Department of Radiology and Research Institute of Radiological Science, Severance Children's Hospital, Yonsei University, College of Medicine, Seoul, Republic of Korea.
Eur J Radiol. 2012 Sep;81(9):e938-43. doi: 10.1016/j.ejrad.2012.06.013. Epub 2012 Jul 12.
To retrospectively compare radiation dose and image quality of pediatric chest CT using a routine dose protocol reconstructed with filtered back projection (FBP) (the Routine study) and a low-dose protocol with 50% adaptive statistical iterative reconstruction (ASIR) (the ASIR study).
We retrospectively reviewed chest CT performed in pediatric patients who underwent both the Routine study and the ASIR study on different days between January 2010 and August 2011. Volume CT dose indices (CTDIvol), dose length products (DLP), and effective doses were obtained to estimate radiation dose. The image quality was evaluated objectively as noise measured in the descending aorta and paraspinal muscle, and subjectively by three radiologists for noise, sharpness, artifacts, and diagnostic acceptability using a four-point scale. The paired Student's t-test and the Wilcoxon signed-rank test were used for statistical analysis.
Twenty-six patients (M:F=13:13, mean age 11.7) were enrolled. The ASIR studies showed 60.3%, 56.2%, and 55.2% reductions in CTDIvol (from 18.73 to 7.43 mGy, P<0.001), DLP (from 307.42 to 134.51 mGy×cm, P<0.001), and effective dose (from 4.12 to 1.84 mSv, P<0.001), respectively, compared with the Routine studies. The objective noise was higher in the paraspinal muscle of the ASIR studies (20.81 vs. 16.67, P=0.004), but was not different in the aorta (18.23 vs. 18.72, P=0.726). The subjective image quality demonstrated no difference between the two studies.
A low-dose protocol with 50% ASIR allows radiation dose reduction in pediatric chest CT by more than 55% while maintaining image quality.
回顾性比较使用滤波反投影（FBP）重建的常规剂量方案（常规研究）和 50%自适应统计迭代重建（ASIR）的低剂量方案（ASIR 研究）对儿童胸部 CT 的辐射剂量和图像质量的影响。
我们回顾性分析了 2010 年 1 月至 2011 年 8 月期间在不同日期进行常规研究和 ASIR 研究的 26 例儿童患者的胸部 CT 资料。测量降主动脉和椎旁肌肉的噪声，获取容积 CT 剂量指数（CTDIvol）、剂量长度乘积（DLP）和有效剂量来评估辐射剂量。三位放射科医生采用 4 分制对噪声、锐利度、伪影和诊断可接受性进行了客观和主观评估。采用配对学生 t 检验和 Wilcoxon 符号秩检验进行统计学分析。
26 例患者（男：女=13：13，平均年龄 11.7 岁）纳入研究。与常规研究相比，ASIR 研究的 CTDIvol（从 18.73 降至 7.43 mGy，P<0.001）、DLP（从 307.42 降至 134.51 mGy×cm，P<0.001）和有效剂量（从 4.12 降至 1.84 mSv，P<0.001）分别降低了 60.3%、56.2%和 55.2%。ASIR 研究的椎旁肌肉的客观噪声（20.81 比 16.67，P=0.004）较高，但主动脉的噪声（18.23 比 18.72，P=0.726）无差异。两种研究方法的主观图像质量无差异。
50%ASIR 的低剂量方案可使儿童胸部 CT 的辐射剂量降低 55%以上，同时保持图像质量。
