Frush Donald P, Slack Christopher C, Hollingsworth Caroline L, Bisset George S, Donnelly Lane F, Hsieh Jiang, Lavin-Wensell Trudy, Mayo John R
Division of Pediatric Radiology, 1905 McGovern-Davison Children's Health Center, Box 3808, Department of Radiology, Duke University Medical Center, Erwin Rd., Durham, NC 22710, USA.
AJR Am J Roentgenol. 2002 Nov;179(5):1107-13. doi: 10.2214/ajr.179.5.1791107.
Limiting CT radiation dose is especially critical when imaging children. The purpose of our study was to modify and test an accurate and safe tool for evaluating systematic dose reduction for abdominal multidetector CT (MDCT) in pediatric patients.
After validating the computer-simulation technique with a water phantom, we subjected the original digital scanning data for 26 contrast-enhanced abdominal MDCT scans (120 mA) obtained in infants and children (age range, 1 month-9 years; mean age, 3.1 years) to simulated tube current reduction (100, 80, 60, and 40 mA) by adding noise. this procedure created four additional examinations per child that were identical to the originals except for image noise. The 130 examinations were scored randomly, independently, and without prior knowledge of the children's diagnoses by three radiologists for depiction of high-visibility structures, such as adrenal glands and fat in the intrahepatic falciform ligament, and low-visibility structures, such as the extrahepatic hepatic artery, small intrahepatic vessels, and common bile duct. Aligned rank and Wilcoxon's signed rank tests were used for statistical analyses.
Simulated tube current reduction significantly affected the detection of low-visibility structures (p < 0.001). Reduced detection in low-visibility structures was evident at a level less than or equal to 80 mA. No loss of detection in high-visibility structures was found at any tube current level (p > 0.5).
The results of this computer simulation suggest that accurate abdominal MDCT can be performed in pediatric patients using substantially reduced radiation, depending on the indication for imaging. (In our case, the reduction was between 33% and 67%, depending on whether a high-visibility or low-visibility structure was being assessed.) This simulation technology can be applied to MDCT of other organ systems for systematic evaluation of radiation dose reduction.
对儿童进行成像时，限制CT辐射剂量尤为关键。我们研究的目的是改进并测试一种准确且安全的工具，用于评估儿科患者腹部多排CT（MDCT）的系统剂量降低情况。
在用水体模验证计算机模拟技术后，我们对在婴儿和儿童（年龄范围1个月至9岁；平均年龄3.1岁）中获得的26例腹部增强MDCT扫描（120 mA）的原始数字扫描数据，通过添加噪声来模拟管电流降低（100、80、60和40 mA）。此过程为每个儿童额外创建了四项检查，这些检查除图像噪声外与原始检查相同。130项检查由三位放射科医生随机、独立且在不了解儿童诊断情况的前提下进行评分，以评估高可见度结构（如肾上腺和肝镰状韧带内的脂肪）以及低可见度结构（如肝外肝动脉、肝内小血管和胆总管）的显示情况。采用对齐秩和Wilcoxon符号秩检验进行统计分析。
模拟管电流降低对低可见度结构的检测有显著影响（p < 0.001）。在管电流小于或等于80 mA时，低可见度结构的检测明显减少。在任何管电流水平下，高可见度结构的检测均未出现丢失情况（p > 0.5）。
该计算机模拟结果表明，根据成像指征，儿科患者可以使用大幅降低的辐射剂量进行准确的腹部MDCT检查。（在我们的案例中，根据评估的是高可见度还是低可见度结构，辐射剂量降低幅度在33%至67%之间。）这种模拟技术可应用于其他器官系统的MDCT，以系统评估辐射剂量降低情况。
