基于模型及自适应统计迭代重建优化儿童腹部低剂量CT血管造影图像质量

Optimization of image quality of abdominal low dose CT angiography in children based on model and adaptive statistical iterative reconstruction

目的评价基于模型的迭代重建(MBIR)及自适应统计迭代重建(ASIR)优化100 kV儿童腹部CT血管造影(CTA)图像质量的价值。方法对55例患儿行100 kV低剂量腹部CTA,分别采用MBIR、100%ASIR、80%ASIR、60%ASIR、40%ASIR及滤过反向投影(FBP)算法重建为6组图像,评价图像质量,包括图像噪声、大动脉(LA)及小动脉(SA)显示能力;对比各级动脉CT值及标准差(SD),计算信噪比(SNR)及对比噪声比(CNR)。结果图像噪声主观评分及LA评分以MBIR图像最高,ASIR次之,FBP图像质量最差;SA评分以MBIR图像最佳,FBP次之;随权重提升,ASIR图像评分逐渐降低,100%ASIR最低(P均<0.05)。MBIR图像SD最低,其SNR及CNR明显高于其他图像(P均<0.05)。结论MBIR可明显提高儿童低剂量CTA图像质量,100%ASIR仅可提高图像显示LA能力。

Objective To observe value of model based iterative reconstruction(MBIR)and adaptive statistical iterative reconstruction(ASIR)for optimizing image quality of 100 kV abdominal CT angiography(CTA)in children.Methods A total of 55 children underwent low-dose abdominal CTA examination at 100 kV,and 6 groups of images were reconstructed using MBIR,100%ASIR,80%ASIR,60%ASIR,40%ASIR and filtered back projection(FBP),respectively.The quality of the images were subjectively evaluated,including image noise and display ability of large artery(LA)and small artery(SA).CT values and standard deviations(SD)of all arteries were compared,and signal-to-noise ratio(SNR)and contrast to noise ratio(CNR)were calculated.Results MBIR images had the highest subjective image noise score and LA score,followed by ASIR image,and FBP images had the worst quality.MBIR images had the best SA scores,followed by FBP images.With weight of ASIR increased,SA scores gradually decreased,and 100%ASIR had the lowest SA scores(all P<0.05).SD of MBIR images were significantly lower than that of the other images,while SNR and CNR of MBIR images were significantly higher than those of the other images(all P<0.05).Conclusion MBIR could significantly improve image quality of low dose CTA in children,while 100%ASIR could only improve image quality of LA.