Dynamic CT myocardial perfusion measurements of resting and hyperaemic blood flow in low-risk subjects with 128-slice...

The aim of the study was to measure rest and stress myocardial blood flow (MBF) values prospectively in a low-risk population with 128-slice dual-source computed tomography (CT) and to compare MBF/coronary flow reserve (CFR) values to that of a second population with a documented coronary artery disease (CAD).

This study evaluates resting and hyperaemic MBF in 35 low-risk individuals identified by the modified Framingham Risk score and a calcium score of <100. The patients were scanned using 80 kV and quantitative blood flow values were generated using complete time-attenuation curves. Global resting and hyperaemic MBF was 74.08 ± 16.30 and 135.24 ± 28.89 mL/100 g/min, respectively, with CFR of 1.86 ± 0.38. Resting MBF was 76.98 ± 25.68, 66.98 ± 19.66, 81.34 ± 21.40, and 63.35 ± 16.35 mL/100 g/min in anterior, septal, lateral, and inferior walls, respectively, and corresponding hyperaemic MBF was 133.25 ± 29.80, 123.47 ± 31.03, 148.60 ± 32.69, and 124.21 ± 31.54 mL/100 g/min, respectively. In the population with CAD, global resting and hyperaemic MBF were 82.29 ± 16.87 and 81.98 ± 18.54 mL/100 g/min and 107.95 ± 25.25 and 106.93 ± 32.91 mL/100 g/min in the group with ischaemia only and infarction only, respectively, with corresponding CFR of 1.33 ± 0.27 and 1.33 ± 0.46, respectively (statistically different from the low-risk population). Radiation dose for CT myocardial perfusion imaging (CTMPI) was 6.72 ± 2.71 and 6.19 ± 2.19 mSv for stress and rest scans, respectively. This was 30% lower than a radiation dose in the scanning historical cohort at 100 kV. There was no significant difference in the signal-to-noise ratio and contrast-to-noise ratio between low-risk cohort and historical cohort scanned at 80 and 100 kV, respectively.

Baseline, hyperaemic MBF and CFR values in a low-risk cohort can be evaluated with dynamic myocardial perfusion imaging using 80 kV.