Anatomical-based partial volume correction for low-dose dedicated cardiac SPECT/CT.
Anatomical-based partial volume correction for low-dose dedicated cardiac SPECT/CT.
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DOI：
10.1088/0031-9155/60/17/6751
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发表时间：
2015-09-07
影响因子：
3.5
通讯作者：
Liu C
中科院分区：
文献类型：
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作者：
Liu H;Chan C;Grobshtein Y;Ma T;Liu Y;Wang S;Stacy MR;Sinusas AJ;Liu C
由于空间分辨率有限，部分体积效应（PVE）一直是影响发射层析成像系统定量精度的主要因素。本研究旨在研究几种基于解剖的部分体积校正（PVC）方法在专用心脏SPECT/CT系统（GE Discovery NM/CT 570c）中的性能，该系统具有聚焦视场（FOV），在两种不同的放射性示踪剂分布的临床相关高、低计数水平范围内。这些PVC方法包括摄动几何传递矩阵（pGTM）、摄动几何传递矩阵后再进行多目标校正（MTC）、已知血池浓度的pGTM、摄动几何传递矩阵后再进行多目标校正（MTC）和我们提出的新方法，该方法迭代执行MTC方法，在迭代过程中，每次用MTC校正后的图像估计和更新所有区域的平均值。用99mTc-tetrofosmin（一种心肌灌注剂）和99mTc-red blood cell (RBC)（一种纯血管内显像剂）模拟NCAT幻影进行心血管成像。在六种不同计数水平下获取图像，以研究PVC方法在低剂量应用的高和低计数水平下的性能。我们在注射99mTc-RBC后进行了两次大型动物体内心脏成像实验，以评估心肌内血容量（IMBV）。仿真结果表明，我们提出的迭代方法在图像质量、定量准确性和再现性（标准偏差）方面优于其他现有的PVC方法，特别是对于低计数数据。即使在低计数水平下，迭代方法对于99mTc-tetrofosmin灌注成像和99mTc-RBC IMBV和血池活性成像都是稳健的。动物实验结果表明，PVC可有效纠正因血池污染而导致的IMBV高估。总之，迭代PVC方法可以实现更准确的定量，特别是对于低计数心脏SPECT研究，通常从低剂量方案，门控研究和动态应用中获得。
Due to the limited spatial resolution, partial volume effect (PVE) has been a major degrading factor on quantitative accuracy in emission tomography systems. This study aims to investigate the performance of several anatomical-based partial volume correction (PVC) methods for a dedicated cardiac SPECT/CT system (GE Discovery NM/CT 570c) with focused field-of-view (FOV) over a clinically relevant range of high and low count levels for two different radiotracer distributions. These PVC methods include perturbation Geometry Transfer Matrix (pGTM), pGTM followed by multi-target correction (MTC), pGTM with known concentration in blood pool, the former followed by MTC and our newly proposed methods, which perform the MTC method iteratively, where the mean values in all regions are estimated and updated by the MTC-corrected images each time in the iterative process. The NCAT phantom was simulated for cardiovascular imaging with 99mTc-tetrofosmin, a myocardial perfusion agent, and 99mTc-red blood cell (RBC), a pure intravascular imaging agent. Images were acquired at six different count levels to investigate the performance of PVC methods in both high and low count levels for low-dose applications. We performed two large animal in vivo cardiac imaging experiments following injection of 99mTc-RBC for evaluation of intramyocardial blood volume (IMBV). The simulation results showed our proposed iterative methods provide superior performance than other existing PVC methods in terms of image quality, quantitative accuracy, and reproducibility (standard deviation), particularly for low-count data. The iterative approaches are robust for both 99mTc-tetrofosmin perfusion imaging and 99mTc-RBC imaging of IMBV and blood pool activity even at low count levels. The animal study results indicated the effectiveness of PVC to correct the overestimation of IMBV due to blood pool contamination. In conclusion, the iterative PVC methods can achieve more accurate quantification, particularly for low count cardiac SPECT studies, typically obtained from low-dose protocols, gated studies, and dynamic applications.