Abstract 12497: Comparison of Absolute and Relative Quantification of Rubidium-82 PET for Detection of Coronary Artery Disease
Background: We aimed to compare the diagnostic accuracy of relative quantification of perfusion and absolute quantification of myocardial blood flow (MBF) and coronary flow reserve (CFR) from 82-Rubidium (Rb-82) PET/CT myocardial perfusion imaging (MPI) for detection of epicardial obstructive coronary artery disease (CAD, ≥50% diameter stenosis) using invasive coronary angiography (ICA) as the reference standard.
Methods: We studied 70 consecutive patients (64% males, age 70±12) without known CAD undergoing 3D Rb-82 PET/CT MPI with list mode data acquisition allowing for absolute dynamic flow measurements. All patients had diagnostic ICA within 6 months of PET/CT. Relative rest and stress perfusion abnormality was quantified by QPET software and expressed as total perfusion deficit (TPD), and ischemic TPD (I-TPD) was defined as stress-rest TPD. For overall CAD detection, I-TPD ≥5% was considered as abnormal. Regional I-TPD ≥2% in each vascular territory was considered abnormal for detection of CAD in individual vessels. Absolute MBF and CFR (stress/rest MBF) were quantified by QPET software. Regional CFR <2.0 in any vascular territory was considered abnormal for overall CAD detection as well as for detection of CAD in individual vessels.
Results: For overall CAD detection, the ROC area under the curve (ROC-AUC) was 0.82 for I-TPD and 0.81 for CFR. The sensitivity/specificity/accuracy was 84/71/80% for I-TPD and 76/86/79% for CFR. By the criterion of either abnormal I-TPD or CFR, ROC-AUC was 0.76 and the sensitivity/specificity/accuracy was 90/62/81% (p=0.08, 0.2, and 0.03, respectively, vs. I-TPD alone). For detecting stenosis in individual vessels, ROC-AUC was 0.79 for I-TPD and 0.80 for CFR. The sensitivity/specificity/accuracy was 67/84/76% and 74/76/75% for I-TPD and CFR, respectively. By the criterion of either abnormal I-TPD or CFR, ROC-AUC was 0.78 and the sensitivity/specificity/accuracy was 83/74/78% (p=0.0001, 0.001, and 0.0001, respectively, vs. I-TPD alone).
Conclusion: Quantification of MPI and CFR show similar diagnostic accuracy for overall detection of epicardial obstructive CAD. The combination of MPI and CFR appears to improve the sensitivity and accuracy for detection of CAD in individual vessels.
- © 2011 by American Heart Association, Inc.