From the Experimental Imaging Centre, Radiology Unit, IRCCS San Raffaele Scientific Institute, Vita-Salute San Raffaele University, Via Olgettina 60, 20132 Milan, Italy (A.P., G.B., E.B., A.D.M., F.D.C., A.E.); School of Medicine, Vita-Salute San Raffaele University, Milan, Italy (A.P., A.D.M., F.D.C., A.E.); Department of Radiology, Guy's and St Thomas' NHS Foundation Trust, London, England (G.B.); Department of Surgical Sciences, Radiology Unit, University of Turin, Turin, Italy (R.F., M.G.); University Centre for Statistics in the Biomedical Sciences, Vita-Salute San Raffaele University, Milan, Italy (P.M.V.R.); Department of Cardiac Electrophysiology and Arrhythmology, IRCCS San Raffaele Scientific Institute, Milan, Italy (G.P., S.S.); Department of Radiological, Oncological and Pathological Sciences, "La Sapienza" University of Rome, Rome, Italy (M.F., N.G.); and Cardiovascular Pathology Unit, Department of Cardiac, Thoracic, Vascular Sciences and Public Health, University of Padua, Padua, Italy (C.B.).
Radiology. 2020 May;295(2):316-325. doi: 10.1148/radiol.2020191623. Epub 2020 Mar 10.
Background Hyperemia is a key component of acute myocarditis (AM). Early gadolinium uptake because of myocardial hyperemia may be quantified by using T1 mapping. Purpose To evaluate the value of early enhanced T1 shortening for the diagnosis of acute myocarditis. Materials and Methods Study participants suspected of having AM and healthy control (HC) participants were prospectively enrolled from September 2016 to May 2019. Participants underwent 1.5-T cardiac MRI including Lake Louise criteria, T2 mapping, native T1, and extracellular volume, with the addition of early enhanced T1 mapping (2 minutes after intravenous administration of 0.15 mmol/kg gadobutrol). Color-coded maps of the percentage of T1 shortening from precontrast to early postcontrast were generated. Optimal early T1 shortening cut-off value and its diagnostic performance in the identification of acute myocarditis were calculated. Results Forty-five study participants with AM (median age, 40 years; interquartile range [IQR], 20-46 years; 22 women) diagnosed according to multidisciplinary clinical evaluation, electrocardiography, laboratory test, echocardiography, cardiac MRI, and coronary CT and/or invasive angiography. Findings were confirmed by endomyocardial biopsy in 64% (29 of 45) of participants. MRI parameters were compared with 19 HC participants (median age, 39 years; IQR, 28-46 years; seven women). Median early T1 shortening was 75% (IQR, 72%-78%) in participants with AM versus 65% (IQR, 61%-66%) in HC participants ( < .001). Early T1 shortening showed high diagnostic performance (area under the receiver operating characteristic curve [AUC], 0.97; 95% confidence interval [CI]: 0.94, 1.00) and excellent interobserver reproducibility (intraclass correlation coefficient: 0.98; 95% CI: 0.96, 1.00). Early T1 shortening of 70% or greater identified acute myocarditis with 93% sensitivity, 100% specificity, and 95% diagnostic accuracy. Early T1 shortening had better diagnostic performance than late percentage T1 shortening (AUC, 0.97 vs 0.90, respectively; = .03) and extracellular volume (AUC, 0.97 vs 0.88, respectively; = .046), and similar to native T1 (AUC, 0.97 vs 0.93, respectively; = .63) and T2 mapping (AUC, 0.97 vs 0.97, respectively; > .99). Conclusion In this proof-of-concept study, percentage of T1 shortening at early enhanced T1 mapping showed high accuracy for the diagnosis of acute myocarditis. © RSNA, 2020 See also the editorial by De Cecco and Monti in this issue.
背景 充血是急性心肌炎（AM）的一个关键组成部分。由于心肌充血，早期钆摄取可以通过 T1 映射来定量。目的 评估早期增强 T1 缩短对急性心肌炎诊断的价值。材料与方法 2016 年 9 月至 2019 年 5 月前瞻性纳入疑似 AM 和健康对照（HC）参与者。参与者接受了包括 Lake Louise 标准、T2 映射、原生 T1 和细胞外容积在内的 1.5-T 心脏 MRI，另外还进行了早期增强 T1 映射（静脉注射 0.15 mmol/kg 钆布醇后 2 分钟）。生成了从对比前到早期对比后 T1 缩短百分比的彩色编码图。计算了最佳的早期 T1 缩短截断值及其在识别急性心肌炎中的诊断性能。结果 根据多学科临床评估、心电图、实验室检查、超声心动图、心脏 MRI、冠状动脉 CT 和/或有创血管造影，对 45 名 AM 患者（中位年龄 40 岁；四分位距 [IQR]，20-46 岁；22 名女性）进行了研究。45 名参与者中有 64%（29 名）根据心内膜活检证实了发现。将 MRI 参数与 19 名 HC 参与者（中位年龄 39 岁；IQR，28-46 岁；7 名女性）进行了比较。AM 组的早期 T1 缩短中位数为 75%（IQR，72%-78%），HC 组为 65%（IQR，61%-66%）（<.001）。早期 T1 缩短表现出较高的诊断性能（受试者工作特征曲线下面积 [AUC]：0.97；95%置信区间 [CI]：0.94，1.00）和出色的观察者间可重复性（组内相关系数：0.98；95%CI：0.96，1.00）。早期 T1 缩短达到 70%或更高可识别出急性心肌炎，具有 93%的敏感性、100%的特异性和 95%的诊断准确性。早期 T1 缩短的诊断性能优于晚期 T1 缩短百分比（AUC：0.97 与 0.90，分别；=0.03）和细胞外容积（AUC：0.97 与 0.88，分别；=0.046），与原生 T1（AUC：0.97 与 0.93，分别；=0.63）和 T2 映射（AUC：0.97 与 0.97，分别；>.99）相似。结论 在这项概念验证研究中，早期增强 T1 映射的 T1 缩短百分比具有很高的急性心肌炎诊断准确性。
