Clinical Feasibility of Synthetic Magnetic Resonance Imaging in the Diagnosis of Internal Derangements of the Knee

Objective: To evaluate the feasibility of synthetic magnetic resonance imaging (MRI) compared to conventional MRI for the diagnosis of internal derangements of the knee at 3T. Materials and Methods: Following Institutional Review Board approval, image sets of conventional and synthetic MRI in 39 patients were included. Two musculoskeletal radiologists compared the image sets and qualitatively analyzed the images. Subjective image quality was assessed using a four-grade scale. Interobserver agreement and intersequence agreement between conventional and synthetic images for cartilage lesions, tears of the cruciate ligament, and tears of the meniscus were independently assessed using Kappa statistics. In patients who underwent arthroscopy (n = 8), the sensitivity, specificity, and accuracy for evaluated internal structures were calculated using arthroscopic findings as the gold standard. Results: There was no statistically significant difference in image quality (p = 0.90). Interobserver agreement (${\kappa}=0.649-0.981$) and intersequence agreement (${\kappa}=0.794-0.938$) were nearly perfect for all evaluated structures. The sensitivity, specificity, and accuracy for detecting cartilage lesions (sensitivity, 63.6% vs. 54.6-63.6%; specificity, 91.9% vs. 91.9%; accuracy, 83.3-85.4% vs. 83.3-85.4%) and tears of the cruciate ligament (sensitivity, specificity, accuracy, 100% vs. 100%) and meniscus (sensitivity, 50.0-62.5% vs. 62.5%; specificity, 100% vs. 87.5-100%; accuracy, 83.3-85.4% vs. 83.3-85.4%) were similar between the two MRI methods. Conclusion: Conventional and synthetic MRI showed substantial to almost perfect degree of agreement for the assessment of internal derangement of knee joints. Synthetic MRI may be feasible in the diagnosis of internal derangements of the knee.