Background: Cardiac magnetic resonance (CMR) may radiologically identify or confirm underlying pathophysiologies in myocardial infarction with non-obstructive coronary arteries (MINOCA), however, there are scant prospective data evaluating the impact on routine clinical care.

Methods: In a multicentre international cohort study of MINOCA, clinical diagnosis, diagnostic certainty and intended clinical management were prospectively determined before and again after CMR. The primary outcome was a composite of change in clinical diagnosis and/or management. Secondary outcomes were individual components of the primary outcome, change in diagnostic certainty and number-needed-to-test for deprescription of dual antiplatelet therapy (DAPT). Predictors of the primary outcome were evaluated by multivariable logistic regression analysis.

Results: In 320 patients, CMR was associated with change in diagnosis and/or management in 63% (95% CI 57% to 68%, p<0.001) and significantly increased diagnostic certainty (8/10 post-CMR (5-9) vs 6/10 pre-CMR (4-7), p<0.0001). Relevant predictors of the primary outcome on multivariable analysis were early CMR (≤14 days), absence of atheroma on coronary angiography and significant pre-CMR diagnostic uncertainty (≤5/10); CMR changed diagnosis and/or management in 80% of individuals with all three predictors versus 40% in those with none. In individuals where treating physicians initially chose to prescribe DAPT despite no obstructive culprit lesion, number-needed-to-test by CMR for DAPT deprescription was 3.

Conclusions: CMR in MINOCA is associated with significant changes in clinical diagnosis, diagnostic certainty and management. The impact on deprescription of unnecessary DAPT could have important implications for patient safety and costs and warrants further evaluation. Early CMR should be considered to augment diagnosis and management in MINOCA.

Trial registration number: ISRCTN75233845.

Keywords: Diagnostic Imaging; Magnetic Resonance Imaging; Myocardial Infarction; Myocarditis; Quality of Health Care.

© Author(s) (or their employer(s)) 2025. No commercial re-use. See rights and permissions. Published by BMJ Group.

背景： 心肌梗死伴非阻塞性冠状动脉疾病（MINOCA）的心脏磁共振成像（CMR）可以放射学上识别或确认潜在的病理生理机制，然而，在常规临床护理中评估其影响的前瞻性数据很少。

方法： 在一个多中心国际队列研究中，MINOCA患者在进行CMR之前和之后分别确定了临床诊断、诊断确实性和预期临床管理。主要结局指标是临床诊断和/或管理的变化。次要结局指标是一级结果的各个组成部分、诊断确实性的变化以及为了减少双重抗血小板治疗（DAPT）所需的检测次数。通过多元逻辑回归分析评估了一级结果的影响因素。

结果： 在320名患者中，CMR与63%的临床诊断和/或管理的变化相关（95% CI 57%-68%，P

结论： MINOCA中的心脏磁共振成像与临床诊断、诊断确实性和管理的显著变化有关。对于减少不必要的双重抗血小板治疗的重要性可能对患者安全和成本有重要影响，需要进一步评估。早期进行CMR应考虑用于增强MINOCA的诊断和管理。

试验注册号： ISRCTN75233845.

关键词： 诊断成像；磁共振成像；心肌梗死；心肌炎；医疗质量。