基于模型的迭代重建算法应用于80kV低剂量儿童胸部CT的可行性

摘要

目的 评价基于模型的迭代重建算法(MBIR)应用于80 kV低剂量儿童胸部CT检查的可行性.方法 收集44例因脊柱侧弯治疗后复查的患儿资料,所有患儿接受脊柱CT检查,扫描电压80 kV,固定管电流50 mA.对所得胸部图像采用MBIR重建(观察组).所有患儿术前脊柱CT检查,扫描管电压120 kV,对所得胸部图像采用滤波反射投影(FBP)重建(对照组).两组图像质量主观评价由2名医师采用1～3分制,评价图像主观噪声及肺组织图像质量;图像质量客观评价为测量左心室最大层面的肺野、背部肌肉的噪声值,并计算肺野的SNR及CNR.并记录两次检查的容积CT剂量指数(CTDIvol).结果 观察组主观噪声评分明显高于对照组(P＜0.05).观察组较对照组肺野噪声降低40.36％,SNR提高72.37％,CNR提高78.69％,CTDIvol降低66.52％,两组差异均有统计学意义(P均＜0.001).结论 80 kV低剂量儿童胸部CT可以满足诊断要求.%Objective To evaluate the feasibility of model-based iterative reconstruction (MBIR) in low-dose chest CT (80 kV) examination in children.Methods Forty-four children who had post-operation scoliosis and received low dose chest CT scans were included.The fix tube voltage was 80 kV,fix current was 50 mA.Images were reconstructed with MBIR (observation group).The pre-operation scan were used 120 kV and 50 mA for acquisition,and images were reconstructed with filtered back-projection (FBP) mehed (control group).The subjective quality of the images was independently evaluated by two radiologists.Objective noises in the muscle and lung field were measured,the SNR,CNR were calculated,and the CTDIvol was record.Results The subjective noise score in the observation group was significantly higher than that in the control group (P＜0.05).Objective noise reduced about 40.36％,SNR increased 72.37％,CNR increased 78.69％,CTDIvol decreased by 66.52％,all of which had statistical difference between both groups (all P＜0.001).Conclusion Low-dose chest CT (80 kV) examination in children can meet the requirements of diagnosis for children.