Department of Radiology, Massachusetts General Hospital, Harvard Medical School, White 270, 55 Fruit St, Boston, MA 02114, USA.
AJR Am J Roentgenol. 2011 Jun;196(6):W743-52. doi: 10.2214/AJR.10.5303.
The purpose of this study was to evaluate the image quality and diagnostic performance of low-dose MDCT and CT enterography with adaptive statistical iterative reconstruction (ASIR) in the evaluation of Crohn disease.
Forty-eight patients (20 men, 28 women; mean age, 33.3 years; range, 17-83 years) with known or suspected Crohn disease who underwent low-dose MDCT and CT enterography with ASIR between December 2008 and December 2009 were included in the study. Twenty-seven patients had previously undergone standard-dose 64-MDCT and CT enterography with filtered back projection (FBP), and those images were used for comparison. The weight-based i.v. contrast protocol and scan parameters (120 kVp, 5-mm section thickness, 0.5-second rotation, pitch of 1.375, 64 × 0.625 mm detector configuration) were constant for the two techniques except for a higher noise index (×1.3) in the ASIR group. Two blinded readers reviewed 75 randomized MDCT-CT enterographic scans of 48 patients to assess image quality and diagnostic performance in the evaluation of Crohn disease, and the radiation dose for the studies was estimated.
All 75 MDCT and CT enterographic scans had acceptable quality for diagnostic interpretation. Findings of Crohn disease were seen on 63 of 75 scans (84%). Low-dose scans in the ASIR group had optimal image quality and were rated comparable to or better than standard-dose FBP images (mean score, 4.2 vs 3.87; p = 0.007). The subjective image noise score (mean, 1.43 vs 1.58; p = 0.2) and objective image noise measurements were lower for ASIR images (p < 0.001). Low-dose studies with ASIR allowed average dose reduction of 34.5% compared with standard-dose scans with FBP (volume CT dose index for ASIR, 7.7 ± 2.1 mGy; for FBP, 12 ± 5.5 mGy; p < 0.01).
Low-dose MDCT and CT enterographic studies reconstructed with ASIR were of appropriate quality for confident evaluation of the manifestations of Crohn disease while allowing approximately 34% dose reduction in comparison with FBP technique.
本研究旨在评估低剂量 MDCT 和 CT 肠造影术联合自适应统计迭代重建（ASIR）在克罗恩病诊断中的图像质量和诊断性能。
本研究纳入了 2008 年 12 月至 2009 年 12 月期间接受低剂量 MDCT 和 CT 肠造影术联合 ASIR 检查的 48 例（20 例男性，28 例女性；平均年龄 33.3 岁；范围 17-83 岁）已知或疑似克罗恩病患者。其中 27 例患者之前接受过标准剂量 64 层 MDCT 和 CT 肠造影术联合滤波反投影（FBP）检查，这些图像用于对比。两种技术的静脉对比方案和扫描参数（120kVp、5mm 层厚、0.5 秒旋转、1.375 螺距、64×0.625mm 探测器配置）保持不变，但 ASIR 组的噪声指数（×1.3）更高。两名盲法读者对 48 例患者的 75 次随机 MDCT-CT 肠造影扫描进行了评估，以评估在克罗恩病评估中图像质量和诊断性能，并估计研究的辐射剂量。
所有 75 次 MDCT 和 CT 肠造影扫描均具有可接受的诊断解读质量。63 次（84%）扫描可见克罗恩病的表现。ASIR 组的低剂量扫描具有最佳的图像质量，评分与标准剂量 FBP 图像相当或更高（平均评分为 4.2 比 3.87；p=0.007）。ASIR 图像的主观图像噪声评分（平均 1.43 比 1.58；p=0.2）和客观图像噪声测量值较低（p<0.001）。与标准剂量 FBP 扫描相比，ASIR 组的低剂量研究平均可降低 34.5%的剂量（ASIR 的容积 CT 剂量指数为 7.7±2.1mGy；FBP 为 12±5.5mGy；p<0.01）。
低剂量 MDCT 和 CT 肠造影术联合 ASIR 重建的图像质量足以对克罗恩病的表现进行有信心的评估，同时与 FBP 技术相比，可降低约 34%的剂量。
