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.

Abstract

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 μg/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 (MBFCT) was calculated using a model-based parametric deconvolution method and correlated to that of fluorescent microspheres (MBFmic) 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, MBFCT 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 MBFmic (r = 0.67, P < 0.001). MBFCT overestimated MBFmic, independently of adenosine-stress and degree of coronary stenosis (β = 2.3, 95% confidence interval: 1.81-2.79 mL/g/min, P < 0.001). Although there were no differences in MBFCT between 50% and 75% coronary stenosis at rest (0.01 ± 0.08 mL/g/min, P = 0.86), MBFCT 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.

• Authors: Fabian Bamberg, Rabea Hinkel, Florian Schwarz, Torleif A Sandner, Elisabeth Baloch, Roy Marcus, Alexander Becker, Christian Kupatt, Bernd J Wintersperger, Thorsten R Johnson, Daniel Theisen, Ernst Klotz, Maximilian F Reiser, Konstantin Nikolaou
• Journal: Investigative radiology (Invest Radiol) Vol. 47 Issue 1 Pg. 71-7 (Jan 2012) ISSN: 1536-0210 [Electronic] United States
• PMID: 22178894 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Vasodilator Agents
• Adenosine

Topics

• Adenosine
• Animals
• Blood Flow Velocity
• Coronary Angiography (methods)
• Coronary Circulation
• Coronary Stenosis (diagnostic imaging, physiopathology)
• Exercise Test
• Humans
• Myocardial Perfusion Imaging (methods)
• Reproducibility of Results
• Sensitivity and Specificity
• Swine
• Tomography, X-Ray Computed (methods)
• Vasodilator Agents