From the Departments of Diagnostic Radiology (C.T.J., N.A.W., L.N.V., B.R., D.M., S.G.), Biostatistics (W.W.), and Physics (X.L.), University of Texas MD Anderson Cancer Center, 1400 Pressler St, Unit 1473, Houston, TX 77030-4009; and Duke University Medical Center, Durham, NC (Y.C., E.S.).
Radiology. 2019 Feb;290(2):400-409. doi: 10.1148/radiol.2018181657. Epub 2018 Nov 27.
Purpose To evaluate colorectal cancer hepatic metastasis detection and characterization between reduced radiation dose (RD) and standard dose (SD) contrast material-enhanced CT of the abdomen and to qualitatively compare between filtered back projection (FBP) and iterative reconstruction algorithms. Materials and Methods In this prospective study (from May 2017 through November 2017), 52 adults with biopsy-proven colorectal cancer and suspected hepatic metastases at baseline CT underwent two portal venous phase CT scans: SD and RD in the same breath hold. Three radiologists, blinded to examination details, performed detection and characterization of 2-15-mm lesions on the SD FBP and RD adaptive statistical iterative reconstruction (ASIR)-V 60% series images. Readers assessed overall image quality and lesions between SD FBP and seven different iterative reconstructions. Two nonblinded consensus reviewers established the reference standard using the picture archiving and communication system lesion marks of each reader, multiple comparison examinations, and clinical data. Results RD CT resulted in a mean dose reduction of 54% compared with SD. Of the 260 lesions (233 metastatic, 27 benign), 212 (82%; 95% confidence interval [CI]: 76%, 86%) were detected with RD CT, whereas 252 (97%; 95% CI: 94%, 99%) were detected with SD (P < .001); per-lesion sensitivity was 79% (95% CI: 74%, 84%) and 94% (95% CI: 90%, 96%) (P < .001), respectively. Mean qualitative scores ranked SD images as higher quality than RD series images, and ASIR-V ranked higher than ASIR and Veo 3.0. Conclusion CT evaluation of colorectal liver metastases is compromised with modest radiation dose reduction, and the use of iterative reconstructions could not maintain observer performance. © RSNA, 2018.
目的 评估腹部低辐射剂量（RD）与标准剂量（SD）对比增强 CT 对结直肠癌肝转移的检测和特征描述能力，并对滤波反投影（FBP）与迭代重建算法进行定性比较。
材料与方法 本前瞻性研究（2017 年 5 月至 2017 年 11 月）纳入 52 例经活检证实患有结直肠癌且基线 CT 检查疑似肝转移的成年患者，所有患者均行两次门脉期 CT 扫描：同屏吸气末行 SD 和 RD。3 名放射科医师在不知晓检查细节的情况下，对 SD FBP 和 RD 自适应统计迭代重建（ASIR）-V 60%系列图像上的 2-15-mm 病变进行检测和特征描述。读者评估 SD FBP 和 7 种不同迭代重建图像的总体图像质量和病变。2 名非盲共识审查员使用每位读者的图像存档与通信系统病变标记、多次比较检查和临床数据建立参考标准。
结果 RD CT 较 SD 平均剂量降低 54%。260 个病灶（233 个转移性，27 个良性）中，RD CT 检出 212 个（82%；95%置信区间[CI]：76%，86%），而 SD 检出 252 个（97%；95% CI：94%，99%）（P<.001）；病变检出的病灶敏感性分别为 79%（95% CI：74%，84%）和 94%（95% CI：90%，96%）（P<.001）。平均定性评分显示 SD 图像质量高于 RD 系列图像，ASIR-V 评分高于 ASIR 和 Veo 3.0。
结论 结直肠癌肝转移 CT 评估结果因适度降低辐射剂量而受到影响，迭代重建的应用不能保持观察者的性能。
