Multidetector Computed Tomography Myocardial Perfusion Imaging During Adenosine Stress

Multidetector Computed Tomography Myocardial Perfusion Imaging During Adenosine Stress Richard T. George, Caterina Silva, Marco A. S. Cordeiro, Anthony DiPaula, Douglas R. Thompson, William F. McCarthy, Takashi Ichihara, Joao A. C. Lima, Albert C. Lardo This study investigates the feasibility of myocardial perfusion imaging (MPI) using helical multidetector computed tomography (MDCT) in a canine model of left anterior descending artery stenosis. Results indicate that adenosine-augmented MDCT MPI can be performed in a single scan during first-pass contrast-enhancement, and MDCT myocardial signal density ratio correlates well with microsphere-derived myocardial blood flow. The ability to perform MPI during first-pass contrast-enhanced MDCT imaging could have significant implications in the diagnosis and treatment of coronary artery disease. The purpose of this study is to validate the accuracy of multidetector computed tomography (MDCT) to measure differences in regional myocardial perfusion during adenosine stress in a canine model of left anterior descending (LAD) artery stenosis, during first-pass, contrast-enhanced helical MDCT. Myocardial perfusion imaging by MDCT may have significant implications in the diagnosis and treatment of coronary artery disease. Eight dogs were prepared with a LAD stenosis, and contrast-enhanced MDCT imaging was performed 5 min into adenosine infusion (0.14 to 0.21 mg/kg/min). Images were analyzed using a semiautomated approach to define the regional signal density (SD) ratio (myocardial SD/left ventricular blood pool SD) in stenosed and remote territories, and then compared with microsphere myocardial blood flow (MBF) measurements. Mean MBF in stenosed versus remote territories was 1.37 ± 0.46 ml/g/min and 1.29 ± 0.48 ml/g/min at baseline (p = NS) and 2.54 ± 0.93 ml/g/min and 8.94 ± 5.74 ml/g/min during adenosine infusion, respectively (p < 0.05). Myocardial SD was 92.3 ± 39.5 HU in stenosed versus 180.4 ± 41.9 HU in remote territories (p < 0.001). There was a significant linear association of the SD ratio with MBF in the stenosed territory (R = 0.98, p = 0.001) and between regional myocardial SD ratio and MBF