Department of Radiology, Massachusetts General Hospital, Boston, MA 02114, USA.
Radiology. 2012 May;263(2):537-46. doi: 10.1148/radiol.12110268.
To assess image quality and radiation dose reduction with hybrid iterative reconstruction of pediatric chest and abdominal computed tomographic (CT) data compared with conventional filtered back projection (FBP).
A total of 234 patients (median age, 12 years; age range, 6 weeks to 18 years) underwent chest and abdominal CT in this institutional review board-approved HIPAA-compliant retrospective study. CT was performed with a hybrid adaptive statistical iterative reconstruction (ASIR)-enabled 64-detector row CT scanner. Scanning protocols were adjusted for clinical indication and patient weight to enable acquisition of reduced-dose CT images in all patients, and tube current was further lowered for ASIR protocols. Weight, age, and sex were recorded, and objective noise was measured in the descending thoracic aorta for chest CT and in the liver for abdominal CT. Of the 234 consecutive patients who underwent ASIR-enabled CT (115 chest and 119 abdominal examinations), 70 patients had undergone prior FBP CT. ASIR and FBP CT studies (29 chest and 41 abdominal studies) in these 70 patients were reviewed for image quality, artifacts, and diagnostic confidence by two pediatric radiologists working independently. Data were analyzed with multiple paired t tests.
Compared with FBP, ASIR enabled dose reduction of 46.4% (3.7 vs 6.9 mGy) for chest CT and 38.2% (5.0 vs 8.1 mGy) for abdominal CT (P < .0001). Both radiologists deemed image quality of and diagnostic confidence with ASIR and FBP CT images as acceptable, without any artifacts. Despite the lower radiation dose used, ASIR images (chest, 10.7 ± 2.5 [mean ± standard deviation]; abdomen, 11.8 ± 3.4) had substantially less objective noise than did FBP images (chest, 13.3 ± 3.8; abdomen, 13.8 ± 5.2) (P = .001, P =.006, respectively).
Use of a hybrid iterative reconstruction technique, such as ASIR, enables substantial radiation dose reduction for pediatric CT when compared with FBP and maintains image quality and diagnostic confidence.
与传统滤波反投影（filtered back projection，FBP）相比，评估儿童胸部和腹部 CT 数据的混合迭代重建在图像质量和辐射剂量降低方面的效果。
在这项经机构审查委员会批准并符合 HIPAA 规定的回顾性研究中，共有 234 名患者（中位年龄 12 岁；年龄范围 6 周至 18 岁）接受了胸部和腹部 CT 检查。使用具有混合自适应统计迭代重建（adaptive statistical iterative reconstruction，ASIR）功能的 64 排探测器 CT 扫描仪进行 CT 扫描。根据临床指征和患者体重调整扫描方案，以便在所有患者中获得低剂量 CT 图像，并且对于 ASIR 方案进一步降低管电流。记录体重、年龄和性别，并在胸部 CT 中测量降主动脉和腹部 CT 中测量肝脏的客观噪声。在接受 ASIR 增强 CT（115 例胸部和 119 例腹部检查）的 234 例连续患者中，有 70 例患者曾接受过 FBP CT 检查。对这 70 例患者的 29 例胸部和 41 例腹部 ASIR 和 FBP CT 研究进行了两位儿科放射科医生的独立图像质量、伪影和诊断信心评估。使用多个配对 t 检验进行数据分析。
与 FBP 相比，ASIR 可使胸部 CT 的剂量降低 46.4%（3.7 与 6.9 mGy），腹部 CT 的剂量降低 38.2%（5.0 与 8.1 mGy）（P <.0001）。两位放射科医生均认为，ASIR 和 FBP CT 图像的图像质量和诊断信心均为可接受的，且没有任何伪影。尽管使用的辐射剂量较低，但 ASIR 图像（胸部，10.7 ± 2.5[均值 ± 标准差]；腹部，11.8 ± 3.4）的客观噪声明显低于 FBP 图像（胸部，13.3 ± 3.8；腹部，13.8 ± 5.2）（P =.001，P =.006）。
与 FBP 相比，使用混合迭代重建技术（如 ASIR）可显著降低儿科 CT 的辐射剂量，同时保持图像质量和诊断信心。
