Higuchi T, Taki J, Nakajima K, Horii J, Yamada M, Tonami N
Department of Nuclear Medicine, School of Medicine, Kanazawa University.
Kaku Igaku. 1999 May;36(4):357-68.
ECG-gated myocardial SPECT program (QGS) is coming into wide use. This program permits measurement of end-diastolic volume (EDV), and end-systolic volume (ESV) and ejection fraction (EF) by automatic detection of myocardial edges. We assessed the reproducibility, accuracy, factors that affect the measurement of these indices using a cardiac phantom and clinical data.
In the phantom study, we evaluated the effects of ventricular volume, location, absorption, acquisition time, enlarged acquisition and pre-filter on the calculated indices. In the clinical study using 99mTc-MIBI, reproducibility between 2 observers, comparison with left ventriculography and effects of pre-filter were assessed. In clinical cases of 201TI and 123I-BMIPP, left ventricular volume and EF were also analyzed by QGS with various pre-filters.
Although the true phantom volumes (y) and calculated volumes (x) showed an excellent linear correlation (y = 0.94x - 13.8, r = 0.999), calculated volumes were significantly under-estimated by 14.5-33.8%. An absorbent material around the phantom caused reduction in calculated volumes by 4.1-9.1%. Duration of acquisition times, 3 to 60 seconds per projection, did not influence the calculation of the parameters. With enlarged data collection, calculated volume (37 ml) was larger than that of normal acquisition (33 ml). When the cut-off frequency of Butterworth filter was changed, these indices of volume and EF were almost stable over 0.41 cycle/cm. There was an excellent correlation in intra-observer measurements for EDV (r = 0.998, p < 0.0001), ESV (r = 0.998, p < 0.0001) and EF (r = 0.995, p < 0.0001). In comparison with left ventriculography, correlation of parameters was good in ESV (r = 0.91, p < 0.0001), EF (r = 0.88, p < 0.0001), but was fair in EDV (r = 0.78, p < 0.0001). The QGS program underestimated EDV, ESV and EF.
QGS program with gated SPECT is useful to calculate relative volume and EF. However, to calculate absolute values, we should understand the various factors that affect the result of QGS.
心电图门控心肌单光子发射计算机断层扫描程序（QGS）正在广泛应用。该程序可通过自动检测心肌边缘来测量舒张末期容积（EDV）、收缩末期容积（ESV）和射血分数（EF）。我们使用心脏模型和临床数据评估了这些指标测量的可重复性、准确性以及影响测量的因素。
在模型研究中，我们评估了心室容积、位置、吸收、采集时间、扩大采集和预滤波对计算指标的影响。在使用99mTc - MIBI的临床研究中，评估了两名观察者之间的可重复性、与左心室造影的比较以及预滤波的影响。在201TI和123I - BMIPP的临床病例中，还通过使用各种预滤波的QGS分析了左心室容积和EF。
尽管模型的真实容积（y）与计算容积（x）显示出极好的线性相关性（y = 0.94x - 13.8，r = 0.999），但计算容积被显著低估了14.5 - 33.�%。模型周围的吸收材料使计算容积减少了4.1 - 9.1%。每个投影采集时间为3至60秒，这对参数计算没有影响。随着数据采集的扩大，计算容积（37毫升）大于正常采集时的容积（33毫升）。当巴特沃斯滤波器的截止频率改变时，这些容积和EF指标在0.41周期/厘米以上几乎保持稳定。观察者内测量的EDV（r = 0.998，p < 0.0001）、ESV（r = 0.998，p < 0.0001）和EF（r = 0.995，p < 0.0001）之间存在极好的相关性。与左心室造影相比，ESV（r = 0.91，p < 0.0001）、EF（r = 0.88，p < 0.0001）参数的相关性良好，但EDV的相关性一般（r = 0.78，p < 0.0001）。QGS程序低估了EDV、ESV和EF。
门控单光子发射计算机断层扫描的QGS程序对于计算相对容积和EF很有用。然而，要计算绝对值，我们应该了解影响QGS结果的各种因素。
