Jin Mingwu, Yang Yongyi, Niu Xiaofeng, Marin Thibault, Brankov Jovan G, Feng Bing, Pretorius P Hendrik, King Michael A, Wernick Miles N
Colorado Translational Research Imaging Center and Department of Radiology, School of Medicine, University of Colorado Denver, Aurora, CO 80045, USA.
Phys Med Biol. 2009 Sep 21;54(18):5643-59. doi: 10.1088/0031-9155/54/18/019. Epub 2009 Sep 1.
In practice, gated cardiac SPECT images suffer from a number of degrading factors, including distance-dependent blur, attenuation, scatter and increased noise due to gating. Recently, we proposed a motion-compensated approach for four-dimensional (4D) reconstruction for gated cardiac SPECT and demonstrated that use of motion-compensated temporal smoothing could be effective for suppressing the increased noise due to lowered counts in individual gates. In this work, we further develop this motion-compensated 4D approach by also taking into account attenuation and scatter in the reconstruction process, which are two major degrading factors in SPECT data. In our experiments, we conducted a thorough quantitative evaluation of the proposed 4D method using Monte Carlo simulated SPECT imaging based on the 4D NURBS-based cardiac-torso (NCAT) phantom. In particular, we evaluated the accuracy of the reconstructed left ventricular myocardium using a number of quantitative measures including regional bias-variance analyses and wall intensity uniformity. The quantitative results demonstrate that use of motion-compensated 4D reconstruction can improve the accuracy of the reconstructed myocardium, which in turn can improve the detectability of perfusion defects. Moreover, our results reveal that while traditional spatial smoothing could be beneficial, its merit would become diminished with the use of motion-compensated temporal regularization. As a preliminary demonstration, we also tested our 4D approach on patient data. The reconstructed images from both simulated and patient data demonstrated that our 4D method can improve the definition of the LV wall.
在实际应用中，门控心脏单光子发射计算机断层扫描（SPECT）图像存在许多降质因素，包括距离依赖性模糊、衰减、散射以及由于门控导致的噪声增加。最近，我们提出了一种用于门控心脏SPECT的四维（4D）重建的运动补偿方法，并证明使用运动补偿时间平滑对于抑制由于各个门中计数降低而增加的噪声是有效的。在这项工作中，我们通过在重建过程中也考虑衰减和散射进一步开发了这种运动补偿4D方法，衰减和散射是SPECT数据中的两个主要降质因素。在我们的实验中，我们基于4D基于非均匀有理B样条（NURBS）的心脏躯干（NCAT）体模，使用蒙特卡罗模拟SPECT成像对所提出的4D方法进行了全面的定量评估。特别是，我们使用包括区域偏差 - 方差分析和壁强度均匀性在内的多种定量措施评估了重建左心室心肌的准确性。定量结果表明，使用运动补偿4D重建可以提高重建心肌的准确性，进而可以提高灌注缺损的可检测性。此外，我们的结果表明，虽然传统的空间平滑可能是有益的，但随着运动补偿时间正则化的使用，其优点会减弱。作为初步演示，我们还在患者数据上测试了我们的4D方法。来自模拟数据和患者数据的重建图像都表明我们的4D方法可以改善左心室壁的清晰度。
