Dynamic perfusion CT: what is normal myocardial blood flow?

Abstract

Coronary computed tomography angiography (CTA) is an established, reliable test for the anatomical diagnosis of obstructive coronary artery disease (CAD). However, although coronary CTA provides high sensitivity and a negative predictive value for detecting ≥50% diameter stenosis, it is limited in its ability to diagnose myocardial ischaemia. Since the discrepancies between the anatomical severity of a lesion and its haemodynamic significance are common, functional evaluation of intermediate stenoses is recommended for therapeutic decisions.1 Adding myocardial CT perfusion (CTP) imaging to CTA provides an opportunity for combined evaluation of coronary anatomy and functional significance of coronary stenosis.2,3 Myocardial CTP imaging is based on the assessment of contrast attenuation in the myocardium, which is proportional to tissue concentration of iodinated contrast agent. Myocardial CTP imaging can be performed on two ways.2 Static CTP imaging is based on acquisition of an image of the myocardium during the approximate peak of the contrast bolus that enables qualitative evaluation of differences in enhancement between hypoperfused and normally perfused myocardium. Dynamic CTP is based on repetitive acquisition of images before and during the first pass of a contrast …