The relationship between acquisition count and each index for LV function analysis in gated myocardial perfusion SPECT

2654 Objectives Left ventricular function and phase analysis indices can be obtained from gated myocardial perfusion SPECT. Those values are important indices for determining the adaptation of cardiac resynchronization therapy and diagnosis of myocardial ischemia. However, pharmaceutical preparation, dosage, and acquisition time for gated myocardial perfusion SPECT scintigraphy vary depending on the each institution. In addition the dosage is administered regardless of weight and age. Therefore, acquisition counts for myocardium are also different from each examination. The aim of this study is to examine the impact on Left ventricular function and phase analysis indices by the difference in acquisition counts. Methods The acquisition time was modified to 3, 6, 9, 15, 21 and 30 sec / view (each acquisition count of myocardial is 9, 18, 29, 47, 67 and 98counts / view), and implemented by using Cleavage type Gated Myocardial Perfusion phantom (HL-D type). Using QGS software (2009), Left ventricular function analysis and phase analysis were measured. The calculated values are ejection fraction (EF), end diastolic volume (EDV), end systolic volume (ESV), a band width, phase SD, and entropy. Results For left ventricular function analysis, only the value of ESV for 3 sec/view was extremely high. Other value had no impact from the difference in the counts. (The each coefficient of variation of EF, EDV, and ESV was 2.5%, 2.6%, and 7.3%.) For phase analysis, indices had impact from the difference in the counts. when the acquisition count was reduced, phase analysis index become high. (The each coefficient of variation of Bandwidth, phaseSD, and Entropy was 21.8%,9.4%, and 21.9%.) Conclusions As long as the acquisition counts is very poor, left ventricular function analysis indices are hardly affected. However, phase analysis indices are affected by acquisition counts. Therefore, actual obtained count is checked in clinical study, and the indices should be treated carefully. In this study, it did not lead to the presentation of the appropriate counts for performing Phase Analysis. Hence, the presentation of the appropriate counts should be considered in detail.