迭代模型重建技术在低剂量胸部CT双期增强扫描中的可行性

目的 探讨低剂量扫描联合迭代模型重建技术在胸部CT双期增强检查中的可行性。方法 130例拟诊为肺部占位的患者接受胸部双期增强扫描，随机分为A组和B组，每组65例。A组扫描采用管电压100 kV，自动管电流调制技术，图像质量指数10；B组管电压80 kV，自动管电流调制技术，图像质量指数8。A组图像采用混合迭代重建技术（iDose⁴）重建，B组图像采用迭代模型重建技术（IMR）重建。比较两组图像肺动脉（PA）期及支气管动脉（BA）期的客观图像质量、主观图像质量和血管显示优良率并计算辐射剂量。结果 A组有效辐射剂量为（3.30±0.89）mSv，B组为（1.27±0.19）mSv，B组较A组下降61.52%（P<0.001）。PA期和BA期，B组图像噪声显著低于A组，CNR显著高于A组（P均<0.001）；两组肺窗和纵隔窗主观图像质量均达到较高评分，双期血管显示优良率均较高，差异无统计学意义（P均>0.05）。结论 采用迭代模型重建技术，低剂量胸部双期增强扫描可在较常规剂量降低61.52%的条件下，保证图像质量并满足诊断要求。

Feasibility of iterative model reconstruction technique in low dose dual phase contrast-enhanced chest CT

Objective To investigate the feasibility of low dose dual phase contrast-enhanced chest CT with iterative model reconstruction (IMR) technique. Methods Totally 130 patients with suspected pulmonary occupying lesions underwent dual phase contrast-enhanced chest CT, who were randomly assigned into 2 groups (group A and group B, each n=65). Patients in group A were scanned with 100 kV, DoseRight technique with dose right index 10, and images were reconstructed with the hybrid iterative reconstruction (iDose⁴). While patients in group B were scanned with 80 kV, DoseRight technique with dose right index 8, and images were reconstructed with iterative model reconstruction (IMR). The objective image quality, subjective image scores and the excellence rate of vascular visualization were compared in both pulmonary artery (PA) and bronchial artery (BA) phases. The radiation dose was also calculated. Results The effective dose was (3.30±0.89)mSv in group A and (1.27±0.19)mSv in group B. Compared to group A, the effective dose reduced 61.52% in group B (P<0.001). Lower image noise and greater CNR were obtained in group B compared to group A in both PA and BA phases (all P<0.001). No significant difference was found in subjective image scores of lung and mediastinal setting and the excellence rate of vascular visualization in both groups (all P>0.05). Conclusion Using IMR, dual phase contrast-enhanced chest CT allows for a radiation dose reduction up to 61.52%, meanwhile, ensures the image quality and meets the diagnostic requirements.