基于模型迭代重建与自适应统计迭代重建的上腹部低剂量CT扫描图像质量和肝小病灶检出率的比较

Comparison of image quality and detection rate of small hepatic lesions between the model-based iterative reconstruction and adaptive statistical iterative reconstruction in upper abdominal low-dose CT scanning

目的比较基于模型迭代重建(MBIR)和自适应统计迭代重建(ASIR)的上腹部低剂量CT扫描图像质量和肝小病灶检出率。方法选取本院2019年6月至2019年8月因上腹部疾病行CT增强检查的30例患者作为研究对象。平扫及前两期增强采用常规扫描,噪声(SD)设置为10,延迟扫描应用低剂量,SD设置为20。对延迟期图像分别采用40%ASIR(A组)和MBIR方式重建(B组)。测量病灶和邻近肝实质CT值和SD,计算信噪比(SNR)及对比噪声比(CNR)。以平扫和前两期增强图像检出病灶数量作为"金标准",比较两组图像对肝脏小病灶的检出率。结果B组的肝脏SD低于A组,病灶SNR、病灶CNR高于A组,差异具有统计学意义(P<0.05)。B组的病灶检出率高于A组,差异具有统计学意义(P<0.05)。结论相较于ASIR,MBIR应用于上腹部低剂量CT扫描中能够提高图像质量和肝小病灶的检出率。

Objective To compare the image quality and detection rate of small hepatic lesions between the model-based iterative reconstruction(MBIR)and adaptive statistical iterative reconstruction(ASIR)in upper abdominal low-dose CT scanning.Methods A total of 30 patients with upper abdominal diseases who underwent enhanced CT examination in our hospital from June 2019 to August 2019 were selected as the research objects.Routine scan was used for plain scan and the first two phases of enhancement.Noise(SD)was set to 10.Low dose was used for delayed scan.SD was set to 20.The delayed images were reconstructed by 40%ASIR(group A)and MBIR(group B).The CT values and SD of the lesions and adjacent liver parenchyma were measured,and the signal-to-noise ratio(SNR)and contrast-to-noise ratio(CNR)were calculated.The number of lesions detected by plain scan and the first two enhanced images was regarded as the"gold standard",and the detection rate of small liver lesions was compared between the two groups.Results The liver SD of the group B was lower than that of the group A,and the lesion SNR and CNR of the group B were higher than those of the group A,and the differences were statistically significant(P<0.05).The detection rate of lesions in the group B was higher than that in the group A,and the difference was statistically significant(P<0.05).Conclusion Compared with ASIR,MBIR can improve the image quality and the detection rate of small liver lesions in upper abdominal low-dose CT scanning.