Aim: To evaluate inter-reader performance for cross-sectional area and fat quantification of bilateral sciatic nerves on MRI and assess correlations with anthropometrics. Methods: 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. Results: 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). Conclusion: 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. Key Points: • 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).
- Fat quantification
- Proton density fat fraction
ASJC Scopus subject areas
- Radiology Nuclear Medicine and imaging