional variation in glucose metabolism, measured using [18-F] fluorodeoxyglucose positron emission tomography (FDG-PET), provides a more direct and interpretable measure of neuronal activity. However, while the temporal resolution of BOLD-fMRI is in the order of seconds, standard FDG-PET protocols provide a static snapshot of glucose metabolism. Here, we develop a novel experimental design for measurement of task-evoked changes in regional blood oxygenation and glucose metabolism with high temporal resolution. Over a 90-min simultaneous BOLD-fMRI/FDG-PET scan, [18F] FDG was constantly infused to 10 healthy volunteers, who viewed a flickering checkerboard presented in a hierarchical block design. Dynamic task-related changes in blood oxygenation and glucose metabolism were examined with temporal resolution of 2.5sec and 1-min, respectively. Task-related, temporally coherent brain networks of haemodynamic and metabolic connectivity were jointly coupled in the visual cortex, as expected. Results demonstrate that the hierarchical block design, together with the infusion FDG-PET technique, enabled both modalities to track task-related neural responses with high temporal resolution. The simultaneous MR-PET approach has the potential to provide unique insights into the dynamic haemodynamic and metabolic interactions that underlie cognition in health and disease.

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A registration method for improving quantitative assessment in probabilistic diffusion tractography

Publication date: Available online 3 January 2019

Source: NeuroImage

Author(s): J.L. Waugh, J.K. Kuster, M.L. Makhlouf, J.M. Levenstein, T.J. Multhaupt-Buell, S.K. Warfield, N. Sharma, A.J. Blood

Abstract

Diffusion MRI-based probabilistic tractography is a powerful tool for non-invasively investigating normal brain architecture and alterations in structural connectivity associated with disease states. Both voxelwise and region-of-interest methods of analysis are capable of integrating population differences in tract amplitude (streamline count or density), given proper alignment of the tracts of interest. However, quantification of tract differences (between groups, or longitudinally within individuals) has been hampered by two related features of white matter. First, it is unknown to what extent healthy individuals differ in the precise location of white matter tracts, and to what extent experimental factors influence perceived tract location. Second, white matter lacks the gross neuroanatomical features (e.g., gyri, histological subtyping) that make parcellation of grey matter plausible – determining where tracts "should" lie within larger white matter structures is difficult. Accurately quantifying tractographic connectivity between individuals is thus inherently linked to the difficulty of identifying and aligning precise tract location. Tractography is often utilized to study neurological diseases in which the precise structural and connectivity abnormalities are unknown, underscoring the importance of accounting for individual differences in tract location when evaluating the strength of structural connectivity.

We set out to quantify spatial variance in tracts aligned through a standard, whole-brain registration method, and to assess the impact of location mismatch on groupwise assessments of tract amplitude. We then developed a method for tract alignment that enhances the existing standard whole brain registration, and then tested whether this method improved the reliability of groupwise contrasts. Specifically, we conducted seed-based probabilistic diffusion tractography from primary motor, supplementary motor, and visual cortices, projecting through the corpus callosum. Streamline counts decreased rapidly with movement from the tract center (−35% per millimeter); tract misalignment of a few millimeters caused substantial compromise of amplitude comparisons. Alignment of tracts "peak-to-peak" is essential for accurate amplitude comparisons. However, for all transcallosal tracts registered through the whole-brain method, the mean separation distance between an individual subject's tract and the average tract (3.2 mm) precluded accurate comparison: at this separation, tract amplitudes were reduced by 74% from peak value. In contrast, alignment of subcortical tracts (thalamo-putaminal, pallido-rubral) was substantially better than alignment for cortical tracts; whole-brain registration was sufficient for these subcortical tracts.

We demonstrated that location mismatches in cortical tractography were sufficient to produce false positive and false negative amplitude estimates in both groupwise and longitudinal comparisons. We then showed that our new tract alignment method substantially reduced location mismatch and improved both reliability and statistical power of subsequent quantitative comparisons.

