Department of Radiology, Arkansas Children's Hospital, 1 Children's Way, Slot 105, Little Rock, AR 72202, USA.
AJR Am J Roentgenol. 2012 Aug;199(2):435-40. doi: 10.2214/AJR.11.8014.
Wide-detector CT allows simultaneous imaging of the entire airway and lungs in small children. Images acquired in multiple phases by continuous scanning during respiration are viewed dynamically, allowing more complete airway and pulmonary evaluation than possible with static protocols. The purpose of this study was to evaluate whether low-dose techniques can be applied to dynamic pulmonary CT of small children.
The study included 24 infants and small children with persistent respiratory difficulty who underwent dynamic pulmonary CT (11 with IV contrast administration, 13 without contrast administration). No significant difference in patient age was present in the two groups. Continuous-mode wide-detector scans were obtained at 350-millisecond gantry rotation for a total of 1.4 seconds at 80 kVp. Some contrast-enhanced studies for simultaneous vascular and airway evaluation were performed at slightly greater tube current. The effective dose for each patient was calculated, and the Student t test was performed to compare effective dose measurements.
All studies were of diagnostic quality, frequently yielding critical information not available with other diagnostic tests. The mean effective dose for all patients was 1.7 (SD, 1.1) mSv. In the group who received contrast material, the mean effective dose was greater (1.9 [SD, 1.4] mSv) than in the group who did not receive contrast material (1.5 [SD, 0.7] mSv), but the difference was not significant (p = 0.4).
Wide-detector dynamic CT is ideal for evaluation of the airway and lungs in infants and small children with persistent respiratory distress. Effective doses are low, typically less than 2 mSv.
宽探测器 CT 可在小儿中同时对整个气道和肺部进行成像。通过在呼吸过程中连续扫描获得的多个相的图像可以动态观察，与静态方案相比，可以更全面地评估气道和肺部。本研究的目的是评估低剂量技术是否可应用于小儿动态肺部 CT。
本研究纳入了 24 例持续存在呼吸困难的婴儿和小儿，他们均接受了动态肺部 CT 检查（11 例进行了 IV 造影剂给药，13 例未进行造影剂给药）。两组患者的年龄无显著差异。连续模式宽探测器扫描在 350 毫秒的机架旋转时间内进行，总时长为 1.4 秒，管电压为 80 kVp。一些对比增强研究同时评估血管和气道，使用略高的管电流。计算每位患者的有效剂量，并采用学生 t 检验比较有效剂量测量值。
所有研究均具有诊断质量，经常提供其他诊断测试无法提供的关键信息。所有患者的平均有效剂量为 1.7（标准差，1.1）mSv。接受造影剂的患者组的平均有效剂量（1.9[标准差，1.4]mSv）高于未接受造影剂的患者组（1.5[标准差，0.7]mSv），但差异无统计学意义（p=0.4）。
宽探测器动态 CT 是评估持续呼吸窘迫的婴儿和小儿气道和肺部的理想方法。有效剂量低，通常小于 2 mSv。
