Eosinophilic myocarditis (EM) is a life-threatening acute heart disease. Cardiac magnetic resonance (CMR) excels in the assessment of myocardial diseases but CMR studies of EM are limited. We aimed to describe CMR findings in histologically proven EM. Patients with histologically proven EM seen at an academic center from 2000 through 2020 were identified. Of the 28 patients ascertained, 15 had undergone CMR for diagnosis and constitute our study cohort. The patients, aged 51 ± 17 years, presented with fever (53%), dyspnea (47%), chest pain (53%), heart block (20%), and blood eosinophilia (60%). On CMR, all 15 patients had myocardial edema with 10 of them (67%) having abnormally high left ventricular (LV) mass as well. LV ejection fraction measured < 50% in 11 patients (73%) and < 30% in 2 (13%), but only 6 (40%) had dilated LV size. Eight patients (53%) had pericardial effusion. LV late gadolinium enhancement (LGE) was found in all but one patient (13/14; 93%). LGE was always multifocal and subendocardial but could involve any myocardial layer. Patients with necrotizing EM by histopathology (n = 6) had higher LGE mass (32.1 ± 16.6% vs 14.5 ± 7.7%, p = 0.050) and more LV segments with LGE (15 ± 2 vs 9 ± 3 out of 17, p = 0.003) than patients (n = 9) without myocyte necrosis. Two patients had LV thrombosis accompanying widespread subendocardial LGE. In EM, CMR shows myocardial edema and LGE that is typically subendocardial but can involve any myocardial layer. The left ventricle is often non-dilated with moderate-to-severe systolic dysfunction. Pericardial effusion is common. Necrotizing EM presents with extensive myocardial LGE on CMR.

中文翻译：

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心脏磁共振在组织学证实的嗜酸性心肌炎中的应用

嗜酸性粒细胞性心肌炎（EM）是一种危及生命的急性心脏病。心脏磁共振 (CMR) 在评估心肌疾病方面表现出色，但对 EM 的 CMR 研究有限。我们的目的是描述经组织学证实的 EM 中的 CMR 结果。确定了 2000 年至 2020 年在学术中心就诊的经组织学证实患有 EM 的患者。在确定的 28 名患者中，有 15 名接受了 CMR 诊断，构成了我们的研究队列。这些患者年龄为 51±17 岁，表现为发烧（53%）、呼吸困难（47%）、胸痛（53%）、心脏传导阻滞（20%）和血液嗜酸粒细胞增多（60%）。 CMR 显示，所有 15 名患者均出现心肌水肿，其中 10 名患者 (67%) 左心室 (LV) 质量也异常偏高。测量的 LV 射血分数 < 11 名患者 (73%) 为 50%，并且 < 2 例 (13%) 中 30% 的患者左室尺寸扩张，但只有 6 例 (40%) 出现左室扩张。 8 名患者（53%）有心包积液。除一名患者外，所有患者均发现左室晚期钆增强 (LGE)（13/14；93%）。 LGE 总是多病灶且位于心内膜下，但可能累及任何心肌层。组织病理学显示坏死性 EM 患者 (n = 6) 具有较高的 LGE 质量（32.1 ± 16.6% 与 14.5 ± 7.7%，p = 0.050），且 LGE 的左室节段较多（17 例中有 15 ± 2 比 9 ± 3，p = 0.003）比没有肌细胞坏死的患者（n = 9）高。两名患者出现左心室血栓形成并伴有广泛的心内膜下 LGE。在 EM 中，CMR 显示心肌水肿和 LGE，通常位于心内膜下，但可累及任何心肌层。左心室通常不扩张，伴有中度至重度收缩功能障碍。心包积液很常见。 CMR 显示坏死性 EM 表现为广泛的心肌 LGE。