Clinical results of a novel wide beam reconstruction method for shortening scan time of Tc-99m cardiac SPECT perfusion studies
Clinical results of a novel wide beam reconstruction method for shortening scan time of Tc-99m cardiac SPECT perfusion studies
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DOI：
10.1016/j.nuclcard.2007.04.022
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发表时间：
2007-07-01
影响因子：
2.4
通讯作者：
Coleman, Ralph Edward
中科院分区：
文献类型：
--
作者：
Borges-Neto, Salvador;Pagnanelli, Robert A.;Coleman, Ralph Edward
背景。新开发的重建算法能够在保持图像质量的同时以一半的扫描时间获取图像。本研究的目的是评估UltraSPECT开发的一种新型宽波束重建（WBR）方法，以减少扫描时间，并将其与常规使用的滤波反向投影（FBP）技术进行比较。方法与结果。进行了幻影和临床研究。通过WBR、FBP和有序子集期望最大化重建热球、冷球和心虚影图像。采用标准和短方案对50例患者进行前瞻性研究。短方案首先通过8帧门控锝99m应力单光子发射计算机断层扫描和低能高分辨率准直仪对50名患者中的29名进行。应力Tc-99m研究（30-45 mCi）每帧扫描20秒。对于短方案，除了每帧时间外，所有参数保持不变，在Tc-99m研究中，每帧时间减少了50%。所有静息Tc-99m扫描（36/50例患者）在标准全扫描时间研究中用FBP处理，在短扫描研究中用WBR处理。使用17节段模型和5度严重程度评分对图像进行解释，并确定灌注和功能变量。所有变量的分布包括平均值、中位数和四分位数范围。计算所有变量的差异（FBP - WBR），并使用非参数符号秩检验来确定中位数差异是否为0。差值的绝对值也进行了检验。Spearman秩序相关（一种非参数的关联度量）用于两种方法来确定变量之间的显著相关性。热球和冷球幻影研究表明，与有序子集期望最大化相比，WBR具有更好的对比度恢复和略好的背景均匀性。减弱介质和背景活动的心脏幻影研究表明，与全扫描时间FBP重建相比，WBR处理的半扫描时间图像具有更好的对比度恢复和背景均匀性。在临床研究中，WBR和FBP在功能变量和灌注变量之间观察到高度显著的相关性（P < 0.0001）。FBP与WBR的总应激评分、总休息评分、总差异评分差异无统计学意义（P < 0.05）。左室容积与FBP的相关系数较高，但与wbr的相关系数明显大于FBP。我们的研究结果表明，心脏单光子发射计算机断层扫描灌注研究可以用WBR算法进行，只需一半的扫描时间，而不会影响定性或定量成像结果。
Background. Newly developed reconstruction algorithms enable the acquisition of images at half of the scan time while maintaining image quality. The purpose of this investigation was to evaluate a novel wide beam reconstruction (WBR) method developed by UltraSPECT for decreasing scan times and to compare it with filtered backprojection (FBP), which is the technique routinely used.Methods and Results. Phantom and clinical studies were performed. Hot and cold sphere and cardiac phantom acquisitions were reconstructed via WBR, FBP, and ordered-subsets expectation maximization. Fifty patients were prospectively studied by use of both a standard and a short protocol. The short protocol was performed first on 29 of 50 patients via 8-frame gated technetium 99m stress single photon emission computed tomography and low-energy high-resolution collimators. Stress Tc-99m studies (30-45 mCi) were scanned for 20 seconds per frame. For the short protocol, all parameters remained constant except for the time per frame, which was reduced by 50% on Tc-99m studies. All resting Tc-99m scans (36/50 patients) were processed with FBP for the standard full-scan time studies and with WBR for the short scan studies. The images were interpreted by use of a 17-segment model and 5-degree severity score, and the perfusion and functional variables were determined. Distributions including mean, median, and interquartile ranges were examined for all variables. The differences (FBP - WBR) were computed for all variables and were examined by use of nonparametric signed rank tests to determine whether the median difference was 0. The absolute value of the difference was also examined. Spearman rank-order correlation, a nonparametric measure of association, was used for the 2 methods to determine significant correlations between variables. The hot and cold sphere phantom studies demonstrated that WBR had improved contrast recovery and slightly better background uniformity than did the ordered-subsets expectation maximization. The cardiac phantom studies performed with attenuating medium and background activity showed that the half-scan time images processed with WBR had better contrast recovery and background uniformity than did the full-scan time FBP reconstruction. In the clinical studies, highly significant correlations were observed between WBR and FBP for functional as well as perfusion variables (P < .0001). The summed stress score, summed rest scores, and summed difference score were not statistically different for FBP and WBR (P > .05). Left ventricular volumes had a high correlation coefficient but were significantly larger with FBP than with WBR.Conclusion. Our study results suggest that cardiac single photon emission computed tomography perfusion studies may be performed with the WBR algorithm using half of the scan time without compromising qualitative or quantitative imaging results.