Comparison of 82Rb PET/CT MPI with cardiac catheterization

Objectives St. Joseph’s Hospital utilizes ⁸²Rb PET/CT imaging for myocardial perfusion studies (MPI) on all patients with a BMI ≥ 35. The theory behind this is that the higher energy gammas emitted from the positron annihilation will pass through excess tissue easier resulting in higher quality diagnostic images. The purpose of this study was to compare the ⁸²Rb PET/CT imaging results with cardiac catheterization results on patients that typically prove more difficult to diagnose using traditional SPECT/CT imaging modalities.

Methods Twenty-two patients with a BMI ≥ 35 were imaged on a PET/CT system (Philips Gemini GXL). The imaging protocol included gated rest images, adenosine stress, and gated stress images, along with accompanying CT transmission scans. Images were then processed by a technologist and read by a Nuclear Medicine physician. All 22 patients in this study were referred to cardiac catheterization following the ⁸²Rb PET/CT scan.

Results Cardiac catheterization confirmed the results of the ⁸²Rb PET/CT scans in 21 of 22 patients studied. Eighteen of the patients that had positive perfusion defects were found to have coronary artery stenoses. One patient with a prior MI showed a fixed perfusion defect in the area of that MI. The 2 patients with negative perfusion defects that underwent catheterization were found to have no stenoses. The one false positive scan showed a slight stress induced perfusion defect. In addition, 87% of the LAD, 84% of the RCA, and 100% of the LCX artery blockages seen as perfusion defects on the MPI studies were confirmed with cardiac catheterization.

Conclusions The findings of this study suggest that ⁸²Rb PET/CT myocardial perfusion imaging is an accurate diagnostic tool for obese patients exhibiting symptoms of CAD.