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Neural histology and neurogenesis of the human fetal and infant brain

Publication date: Available online 27 December 2018

Source: NeuroImage

Author(s): I. Kostović, G. Sedmak, M. Judaš

Abstract

The human brain develops slowly and over a long period of time which lasts for almost three decades. This enables good spatio-temporal resolution of histogenetic and neurogenetic events as well as an appropriate and clinically relevant timing of these events. In order to successfully apply in vivo neuroimaging data, in analyzing both the normal brain development and the neurodevelopmental origin of major neurological and mental disorders, it is important to correlate these neuroimaging data with the existing data on morphogenetic, histogenetic and neurogenetic events. Furthermore, when performing such correlation, the genetic, genomic, and molecular biology data on phenotypic specification of developing brain regions, areas and neurons should also be included. In this review, we focus on early developmental periods (form 8 postconceptional weeks to the second postnatal year) and describe the microstructural organization and neural circuitry elements of the fetal and early postnatal human cerebrum.

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Improving the Diagnostic Capability of the Modified Barium Swallow Study Through Standardization of an Esophageal Sweep Protocol

Abstract

The modified  barium swallow (MBS) study is a videofluoroscopic evaluation of oropharyngeal swallow function. Esophageal imaging is not routinely performed during an MBS, and few guidelines for implementation or interpretation exist. Aims of the current investigation were to (1) delineate the percentage of normal, oropharyngeal, esophageal, and mixed swallowing dysfunction, (2) develop operational definitions for rating our standardization cursory view of esophageal bolus flow, and (3) determine inter-rater reliability between speech pathology (SLP) and physician raters for categorizing esophageal abnormalities. A two-phase retrospective review of 358 patient charts and MBS studies was conducted. Esophageal bolus flow was operationally defined as (1) normal, (2) anatomic abnormality, (3) dysmotility and (4) combined. Descriptive statistics, a Chi square with alpha set at 0.05, and Kappa analysis were performed. Esophageal dysfunction was identified in 80 (26%) patients and included: anatomic abnormality (69%), dysmotility (17%), and combined abnormality (14%). Phase one reliability testing yielded fair agreement between SLP and MD raters k = 0.5. Following revision of definitions and consensus training, phase two reliability testing resulted in excellent agreement between the same raters k = 0.9. Multiphase or primary esophageal dysphagia was found in 26% of our sample using a standardized protocol rating esophageal bolus flow from the upper esophageal sphincter through the lower esophageal sphincter during the MBS. Improved agreement between SLP and MD raters after definition revision and training suggests these operational definitions are concise, objective and reliable. An expanded MBS study may lead to early identification of esophageal disorders, encourage multidisciplinary patient care, and improve patient health outcomes.

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Improving the Diagnostic Capability of the Modified Barium Swallow Study Through Standardization of an Esophageal Sweep Protocol

Abstract

The modified  barium swallow (MBS) study is a videofluoroscopic evaluation of oropharyngeal swallow function. Esophageal imaging is not routinely performed during an MBS, and few guidelines for implementation or interpretation exist. Aims of the current investigation were to (1) delineate the percentage of normal, oropharyngeal, esophageal, and mixed swallowing dysfunction, (2) develop operational definitions for rating our standardization cursory view of esophageal bolus flow, and (3) determine inter-rater reliability between speech pathology (SLP) and physician raters for categorizing esophageal abnormalities. A two-phase retrospective review of 358 patient charts and MBS studies was conducted. Esophageal bolus flow was operationally defined as (1) normal, (2) anatomic abnormality, (3) dysmotility and (4) combined. Descriptive statistics, a Chi square with alpha set at 0.05, and Kappa analysis were performed. Esophageal dysfunction was identified in 80 (26%) patients and included: anatomic abnormality (69%), dysmotility (17%), and combined abnormality (14%). Phase one reliability testing yielded fair agreement between SLP and MD raters k = 0.5. Following revision of definitions and consensus training, phase two reliability testing resulted in excellent agreement between the same raters k = 0.9. Multiphase or primary esophageal dysphagia was found in 26% of our sample using a standardized protocol rating esophageal bolus flow from the upper esophageal sphincter through the lower esophageal sphincter during the MBS. Improved agreement between SLP and MD raters after definition revision and training suggests these operational definitions are concise, objective and reliable. An expanded MBS study may lead to early identification of esophageal disorders, encourage multidisciplinary patient care, and improve patient health outcomes.

