Non‐Contrast Coronary MR Angiography for Myocardial Bridging: Diagnostic Accuracy and Morphologic Agreement With Photon‐Counting Coronary CT Angiography

Background Non‐contrast coronary MR angiography (CMRA) is a validated, non‐invasive, radiation‐free technique for coronary stenosis assessment. However, its application to myocardial bridging (MB) is limited, with large‐scale evidence for its diagnostic performance lacking. Purpose To evaluate the diagnostic accuracy and morphological consistency of non‐contrast CMRA for detecting MB, using photon‐counting coronary CT angiography (CCTA) as the reference standard. Study Type Retrospective. Subjects One hundred and ninety‐six patients with suspected or confirmed coronary artery disease (men: 141; mean age: 62.9 ± 10.6 years) who underwent both photon‐counting CCTA and CMRA. Field Strength/Sequences 3.0T; 3D nonselective pulse non‐enhanced whole‐heart balanced steady‐state free precession sequence. Assessment The presence and morphology (location, length, depth, stenosis severity) of MB were assessed using both CMRA and CCTA and compared. Diagnostic performance for diagnosing MB using CMRA was calculated. Statistical Tests Diagnostic performance was assessed using sensitivity, specificity, accuracy, positive predictive value (PPV), negative predictive value (NPV); morphological characteristics of MB were compared using Bland–Altman analysis and intraclass correlation coefficients (ICC). A two‐sided p < 0.05 indicated statistical significance. Results CCTA identified 92 MBs in 87 patients (44.4%; 82 single‐ and 5 multi‐segment), and CMRA detected 89 MBs in 84 patients (42.9%; 79 single‐ and 5 multi‐segment). CMRA had a diagnostic accuracy of 98.5%, sensitivity of 96.6%, specificity of 100%, NPV of 97.3%, and PPV of 100%. CMRA and CCTA demonstrated excellent agreement in the assessment of morphological characteristics for location (ICC = 0.98), length (ICC = 0.98), and depth (ICC = 0.98), with moderate agreement for stenosis severity (ICC = 0.71). Data Conclusion Non‐contrast CMRA showed excellent diagnostic performance for MB assessment and has potential to be a feasible, non‐invasive, radiation‐free, and contrast‐free alternative to CCTA. Level of Evidence 3. Technical Efficacy Stage 2.