Juni J E, Chen C C
Department of Internal Medicine, University of Michigan Medical Center, Ann Arbor.
J Nucl Med. 1988 Jul;29(7):1272-8.
Variations in cardiac cycle length during ECG-gated radionuclide ventriculography cause errors in measurement of left ventricular (LV) diastolic function. We used a computer model to investigate the relative accuracy of forward gating (FG), backward gating (BG), and three methods of combined forward-backward gating (FBG). LV time-activity curves (TAC) were simulated with total cycle lengths randomly varied (1 s.d. = +/- 10%). To match the known differential effects of cycle-length variation on various parts of the cardiac cycle, 90% this variation was placed in diastasis and 10% in the rapid filling phase. Three hundred cycles of TACs were summed to form one "study". A total of 25 studies were performed and systolic and diastolic parameters were determined for each. These were compared to those of the mean length TAC. With a 20% cycle-length acceptance window, error in peak filling rate by FG was 0.7% root-mean-squared (RMS) compared to 18.5% RMS by BG. With a 5% window, RMS error by FG was 0.2% and 2.4% RMS by BG. Combined FBG algorithms gave intermediate results. We conclude that the simplest and most accurate method of analysis is to acquire forward gated TACs with appropriate cycle-length windows.
心电图门控放射性核素心室造影期间心动周期长度的变化会导致左心室（LV）舒张功能测量误差。我们使用计算机模型研究了正向门控（FG）、反向门控（BG）以及三种正向-反向联合门控（FBG）方法的相对准确性。通过随机改变总周期长度（标准差=±10%）来模拟左心室时间-活性曲线（TAC）。为了匹配周期长度变化对心动周期不同部分已知的差异影响，将这种变化的90%置于舒张期，10%置于快速充盈期。将300个周期的TAC相加形成一个“研究”。总共进行了25项研究，并确定了每项研究的收缩期和舒张期参数。将这些参数与平均长度TAC的参数进行比较。在20%的周期长度接受窗口下，FG的峰值充盈率误差为均方根（RMS）0.7%，而BG为RMS 18.5%。在5%的窗口下，FG的RMS误差为0.2%，BG为RMS 2.4%。联合FBG算法给出了中间结果。我们得出结论，最简单且最准确的分析方法是获取具有适当周期长度窗口的正向门控TAC。
