Correlation study of carotid artery plaque components and CT cerebral perfusion by the analysis of CT energy spectrum imaging / 中国医学装备

ABSTRACT

Objective:To quantitatively analyze the plaque components of carotid artery through energy spectrum computed tomography angiography(CTA),and to measure the blood flow perfusion in the blood-supply area of carotid artery through CT perfusion(CTP),so as to explore the relationship among plaque component,the degree of luminal stenosis and cerebral blood flow perfusion.Methods:A total of 68 patients with unilateral plaques of carotid artery and severe vascular stenosis who were screened and diagnosed by ultrasound and CTA in Xiyuan Hospital from December 2017 to July 2019 were selected,and all patients underwent CTA examination and CTP examination.North American symptomatic carotid endarterectomy test(NASCET)method was used to measure the degree of carotid stenosis.The GE AW 4.7 post-process workstation was used to conduct analyses of energy spectrum and cerebral perfusion for the plaque component.And then,the slope of energy spectrum curve and the effective atomic number were obtained.At the same time,the cerebral blood volume(CBV),cerebral blood flow(CBF),time to peak(TTP)and mean transit time(MTT)of contrast agent in blood-supplying area of anterior cerebral artery(ACA)and middle cerebral artery(MCA)at the side of lesion were measured.Results:A total of 68 measured plaques of 68 patients met the condition,including 44 vulnerable plaques(including lipid plaques and mixed plaques)and 24 stable plaques(fibrous plaques).The average slopes of the energy spectrum curves of vulnerable plaque and stable plaque were respectively 0.45±0.45 and 1.15±0.39,and the differences were significant(t=2.413,P<0.05).The averagely effective atomic numbers of vulnerable plaques and stable plaques were respectively 7.21±1.06 and 8.01±0.63,and the difference were significant(t=2.548,P<0.05).The average TTP values of the ACA at the side of lesion of vulnerable plaques and stable plaques were respectively(12.20±1.61)S and(13.59±2.79)S,and the difference was significant(t=-2.607,P<0.05).The mean MTT values of the ACA at the side of lesion of vulnerable plaques and stable plaques were respectively(5.07±1.66)S and(6.09±2.19)S,and the difference was significant(t=-2.177,P<0.05).The degree of vascular stenosis at the side of lesion was positively correlated with TTP and MTT in blood-supplying area of middle cerebral artery(MCA)at the side of lesion(r=0.537,0.465,P<0.05),and that was negatively correlated with CBF values in blood-supplying areas of ACA and MCA at the side of lesion(r=-0.281,-0.569,P<0.05),respectively.The slope of the energy spectrum curve of carotid plaque was positively correlated with the TTP values in blood-supplying areas of ACA and MCA at the side of lesion(r=0.242,0.246,P<0.05),respectively.Conclusion:CT spectral imaging can quantitatively analyze the displayed components of carotid atherosclerotic plaque,and the degree of vascular stenosis can affect the blood flow perfusion of cerebral tissue,and the delays of TTP and MTT are more easily caused by vulnerable plaque,and the TTP of them is more sensitivity.