In contrast to SPECT-myocardial perfusion scintigraphy (MPS), positron emission tomography (PET)-MPS can be acquired during pharmacological stress and provides absolute quantification of stress myocardial blood flow (MBF). PET-MPS is therefore well suited for the more accurate detection of balanced myocardial ischemia in patients with three-vessel coronary artery disease (3V-CAD)

The aim of this study was to compare the diagnostic performances of ^99mTechnetium (Tc)-MIBI-SPECT MPS and ⁸²Rubidium (Rb)-PET MPS for the detection of 3V-CAD.

Two hundred and ninety-two patients underwent gated MPS with Tc-MIBI-SPECT in association to the best stress test feasible (exercise and combined tests were prioritized) and gated MPS with Rb-PET and pharmacological stress using dipyridamole. Patients with at least one MPS considered as positive were referred for coronary angiography (CA). Patients were classified as positive for myocardial ischemia in case of significant stenosis (≥70%, or≥50% and FFR≤0.8) on CA or, in absence of CA, occurrence of cardiovascular event during the following year.

Rb-PET-MPS offered better diagnostic performances than Tc-SPECT-MPS for the identification of stress LV dysfunction in patients with 3V-CAD (sensitivity: 75% vs. 56%, respectively; P=0.18; specificity: 83% vs. 71%, respectively; P<0.05). Quantification of MBF with Rb-PET-MPS provided high sensitivity for the detection of 3V-CAD (94% for global stress MBF<1.8ml/mn/g) but poor specificity (60%). By combining the diagnostic criteria for LV dysfunction and low stress MBF, the specificity of Rb-PET-MPS for the detection of patients with 3V-CAD increased to 92% for global stress MBF<1.8ml/mn/g, whilst maintaining a sensitivity of 75%.

Rb-PET-MPS offers to identify moderate stress LV dysfunction and decreased stress global MBF resulting into higher diagnostic performances for the detection of patients with 3V-CAD in comparison to Tc-SPECT-MPS.