能谱CT迭代重建算法在腹部增强扫描中降低辐射剂量与改善图像质量的可行性研究

Feasibility study of the spectral CT multi-model iterative reconstruction algorithm in reducing the radiation dose and improving the image quality in abdominal enhanced CT scan

目的探讨基于Revolution 256排宽体探测器能谱CT联合不同前置和后置ASiR-V权重水平在腹部能谱增强扫描中降低患者辐射剂量和优化图像质量的价值。方法选择行腹部增强检查患者50例,动脉期30%ASiR-V、静脉期50%ASiR-V、延时期40%ASiR-V,三期扫描ASiR-V权重前后置保持一致。再重建0%ASiR-V、30%ASiR-V、40%ASiR-V、50%ASiR-V、60%ASiR-V、90%ASiR-V权重水平获得重建图像。进行客观评价和主观评价,记录三期扫描辐射剂量。各组间比较采用单因素方差分析。结果三期增强扫描客观和主观评价差异无统计学意义(P>0.05)。前置3组的辐射剂量情况中,50%ASiR-V组的CTDI_(vol)(6.30±0.80)mGy、DLP(197.41±29.76)mGy/cm和ED(2.96±0.45)mSv最低,3组间差异有统计学意义(P<0.05)。在前置50%ASiR-V组再重建的后置0%ASiR-V、30%ASiR-V、40%ASiR-V、50%ASiR-V、60%ASiR-V、90%ASiR-V组的图像客观评价中,随着ASiR-V升高,图像噪声SD值逐渐降低,SNR和CNR值逐渐升高,各组间差异有统计学意义(P<0.05)。主观评价中,后置60%ASiR-V组的评分[(4.52±0.37)分]最高,各组间差异有统计学意义(P<0.05)。结论Revolution 256排宽体探测器能谱CT在腹部增强扫描中联合前置50%ASiR-V和后置60%ASiR-V在保证图像质量的前提下,可明显地降低患者的辐射剂量。

Objective To investigate the value of spectral CT based on Revolution 256 row wide-body detector combined with different anterior and posterior ASiR-V weight levels in reducing patient radiation dose and optimizing image quality in abdominal spectral enhanced scanning.Methods Fifty patients with abdominal enhancement examination were selected,with 30%ASiR-V in the arterial phase,50%ASiR-V in the venous phase and 40%ASiR-V in the extended phase.The ASiR-V weights were kept consistent before and after the three phases.Then the weight levels of 0%ASiR-V,30%ASiR-V,40%ASiR-V,50%ASiR-V,60%ASiR-V,90%ASiR-V were reconstructed to obtain the reconstructed image.All images were objectively evaluated and subjectively evaluated.The radiation doses of the three scans were recorded.One-way analysis of variance was used for comparison among groups.Results There was no significant difference in the objective evaluation and the subjective evaluation among the three groups(P>0.05).Among the radiation doses of the three groups in front,the 50%ASiR-V group had the lowest CTDI_(vol)(6.30±0.80)mGy,DLP(197.41±29.76)mGy/cm and ED(2.96±0.45)mSv,and the difference among the three groups was statistically significant(P<0.05).In the objective evaluation of images in the post-0%ASiR-V,30%ASiR-V,40%ASiR-V,50%ASiR-V,60%ASiR-V,and 90%ASiR-V groups reconstructed in the pre-50%ASiR-V group,the SD value of image noise gradually decreased and the SNR and CNR values gradually increased with increasing ASiR-V,with significant differences between the groups(P<0.05).In the subjective evaluation,the score of the post-60%ASiR-V group(4.52±0.37)points was the highest,and the difference between the groups was statistically significant(P<0.05).Conclusion Revolution256-slice wide-body detector spectral CT in abdominal enhanced scanning combined with anterior 50%ASiR-V and posterior 60%ASiR-V can significantly reduce the radiation dose of patients under the premise of ensuring the image quality.