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Repetition Reduction Revisited: The Prosody of Repeated Words in Papuan Malay.

Conclusions partially confirm previous work and challenge theories on how the prosody and information value of a word are related. PMID: 30618355 [PubMed - as supplied by publisher] (Source: Language and Speech)

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Processing of unfamiliar accents in monolingual and bilingual children: effects of type and amount of accent experience.

We examined how experience with accented speech modulates mono- and bilingual children's (mean age: 9;10) ease of speech comprehension for two unfamiliar accents in German, one foreign and one regional. More experience with regional accents helped children repeat sentences correctly in the regional condition and in the standard condition. More experience with foreign accents did not help in either accent condition. The results suggest that type and amount of accent experience co-determine processing ease of accented speech. PMID: 30616700 [PubMed - as supplied by publisher] (Source: Journal of Child Language)

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Repetition Reduction Revisited: The Prosody of Repeated Words in Papuan Malay.

Conclusions partially confirm previous work and challenge theories on how the prosody and information value of a word are related. PMID: 30618355 [PubMed - as supplied by publisher] (Source: Language and Speech)

from #Head and Neck by Sfakianakis via simeraentaxei on Inoreader http://bit.ly/2D1HguT

Sialoendoscopy: Review and Nuances of Technique

Abstract

Introduction

Sialoendoscopy is a nuanced technique of transluminal management of obstructive and nonneoplastic pathology of the major salivary glands. Techniques have been refined in the last two decades due to advances in optical and endoscopic instrumentation. This minimally invasive technique has both diagnostic and therapeutic applications. Obstructive salivary gland disease due to mineralized stones causes the majority of salivary duct-related pathology. Mucus plugs and strictures are the other causes. Submandibular gland sialolithiasis comprises the majority of salivary ductal pathology, with less than ten percent of obstructive symptoms related to parotid gland.

Objective

The aim of this review is to comprehensively understand the scope of practice, the methodology of management, and the techniques for a successful outcome in sialoendoscopy. Anatomy of the salivary glands and the ductal system is reviewed for a successful outcome. Guidance for patient selection, indications, investigations, and preprocedure preparation for sialoendoscopy are discussed. Algorithms and an instrument checklist are provided in table format in the manuscript for clinical utility.

Conclusion

The author simplifies the various systems of sialoendoscopes and the utility of the instruments. The future of transluminal and intraluminal salivary procedures is within the oral and maxillofacial surgical realm with simulators and multidimensional imaging and navigational advances.

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Evaluation of Three-Dimensional Changes in Pharyngeal Airway Following Isolated Lefort One Osteotomy for the Correction of Vertical Maxillary Excess: A Prospective Study

Abstract

Background

Orthognathic surgery involves movement of jaws in all three planes, and this being a part of airway complex, displacement of jaws can influence the dimension of airway at all levels. Lefort one osteotomy surgery with superior repositioning is a common procedure done for patients with vertical maxillary excess

Purpose

The purpose of this study was to evaluate the three-dimensional volumetric changes in airway after lefort one impaction surgery using three-dimensional cone beam computed tomography (3D-CBCT) in patients with vertical maxillary excess (VME).

Methods

A prospective analysis of 15 patients who underwent isolated lefort one impaction surgery was done with pre-operative (T0) and 3-months (T1) post-operative 3D-CBCT scans. Airway was divided into three segments, nasopharyngeal, velopharyngeal and oropharyngeal. Volumetric analysis of all these segments was done before and after surgery. Paired 't test' was used to assess the mean difference in airway volume and area between T0 and T1. One-way ANOVA was used to check the mean percentage difference in airway volume and area among the three segments.

Results

The mean percentage of nasopharyngeal volume difference was − 0.6299 ± 0.9146%, velopharyngeal volume difference was − 0.5205 ± 1.107%, oropharyngeal volume difference was − 1.492 ± 2.745%. Though volume and area of pharyngeal airway were decreased after maxillary impaction surgery in all three segments of airway studied, they were not statistically significant.

Conclusion

Among the three segments of airway studied, oropharyngeal airway volume has shown the highest post-surgical reduction though statistically insignificant. ESS scores were within normal limits. Hence, we are of the opinion that there is lack of evidence to conclude that the patients undergoing lefort one superior repositioning for the treatment of VME might develop significant narrowing of PAS that may predispose the patient to breathing disorders.

