目的比较全模型迭代重建(Whole Model Iterative Reconstruction,IMR)与混合迭代重建(iDose4)对于肠系膜动脉图像质量的影响。方法对60位临床怀疑肠道疾病患者行肠道CTA检查,采用管电压80 kV、自动管电流,扫描结束后将所有动脉期数据同时进行IMR和iDose^4重建,分别命名为IMR重建和iDose^4重建组,对两组图像质量进行主观评分,并测量肠系膜上动脉、肠系膜下动脉以及同层肌肉CT值,背景噪声SD值,计算肠系膜上动脉、肠系膜下动脉信噪比,对比噪声比,利用统计学软件对各组数据进行统计学分析,比较两组间不同数据差异性。结果两组重建图像在血管强化CT值均值约为462.6 HU,无明显显著性差异。肠系膜上动脉、肠系膜下动脉图像噪声IMR重建组低于iDose^4重建组,两组比较存在统计学差异,P值分别为0.000,0.016;肠系膜上动脉和肠系膜下动脉的信噪比、对比噪声比比较,IMR重建组均高于iDose^4重建组,P值分别为0.004,0.009和0.002,0.005。IMR重建组图像质量主观评分和客观评价均优与iDose^4重建组,两组差异有统计学意义(P<0.05)。结论在肠系膜动脉CTA检查中,IMR全模型迭代重建相对于iDose^4重建技术可以显著减低图像噪声,提高图像空间分辨率,在相同辐射剂量情况下可以提高图像质量。
Objective To compare the effects of whole model iterative reconstruction(IMR) and mixed iterative reconstruction(iDose^4) on the image quality of mesenteric artery. Methods Sixty patients with clinically suspected intestinal diseases were examined by intestinal CTA. All arterial phase data were reconstructed by IMR and iDose4 at the same time after the end of the scan. The image quality of the two groups was subjectively evaluated. CT values of superior mesenteric artery, inferior mesenteric artery and muscle of the same layer were measured. The SD value of scene noise was calculated, the signal-to-noise ratio of superior mesenteric artery and inferior mesenteric artery was calculated, and the noise ratio was compared. Statistical software was used to analyze the data of each group, and the differences of different data between the two groups were compared.Results The mean CT value of the two groups was about 462.6 HU, and there was no significant difference between the two groups.The noise of IMR reconstruction group of superior mesenteric artery and inferior mesenteric artery was lower than that of iDose^4 reconstruction group. There was statistical difference between the two groups, P value was 0.000, 0.016;SNR, CNR and IMR reconstruction group of superior mesenteric artery, inferior mesenteric artery were higher than those of iDose4 reconstruction group,P value was 0.004, 0.009, 0.002, 0.005, respectively. The objective evaluation was superior to iDose4 reconstruction group, and there was significant difference between the two groups(P<0.05). Conclusion Iterative reconstruction of IMR model can significantly reduce image noise and improve image spatial resolution in mesenteric artery CTA examination compared with iDose4 reconstruction technology, and improve image quality under the same radiation dose.
China Medical Devices