1 Department of Radiology, University Hospitals Case Medical Center, Case Western Reserve University School of Medicine, 11100 Euclid Ave, Cleveland, OH 44106.
2 Present address: Department of Radiology, The Hospital for Sick Children, Toronto, ON, Canada.
AJR Am J Roentgenol. 2015 Aug;205(2):392-9. doi: 10.2214/AJR.14.12698.
The purpose of this article is to assess radiation dose reduction, image quality, and diagnostic confidence using low tube voltage in combination with hybrid iterative reconstruction in contrast-enhanced pediatric abdominal CT.
CT examinations of 133 patients (median age, 10 years) were performed at sequentially reduced doses. The first group (group 1) was scanned using dimension-based protocols at 120 kV for all patient sizes. The optimized group (group 5) was scanned at 80 kV for less than 18 cm in the lateral dimension and 100 kV in the 19-30 cm lateral dimension. CT examinations reconstructed with filtered back projection (FBP) and four levels of hybrid iterative reconstruction were reviewed by four blinded readers for subjective image quality and diagnostic confidence. Objective noise, volume CT dose index (CTDIvol), and size-specific dose estimate (SSDE) were recorded. Data were analyzed using t tests, one and two-way ANOVA, and the intraclass correlation coefficient.
Compared with group 1, the radiation dose was reduced for group 5 by 63% measured by SSDE (4.69 vs 10.00 mGy; p < 0.001). Subjective image noise was increased for FBP images (p < 0.001) but not was statistically significantly different for all levels of hybrid iterative reconstruction; artifacts were reduced and visibility of small structures was improved (both p < 0.001). Diagnostic confidence was improved for solid organ injury and metastatic disease (both p < 0.001) and was not statistically significantly different for appendicitis (p = 0.306).
Use of hybrid iterative reconstruction with low-tube-voltage protocols enables substantial radiation dose reduction for pediatric abdominal CT with equivalent to improved subjective image quality and diagnostic confidence.
本文旨在评估低管电压结合混合迭代重建在增强型儿科腹部 CT 中的应用对降低辐射剂量、提高图像质量和诊断信心的效果。
对 133 例患者（中位年龄 10 岁）进行连续剂量降低的 CT 检查。第一组（组 1）采用基于尺寸的方案，所有患者均使用 120kV 进行扫描。优化组（组 5）中，小于 18cm 宽的患者采用 80kV 进行扫描，19-30cm 宽的患者采用 100kV 进行扫描。使用滤波反投影（FBP）和四种不同级别的混合迭代重建对 CT 检查进行重建，由四名盲法读者对主观图像质量和诊断信心进行评估。记录客观噪声、容积 CT 剂量指数（CTDIvol）和体型特异性剂量估计（SSDE）。使用 t 检验、单因素和双因素方差分析以及组内相关系数进行数据分析。
与组 1 相比，组 5 的 SSDE 测量值降低了 63%（4.69 比 10.00mGy；p < 0.001），辐射剂量降低。FBP 图像的主观噪声增加（p < 0.001），但所有级别混合迭代重建的图像噪声差异无统计学意义；图像的伪影减少，小结构的可见度提高（均 p < 0.001）。对实质器官损伤和转移性疾病的诊断信心提高（均 p < 0.001），但对阑尾炎的诊断信心差异无统计学意义（p = 0.306）。
在儿科腹部 CT 中，使用低管电压方案结合混合迭代重建技术可以显著降低辐射剂量，同时提高主观图像质量和诊断信心。
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