Department of Diagnostic Radiology and Nuclear Medicine, University of Maryland School of Medicine, 22 South Greene Street, Baltimore, MD, 21201, USA.
Curr Cardiol Rep. 2019 Jun 26;21(8):76. doi: 10.1007/s11886-019-1158-0.
Diagnosis of myocarditis is challenging given its variable clinical manifestations and non-specific laboratory findings. Cardiac magnetic resonance (MR) is currently the preferred imaging modality for the diagnosis of myocarditis. F-fluoro-deoxy-glucose (FDG) positron emission tomography/computed tomography (PET/CT), as a functional imaging tool, has a potential role in the assessment of myocarditis by detecting the underlying myocardial inflammatory activity. Data are accumulating that simultaneous cardiac PET/MR may have complementary and incremental values for the evaluation of myocarditis compared to PET/CT or cardiac MR alone. The article aims to summarize the findings in the literature and discuss future directions of cardiac PET/MR for myocarditis.
The Lake Louis Criteria (CLL) of cardiac MR is widely used for the diagnosis of myocarditis. It has an overall acceptable sensitivity of 67% and specificity of 91% for acute myocarditis but does not have the same accuracy for chronic myocarditis. FDG PET/CT is capable of assessing myocarditis by providing metabolic information of inflammation as increased myocardial FDG uptake. In addition to reduced radiation exposure, FDG PET performed on a hybrid PET/MR may detect more myocarditis than FDG PET/CT, because of the delayed PET acquisition time on PET/MR. Case-based observations and small clinical studies of FDG PET/MR have shown that FDG PET findings as abnormally increased myocardial uptake correlate well with the cardiac MR biomarkers. FDG PET findings may add complementary and incremental values to cardiac MR by improving the sensitivity of cardiac MR for mild or borderline myocarditis, and increasing specificity for chronic myocarditis. Preliminary data from retrospective and case-based observational studies have suggested the complementary and incremental values of simultaneous cardiac FDG PET/MR for evaluation of myocarditis, compared to PET/CT or MR alone. Well-designed studies are needed to confirm the findings and to assess the value of cardiac PET/MR for clinical management and more importantly patient's outcome in both acute and chronic myocarditis.
鉴于心肌炎临床表现多样且实验室检查无特异性，其诊断颇具挑战。心脏磁共振（CMR）目前是心肌炎诊断的首选影像学方法。氟-18 氟代脱氧葡萄糖（FDG）正电子发射断层扫描/计算机断层扫描（PET/CT）作为一种功能成像工具，通过检测潜在的心肌炎症活动，在心肌炎评估中具有一定作用。越来越多的数据表明，与 PET/CT 或单独的心脏磁共振相比，心脏同步 PET/MR 可能具有补充和增量价值，用于评估心肌炎。本文旨在总结文献中的发现，并讨论心脏 PET/MR 用于心肌炎的未来方向。
心脏磁共振的莱克星敦标准（CLL）广泛用于心肌炎的诊断。其对急性心肌炎的总体敏感性为 67%，特异性为 91%，但对慢性心肌炎的准确性则不尽相同。FDG PET/CT 能够通过提供炎症的代谢信息（即心肌 FDG 摄取增加）来评估心肌炎。除了辐射暴露减少外，由于在 PET/MR 上的延迟 PET 采集时间，在混合式 PET/MR 上进行的 FDG PET 可能会检测到比 FDG PET/CT 更多的心肌炎。基于病例观察和小型临床研究的 FDG PET/MR 表明，异常增加的心肌摄取 FDG 与心脏磁共振生物标志物具有良好相关性。FDG PET 结果可能通过提高心脏磁共振对轻度或边界性心肌炎的敏感性，并提高对慢性心肌炎的特异性，为心脏磁共振提供补充和增量价值。回顾性和基于病例的观察性研究的初步数据表明，与 PET/CT 或单独的 MR 相比，心脏同步 FDG PET/MR 对心肌炎的评估具有补充和增量价值。需要精心设计的研究来证实这些发现，并评估心脏 PET/MR 在急性和慢性心肌炎的临床管理中的价值，更重要的是评估对患者预后的影响。
