| Objective:we apply 64 row 128-slice spiral CT angiography to measure the length,the volume of carotid atherosclerosis plaque, the rate of arterial stenosis and to analyse the composition of atherosclerosis plaque base on HU values for assessing its stability,and then to investigate the relationship between plaque volume and the rate of stenosis,the composition of atherosclerosis plaque in different degree of stenosis,the relationship between the type of plaque, the rate of stenosis , CT-detectable lesions in the brain and clinical symptoms.in order to provide a imging basis for prevention and treatment of ischemic cerebrovascular disease. Materials and methodologies:Collected from 206 cases of ischemic cerebrovascular disease who underwent CT scan and angiography,with slice thickness:0.625mm,reconstruction interval:0.625mm.the original data were reconstructed to vascular with volume rendering,(VR), multiple planar reconstruction(MPR), curved planar reconstruction(CPR), maximum intensity projection (MIP) and CT virtue endoscope(CTVE) and other techniques of vascular reconstruction on ADW4.4 workstation.Then measure of stenosis of carotid artery, the length and volume of atherosclerosis plaque and analyse the components of plaque combining axial magnification images.We reference the North American Symptomatic Carotid Endarterectomy Trial for the grading criterions of vascular stenosis,then assessed the association between plaque stenosis, the length, volume, composition ,vulnerability of plaque and CT-detectable lesions in the brain and clinical symptoms indifferent degree of stenosis respectively.The results were analysed together by two experienced imaging physicians ,SPSS13.0 software were used for statistical analysis.Results: (1)153 patients in 206 patients were found carotid artery atherosclerosis,total 256 vascular were analysed.all patients were successfully scanned, the resulting image all can meet the requirements of analysis .the plaque volume(PV) of 30 carotid artery which have no significant stenosis was 232±248mm3; plaque volume of 135 mild stenosis (1% ~ 30%) arterys was about 538±342mm3; plaque volume of 59 moderate stenosis (30% ~ 70%) arterys was about 1150±451mm3, plaque volume of 32 severe stenosis (> 70%) was about 1680±682mm3.And total 256 carotid artery with atherosclerotic plaque ,the correlation between plaque volume and severity of stenosis was moderate (R = 0.61, P <0.001), but that cant not necessarily reflect the amount of atherosclerosis.(2)with increasing plaque volume ,the contribution of fibrous tissue decreased (R=-0.85,P<0.001) and the contribution of lipid increased(R=0.52 ,P<0.001).with an increase in plaque volume,the contribution of calcium increased slightly(R=0.43,P=0.02).(3) 64 of 133 patients with minor stroke ,37 patients of which with transient ischemic attack(TIA),15 patients of which with amaurosis fugax(AF).The PV in patients with minor stroke(884±685mm3) was larger than the PV in patients with ITA(783±937mm3, p=0.23) and PV in patients with AF(435±546mm3,p=0.08),There was statisitically significant when P<0.05.(4)A statistically significant association between the presence of fatty plaques(P<0.001) and CT-detectable lesions in the brain and the clinical symptoms, Logistic analysis showed that the fatty plaques(OR = 0.832, CI 0.793 ~ 0.873, P <0.01) is important risk factors in ischemic cerebrovascular disease risk factors.Calcified plaques have lower incidence of CT-detectable lesions and , severe stenosis of the lumen (P <0.001).(5)32 carotid artery with severe stenosis , in which 23 occurred in nternal carotid artery severe stenosis of carotid artery were most mixed plaques.the degree of Stenosis > 70% group have CT-detectable cerebral ischemia lesions were significantly higher than other narrow groups (χ2 = 7.63, P = 0.006). Conclusions:1.Analysis and assess of carotid artery plaque, and measurement of luminal stenosis with MSCT carotid artery angiography have a particular value, can be a non-invasive mean for assessing risk accident of cerebral vascular and providing important imaging evidence for clinical treatment.2.Rate of carotid artery stenosis and plaque volume has some relevance, but some patients with mild luminalstenosis have severe symptoms and ischemic brain damage, therefore, relying on the rate of carotid artery stenosis only for risk assessment of stroke is not enough, plaque volume measurement can be used for its important supplementary means.3.There was a decreasing trend in degree of stenosis in mixed plaque, fibrous plaque, lipid plaque, and calcified plaque ,the presence of lipid plaque, vulnerable plaque increased the risk of ischemic stroke significantly, to analysis the components of plaque and its stability is very important.4.There were no significant statistical difference between the volume of carotid atherosclerotic plaque and clinical symptoms of ischemic cerebrovascular disease.5. Measurement of plaque volume, analysis of plaque composition , detection the vulnerability of plaque , measurement of luminal stenosis should be combined with each in order to better assess and predict the risk of cerebral vascular disease. |
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