De Bondt Pieter, Nichols Kenneth, Vandenberghe Stijn, Segers Patrick, De Winter Olivier, Van de Wiele Christophe, Verdonck Pascal, Shazad Arsalan, Shoyeb Abu H, De Sutter Johan
Nuclear Medicine Division, Ghent University Hospital, Ghent, Belgium.
J Nucl Med. 2003 Jun;44(6):967-72.
We have developed a biventricular dynamic physical cardiac phantom to test gated blood-pool (GBP) SPECT image-processing algorithms. Such phantoms provide absolute values against which to assess accuracy of both right and left computed ventricular volume and ejection fraction (EF) measurements.
Two silicon-rubber chambers driven by 2 piston pumps simulated crescent-shaped right ventricles wrapped partway around ellopsoid left ventricles. Twenty experiments were performed at Ghent University, for which right and left ventricular true volume and EF ranges were 65-275 mL and 55-165 mL and 7%-49% and 12%-69%, respectively. Resulting 64 x 64 simulated GBP SPECT images acquired at 16 frames per R-R interval were sent to Columbia University, where 2 observers analyzed images independently of each other, without knowledge of true values. Algorithms automatically segmented right ventricular activity volumetrically from left ventricular activity. Automated valve planes, midventricular planes, and segmentation regions were presented to observers, who accepted these choices or modified them as necessary. One observer repeated measurements >1 mo later without reference to previous determinations.
Linear correlation coefficients (r) of the mean of the 3 GBP SPECT observations versus true values for right and left ventricles were 0.80 and 0.94 for EF and 0.94 and 0.95 for volumes, respectively. Correlations for right and left ventricles were 0.97 and 0.97 for EF and 0.96 and 0.89 for volumes, respectively, for interobserver agreement and 0.97 and 0.98 for EF and 0.96 and 0.90 for volumes, respectively, for intraobserver agreement. No trends were detected, though volumes and right ventricular EFs were significantly higher than true values.
Overall, GBP SPECT measurements correlated strongly with true values. The phantom evaluated shows considerable promise for helping to guide algorithm developments for improved GBP SPECT accuracy.
我们开发了一种双心室动态物理心脏模型，用于测试门控心血池（GBP）单光子发射计算机断层显像（SPECT）图像处理算法。此类模型可提供绝对值，据此评估右心室和左心室计算容积及射血分数（EF）测量的准确性。
由两个活塞泵驱动的两个硅橡胶腔模拟新月形右心室，其部分环绕椭圆形左心室。在根特大学进行了20次实验，右心室和左心室的真实容积及EF范围分别为65 - 275 mL和55 - 165 mL，以及7% - 49%和12% - 69%。以每个R - R间期16帧采集得到的64×64模拟GBP SPECT图像被发送至哥伦比亚大学，由两名观察者相互独立地分析图像，且不知晓真实值。算法自动从左心室活动中按体积分割出右心室活动。自动生成的瓣膜平面、心室中部平面及分割区域呈现给观察者，观察者可接受这些选择或根据需要进行修改。一名观察者在1个月后不参考先前测定结果重复测量。
3次GBP SPECT观察均值与右心室和左心室真实值的线性相关系数（r），EF分别为0.80和0.94，容积分别为0.94和0.95。右心室和左心室的观察者间一致性，EF分别为0.97和0.97，容积分别为0.96和0.89；观察者内一致性，EF分别为0.97和0.98，容积分别为0.96和0.90。虽未检测到趋势，但容积和右心室EF显著高于真实值。
总体而言，GBP SPECT测量与真实值高度相关。所评估的模型在帮助指导算法开发以提高GBP SPECT准确性方面显示出相当大的前景。
