低剂量脑 CT 灌注的迭代重建研究

A study of Iterative reconstruction algorithm in low dose CT perfusion of brain

目的:探讨迭代重建(IR)技术对低剂量脑CT灌注(CTP)图像质量的影响。方法:43例缺血性脑血管病患者行低剂量脑CTP,CTP原始图像分别经IR和滤波反投影(FBP)重建得到两组图像,比较两组图像客观质量及灌注参数图的主观质量。结果:对经IR及FBP重建的灌注参数图(CBV、CBF、MTT、TTP)进行评分并比较,两组各灌注参数图脑灰白质分界评分P值分别为0.317、0.157、0.257、0.083,图像伪影严重程度评分P值分别为0.083、0.046、<0.001、0.011。经IR重建的CTP原始图像客观质量及灌注参数图的图像均匀性、总体图像质量均优于FBP重建,且差异均有统计学意义(P<0.05)。结论:低剂量脑CT灌注迭代重建能明显降低患者所接受的辐射剂量,改善图像质量,且具有较高的诊断效能。

Objective：To assess the image quality of low dose CT perfusion （CTP）of brain with iterative reconstruc-tion algorithm.Methods：43 patients with suspected cerebrovascular ischemic disorders were enrolled in the study.All pa-tients underwent CTP of brain.Datasets of CTP were reconstructed by using IR and FBP algorithms.The objective image quality of CTP source image and the subjective quality of color coded perfusion maps of the two sets were assessed and com-pared.Results：Comparing the imaging scores of the four perfusion maps （CBV、CBF、MTT、TTP）after IR and FBP recon-struction,the P values of differentiating gray/white matter with these two algorithms were 0.317,0.157,0.257,0.083 re-spectively;the P values of scoring artifacts severity of images were 0.083,0.046;＆lt;0.001,0.011 respectively.The brain CTP reconstructed by using IR was superior to those reconstructed by FBP in following aspects：objective image quality,im-aging scores and total image quality.Significant statistical differences were showed in all above aspects （P ＆lt;0.05）.Conclu-sion：Employing IR algorithm to reconstruct low dose CT perfusion of brain,not only can improve the image quality,but also reduce radiation dose.Additionally,high diagnostic effectiveness could be obained.