Preliminary Study of the Scan-delay-time During the Combined Examation of CT Perfusion and CT Angiography After Contrast Media Administration in Cerebral and Cervical CT Angiography

Objective To discuss the feasibility of the time to peak of cerebral CT perfusion (CTP) in predicting the scan-delay-time after contrast media administration in cerebral and cervical CT angiography (CTA).Methods Retrospective Analysis was performed in eighty patients who had been examined with cerebral and cervical CTA,they were divided randomly into two groups.Group A:40 patients were performed by the method of experience of 20 seconds as scan-delay-time.Group B:the other 40 patients were examined with the combination scanning technology of CTP-CTA.They were all measured with enhancement value of CT in the M1 segment of left middle cerebral artery、superior sagittal sinus 、left common carotid artery adjacent to the fourth cervical vertebrace and internal jugular vein,and then calculate the difference between the arterys and the veins in the same layer.Statistical significance was determined with t test.Results (1)The enhancement value of CT in the cerebral and cervical artery vessels and the resolving power between the arterys and the veins in the same layer of group B were higher than that in group A.(2)Group B whose cerebral and cervical artery vessels rescontructed from the raw CT data set showed clearly;There were an advance in 3 cases(7.5%),a delay in 5 cases (12.5%)in group A whose cerebral and cervical artery vessels rescontructed from the raw CT data set didn’t show clearly.Conclusion It's a satisfactory method based on successful cerebral and cervical CTA study to take the time to peak in CT perfusion as the scan-delay-time during the combined examination of CTP and CTA with 64-detector spiral CT.