From the Departments of Magnetic Resonance Imaging (J.H.L., M.J.L., S.H.Z.) and Pathology (H.Y.W.), Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, No. 167 Beilishi Rd, Beijing 100037, China; Department of Cardiology, State Key Laboratory of Complex Severe and Rare Diseases (X.Q.X., Y.J.Z., Z.C.J.), and Department of Radiology (Y.N.W.), Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China; and Department of Cardiac, Thoracic, Vascular Sciences and Public Health, University of Padua Medical School, Padova, Italy (C.Y.C.).
Radiology. 2022 Jan;302(1):61-69. doi: 10.1148/radiol.2021211276. Epub 2021 Oct 12.
Background Subendocardial late gadolinium enhancement (LGE) detected with cardiac MRI in myocarditis represents a diagnostic dilemma, since it may resemble myocardial ischemia. Purpose To explore and compare the histopathologic characteristics and clinical features and outcomes in patients with myocarditis with and without subendocardial involvement at cardiac MRI. Materials and Methods This retrospective study evaluated 39 patients with myocarditis pathologically proven by means of either endomyocardial biopsy or explant pathologic findings between 2015 and 2020. Patients were divided into two groups according to cardiac MRI phenotype: 18 with subendocardial involvement (mean age ± standard deviation, 40 years ± 17; 10 women) and 21 with no subendocardial involvement (mean age, 35 years ± 11; six women). The median follow-up period was 784 days (interquartile range [IQR], 90-1123 days). The Student test, Mann-Whitney test, and univariable Cox regression were used for statistical analyses. Results In the 18 patients with subendocardial involvement, 12 (67%) had lymphocytic myocarditis and six (33%) had giant cell myocarditis. Patients with subendocardial involvement compared with those without subendocardial involvement had lower left ventricular ejection fraction (mean ± standard deviation, 27% ± 11 vs 41% ± 19; = .004), larger LGE extent (median, 13% [IQR, 10%-22%] vs 5% [IQR, 2%-17%]; < .001), higher rates of cardiac death or transplant (eight of 18 patients [44%] vs one of 21 patients [4.8%]; = .006), higher probability of giant cell myocarditis (six of 18 [33%] vs one of 21 [4.8%]; = .02), and more major adverse cardiovascular events (MACE) (15 of 18 [83%] vs seven of 21 [33%]; = .002). In a subgroup of patients with comparable LGE extent (median, 15% vs 16%; = .40) and left ventricular ejection fraction (median, 27% vs 31%; = .26), the prognostic difference in terms of MACE remained (15 of 17 patients [88%] vs five of 10 [50%]; = .02). Conclusion Subendocardial involvement detected with cardiac MRI in myocarditis indicated more severe clinical features, including a higher frequency of severe lymphocytic myocarditis or giant cell myocarditis and worse prognosis. © RSNA, 2021 See also the editorial by de Roos in this issue.
背景 心脏 MRI 检测到心肌炎的心脏下壁延迟钆增强（LGE）表现为一种诊断难题，因为它可能类似于心肌缺血。
目的 探讨并比较心脏 MRI 显示有和无下壁受累的心肌炎患者的组织病理学特征、临床特征和结局。
材料与方法 本回顾性研究评估了 2015 年至 2020 年间通过心内膜心肌活检或心外膜病理检查证实的 39 例心肌炎患者。根据心脏 MRI 表型将患者分为两组：18 例有下壁受累（平均年龄±标准差，40 岁±17；10 例女性）和 21 例无下壁受累（平均年龄，35 岁±11；6 例女性）。中位随访时间为 784 天（四分位距[IQR]，90-1123 天）。采用学生 t 检验、Mann-Whitney U 检验和单变量 Cox 回归进行统计学分析。
结果 在 18 例有下壁受累的患者中，12 例（67%）为淋巴细胞性心肌炎，6 例（33%）为巨细胞性心肌炎。与无下壁受累的患者相比，有下壁受累的患者左心室射血分数较低（平均值±标准差，27%±11 比 41%±19； =.004），LGE 范围较大（中位数，13%[IQR，10%-22%]比 5%[IQR，2%-17%]； <.001），心脏死亡或移植发生率较高（18 例患者中有 8 例[44%]比 21 例患者中有 1 例[4.8%]； =.006），巨细胞性心肌炎发生率较高（18 例患者中有 6 例[33%]比 21 例患者中有 1 例[4.8%]； =.02），主要不良心血管事件（MACE）发生率较高（18 例患者中有 15 例[83%]比 21 例患者中有 7 例[33%]； =.002）。在 LGE 范围（中位数，15%比 16%； =.40）和左心室射血分数（中位数，27%比 31%； =.26）相似的亚组患者中，MACE 的预后差异仍存在（17 例患者中有 15 例[88%]比 10 例患者中有 5 例[50%]； =.02）。
结论 心脏 MRI 检测到心肌炎的下壁受累提示更严重的临床特征，包括更频繁的严重淋巴细胞性心肌炎或巨细胞性心肌炎和更差的预后。
