迭代重建在学龄前儿童胸部CT低剂量平扫中的应用研究

Application of Iterative Reconstruction in Low-dose Chest CT Scans of Preschool Children

目的:探讨iDose4迭代重建技术在学龄前儿童胸部CT低剂量平扫中的应用研究。方法:连续选取150例行胸部CT平扫2~6岁患儿,随机分为常规剂量组(50 mAs)、低剂量25 mAs组和低剂量10 mAs组。常规剂量组采用FBP重建作为常规对照组,低剂量扫描组分别采用FBP及iDose4-5对图像进行重建。2名放射科副主任医师对图像主观质量行盲法阅片,比较不同毫安秒和重建算法组图像主客观质量及辐射剂量并行统计学分析。结果:25 mAs iDose4组较25 mAs FBP组图像主客观质量增高,10 mAs iDose4组较10 mAs滤波反投影(FBP)组图像主客观质量增高。与常规剂量组比较,25 mAs FBP组图像主客观质量降低,25 mAs iDose4组图像主客观质量增高,10 mAs FBP组图像主客观质量降低,10 mAs iDose4组图像主客观质量差异无统计学意义。低剂量25 mAs、10 mAs组有效剂量较常规剂量组分别降低52.6%和78.2%。结论:行学龄前儿童胸部CT低剂量平扫时,采用25 mAs、10 mAs联合iDose4-5技术,能在降低辐射剂量的同时,获得与常规剂量更优或相当的图像质量。

Objective： To explore the feasibility of iDose4 iterative reconstruction technique in low-dose chest CT scans of preschool children. Methods： One hundred and fifty patients underwent non-contrast chest CT examinations, they were randomly assigned into three groups： control group（standard dose protocol 120 kV, 50 mAs） （n = 50）; 25 mAs group （low dose protocol 120 kV, 25 mAs） （n = 50）; and I0 mAs group （low dose protocol 120 kV, 10 mAs） （n = 50）. Images from control group were reconstructed by FBP, and low-dose groups were reconstructed by FBP and iDose4. Subjective image quality was assessed by two associate chief physicians of radiology department in a blinded manner. Image quality and radiation dose of the 3 groups were compared and analyzed statistically. Results： Subjective and objective image quality in 25 mAs group with iDose4 compared with FBP was increased. Subjective and objective image quality in 10 mAs group with iDose4 compared with FBP was increased either. Subjective and objective image quality in 25 mAs with iDose4 was increased compared with control group. Subjective and objective image quality has no significant statistical difference between 10 mAs with iDose4 and control group. Effective dose in low dose groups 50 mAs and 25 mAs was decreased by 52.6% and 78.2% respectively. Conclusions： 50 and 25 mAs groups with iDose4 technique （iDose4-5） could obtain acceptable image quality in low-dose chest CT scans of preschool children while decreasing radiation dose.