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

Abstract 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.