Abstract
1613
Introduction: Positron emission tomography (PET) allows improved functional assessment of myocardial perfusion and left ventricular (LV) function. Currently, no scientific data exists about the differences between 8- and 16-frame PET left ventricular volumes and ejection fraction (EF); In addition, the influence of framing on detection of stress-induced functional changes is not known. The aim of this study is to compare the effect of 8-frame and 16-frame gated PET on measurements of LV volumes and EF and also to evaluate the influence of framing on detection of stress-induced functional changes.
Methods: In this institutional IRB approved retrospective study, 100 patients each undergoing rest and stress studies using 82Rb Rubidium Chloride (82RbCl2) PET were analyzed. 21.3± 5 mCi of 82RbCl2 was infused using the RubyfillTM rubidium generator in constant activity or constant flow mode. All data was acquired using Biograph Horizon (Siemens) PET/CT in list-mode couples with ECG gating and binned into 8-frame and 16- frame per cardiac cycle. Images were reconstructed using iterative algorithm with time-of-flight, non-time-of-flight, and resolution recovery. The data was corrected for attenuation and scatter using low-dose CT. Left ventricular end-diastolic volume (EDV), end-systolic volume (ESV), EF, cardiac output (CO), stress summed score, wall motion and thickening scores were calculated using 4DM (Invia) software. Stress-induced ischemia was identified on summed perfusion images.
Results: For both 8-frame and 16- frame, there is no significant difference in stress EDV (136±71 ml vs 135±70 ml, p-value=0.47), ESV (62±48 ml vs 62±52 ml, p-value=0.48), LVEF (56±14 ml vs 57±15 ml, p-value=0.41), CO (6.3±2.8 ml vs 6.27±2.5 ml, p-value=0.46) and in rest EDV (130±69 ml vs 129±68 ml, p-value=0.47), ESV (65±50 ml vs 64±50 ml, p-value=0.49), LVEF (52±13 ml vs 52±13 ml, p-value=0.48), CO (4.8±2.1 ml vs 4.75±2.1 ml, p-value=0.47). Both using 8 and 16 frames, there was no significant differences in SSS, wall motion and thickness scores for both stress and rest. There is no significant change in LV function in either ischemic or non-ischemic patients when using either 8-frames or 16- frames. Use of time-of-flight and resolution recovery produced reproducible functional parameters.
Conclusions: Clinical use of 16- or 8-frames has no significant influence on 82Rb PET cardiac left ventricular quantified functional parameters or on the detection of stress-induced functional changes.