Application Of Third-generation Dual-source CT Whole Brain Perfusion In Chronic Ischemic Encephalopathy

Objective:To explore the feasibility of one-stop whole brain CTP scan under low-dose conditions,and to study the changes of cerebral perfusion parameters and the effect of collateral circulation on cerebral perfusion parameters in patients with chronic ischemic cerebral artery stenosis or occlusion.Methods:From November 2016 to November 2018,156 patients with chronic ischemic encephalopathy were enrolled in the Department of Neurology,and were divided into 3groups.The first group of 52 patients underwent head CT plain scan and one-stop whole brain CTP examination.CBF,CBV,MTT,TTD,TTS and Tmax data were obtained from whole brain CTP examination,and dynamic CTA was reconstructed from whole brain CTP thin layer data.According to the stenosis of the MCA in the CTA image or the collateral circulation after occlusion,52 patients were divided into the collateral-rich group(lateral vascular≥50%contralateral)and the collateral reduction group(lateral vascular<50%opposite).Analysis of changes in CTP parameters between the two groups.In the first group,all 52 patients underwent whole brain vascular DSA examination within 1 week to compare the accuracy of vascular stenosis and collateral circulation in one-stop CTA.The second group of 52 patients underwent routine CTA examination to compare the quality of CTA and conventional CTA in one-stop.The third group of 52 patients underwent 64-slice CT cerebral perfusion examination,comparing the radiation doses of one-stop CTP and64-slice CTP.Results:The CTA images of all one-stop CTP patients met the diagnostic criteria,and the difference between the quality of conventional CTA images was not statistically significant(?~2=2.17,P>0.05),the image quality was still lower than the conventional CTA;the one-stop CTP examination radiation dose was significantly lower than the one.64-channel CT,the difference in radiation dose between the two was statistically significant(P<0.01).One-stop CTA had no statistical difference in the difference between MCA stenosis or occlusion and collateral circulation status compared with DSA(?~2=1.94,P>0.05).In 52patients with unilateral MCA stenosis or occlusion,one-stop examination showed mild CBF and mild CBV in the affected side.There was no significant difference in CBF and CBV between the affected side and the healthy side(P>0.05).In the collateral-rich group(22 cases),the CBF of the affected side was slightly reduced,the CBV of the affected side increased slightly,the MTT of the affected side was slightly prolonged,and the TTD,TTS,and Tmax of the affected side were significantly prolonged.The CBF and CBV of the affected side and the healthy side were significantly increased.There was no significant difference in MTT between the two groups(t=-1.26,0.57,1.94,P>0.05).The difference of TTD,TTS and Tmax between the affected side and the healthy side was statistically significant(t=6.95,7.95,8.70,P<0.01).In the collateral reduction group(30 cases),the CBF of the affected side was slightly reduced,and the CBV was slightly increased.There was no significant difference in the CBF and CBV between the affected side and the healthy side(t=-1.36,1.76,P>0.05);MTT,TTD,TTS and Tmax were significantly prolonged,and the difference between the affected side and the healthy side was statistically significant(t=6.91,17.94,10.55,16.38,P<0.01).Conclusion:1.the third generation of dual-source CT whole brain perfusion,can complete the"one-stop"scan of the whole brain CTP,and reduce the radiation dose.2.In chronic ischemic encephalopathy,MTT has important significance in the judgment of ischemic collateral circulation.MTT,TTD,TTS and Tmax are more sensitive to ischemic changes than CBF and CBV.CTA in one-stop CTP contributes to the diagnosis of cerebrovascular disease by whole brain CTP and conventional CTA.