Barrett E, Barr F, Owen M, Bradley K. Department of Clinical Veterinary Science, University of Bristol, North Somerset. JSAP 2009 Sep 50 9 448-55 OBJECTIVES: To make an objective assessment of the usefulness of magnetic resonance imaging in the diagnosis of meniscal damage and cranial cruciate ligament disease in the canine stifle by comparing magnetic resonance imaging findings with surgical findings. METHODS: Magnetic resonance images of 18 stifles from 18 dogs which had undergone magnetic resonance imaging for the investigation of stifle disease were reviewed. For every stifle, the menisci and cranial cruciate ligaments were assessed according to predetermined criteria. The magnetic resonance imaging findings were compared with the reported surgical findings and the sensitivity, specificity, positive and negative predictive values (PPV and NPV) were calculated using the surgical findings as the gold standard. Kappa analysis was used as an objective measure of agreement between surgical and magnetic resonance imaging findings. For 11 stifles, meniscal evaluation by three different observers was used to measure interobserver agreement using Kappa analysis. RESULTS: Magnetic resonance imaging was demonstrated to be an accurate technique in the detection of meniscal injury (k=0.86), with excellent interobserver agreement (k=0.89 to 1.0). Disruption of cranial cruciate ligament continuity and an increase in ligament intensity were found to be useful criteria in the diagnosis of cranial cruciate ligament rupture. CLINICAL SIGNIFICANCE: Magnetic resonance imaging offers a non-invasive alternative to exploratory surgery in the evaluation of cranial cruciate ligament and meniscal disease.