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

Optimizing diagnosis and risk stratification of ischemic heart disease by myocardial perfusion imaging: The incremental values of non-perfusion variables during vasodilator stress

“…In the study by Frey et al, 1 the definition of abnormal scan was SSS C 4, similar to most of the previous studies. Since SSS is a mixed marker of Figure 1.…”

“…In this issue of Journal of Nuclear Cardiology, Frey et al retrospectively enrolled a very large-scale population of 2496 patients to study the stress-induced effects of two vasodilator agents (adenosine and regadenoson) by ECG-gated myocardial perfusion imaging (MPI) with Rb-82 PET/CT on functional variables including stress left ventricular ejection fraction (LVEF), rest LVEF, LVEF reserve, stress myocardial blood flow (MBF), rest MBF, MBF reserve and hemodynamic variables in patients with or without prior history of coronary artery disease (CAD) and normal or abnormal scan results (summed stress score [SSS] \ 4 or SSS C 4). 1 Although similar studies on comparing different vasodilator agents had been reported, this study was likely the largest single center study of Rb-82 PET data. The main findings concluded by the authors were: (1) The clinical significance of non-perfusion variables obtained from vasodilator-stress gated MPI with SPECT or PET, such as LVEF, LVEF reserve, wall motion, transient LV ischemic dilation (TID), and dyssynchrony had been widely studied and shown to have incremental values on the diagnosis and risk stratification of patients with ischemic heart disease.…”

“…1 Although similar studies on comparing different vasodilator agents had been reported, this study was likely the largest single center study of Rb-82 PET data. The main findings concluded by the authors were: (1) The clinical significance of non-perfusion variables obtained from vasodilator-stress gated MPI with SPECT or PET, such as LVEF, LVEF reserve, wall motion, transient LV ischemic dilation (TID), and dyssynchrony had been widely studied and shown to have incremental values on the diagnosis and risk stratification of patients with ischemic heart disease. [2][3][4][5][6][7][8][9] As the example shown in Figure 1, the non-perfusion variables are especially useful for the patients whose perfusion abnormality was underestimated or falsely negative due to ''balanced ischemia''.…”

“…However, it should be noticed that the ''ischemia'' shown on MPI (SDS [ 0) in fact is ''perfusion gradient'' between different vascular territories. Certain percentages of those with a positive SDS do experience ''real ischemia'' during vasodilator stress and express ischemic stunning (low stress LVEF or negative LVEF reserve), but others may not have ischemic stunning and express high stress LVEF or positive LVEF reserve even though SDS was high (highrisk perfusion pattern) as shown in Figure 2 of Frey et al 1 On the other hand, some patients with a zero or low SDS (low-risk perfusion pattern) had low stress LVEF or negative LVEF reserve (high-risk function pattern). Such patients needed special cautions for severe and extensive CAD with balanced ischemia on perfusion images.…”

Developing a framework for evaluating and comparing risk models

“…2 Earlier acquisitions also facilitate measurement of left ventricular ejection fraction (LVEF) reserve, which is also helpful in estimating risk of cardiovascular outcomes. 3,4 While it is possible to quantify both parameters with the latest generation solid-state SPECT camera systems, 5,6 their clinical utility is less well-established. Lastly, the CT obtained for attenuation correction can be used to quantify coronary artery calcification which improves the diagnostic and prognostic utility of PET/CT MPI.…”