Cardiomyopathy is the leading cause of death in Duchenne muscular dystrophy (DMD). Cardiac magnetic resonance (CMR) parametric mapping sequences offer insights into disease pathophysiology. We propose a novel approach by leveraging T2 mapping in conjunction with T1 and extracellular volume (ECV) mapping to perform a virtual myocardial biopsy. While previous work has attempted to describe myocardial changes in DMD, our inclusion of T2 mapping enables comprehensive categorization of myocardial tissue characteristics of fibrosis, edema, and fat to better understand the pathological composition of the myocardium with disease progression. DMD patients (n = 49; median: 12 years-old) underwent CMR, including T1, T2, and ECV. Categories were defined as normal, isolated high T1 (normal ECV, high T1, normal T2), fibrosis (high ECV, normal or high T1, normal T2), edema (normal or high ECV, normal or high T1, high T2), fat (normal ECV, low T1, high T2) or fibrofatty (high ECV, low T1, high T2). Median left ventricular ejection fraction (LVEF) was 59% with 27% having LVEF < 55%. Those with normal LVEF and no late gadolinium enhancement (37%) were younger in age (10.5 ± 2.6 vs. 15.0 ± 4.3 years-old, p < 0.001). Native T1 was elevated in at least one slice in 82% of patients. Those with high T2 at any slice (27%) were older (p = 0.005) and had lower LVEF (p = 0.005) compared with subjects with normal T2 (73%). The most common myocardial characterization was fibrosis (43%) followed by isolated high T1 (24%). Of the 13 with high T2, ten were categorized as edema, two as fibrofatty, and one as fat. CMR parametric mapping sequences offer insights into Duchenne cardiomyopathy pathophysiology, which should drive development of therapeutic interventions aimed at these targets. Myocardial fibrosis is common in DMD. Patients with elevated T2 were older and had lower LVEF. Though fat infiltration was present, the majority of subjects with elevated T2 met criteria for myocardial edema.

中文翻译：

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综合心脏磁共振 T1、T2 和细胞外体积图来定义杜氏心肌病

心肌病是杜氏肌营养不良症 (DMD) 死亡的主要原因。心脏磁共振 (CMR) 参数映射序列提供了对疾病病理生理学的见解。我们提出了一种新方法，利用 T2 映射结合 T1 和细胞外体积 (ECV) 映射来执行虚拟心肌活检。虽然之前的工作试图描述 DMD 中的心肌变化，但我们纳入 T2 映射可以对纤维化、水肿和脂肪的心肌组织特征进行全面分类，以更好地了解心肌随疾病进展的病理组成。DMD 患者（n = 49；中位年龄：12 岁）接受了 CMR，包括 T1、T2 和 ECV。类别定义为正常、孤立性高 T1（正常 ECV、高 T1、正常 T2）、纤维化（高 ECV、正常或高 T1、正常 T2）、水肿（正常或高 ECV、正常或高 T1、高 T2）、脂肪（正常 ECV、低 T1、高 T2）或纤维脂肪（高 ECV、低 T1、高 T2）。中位左心室射血分数 (LVEF) 为 59%，其中 27% 的 LVEF < 55%。LVEF 正常且无晚期钆增强的患者 (37%) 年龄较小（10.5 ± 2.6 岁 vs. 15.0 ± 4.3 岁，p < 0.001）。82% 的患者至少有一个切片的天然 T1 升高。与 T2 正常的受试者 (73%) 相比，任何切片 T2 高的受试者 (27%) 年龄较大 (p = 0.005)，LVEF 较低 (p = 0.005)。最常见的心肌特征是纤维化（43%），其次是孤立性高 T1（24%）。在 13 例 T2 高的患者中，有 10 例被归类为水肿，2 例被归类为纤维脂肪，1 例被归类为脂肪。CMR 参数映射序列提供了对杜氏心肌病病理生理学的见解，这应该推动针对这些目标的治疗干预措施的发展。心肌纤维化在 DMD 中很常见。T2 升高的患者年龄较大且 LVEF 较低。尽管存在脂肪浸润，但大多数 T2 升高的受试者符合心肌水肿的标准。