Clinical Implementation of Sixfold-Accelerated Deep Learning Superresolution Knee MRI in Under 5 Minutes: Arthroscopy-Validated Diagnostic Performance

BACKGROUND. Deep learning (DL) superresolution image reconstruction enables higher acceleration factors for combined parallel imaging–simultaneous multislice–accelerated knee MRI but requires performance validation against external reference standards. OBJECTIVE. The purpose of this study was to validate the clinical efficacy of sixfold-accelerated sub–5-minute 3-T knee MRI using combined threefold parallel imaging (PI) and twofold simultaneous multislice (SMS) acceleration and DL superresolution image reconstruction against arthroscopic surgery. METHODS. Consecutive adult patients with painful knee conditions who underwent sixfold PI-SMS–accelerated DL superresolution 3-T knee MRI and arthroscopic surgery between October 2022 and July 2023 were retrospectively included. Seven fellowship-trained musculoskeletal radiologists independently assessed the MRI studies for image-quality parameters; presence of artifacts; structural visibility (Likert scale: 1 [very bad/severe] to 5 [very good/absent]); and the presence of cruciate ligament tears, collateral ligament tears, meniscal tears, cartilage defects, and fractures. Statistical analyses included kappa-based interreader agreements and diagnostic performance testing. RESULTS. The final sample included 124 adult patients (mean age ± SD, 46 ± 17 years; 79 men, 45 women) who underwent knee MRI and arthroscopic surgery within a median of 28 days (range, 4–56 days). Overall image quality was good to very good (median, 4 [IQR, 4–5]) with very good interreader agreement (κ = 0.86). Motion artifacts were absent (median, 5 [IQR, 5–5]), and image noise was minimal (median, 4 [IQR, 4–5]). Visibility of anatomic structures was very good (median, 5 [IQR, 5–5]). Diagnostic performance for diagnosing arthroscopy-validated structural abnormalities was good to excellent (AUC ≥ 0.81) with at least good interreader agreement (κ ≥ 0.72). The sensitivity, specificity, accuracy, and AUC values were 100%, 99%, 99%, and 0.99 for anterior cruciate ligament tears; 100%, 100%, 100%, and 1.00 for posterior cruciate ligament tears; 90%, 95%, 94%, and 0.93 for medial meniscus tears; 76%, 97%, 90%, and 0.86 for lateral meniscus tears; and 85%, 88%, 88%, and 0.81 for articular cartilage defects, respectively. CONCLUSION. Sixfold PI-SMS–accelerated sub–5-minute DL superresolution 3-T knee MRI has excellent diagnostic performance for detecting internal derangement. CLINICAL IMPACT. Sixfold PI-SMS–accelerated PI-SMS DL superresolution 3-T knee MRI provides high efficiency through short scan times and high diagnostic performance.