Hemodynamic Assessment of Coronary Flow: Myocardial Perfusion Using CT/MR
摘要
Despite a downward trend in cardiovascular disease (CVD) incidence, they remain the leading cause of mortality and morbidity worldwide. One of their most lethal manifestations is coronary artery disease (CAD), in which alteration of the blood supply to the myocardium may cause transitory or definitive loss of function (Amini et al. 2021). To tackle the burden of cardiovascular disease, research has been driven toward finding appropriate techniques to assess coronary flow. Early techniques required placement of a catheter in the coronary arteries. While they currently remain the modality of choice for real-time flow or pressure measurement, they are increasingly challenged by newer less invasive diagnostic imaging techniques (Neumann et al. 2019). Isotopic imaging techniques, including single-photon emission computed tomography (SPECT) and later positron emission tomography (PET), were the first to build on the insight that the myocardial uptake of an intravenously injected tracer can provide valuable information that could replace that obtained by invasive coronary flow assessment (Flotats et al. 2011). Furthermore, contrast-enhanced computed tomography (CT) and magnetic resonance imaging (MRI) have contrast enhancement kinetics largely similar to that of radioisotopes and microspheres. Also, recent software and hardware developments in CT and MRI have enabled the rapid consecutive acquisition of (dynamic) volumetric or sequential datasets with higher spatial and temporal resolution as compared to isotopic imaging (Coelho-Filho et al. 2013; Dewey et al. 2020). The prospect of extracting clinically useful information from the kinetic information of a bolus of contrast would further improve the overall morphological and functional evaluation of the major coronary arteries. However, challenges remain posed by the contribution to the disease process of the distal coronary arteries, subject to the same obstructive process or compensatory vasodilatation. Despite ongoing progress (Hsu et al. 2018), challenges posed by the reproducibility of the processing of dynamic CT/MRI examination and the less widespread availability of platforms providing quantitative perfusion from these data in clinical practice currently restrict these approaches to research centers. In this chapter, we will briefly describe diagnostic approaches to the evaluation of myocardial perfusion from dynamic CT and MRI and discuss their clinical usefulness.