Department of Radiology, University of Massachusetts Medical School, 55 Lake Avenue North, Worcester, MA, 01655, USA.
Illinois Institute of Technology, Medical Imaging Research Center, Chicago, IL, USA.
J Nucl Cardiol. 2021 Apr;28(2):624-637. doi: 10.1007/s12350-019-01743-7. Epub 2019 May 10.
In the ongoing efforts to reduce cardiac perfusion dose (injected radioactivity) for conventional SPECT/CT systems, we performed a human observer study to confirm our clinical model observer findings that iterative reconstruction employing OSEM (ordered-subset expectation-maximization) at 25% of the full dose (quarter-dose) has a similar performance for detection of hybrid cardiac perfusion defects as FBP at full dose.
One hundred and sixty-six patients, who underwent routine rest-stress Tc-99m sestamibi cardiac perfusion SPECT/CT imaging and clinically read as normally perfused, were included in the study. Ground truth was established by the normal read and the insertion of hybrid defects. In addition to the reconstruction of the 25% of full-dose data using OSEM with attenuation (AC), scatter (SC), and spatial resolution correction (RC), FBP and OSEM (with AC, SC, and RC) both at full dose (100%) were done. Both human observer and clinical model observer confidence scores were obtained to generate receiver operating characteristics (ROC) curves in a task-based image quality assessment.
Average human observer AUC (area under the ROC curve) values of 0.725, 0.876, and 0.890 were obtained for FBP at full dose, OSEM at 25% of full dose, and OSEM at full dose, respectively. Both OSEM strategies were significantly better than FBP with P values of 0.003 and 0.01 respectively, while no significant difference was recorded between OSEM methods (P = 0.48). The clinical model observer results were 0.791, 0.822, and 0.879, respectively, for the same patient cases and processing strategies used in the human observer study.
Cardiac perfusion SPECT/CT using OSEM reconstruction at 25% of full dose has AUCs larger than FBP and closer to those of full-dose OSEM when read by human observers, potentially replacing the higher dose studies during clinical reading.
在降低常规 SPECT/CT 系统心脏灌注剂量（注射放射性药物）的持续努力中，我们进行了一项人体观察者研究，以确认我们的临床模型观察者研究结果，即使用 OSEM（有序子集期望最大化）进行迭代重建，以全剂量的 25%（四分之一剂量），对于检测混合心脏灌注缺陷的性能与全剂量的 FBP 相似。
本研究纳入了 166 名接受常规静息-应激 Tc-99m sestamibi 心脏灌注 SPECT/CT 成像且临床检查为正常灌注的患者。通过正常阅读和插入混合缺陷来确定真实情况。除了使用具有衰减（AC）、散射（SC）和空间分辨率校正（RC）的 OSEM 重建全剂量的 25%数据外，还进行了 FBP 和 OSEM（具有 AC、SC 和 RC）的全剂量（100%）重建。获得了人体观察者和临床模型观察者的置信度评分，以在基于任务的图像质量评估中生成 ROC 曲线。
全剂量 FBP、全剂量 OSEM 四分之一剂量和全剂量 OSEM 的人体观察者 AUC（ROC 曲线下面积）平均值分别为 0.725、0.876 和 0.890。两种 OSEM 策略均明显优于 FBP，P 值分别为 0.003 和 0.01，而 OSEM 方法之间无显著差异（P=0.48）。对于相同的患者病例和处理策略，临床模型观察者的结果分别为 0.791、0.822 和 0.879。
使用 OSEM 重建进行心脏灌注 SPECT/CT，以全剂量的 25%进行重建，当由人体观察者阅读时，AUC 大于 FBP，且更接近全剂量 OSEM 的 AUC，这可能会在临床阅读期间替代更高剂量的研究。
