Assessment of left ventricular function at rest using rubidium-82 myocardial perfusion PET: comparison of four software algorithms with simultaneous 64-slice coronary CT angiography

Left ventricular ejection fraction, myocardial blood flow and hemodynamic variables in adenosine and regadenoson vasodilator 82-Rubidium PET

AIMS

In most Rubidium-(Rb)-positron emission tomography (PET) studies, dipyridamole was used as vasodilator. The aim was to evaluate vasodilator PET left ventricular ejection fraction (LVEF), myocardial blood flow (MBF), hemodynamics, and the influence of adenosine and regadenoson on these variables.

METHODS AND RESULTS

Consecutive patients (N = 2299) with prior coronary artery disease (CAD) or no prior CAD undergoing adenosine/regadenoson 82Rb-PET were studied and compared according to CAD status and normal/abnormal PET (summed stress score 0-3 vs. ≥4). Rest and stress LVEF differed significantly depending on CAD status and scan results. In patients with no prior CAD, rest/stress LVEF were 68% and 72%, in patients with prior CAD 60% and 63%. LVEF during stress increased 5 ± 6% in normal compared to 1 ± 8% in abnormal PET (P<0.001). Global rest myocardial blood flow(rMBF), stress MBF(sMBF) and myocardial flow reserve (sMBF/rMBF) were significantly higher in no prior CAD patients compared to prior CAD patients(1.3 ± 0.5, 3.3 ± 0.9, 2.6 ± 0.8 and 1.2 ± 0.4, 2.6 ± 0.8, 2.4 ± 0.8 ml/g/min, respectively, P<0.001) and in normal versus abnormal scans, irrespective of CAD status(no prior CAD: 1.4 ± 0.5, 3.5 ± 0.8, 2.8 ± 0.8 and 1.2 ± 0.8, 2.5 ± 0.8, 2.2 ± 0.7; prior CAD: 1.3 ± 0.4, 3.1 ± 0.8, 2.7 ± 0.8 and 1.1 ± 0.4, 2.3 ± 0.7, 2.2 ± 0.7 ml/g/min, respectively, P<0.001). LVEF and hemodynamic values were similar for adenosine and regadenoson stress. Stress LVEF ≥70% excluded relevant ischemia (≥10%) with a negative predictive value (NPV) of 94% (CI 92-95%).

CONCLUSIONS

Rest/stress LVEF, LVEF reserve and MBF values are lower in abnormal compared to normal scans. Adenosine and regadenoson seem to have similar effect on stress LVEF, MBF and hemodynamics. A stress LVEF ≥70% has a high NPV to exclude relevant ischemia.

The future of hybrid imaging-part 2: PET/CT

Since the 1990s, hybrid imaging by means of software and hardware image fusion alike allows the intrinsic combination of functional and anatomical image information. This review summarises the state-of-the-art of dual-modality imaging with a focus on clinical applications. We highlight selected areas for potential improvement of combined imaging technologies and new applications. In the second part, we briefly review the background of dual-modality PET/CT imaging, discuss its main applications and attempt to predict technological and methodological improvements of combined PET/CT imaging. After a decade of clinical evaluation, PET/CT will continue to have a significant impact on patient management, mainly in the area of oncological diseases. By adopting more innovative acquisition schemes and data processing PET/CT will become a fast and dose-efficient imaging method and an integral part of state-of-the-art clinical patient management.