George Washington University Medical Center, Washington, District of Columbia 20037, USA.
J Am Coll Radiol. 2011 Apr;8(4):275-80. doi: 10.1016/j.jacr.2010.08.021.
The aim of this study was to determine, for 3 basic clinical examinations, whether blinded, experienced CT radiologists participating in the ACR's CT Accreditation Program could use scan parameters such as tube current-time product (mAs), tube voltage (kVp), and pitch to predict scanner output settings, expressed as weighted CT dose index (CTDIw) and volume CT dose index (CTDIvol), exceeding CTDIw diagnostic reference levels (DRLs) set by the ACR in 2002 and CTDIvol DRLs adopted by the ACR in 2008.
CT sites with 829 scanners submitted examinations to the ACR between 2002 and 2004, yielding 518 eligible examinations for analysis (138 adult head CT scans, 333 adult abdominal CT scans, and 47 pediatric abdominal CT scans). The sites' measured CTDIw values for each type of examination were compared with the ACR's CTDIw DRLs in effect from 2002 to 2004 and compared with comments regarding excessively high mAs or kVp made by radiologist clinical reviewers to determine if excessively high-dose index measurements could be predicted. The same analysis was repeated using CTDIvol DRLs adopted by the ACR in 2008 and compared with excessively high mAs or kVp and excessively low-pitch comments.
Excessively high mAs or kVp comments yielded sensitivity of only 21.2% in predicting examinations above the CTDIw DRLs, with specificity of 87.6%. Using the 2008 CTDIvol DRLs, the corresponding sensitivity was 13.1% and specificity was 86.2%. Significance was not achieved for use of clinical parameters in predicting either the CTDIw or CTDIvol.
Experienced CT radiologists cannot reliably use scan parameters to predict examinations that exceed CTDIw or CTDIvol DRLs.
本研究旨在确定 3 项基本临床检查中，参与美国放射学院（ACR）CT 认证计划的有经验的 CT 放射科医师能否使用管电流-时间乘积（mAs）、管电压（kVp）和螺距等扫描参数来预测扫描器输出设定值，以加权 CT 剂量指数（CTDIw）和容积 CT 剂量指数（CTDIvol）表示，超过 2002 年 ACR 设定的 CTDIw 诊断参考水平（DRL）和 2008 年 ACR 采用的 CTDIvol DRL。
2002 年至 2004 年间，829 个 CT 站点向 ACR 提交了检查，其中 518 项符合分析条件（138 项成人头部 CT 扫描、333 项成人腹部 CT 扫描和 47 项儿科腹部 CT 扫描）。将各类型检查的实际 CTDIw 值与 2002 年至 2004 年期间有效的 ACR CTDIw DRL 进行比较，并与放射科临床审查员对过高 mAs 或 kVp 的评论进行比较，以确定是否可以预测过高剂量指数测量值。使用 ACR 于 2008 年采用的 CTDIvol DRL 进行了相同的分析，并与过高的 mAs 或 kVp 和过低的螺距评论进行了比较。
过高的 mAs 或 kVp 评论在预测超过 CTDIw DRL 的检查时，其灵敏度仅为 21.2%，特异性为 87.6%。使用 2008 年的 CTDIvol DRL，相应的灵敏度为 13.1%，特异性为 86.2%。在预测 CTDIw 或 CTDIvol 时，临床参数的使用均未达到统计学意义。
有经验的 CT 放射科医师无法可靠地使用扫描参数来预测超过 CTDIw 或 CTDIvol DRL 的检查。
