Bae Sohi, Kim Myung-Joon, Yoon Choon-Sik, Kim Dong Wook, Hong Jung Hwa, Lee Mi-Jung
Department of Radiology and Research Institute of Radiological Science, Severance Children's Hospital, Yonsei University College of Medicine, 50-1, Yonsei-ro, Seodaemun-gu, 120-752, Seoul, South Korea.
Pediatr Radiol. 2014 Dec;44(12):1541-7. doi: 10.1007/s00247-014-3058-1. Epub 2014 Jul 8.
Since children are more radio-sensitive than adults, there is a need to minimize radiation exposure during CT exams.
To evaluate the effects of adaptive statistical iterative reconstruction (ASIR) on radiation dose reduction, image quality and diagnostic accuracy in pediatric abdominal CT.
We retrospectively reviewed the abdominal CT examinations of 41 children (24 boys and 17 girls; mean age: 10 years) with a low-dose radiation protocol and reconstructed with ASIR (the ASIR group). We also reviewed routine-dose abdominal CT examinations of 41 age- and sex-matched controls reconstructed with filtered-back projection (control group). Image quality was assessed objectively as noise measured in the liver, spleen and aorta, as well as subjectively by three pediatric radiologists for diagnostic acceptability using a four-point scale. Radiation dose and objective image qualities of each group were compared with the paired t-test. Diagnostic accuracy was evaluated by reviewing follow-up imaging studies and medical records in 2012 and 2013.
There was 46.3% dose reduction of size-specific dose estimates in ASIR group (from 13.4 to 7.2 mGy) compared with the control group. Objective noise was higher in the liver, spleen and aorta of the ASIR group (P < 0.001). However, the subjective image quality was average or superior in 84-100% of studies. Only one image was subjectively rated as unacceptable by one reviewer. There was only one case with interpretational error in the control group and none in the ASIR group.
Use of the ASIR technique resulted in greater than a 45% reduction in radiation dose without impairing subjective image quality or diagnostic accuracy in pediatric abdominal CT, despite increased objective image noise.
由于儿童比成人对辐射更敏感，因此在CT检查期间需要尽量减少辐射暴露。
评估自适应统计迭代重建（ASIR）对小儿腹部CT辐射剂量降低、图像质量及诊断准确性的影响。
我们回顾性分析了采用低剂量辐射方案的41例儿童（24例男孩和17例女孩；平均年龄：10岁）的腹部CT检查，并采用ASIR进行重建（ASIR组）。我们还回顾了41例年龄和性别匹配的对照者的常规剂量腹部CT检查，采用滤波反投影法进行重建（对照组）。图像质量的客观评估指标为肝脏、脾脏和主动脉中的噪声，主观评估由三名儿科放射科医生使用四点量表对诊断可接受性进行评价。采用配对t检验比较两组的辐射剂量和客观图像质量。通过回顾2012年和2013年的随访影像学研究和病历评估诊断准确性。
与对照组相比，ASIR组的特定体型剂量估计值降低了46.3%（从13.4降至7.2 mGy）。ASIR组肝脏、脾脏和主动脉的客观噪声更高（P<0.001）。然而，在84%-100%的研究中，主观图像质量为中等或优等。只有一张图像被一名评估者主观评为不可接受。对照组仅有1例解释错误，ASIR组无解释错误。
在小儿腹部CT中，使用ASIR技术可使辐射剂量降低超过45%，且不影响主观图像质量或诊断准确性，尽管客观图像噪声增加。
