Combined 82-rubidium PET and coronary computed tomography in coronary artery disease: insights into the association between calcium score, coronary artery disease-reporting and data system, ischemia, and blood flow.

Abstract

Purpose: This study aimed to evaluate correlation between various parameters from integrated 82-rubidium PET/coronary computed tomography angiography (RbPET/CCTA), like coronary artery calcium (CAC) score, coronary artery disease-reporting and data system (CAD-RADS), myocardial ischemia scores, and myocardial blood flow parameters [stress myocardial blood flow (sMBF) and myocardial flow reserve (MFR)].

Methods: In this retrospective study, 184 consecutive patients [107 women, 77 men, median age: 67 years [(interquartile range: 61-74 years)] with suspicion of CAD were imaged with RbPET/CCTA in the 'one-stop imaging' approach. The association between CAC score, CAD-RADS, relative perfusion, and myocardial blood flow was assessed.

Results: There was a weak but statistically significant inverse correlation between the global CAD-RADS score and global sMBF ( ρ = -0.239, P = 0.001) and global MFR ( ρ = -0.248, P = 0.0001). There was a significant difference in CAD-RADS 3-5 vs. CAD-RADS 0-2 for global as well as per-vessel sMBF and MFR values ( P < 0.05). There was a very weak inverse correlation between global CAC and global sMBF ( ρ = -0.165, P = 0.026) and a nonsignificant, very weak inverse correlation between global CAC and global MFR ( ρ = -0.120, P = 0.106).

Conclusion: Combined CCTA and RbPET 'one-stop imaging' provides comprehensive anatomical and physiological information in patients with suspected CAD. The PET and computed totmography parameters seem to lack linear and robust correlation. In the given circumstances, CAD-RADS scores appear to have a relatively better, though weak, correlation with sMBF, MFR, and relative ischemia scores compared with CAC scores.