Extremity-dedicated low-field MRI shows good diagnostic accuracy and interobserver agreement for the diagnosis of the acutely injured knee

Objectives: To estimate diagnostic accuracy and interobserver agreement of extremity-dedicated low-field magnetic resonance imaging (lfMRI) for meniscal tears, anterior cruciate ligament (ACL) tears and knee fractures. Methods: We enrolled 62 patients with acute knee trauma and 19 patients with suspected knee fracture. Arthroscopy/Computed tomography was regarded the gold standard for cruciate ligament and meniscal tears/fractures. Results: Arthroscopy showed 39 meniscal tears. Sensitivity/Specificity of lfMRI was 95.8%/97.4% (reader 1)/100%/100% (reader 2) for medial and 93.3%/100% (reader 1)/93.3%/93.6% (reader 2) for lateral meniscal tears. Sensitivity/Specificity was 100% for ACL tears and fractures. Interobserver agreement was very good. Conclusion: lfMRI showed reproducible high sensitivity and specificity for the diagnosis of the acutely injured knee.