Toward a New Era in Fracture Imaging: Zero Echo Time MRI vs CT in Intra-Articular Distal Radius Fractures - A Proof-Of Study

Abstract

Background: Computed tomography (CT) is the current reference standard for evaluating intra-articular distal radius fractures, however concerns remain regarding radiation exposure and limited soft tissue assessment. Zero Echo Time (ZTE) MRI is a novel technique that enables direct cortical bone imaging with contrast similar to CT, while avoiding radiation. This proof-of-concept study aimed to compare the diagnostic performance of ZTE MRI with CT in fracture classification, articular involvement, and treatment planning. Methods: In this prospective comparative study, 28 patients with acute intra-articular distal radius fractures underwent both CT and ZTE MRI within 7 days of injury. Fractures were classified according to AO/OTA, Fernandez classifications, quantitative parameters (angulation, radial inclination, ulnar variance, articular fragment count) and binary findings (distal ulna fracture, distal radioulnar joint (DRUJ) involvement) were assessed. Two orthopedic surgeons and two musculoskeletal radiologists independently reviewed all images. Inter- and intraobserver agreement was calculated using Cohen's and Fleiss' kappa and intraclass correlation coefficients. Results: Agreement among surgeons for AO/OTA classification was good on CT (kappa = 0.767) and good on ZTE MRI (kappa = 0.680). For Fernandez classification, agreement was good on CT (kappa = 0.780) and ZTE (kappa = 0.736). Surgeons demonstrated higher agreement (kappa approximate to 0.68-0.78) than radiologists (kappa approximate to 0.56-0.65). For binary parameters, agreement among radiologists was very good (kappa = 0.820-0.880), while inter-surgeon agreement ranged from moderate to good (kappa = 0.500-0.714). Continuous measures showed good reproducibility for angulation (ICC = 0.762-0.858), but lower values for inclination among surgeons (ICC <= 0.492-0.531). ZTE MRI demonstrated sensitivity, specificity, and accuracy comparable to CT for classification and detection of DRUJ involvement and distal ulna fractures (approximately 85-93 %). Treatment decisions showed very good agreement (kappa = 0.855), with ZTE altering CT-based management in 3/28 (10.7 %) cases for Surgeon 1 and 2/28 (7.1 %) for Surgeon 2. Conclusion: ZTE MRI provides diagnostic performance comparable to CT for intra-articular distal radius fractures, with high reliability for fracture classification, joint involvement, and treatment decision-making. As a radiation-free modality that also permits concurrent soft tissue assessment, ZTE MRI may serve as a promising alternative to CT in selected clinical scenarios.