利用快速千伏切换双能CT的多物质分解生成的虚拟平扫图像中CT衰减测量的变异性
Variability of CT Attenuation Measurements in Virtual Unenhanced Images Generated Using Multimaterial Decomposition from Fast Kilovoltage-switching Dual-energy CT.
作者信息
Kaza Ravi K, Raff Evan A, Davenport Matthew S, Khalatbari Shokoufeh
机构信息
Department of Radiology, Division of Abdominal Imaging, University of Michigan Health System, University of Michigan Hospital, Ann Arbor, Michigan 48109.
Department of Radiology, Division of Abdominal Imaging, University of Michigan Health System, University of Michigan Hospital, Ann Arbor, Michigan 48109; Department of Radiology, University of Southern California, Los Angeles, California.
出版信息
Acad Radiol. 2017 Mar;24(3):365-372. doi: 10.1016/j.acra.2016.09.002. Epub 2016 Oct 18.
RATIONALE AND OBJECTIVES
To compare Hounsfield unit (HU) data obtained from true-unenhanced (TUE) and virtual-unenhanced (VUE) imaging obtained with a fast kv-switching dual-energy computed tomography (CT) scanner using multimaterial decomposition algorithm.
MATERIALS AND METHODS
In this Institutional Review Board-approved, Health Insurance Portability and Accountability Act-compliant, retrospective cohort study, CT scans of 19 patients undergoing multiphasic renal protocol abdominal CT on a fast kv-switching dual-energy CT scanner were reviewed. CT numbers were measured on the matched TUE and VUE generated using a multimaterial decomposition algorithm with selective iodine suppression, and postcontrast images at predefined locations in seven organs. Six hundred sixty regions of interest were placed at 132 locations. Agreement was assessed with paired t test, Pearson's correlation, and Bland-Altman analysis.
RESULTS
Mean TUE and VUE measurements were not significantly different in the corticomedullary (P = 0.25) or nephrographic (P = 0.10) phases. There was a strong correlation between TUE and VUE CT numbers (corticomedullary: r = 0.90, nephrographic: r = 0.90, each P < 0.001). Discrepancies ≥5 HU occurred 46 times (35%, 46 of 132) in the corticomedullary phase and 44 times (33%, 44 of 132) in the nephrographic phase. Discrepancies ≥10 HU occurred in 7% (9 of 132 in both corticomedullary and nephrographic phases). Interphase, intrasubject VUE CT numbers were strongly correlated (r = 0.93, P < 0.001), but discrepancies ≥5 HU (22% [29 of 132]) and ≥10 HU (2% [3 of 132]) occurred. There was no significant correlation between the true postcontrast CT number and the magnitude of VUE-TUE discrepancy (r = -0.04, P = 0.6).
CONCLUSION
CT numbers on VUE images generated from fast kv-switching dual-energy CT scans strongly correlate with TUE CT numbers on a population basis, but commonly vary 5-9 HU on a per-patient basis.
原理与目的
使用多物质分解算法，比较通过快速千伏切换双能计算机断层扫描（CT）扫描仪获得的真实非增强（TUE）成像和虚拟非增强（VUE）成像的亨氏单位（HU）数据。
材料与方法
在这项经机构审查委员会批准、符合《健康保险流通与责任法案》的回顾性队列研究中，对19例行多期肾脏扫描方案腹部CT检查的患者在快速千伏切换双能CT扫描仪上的CT扫描图像进行了回顾。使用具有选择性碘抑制功能的多物质分解算法生成匹配的TUE和VUE图像，并在七个器官的预定义位置测量造影后图像的CT值。在132个位置放置了660个感兴趣区。采用配对t检验、Pearson相关性分析和Bland-Altman分析评估一致性。
结果
在皮质髓质期（P = 0.25）或肾实质期（P = 0.10），TUE和VUE的平均测量值无显著差异。TUE和VUE的CT值之间存在强相关性（皮质髓质期：r = 0.90，肾实质期：r = 0.90，P均<0.001）。在皮质髓质期，差异≥5 HU出现46次（35%，132次中的46次），在肾实质期出现44次（33%，132次中的44次）。差异≥10 HU在皮质髓质期和肾实质期均出现7%（132次中的9次）。在不同期相内，受试者内VUE的CT值之间存在强相关性（r = 0.93，P < 0.001），但差异≥5 HU（22% [132次中的29次]）和≥10 HU（2% [132次中的3次]）仍有出现。真实造影后CT值与VUE - TUE差异幅度之间无显著相关性（r = -0.04，P = 0.6）。
结论
快速千伏切换双能CT扫描生成的VUE图像上的CT值在总体上与TUE的CT值密切相关，但在个体患者中通常相差5 - 9 HU。
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