| 徐蕾,李惠民,程爱兰,蔡静.儿童胸部CT检查极限低剂量的可行性[J].中华放射医学与防护杂志,2018,38(6):461-465 |
| 儿童胸部CT检查极限低剂量的可行性 |
| Feasibility of chest limit low dose CT in children |
| 投稿时间：2017-12-12 |
| DOI：10.3760/cma.j.issn.0254-5098.2018.06.013 |
| 中文关键词: 低剂量CT 儿童 胸部 迭代重建 辐射剂量 |
| 英文关键词:Low-dose CT Children Chest Iterative reconstruction algorithm Radiation dose |
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| 中文摘要: |
| 目的 以Philips iCT扫描仪为例，探讨机器极限低剂量进行儿童胸部CT成像的可行性。方法 临床建议胸部CT扫描的连续28例儿童患者纳入研究，年龄1个月~7岁，中位年龄8个月。采用Philips iCT 256层螺旋CT扫描仪，进行极限低剂量扫描方案扫描：80 kV，10 mAs，0.625 mm×128，螺距1。首先用迭代重建（iDose4 4）、分别以肺算法和标准算法获得肺算法组和标准算法组两组4 mm层厚图像，再回顾性重建层厚0.67 mm图像（iDose4 4，Smooth A），转换为4 mm层厚图像（图像转换组）并重组出气道冠状面多平面重组（MPR）图像和容积成像图像。3组横断面图像在同一肺窗条件下进行噪声测量（SD值）和主观评价（5分制）。记录剂量长度乘积（DLP），并计算有效剂量E。结果 肺算法组、标准算法组和图像转换组的SD值分别为26.7±7.6、15.1±5.5和16.7±4.9，3组间差异具有统计学意义（F=29.6，P<0.05），肺算法组噪声高于标准算法组和图像转换组（均数差分别为11.6和9.6，P<0.05），标准算法组与图像转换组之间差异没有统计学意义（P>0.05）。主观评价3组图像均完全达到诊断水平。冠状面MPR和容积图像帮助更好地阅读横断面图像。平均DLP和E分别为（8.65±2.97）mGy·cm和（0.21±0.10）mSv，最低分别至4.40 mGy·cm和0.08 mSv。结论 以Philips iCT扫描仪为例，机器极限低剂量应用于儿童胸部CT扫描完全可行，充分利用迭代重建算法和图像转换可保障图像质量，结合三维重组可更好地进行胸部影像诊断。 |
| 英文摘要: |
| Objective To evaluate the feasibility of chest limit low dose CT in children using Philips iCT scanner as an example. Methods A total of 28 consecutive children aged between 1 month and 7 years (median age 8 months) who were claimed CT exam by clinicians and received limit low dose CT scans were enrolled. The limit low dose CT were undertaken on a 256-slice CT scanner (Brilliance iCT, Philips) with parameters as 80 kV, 10 mAs, 0.625 mm×128, and pitch=1. Firstly, lung algorithm group and standard algorithm group 4 mm slice-thickness image series were reconstructed with lung and standard algorithm respectively using iterative reconstruction (IR) algorithm (iDose44). Then a series of 0.67 mm slice-thickness images were reconstructed with IR (iDose44) and smooth A algorithm, and was transformed into transverse 4 mm images (image transformation group) and coronal multiple planar reformatted (MPR) and volume-rendered (VR) images along the central airway. The transverse images in above three groups were displayed in the same lung window for SD measurement and subjective image quality evaluation on a 5-point scale. The dose length product (DLP) was recorded and the effective dose (E) was calculated. Results The SD values of lung algorithm group,standard algorithm group and image transformation group were 26.7±7.6, 15.1±5.5 and 16.7±4.9, respectively, which showed statistically significant difference (F=29.6, P<0.05). The noise of lung algorithm group was higher than those of standard algorithm group and image transformation group (mean difference values were 11.6 and 9.6,respectively, P<0.05),but there were no significant difference between standard algorithm group and image transformation group (P>0.05). All images had enough diagnostic image quality. The coronal MPR and VR images were helpful for interpretation of axial images. The mean DLP and E were (8.65±2.97) mGy·cm and (0.21±0.10) mSv, respectively. The lowest DLP and E were 4.40 mGy·cm and 0.08 mSv, respectively. Conclusions Using Philips iCT scanner as an example, chest limit low dose CT scanning was feasible for children. Combining with IR and image transformation, the image quality was fully guaranteed and 3D images increased diagnostic confidence. |
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