Low-field magnetic resonance imaging (0.2 T) of tendons with sonographic and histologic correlation. Cadaveric study

RATIONALE AND OBJECTIVES: The authors evaluate the role of low-field strength magnetic resonance imaging (MRI) compared with sonography in the evaluation of degenerative changes of tendons, with histologic correlation, based on investigations of horse cadavers. METHODS: Low-field MRI and sonography was performed in 42 hours specimens for the evaluation of tendons and ligaments. Magnetic resonance imaging included sagittal and axial T1-weighted, T2-weighted, and gradient echo images. Sonography and MR images were evaluated for degenerative changes or tears and the findings were correlated with the histologic results. RESULTS: Using histologic findings as a gold standard, the accuracy for the sonographic evaluation was 65.9%, sensitivity was 16.7%, and specificity was 100%. The corresponding data for low-field MR imaging were 70.5% accuracy, 44.4% sensitivity, and 88.5% specificity. CONCLUSIONS: Low-field MRI investigation allows more accurate staging of tendinous changes than sonography. It is more reproducible and potentially includes the advantages of the combined evaluation of bones, ligaments, and soft tissue.