The Accuracy of Diffusion‐Weighted Imaging in the Assessment of Acute Myocardial Infarction: A Preliminary Study

ABSTRACT Background Cardiac magnetic resonance imaging (MRI) plays a key role in assessing acute myocardial infarction (AMI) and detecting myocardial edema. Diffusion‐weighted imaging (DWI) has recently been applied to cardiac exploration and is perceived as a promising method for evaluating cardiomyopathies. This study aims to evaluate the role of DWI in the assessment of AMI by analyzing the accuracy of both low b ‐value diffusion‐weighted (DW) spin‐echo (SE) echo‐planar imaging (EPI) sequence and apparent diffusion coefficient (ADC) mapping in detecting ischemia‐induced myocardial edema. Methods This study included 13 patients with recent reperfused AMI who underwent cardiac MRI. A cardiac protocol was applied, including black blood T2‐weighted imaging (BB‐T2W), two low b ‐value DW SE EPI ( b = 20 s/mm 2 ), one for low b ‐value DW SE EPI in free‐breathing (DWF) and the other for low b ‐value DW SE EPI in breath‐holding (DWH), T2 mapping, and ADC mapping. BB‐T2W, DWH, and DWF images were analyzed quantitatively and qualitatively. The T2 and ADC values were measured within the infarct and remote myocardium. Statistical analysis was performed using a nonparametric Wilcoxon test. Results ADC values in the infarct area were significantly higher than the remote myocardium ([2.36 ± 0.34] × 10 −3 mm 2 /s and [1.20 ± 0.14] × 10 −3 mm 2 /s, respectively; p = 0.001). Besides, low b ‐value DW SE EPI (DWH and DWF) allowed the detection of ischemia‐induced myocardial edema in a way surpassing the BB‐T2W sequence with a higher sensitivity to edema (96.7%, 96.7%, and 87.9%, respectively). No statistically significant difference was noted between DWH and DWF sequences. Conclusion DWI may be a promising technique for the exploration of AMI, with the advantage of being feasible for dyspneic patients.