Myocardial CT Perfusion: A Review of Current Modalities, Technology, and Clinical Performance

Abstract

This review describes the current techniques for CT myocardial perfusion, reviews the current literature, and discusses future directions for CT perfusion. Myocardial CT perfusion (CTP) is an emerging technology for evaluation of myocardial ischemia and infarction, and has the benefit of having both morphologic (coronary CT angiography) and physiologic (CTP) measures in the same setting. CTP has primarily been developed as an adjunct to coronary CT angiography in an effort to improve diagnostic performance, specifically in patients with luminal coronary artery disease. The principle of CTP is to estimate myocardial blood after an iodinated contrast bolus on a single image (static CTP) or with subsequent contrast enhancement over time (dynamic CTP). Either CTP modality is usually combined with vasodilator stress studies to improve accuracy for ischemia. Delayed CTP imaging also allows for assessment of myocardial viability, as contrast is retained in infarcted tissue. Finally, dual energy CTP studies allow for specific imaging of the iodinated contrast, potentially improving contrast resolution. The performance characteristics of CTP have been compared and found to generally be as good as or better than standard of care, such as nuclear, echocardiography, and invasive measures. However, there are substantial heterogeneity of protocols and limited data on patient outcomes which limits widespread use. Future studies designed to assess these opportunities may lead to wider clinical adoption of this promising new technology. Myocardial perfusion computed tomography shows great promise to add in the noninvasive diagnosis of ischemia and infarction, although heterogeneity in protocols and limited outcome data need to be addressed prior to adoption of CT perfusion as a viable diagnostic modality.