低剂量脑CT灌注成像联合IMR的图像质量评价

目的 探讨低剂量脑CT灌注成像(CTPI)联合全模型迭代重组(IMR)技术临床应用的可行性.方法 收集因临床怀疑急性脑梗死行脑CTPI检查的患者80例.A组35例, B组45例.A、B组分别采用80 kV,150 mAs+传统滤波反投影(FBP)及80 kV,30 mAs+IMR重建.选取A、B 组脑灌注正常的一侧脑各30侧.比较2组图像主观评分、有效剂量(ED)和阿尔伯塔脑卒中计划早期CT评分层面2(ASPECTS2)水平大脑中动脉供血区灰白质的CT值、图像噪声(SD)、信噪比(SNR)、对比噪声比(CNR)以及灌注参数值.结果 A、B 2组ED分别为2.52、0.50 mSv;2组灰白质的灌注参数、CT值、SD,CNR,灰质SNR及主观评分之间无明显统计学差异(P>0.05);2组白质SNR存在明显统计学差异(P<0.05).结论 IMR联合30 mAs的CTPI在保证图像质量和灌注参数稳定的前提下明显降低辐射剂量.

Image quality evaluation of low-dose CT perfusion examination combined with IMR in the brain

Objective To investigate the feasibility of low-dose CT perfusion imaging(CTPI)examination combined with iterative model reconstruction (IMR) in the brain.Methods 80 patients with clinical suspicion of acute cerebral infarction underwent the cerebral CTPI were enrolled in this study.30 normal hemispheres on group A 35 cases,80 kV,150 mAs, filtered back projection(FBP)] and group B(45 cases,80 kV,30 mAs, IMR) were selected to evaluate respectively.The pictures' subjective scores, effective radiation dose (ED),CT value,SD,signal to noise ratio(SNR), contrast to noise ratio(CNR) and the perfusion parameters of the grey matter (GM) and white matter(WM) in each hemisphere of the middle cerebral artery(MCA) territory were respectively compared at ASPECTS level 2 for the two groups.Results The ED were 2.52,0.50 mSv for group A,B.There were no statistical significances in the perfusion parameters,CT value, SD, CNR of the ROIs of the GM and WM,the SNR of the ROIs of the GM and the pictures' subjective scores between group A, B (P>0.05).There was statistical significance in the SNR of the ROIs of the WM between group A,B (P<0.05).Conclusion IMR combined with 30 mAs of the CTPI can reduce the radiation dose apparently while maintain the stability of the image quality and perfusion parameters.