256层螺旋iCT IMR技术在低剂量肝脏增强中的应用

Application of 256-slice helical iCT IMR technique in low-dose liver enhancement

目的比较256层螺旋CT全模型迭代重建技术(IMR)和混合迭代重建技术(iDose4)在低辐射剂量肝脏增强中的图像质量和辐射剂量,探讨相较于磁共振(MRI)动态增强在肝癌诊断中的价值。方法收集2021年1月~10月同时行肝脏增强平扫使用常规剂量、三期增强使用相对低剂量CT扫描和MRI动态增强,并病理确诊为肝癌的40例患者,对肝脏三期薄层图像分别行混合迭代算法(iDose4)重建(A组)和全模型迭代算法(IMR)重建(B组),比较两组客观评价指标噪声、信噪比(SNR)和对比噪声比(CNR)及主观评价指标低对比分辨率、图像失真度及诊断信心度,计算有效辐射剂量,并对比MRI动态增强对肝癌检出率进行分析。结果两种重建组算法下所有图像均能满足诊断需求,两组在噪声、SNR和CNR比较差异均有统计学意义(P<0.05),B组图像质量均优于A组;三期增强辐射剂量较平扫有明显降低,比较差异均有统计学意义(P<0.05);B组低对比分辨率和诊断信心度高于A组,图像失真度低于A组,差异有统计学意义(P<0.05);对比MRI动态增强三组对肝癌检出率差异无统计学意义(P>0.05),但IMR重建技术对细微征象显示更清晰。结论256层螺旋CT中全迭代重建(IMR)技术可改善肝脏低剂量增强扫描的图像质量,在肝癌的临床诊断中具有一定的应用价值。

Objective To compare the image quality and radiation dose of 256-slice spiral CT full iterative model reconstruction(IMR)and hybrid iterative reconstruction(iDose4)in low radiation dose liver enhancement.And explore the value of(MRI)dynamic enhancement in the diagnosis of liver cancer.Methods From January 2021 to October 2021,40 patients who underwent liver enhanced plain scan at the same time using conventional doses and three-phase enhancement using relatively low-dose CT scan and MRI dynamic enhancement,and were pathologically diagnosed with liver cancer were collected.The slice images were reconstructed by the hybrid iterative algorithm(iDose4)and the full model iterative algorithm(IMR)respectively,and the noise,signal-to-noise ratio,contrast signal-to-noise ratio and radiation dose indicators of the two groups were compared.The detection rate of liver cancer was compared with the dynamic enhancement of MRI.analyze.Results All images could meet the diagnostic requirements under the two reconstruction group algorithms.Noise,SNR and CNR comparison difference between two groups had statistical significance(P<0.05).The image quality of group B was better than that of group A.Three periods of enhanced radiation dose is scan has significantly reduced,comparative differences are statistically significant(P<0.05).The low contrast resolution and diagnostic confidence degree of group B was higher than that of group A(P<0.05).The image distortion degree of group B was lower than that of group A(P<0.05).MRI dynamic contrast enhanced three groups of liver cancer there was no statistically significant difference detection rate(P>0.05),but IMR reconstruction technique to subtle signs show more clearly.Conclusion The full iterative reconstruction(IMR)technique in 256-slice spiral CT can improve the image quality of liver low-dose enhanced scan,and has a certain application value in the clinical diagnosis of liver cancer.