Dynamic myocardial stress CT perfusion appears feasible and accurate

Cardiac MRI could potentially face some competition from adenosine-stress first-pass myocardial CT perfusion, according to an initial study from the Medical University of South Carolina in Charleston. The study won an RSNA trainee research prize for Markus Weininger, MD, who will discuss his group's initial experience with the dual-source CT technique.

The group examined 20 patients who underwent dual-source cardiac CT imaging using prospectively triggered coronary CT angiography, dynamic adenosine-stress myocardial perfusion imaging using the scanner's "shuttle" mode, and delayed-enhancement acquisitions. Following CT, all subjects underwent stress/rest perfusion and delayed-enhancement MRI.

Two independent and blinded observers looked for myocardial perfusion defects, and compared CT- and MRI-derived myocardial-to-left-ventricular upslope indices along with other measures.

In all, 89% (n = 303 segments) were evaluable. Compared to MRI, CT was 86% sensitive and 98% specific for the detection of defects, with positive and negative predictive values of 93% and 94%, respectively. There was moderate correlation between absolute CT quantification of myocardial blood flow and semiquantitative CT measurements.

Adenosine-stress first-pass myocardial CT perfusion imaging enables the evaluation of qualitative and semiquantitative parameters of myocardial perfusion in a comparable fashion as MRI, and may enable absolute quantification of myocardial blood flow, the group concluded.