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A Woman Oral and Maxillofacial Surgeon of India: Is She Satisfied with Her Career Choice?

Abstract

Just as other surgical fields, maxillofacial surgery also was considered a male-dominated field since long. In the recent past, though, we are witnessing change in this trend. Dentistry in general, and maxillofacial surgery in particular, is seeing a large number of women choosing it as their career option, more so in the last decade and a half. This study was conducted in order to understand issues affecting women maxillofacial surgeons in their career as an academician or a private practitioner. We wanted to analyze the factors leading to career satisfaction and estimate the current work scenario for women maxillofacial surgeons. Since the study is one of its first in the country, the conclusions are not definite. Further studies in the future are needed to understand various factors affecting position of women maxillofacial surgeons in academics, private practice, and residents and role of gender in career advancement and in pursuing leadership positions.

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Efficacy of Neurectomy of Peripheral Branches of the Trigeminal Nerve in Trigeminal Neuralgia: A Critical Review of the Literature

Abstract

Introduction

Of the many chronic painful conditions, trigeminal neuralgia (TN) affecting the orofacial region needs the particular attention of physicians and surgeons, especially those specialising in the maxillofacial region. Treatment protocols for the management of classic TN include pharmacology and surgical intervention. Oral and maxillofacial surgeons have traditionally employed the peripheral neurectomy in the surgical management of TN. This review aims to evaluate the efficacy of peripheral neurectomy in the management of TN with regard to (a) the relief of symptoms in comparison with standard neurosurgical procedures and (b) the duration of pain relief and complications observed compared to standard neurosurgical procedures.

Methods

The review of the literature was done according to PRISMA guidelines and included randomised controlled trials, reviews and prospective clinical studies involving surgical procedures for the management of TN. The primary outcomes evaluated were (a) initial relief of pain, (b) duration of relief of pain, (c) complications observed with ablative procedures and (d) recurrence of symptoms. A total of 43 studies fulfilled the inclusion criteria.

Results

In a total of 7913 patients from the 43 studies, central procedures were found to have best results for both quality and duration of pain relief. Percutaneous and peripheral procedures were associated with increased recurrence rates. The consolidated rates of complication for peripheral, percutaneous and central procedures were 39.46, 65.42 and 10.41%, respectively. The use of peripheral neurectomy alone in the management of classic TN was observed in 10 studies.

Conclusion

Peripheral neurectomy in TN is associated with lesser quality of pain relief in comparison with central neurosurgical procedures. It also provides only short- to medium-term pain relief. Most studies with the use of peripheral neurectomy involved only a small group of patients with short follow-up periods. Oral and maxillofacial surgeons must not consider the peripheral neurectomy as the first surgical option in the management of classic TN. Long-term results can be achieved better with appropriate central neurosurgical procedures and pharmacotherapy.

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A Simple Approach to Intraoperative Handling of Split Thickness Skin Grafts in the Oral Cavity

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Traumatic Pseudoaneurysm: A Life-Threatening Complication After Surgical Extraction of Impacted Maxillary Third Molar

Abstract

Pseudoaneurysms are rare lesions secondary to blunt or penetrating trauma, temporomandibular joint surgery, or orthognathic surgery. They are usually produced by arterial breach leading to extravasation of blood. The compressed perivascular tissue forms the wall of aneurysmal sac. This sac gradually expands and can be damaged. Nonsurgical interventions are the treatment of choice for pseudoaneurysms. In the case reported here, emergent endovascular injection of acrylic glue was successful in the treatment of a pseudoaneurysm from a branch of the internal maxillary artery secondary to surgical extraction of impacted maxillary third molar.

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The Importance of Panitumumab in Radiotherapy Involving Head and Neck Region

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Reconstruction of Acquired Frontal Bone Defects Using Titanium Mesh Implants: A Retrospective Study

Abstract

Purpose

Frontal bone deformities can be acquired due to trauma or ablative tumor resection surgeries and osteomyelitis. It may also occur due to congenital malformations. Repair of these defects have long been a challenge to oral and maxillofacial surgeons. We report our experience in the reconstruction of acquired frontal bone defects by titanium mesh implant.

