Sciatic neurosteatosis: Relationship with age, gender, obesity and height
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To evaluate inter-reader performance for cross-sectional area and fat quantification of bilateral sciatic nerves on MRI and assess correlations with anthropometrics.
In this IRB-approved, HIPPA-compliant study, three readers performed a cross-sectional analysis of 3T lumbosacral plexus MRIs over an 18-month period. Image slices were evaluated at two levels (A and B). The sciatic nerve was outlined using a free hand region of interest tool on PACS. Proton-density fat fraction (FF) and cross-sectional areas were recorded. Inter-reader agreement was assessed using intra-class correlation coefficient (ICC). Spearman correlation coefficients were used for correlations with age, BMI and height and Wilcoxon rank sum test was used to assess gender differences.
A total of 67 patients were included in this study with male to female ratio of 1:1. Inter-reader agreement was good to excellent for FF measurements at both levels (ICC=0.71–0.90) and poor for sciatic nerve areas (ICC=0.08–0.27). Positive correlations of sciatic FF and area were seen with age (p value<0.05). Males had significantly higher sciatic intraneural fat than females (p<0.05).
Fat quantification MRI is highly reproducible with significant positive correlations of sciatic FF and area with age, which may have implications for MRI diagnosis of sciatic neuropathy.
• MR proton density fat fraction is highly reproducible at multiple levels.
• Sciatic intraneural fat is positively correlated with increasing age (p < 0.05).
• Positive correlations exist between bilateral sciatic nerve areas and age (p < 0.05).
• Males had significantly higher sciatic intraneural fat than females (p < 0.05).
KeywordsNeurosteatosis MRI Proton density fat fraction Fat quantification Sciatic Neuropathy
Compliance with ethical standards
The scientific guarantor of this publication is Avneesh Chhabra.
Conflict of interest
The authors of this manuscript declare relationships with the following companies:
AC: Consultant ICON Medical, Royalties: Jaypee, Wolters.
SR, RK, LZ, RD, YX, CR: No disclosures
SR received Medical Student Training in Aging Research (MSTAR) funding from the American Federation for Aging Research. RK received funding from the UT Southwestern Medical Student Summer Research Program.
Statistics and biometry
One of the authors (YX) has significant statistical expertise.
Written informed consent was waived by the Institutional Review Board.
Institutional Review Board approval was obtained.
• Diagnostic or prognostic study.
• Performed at one institution
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