Reliability and diagnostic accuracy of qualitative evaluation of diffusion-weighted MRI combined with conventional MRI in differentiating between complete and partial anterior cruciate ligament tears.

ABSTRACT

OBJECTIVES: To assess the reliability and diagnostic accuracy of qualitative evaluation of apparent diffusion coefficient (ADC) mapping with magnetic resonance imaging (MRI) in differentiating between complete and partial anterior cruciate ligament (ACL) tears. METHODS: This prospective study protocol was approved by the institutional ethics review board and informed consent was obtained from all the patients. Eighty-five patients (35 women and 50 men, mean age 34.1 years) with recent (<4 months) knee trauma with suspected ACL injury underwent conventional MRI (T1-weighted and T2-weighted sequences with fat saturation) associated with ADC mapping. MR images were read qualitatively without and then with ADC mapping by three radiologists, with analysis of direct signs of a traumatic ACL tear and a second-reading. Dynamic X-rays (43 patients) or arthroscopies (42 patients) were used as reference standards. RESULTS: For complete ACL tear diagnosis (67 patients), sensitivity and specificity were 87% and 50% respectively with conventional MRI, and 96% and 94% respectively with ADC mapping (P < 0.01 for specificity). Inter-observer correlations between musculoskeletal radiologists were almost perfect (κ = 0.81) with ADC mapping and fair with conventional MRI on the second-reading. CONCLUSIONS: ADC mapping associated with conventional MR sequences is a reproducible method to better differentiate complete and partial ACL tears.