CT myocardial perfusion imaging

Abstract

Coronary artery disease (CAD) is a condition in which blood supply to the heart muscle (myocardium) is reduced as a result of plaque formation within one or more coronary arteries. CAD is one of the leading causes of morbidity and mortality in the world. Due to its high sensitivity and negative predictive value, coronary CT angiography (CCTA) is routinely used for detecting or excluding obstructive coronary artery stenosis in symptomatic patients with suspected CAD. However, anatomical assessment with CCTA alone is not sufficient to determine if a stenosis (lumen narrowing) is functionally significant (flow-limiting), which is critical for decision-making on coronary revascularization. CT myocardial perfusion imaging (CT-MPI) is a technique that can provide functional assessment of a stenosis in an epicardial coronary artery through imaging the first-pass circulation of iodinated contrast agent in the downstream myocardium. CT-MPI can be further classified into “static” or “dynamic,” depending on whether the contrast passage in the myocardium is monitored at a single or multiple time points. The merit of dynamic CT-MPI is that absolute myocardial blood flow values can be derived with advanced analytic algorithms to achieve a more reliable functional assessment of CAD. In this chapter, the theoretical basis of quantitative myocardial perfusion measurement with dynamic CT-MPI and the practical issues of implementation of CT-MPI are reviewed. Examples of clinical application of CT-MPI are also provided for illustration.