ANTERIOR CRUCIATE LIGAMENT TEAR - PROSPECTIVE EVALUATION OF DIAGNOSTIC-ACCURACY OF MIDDLE-FIELD-STRENGTH AND HIGH-FIELD-STRENGTH MR-IMAGINGAT 1.5 AND 0.5 T

PURPOSE: To compare the diagnostic efficacy of current-generation midd le- and high-field-strength magnetic resonance (MR) imagers in the dia gnosis of anterior cruciate ligament (ACL) tears. MATERIALS AND METHOD S: In 114 of 230 patients referred for knee imaging, MR imaging at 0.5 and 1.5 T was performed with identical sequences but with a slightly longer total imaging time and bandwidth optimization at 0.5 T. Radiolo gists were blinded to diagnosis and field strength. Sensitivity, speci ficity, and accuracy were determined, and ACL tear was confirmed by me ans of arthroscopy and pathology. RESULTS: There was no difference bet ween the field strengths in accuracy, sensitivity, or specificity for the diagnosis of ACL tears in 86 patients with disrupted ACLs and 28 p atients with intact ACLs. Accuracy for all ACL tears was 90% at 0.5 T and 91% at 1.5 T. Similarly, there were no differences in diagnosis of meniscal tears (79 with, 149 without) or posterior cruciate ligament tears (seven with, 107 without). CONCLUSION: Higher field strength doe s not confer higher accuracy in the diagnosis of ACL tears at MR imagi ng.