Patients and Methods

Titanium mesh was used for reconstruction in 35 patients (18–55 years age-group) (34 males and 01 females) of acquired frontal bone defects secondary to trauma (RTA). All these patients have been referred to author by Department of Neurosurgery of the institute of Affiliation.

Results

All these cases acquired defects as a result of trauma. Follow-up ranged from 12 to 18 months after the reconstruction. Patients were followed up for the progress of healing, stability of implants, infection, wound dehiscence, discharging sinus, exposure of implants, collections, patient satisfaction regarding esthetics and reaction to thermal changes. No postoperative complications were found.

Conclusion

In reconstruction of frontal bone defects, titanium mesh gives satisfactory results.

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Mandibular Torus Harvesting for Sinus Augmentation: Two-Year Follow-Up

Abstract

Maxillary sinus grafting is a commonly used treatment alternative in cases with insufficient bone height to enable insertion of implants in the posterior maxilla. It is commonly carried out with autogenous grafts, biomaterials or both. Autogenous bone grafts are considered gold standard for this procedure; however, due to donor site morbidity, it is not as commonly used as other biomaterials. Mandibular tori are hyperostoses on the lingual side of the mandible in the premolar region. This a case in which mandibular tori were used for a sinus augmentation procedure. The patient was then followed up for 2 years with no complaints, or objective symptoms.

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Efficacy of Sodium Hyaluronate for Temporomandibular Joint Disorder by Single-Puncture Arthrocentesis

Abstract

Background

The term temporomandibular joint internal derangement has characteristic clinical findings such as restricted mouth opening, pain, irregular deviated jaw function and clicking sounds. The technique of TMJ arthrocentesis has gained widespread acceptance as a simple and effective technique for the treatment of acute persistent closed lock of the TMJ. Arthrocentesis is known as the lavage and lysis of upper joint compartment.

Purpose

To evaluate the efficacy of sodium hyaluronate followed by single-puncture arthrocentesis. Sodium hyaluronate is the sodium salt of hyaluronic acid which is a polysaccharide of the glycosaminoglycans family, found in many extracellular tissues, including synovial fluid and cartilage. Exogenous hyaluronate can stimulate the synthesis of endogenous hyaluronic acid.

Methods

In our study, a sample of 10 patients (7 females and 3 males) with TMJ disorder was selected. Arthrocentesis was done followed by sodium hyaluronate injection for all the patients.

Results

On follow-up ranging from 1 to 3 months, pain at rest and pain on mastication had substantially decreased in all patients and mandibular function and mouth opening had significantly improved.

Conclusion

Our study shows that single-puncture Ringer's lactate arthrocentesis followed by sodium hyaluronate injection is effective in the management of the internal derangement of the temporomandibular joint.

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Sialoendoscopy: Review and Nuances of Technique

Abstract

Introduction

Sialoendoscopy is a nuanced technique of transluminal management of obstructive and nonneoplastic pathology of the major salivary glands. Techniques have been refined in the last two decades due to advances in optical and endoscopic instrumentation. This minimally invasive technique has both diagnostic and therapeutic applications. Obstructive salivary gland disease due to mineralized stones causes the majority of salivary duct-related pathology. Mucus plugs and strictures are the other causes. Submandibular gland sialolithiasis comprises the majority of salivary ductal pathology, with less than ten percent of obstructive symptoms related to parotid gland.

Objective

The aim of this review is to comprehensively understand the scope of practice, the methodology of management, and the techniques for a successful outcome in sialoendoscopy. Anatomy of the salivary glands and the ductal system is reviewed for a successful outcome. Guidance for patient selection, indications, investigations, and preprocedure preparation for sialoendoscopy are discussed. Algorithms and an instrument checklist are provided in table format in the manuscript for clinical utility.

Conclusion

The author simplifies the various systems of sialoendoscopes and the utility of the instruments. The future of transluminal and intraluminal salivary procedures is within the oral and maxillofacial surgical realm with simulators and multidimensional imaging and navigational advances.

from #Head and Neck by Sfakianakis via simeraentaxei on Inoreader http://bit.ly/2STNanr