胰腺全器官 CT 灌注：256 层 CT 迭代重建对图像质量、灌注参数和辐射剂量的影响：初步研究结果。
Whole-organ CT perfusion of the pancreas: impact of iterative reconstruction on image quality, perfusion parameters and radiation dose in 256-slice CT-preliminary findings.
机构信息
Department of Radiology, Huashan Hospital, Fudan University, Shanghai, China.
出版信息
PLoS One. 2013 Nov 26;8(11):e80468. doi: 10.1371/journal.pone.0080468. eCollection 2013.
BACKGROUND
This study was performed to assess whether iterative reconstruction can reduce radiation dose while maintaining acceptable image quality, and to investigate whether perfusion parameters vary from conventional filtered back projection (FBP) at the low-tube-voltage (80-kVp) during whole-pancreas perfusion examination using a 256-slice CT.
METHODS
76 patients with known or suspected pancreatic mass underwent whole-pancreas perfusion by a 256-slice CT. High- and low-tube-voltage CT images were acquired. 120-kVp image data (protocol A) and 80-kVp image data (protocol B) were reconstructed with conventional FBP, and 80-kVp image data were reconstructed with iDose(4) (protocol C) iterative reconstruction. The image noise; contrast-to-noise ratio (CNR) relative to muscle for the pancreas, liver, and aorta; and radiation dose of each protocol were assessed quantitatively. Overall image quality was assessed qualitatively. Among 76 patients, 23 were eventually proven to have a normal pancreas. Perfusion parameters of normal pancreas in each protocol including blood volume, blood flow, and permeability-surface area product were measured.
RESULTS
In the quantitative study, protocol C reduced image noise by 36.8% compared to protocol B (P<0.001). Protocol C yielded significantly higher CNR relative to muscle for the aorta, pancreas and liver compared to protocol B (P<0.001), and offered no significant difference compared to protocol A. In the qualitative study, protocols C and A gained similar scores and protocol B gained the lowest score for overall image quality (P<0.001). Mean effective doses were 23.37 mSv for protocol A and 10.81 mSv for protocols B and C. There were no significant differences in the normal pancreas perfusion values among three different protocols.
CONCLUSION
Low-tube-voltage and iDose(4) iterative reconstruction can dramatically decrease the radiation dose with acceptable image quality during whole-pancreas CT perfusion and have no significant impact on the perfusion parameters of normal pancreas compared to the conventional FBP reconstruction using a 256-slice CT scanner.
背景
本研究旨在评估迭代重建是否能在维持可接受的图像质量的同时降低辐射剂量，并探讨在使用 256 层 CT 进行全胰腺灌注检查时，低管电压（80kVp）下的灌注参数是否与传统滤波反投影（FBP）不同。
方法
76 例已知或疑似胰腺肿块的患者接受了 256 层 CT 全胰腺灌注检查。采集高、低管电压 CT 图像。120kVp 图像数据（方案 A）和 80kVp 图像数据（方案 B）采用传统 FBP 重建，80kVp 图像数据采用 iDose（4）迭代重建（方案 C）。定量评估图像噪声、胰腺、肝脏和主动脉的对比噪声比（CNR）以及每个方案的辐射剂量。定性评估整体图像质量。76 例患者中，23 例最终证实胰腺正常。测量每个方案中正常胰腺的灌注参数，包括血容量、血流量和渗透表面积产物。
结果
在定量研究中，与方案 B 相比，方案 C 降低了 36.8%的图像噪声（P<0.001）。与方案 B 相比，方案 C 使主动脉、胰腺和肝脏的 CNR 显著提高（P<0.001），与方案 A 相比无显著差异。在定性研究中，方案 C 和 A 获得相似的评分，而方案 B 获得整体图像质量的最低评分（P<0.001）。方案 A 的平均有效剂量为 23.37mSv，方案 B 和 C 的平均有效剂量为 10.81mSv。三个不同方案的正常胰腺灌注值无显著差异。
结论
在使用 256 层 CT 扫描仪进行全胰腺 CT 灌注时，低管电压和 iDose（4）迭代重建可以显著降低辐射剂量，同时保持可接受的图像质量，与传统 FBP 重建相比，对正常胰腺的灌注参数没有显著影响。
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