科研之友
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摘要
Purpose: To assess reliability and validity of a semi-automated quantitative method to measure infrapatellar fat pad ( IPFP) signal intensity in patients with knee osteoarthritis ( OA). Methods: Hundred patients with knee OA were selected. Sagittal planes of fat-saturated T2-weighted images obtained on 1.5-T magnetic resonance imaging ( MRI) were utilized to assess IPFP signal intensity using MATLAB. Knee structural abnormalities including cartilage defects, bone marrow lesions ( BML) and radiographic OA ( ROA) were evaluated. Clinical construct validity and concurrent validity were examined through describing associations of IPFP measurements with knee structural abnormalities and a semi-quantitative scoring method, respectively. The reliability was examined by calculating the intra- and inter-observer correlation coefficients. Results: Significantly positive associations were found between standard deviation of IPFP signal intensity [ sDev ( IPFP)], clustering factor ( H) and all knee structural abnormalities. The volume of high signal intensity regions [ Volume ( H)] and the ratio of Volume ( H) to volume of whole IPFP [ Percentage ( H)] were positively associated with cartilage defects and ROA, but not with BMLs. The median value [ Median ( H)] and upper quartile value [ UQ ( H)] of high signal intensity were only significantly associated with quartiles of cartilage defect score. Significant correlations were found between all quantitative measurements and semi-quantitative scores ( All P < 0.001). Intraclass and interclass correlation coefficients for these quantitative measures were high (>0.90). Conclusions: A novel and efficient method to segment IPFP and calculate its signal intensity on T2-weighted MRI images is documented. This method is reproducible, and has concurrent and clinical construct validity, but its predictive validity needs to be examined by future longitudinal studies.
