摘要
目的探讨通过降低CT灌注成像(CTP)采样时间分辨力对CTP灌注参数值准确性的影响而降低CTP扫描射线剂量的可行性。方法对25例有缺血性脑卒中症状的患者进行CTP扫描,球管旋转速度为1转/秒,采样时间分辨力为1s,采集方式为4i×7.2mm,共得到160幅图像。对原始数据(原始数据组)进行降低时间分辨力分组,分别为2、3、4及5s组。使用Neuro PCT软件对5组数据进行后处理,各组选择相同ROI测量脑血流量(CBF)、脑血容量(CBV)及达峰时间(TTP),并与原始数据组处理结果进行比较。结果随着时间分辨力降低,灌注参数伪彩图SNR降低。时间分辨力为2s时,各灌注参数值与原始数据组比较差异无统计学意义;3s及以下时间分辨力图像SNR降低趋于明显。随着时间分辨力降低,CTP扫描射线剂量明显降低。结论 CTP中,时间分辨力为2s时,仍能测得准确的灌注参数值,且可明显降低射线剂量。
Objective To assess the influence of lowering temporal sampling rates of CT perfusion（CTP） on parameters for reducing the radiation dose.Methods Twenty-five patients with ischemic sufferings underwent CTP.Original sampling rate was 1 rotation per second.Data were acquired with 4i×7.2 mm and totally 160 images were obtained.Additional four data sets were obtained with temporal resolution of 2 s,3 s,4 s,5 s,respectively.Data sets were postprocessed with Neuro PCT.Cerebral blood flow（CBF）,cerebral blood volume（CBV） and time to peak（TTP） were measured with the identical ROI.The results of the four data sets were compared with that of the original data sets.Results Signal-noise ratio（SNR） of color-coded parameter maps for CBF,CBV and TTP were lowering as sampling rate reduced,especially under 3 s temporal resolution.All perfusion parameters of 2 s temporal resolution data sets did not differ with that of the original data sets.The radiation reduced significantly when temporal sampling rate decreased.Conclusion Accurate perfusion parameters can be obtained with 2 s temporal resolution for CTP in ischemic stroke,and the radiation dose would be reduced significantly.
出处
《中国医学影像技术》
CSCD
北大核心
2012年第5期856-860,共5页
Chinese Journal of Medical Imaging Technology
基金
德阳市科技局重点科学技术研究项目(2009SZ044-7)
