Oxford Centre for Clinical Magnetic Resonance Research, Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom.
Siemens Healthcare GmbH, Erlangen, Germany.
J Am Coll Cardiol. 2018 Mar 6;71(9):957-968. doi: 10.1016/j.jacc.2017.11.071.
Novel cardiac magnetic resonance (CMR) stress T1 mapping can detect ischemia and myocardial blood volume changes without contrast agents and may be a more comprehensive ischemia biomarker than myocardial blood flow.
This study describes the performance of the first prospective validation of stress T1 mapping against invasive coronary measurements for detecting obstructive epicardial coronary artery disease (CAD), defined by fractional flow reserve (FFR <0.8), and coronary microvascular dysfunction, defined by FFR ≥0.8 and the index of microcirculatory resistance (IMR ≥25 U), compared with first-pass perfusion imaging.
Ninety subjects (60 patients with angina; 30 healthy control subjects) underwent CMR (1.5- and 3-T) to assess left ventricular function (cine), ischemia (adenosine stress/rest T1 mapping and perfusion), and infarction (late gadolinium enhancement). FFR and IMR were assessed ≤7 days post-CMR. Stress and rest images were analyzed blinded to other information.
Normal myocardial T1 reactivity (ΔT1) was 6.2 ± 0.4% (1.5-T) and 6.2 ± 1.3% (3-T). Ischemic viable myocardium downstream of obstructive CAD showed near-abolished T1 reactivity (ΔT1 = 0.7 ± 0.7%). Myocardium downstream of nonobstructive coronary arteries with microvascular dysfunction showed less-blunted T1 reactivity (ΔT1 = 3.0 ± 0.9%). Stress T1 mapping significantly outperformed gadolinium-based first-pass perfusion, including absolute quantification of myocardial blood flow, for detecting obstructive CAD (area under the receiver-operating characteristic curve: 0.97 ± 0.02 vs. 0.91 ± 0.03, respectively; p < 0.001). A ΔT1 of 1.5% accurately detected obstructive CAD (sensitivity: 93%; specificity: 95%; p < 0.001), whereas a less-blunted ΔT1 of 4.0% accurately detected microvascular dysfunction (area under the receiver-operating characteristic curve: 0.95 ± 0.03; sensitivity: 94%; specificity: 94%: p < 0.001).
CMR stress T1 mapping accurately detected and differentiated between obstructive epicardial CAD and microvascular dysfunction, without contrast agents or radiation.
新型心脏磁共振（CMR）压力 T1 映射技术可在不使用造影剂的情况下检测缺血和心肌血容量变化，其可能成为比心肌血流更全面的缺血生物标志物。
本研究描述了首次前瞻性验证压力 T1 映射技术对有创冠状动脉测量结果的性能，以检测通过血流储备分数（FFR<0.8）定义的阻塞性冠状动脉疾病（CAD），以及通过 FFR≥0.8 和微血管阻力指数（IMR≥25 U）定义的冠状动脉微血管功能障碍，与首次通过灌注成像相比。
90 名受试者（60 名心绞痛患者；30 名健康对照者）接受了 CMR（1.5-和 3-T）检查，以评估左心室功能（电影）、缺血（腺苷负荷/静息 T1 映射和灌注）和梗死（晚期钆增强）。FFR 和 IMR 在 CMR 后≤7 天进行评估。压力和静息图像在不了解其他信息的情况下进行盲法分析。
正常心肌 T1 反应性（ΔT1）为 6.2±0.4%（1.5-T）和 6.2±1.3%（3-T）。阻塞性 CAD 下游的缺血性存活心肌几乎没有 T1 反应性（ΔT1=0.7±0.7%）。非阻塞性冠状动脉微血管功能障碍下游的心肌 T1 反应性降低（ΔT1=3.0±0.9%）。压力 T1 映射在检测阻塞性 CAD 方面明显优于基于钆的首次通过灌注，包括心肌血流的绝对定量（曲线下面积：0.97±0.02 对 0.91±0.03，分别；p<0.001）。ΔT1 为 1.5%可准确检测出阻塞性 CAD（敏感性：93%；特异性：95%；p<0.001），而更不迟钝的 ΔT1 为 4.0%可准确检测出微血管功能障碍（曲线下面积：0.95±0.03；敏感性：94%；特异性：94%；p<0.001）。
CMR 压力 T1 映射技术可在不使用造影剂或辐射的情况下准确检测和区分阻塞性心外膜 CAD 和微血管功能障碍。
