Accuracy of Dynamic Computed Tomography Adenosine Stress Myocardial Perfusion Imaging in Estimating Myocardial Blood Flow at Various Degrees of Coronary Artery Stenosis Using a Porcine Animal Model

作者：Bamberg Fabian^*; Hinkel Rabea; Schwarz Florian; Sandner Torleif A; Baloch Elisabeth; Marcus Roy; Becker Alexander; Kupatt Christian; Wintersperger Bernd J; Johnson Thorsten R; Theisen Daniel; Klotz Ernst; Reiser Maximilian F; Nikolaou Konstantin

来源：Investigative Radiology, 2012, 47(1): 71-77.

DOI：10.1097/RLI.0b013e31823fd42b

• cardiac CT perfusion
• dynamic acquisition
• animal model
• ischemia

Objective: To determine the accuracy of computed tomography (CT) dynamic stress myocardial perfusion imaging to estimate myocardial blood flow (MBF) in a porcine animal model with variable degrees of induced coronary artery stenosis in comparison with microsphere-derived MBF.
Methods and Materials: Seven domestic pigs (36 +/- 4 kg) received stents (confirmed 3.0 mm diameter) in the left anterior descending coronary artery distal to first diagonal branch. A balloon catheter was placed within the stent and inflated to various degrees to obtain a defined luminal narrowing (50% and 75% diameter stenosis) as confirmed by intra-arterial flow wire measurement. All models underwent adenosine-mediated (140 mu g/kg/min) dynamic stress and rest myocardial perfusion CT imaging using a dual-source CT scanner (shuttle-mode with 100 kV/300 mAs, 20 mL iopromide) with prospective acquisitions every second heartbeat for 30 seconds. CT-estimated MBF (MBF(CT)) was calculated using a model-based parametric deconvolution method and correlated to that of fluorescent microspheres (MBF(mic)) injected at each perfusion state.
Results: All study procedures were performed without complications, and all animals completed the study protocol. Among 448 myocardial segments, 31 (7%) were considered nonevaluable because of motion artifacts. With stress, MBF(CT) increased significantly (1.10 +/- 0.25 vs. 0.80 +/- 0.28 mL/g/min, P < 0.001; at stress and rest, respectively) in all myocardial segments and correlated with MBF(mic) (r = 0.67, P < 0.001). MBF(CT) overestimated MBF(mic), independently of adenosine-stress and degree of coronary stenosis (beta = 2.3, 95% confidence interval: 1.81-2.79 mL/g/min, P < 0.001). Although there were no differences in MBF(CT) between 50% and 75% coronary stenosis at rest (0.01 +/- 0.08 mL/g/min, P = 0.86), MBF(CT) was significantly lower at 75% than at 50% under stress conditions (0.53 +/- 0.19 vs. 0.71 +/- 0.24 mL/g/min, P = 0.002).
Conclusions: CT-derived MBF measurements at rest and stress with varying degrees of coronary stenosis show a valid difference but an underestimated correlation with microsphere-derived MBF in a porcine animal model.

• 出版日期2012-1