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


RESULTS
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.


CONCLUSIONS
Baseline, hyperaemic MBF and CFR values in a low-risk cohort can be evaluated with dynamic myocardial perfusion imaging using 80 kV.
Mount Alvernia Hospital, Heart Consultants Pte Ltd, 820 Thomson Road, #02-25A, Singapore 574623 drhokt@me.com.
Kheng-Thye
KT
Ho
Khoo Teck Puat Hospital, Singapore.
Hean-Yee
HY
Ong
Siemens Healthcare, Singapore.
Grace
G
Tan
Tan Tock Seng Hospital, Singapore.
Quek-Wei
QW
Yong
D000368:Aged; D000704:Analysis of Variance; D001783:Blood Flow Velocity / Q000502:physiology; D015331:Cohort Studies; D017023:Coronary Angiography / Q000379:methods; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging*; D003326:Coronary Circulation / Q000502:physiology*; D005080:Exercise Test / Q000379:methods; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D008875:Middle Aged; D061330:Multidetector Computed Tomography / Q000379:methods*; D055414:Myocardial Perfusion Imaging / Q000379:methods*; D011446:Prospective Studies; D012146:Rest; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index
Dynamic CT myocardial perfusion; Low-risk subjects; Normal myocardial perfusion values