Only few preliminary experimental studies demonstrated the feasibility of adenosine stress CT myocardial perfusion
imaging to calculate the absolute MBF, thereby providing information whether a coronary stenosis is flow limiting.
In seven pigs, a coronary flow probe and an adjustable hydraulic occluder were placed around the left anterior descending coronary artery to monitor the distal coronary artery blood flow (CBF) while several degrees of coronary
flow reduction were induced. CT perfusion (CT-MBF) was acquired during adenosine stress with no CBF reduction,
an intermediate (15–39%) and a severe (40–95%) CBF reduction. Reference standards were CBF and fractional flow
reserve measurements (FFR). FFR was simultaneously derived from distal coronary artery pressure and aortic pressure measurements.
CT-MBF decreased progressively with increasing CBF reduction severity from 2.68 (2.31–2.81) mL/g/min (normal CBF) to 1.96 (1.83–2.33) mL/g/min (intermediate CBF-reduction) and to 1.55 (1.14–2.06) mL/g/min (severe CBF-reduction) (both P <0.001). We observed very good correlations between CT-MBF and CBF (r=0.85, P<0.001) and CT-MBF and FFR (r=0.85, P<0.001).
Conclusion:Adenosine stress CT myocardial perfusion imaging allows quantification of regional MBF under various degrees of CBF reduction.