Pons-Lladó Guillem, Kellman Peter
Head (Emeritus), Cardiac Imaging Unit, Cardiology Department, Hospital de Sant Pau, Universitat Autònoma de Barcelona, Clínica Creu Banca, 08034 Barcelona, Spain.
National Heart, Lung, and Blood Institute, National Institutes of Health, Department of Health and Human Services, Bethesda, MD 20892, USA.
Rev Cardiovasc Med. 2022 Sep 26;23(10):325. doi: 10.31083/j.rcm2310325. eCollection 2022 Oct.
Ischemic heart disease (IHD) outstands among diseases threatening public health. Essential for its management are the continuous advances in medical and interventional therapies, although a prompt and accurate diagnosis and prognostic stratification are equally important. Besides information on the anatomy of coronary arteries, well covered nowadays by invasive and non-invasive angiographic techniques, there are also other components of the disease with clinical impact, as the presence of myocardial necrosis, the extent of pump function impairment, and the presence and extent of inducible myocardial ischemia, that must be considered in every patient. Cardiovascular Magnetic Resonance (CMR) is a multiparametric diagnostic imaging technique that provides reliable information on these issues. Regarding the detection and grading of inducible ischemia in particular, the technique has been widely adopted in the form of myocardial perfusion sequences under vasodilator stress, which is the subject of this review. While the analysis of images is conventionally performed by visual inspection of dynamic first-pass studies, with the inherent dependency on the operator capability, the recent introduction of a reliable application of quantitative perfusion (QP) represents a significant advance in the field. QP is based on a dual-sequence strategy for conversion of signal intensities into contrast agent concentration units and includes a full automatization of processes such as myocardial blood flow (MBF) calculation (in mL/min/g), generation of a pixel-wise flow mapping, myocardial segmentation, based on machine learning, and allocation of MBF values to myocardial segments. The acquisition of this protocol during induced vasodilation and at rest gives values of stress/rest MBF (in mL/min/g) and myocardial perfusion reserve (MPR), both global and per segment. Dual-sequence QP has been successfully validated against different reference methods, and its prognostic value has been shown in large longitudinal studies. The fact of the whole process being automated, without operator interaction, permits to conceive new interesting scenarios of integration of CMR into systems of entirely automated diagnostic workflow in patients with IHD.
缺血性心脏病（IHD）在威胁公众健康的疾病中尤为突出。尽管及时准确的诊断和预后分层同样重要，但医学和介入治疗的不断进步对于其管理至关重要。除了如今通过侵入性和非侵入性血管造影技术能很好涵盖的冠状动脉解剖信息外，该疾病还有其他对临床有影响的因素，如心肌坏死的存在、泵功能损害的程度以及可诱导心肌缺血的存在和程度，在每位患者中都必须予以考虑。心血管磁共振成像（CMR）是一种多参数诊断成像技术，可提供有关这些问题的可靠信息。特别是在可诱导缺血的检测和分级方面，该技术已以血管扩张剂负荷下的心肌灌注序列形式被广泛采用，这也是本综述的主题。虽然图像分析传统上是通过对动态首过研究进行目视检查来完成的，这固有地依赖于操作者的能力，但最近可靠的定量灌注（QP）应用的引入是该领域的一项重大进展。QP基于一种双序列策略，用于将信号强度转换为造影剂浓度单位，并且包括诸如心肌血流量（MBF）计算（以mL/min/g为单位）、生成逐像素血流图、基于机器学习的心肌分割以及将MBF值分配到心肌节段等过程的完全自动化。在诱导血管扩张期间和静息状态下采集该方案可得到应激/静息MBF（以mL/min/g为单位）和心肌灌注储备（MPR）的全局值和节段值。双序列QP已针对不同的参考方法成功进行了验证，并且其预后价值已在大型纵向研究中得到证实。整个过程无需操作者干预即可自动进行，这使得人们能够设想将CMR集成到IHD患者完全自动化诊断工作流程系统中的新的有趣场景。
