Combination Of Neuro DSA And Agatston Calcium Score Techniques To Evaluate Carotid Plaque And Application Of CT Perfusion In Patients With Carotid Artery Stenosis Or Occlusion

Partâ… Analysis of CT characteristics for carotid artery atherosclerotic plaque by 64 rows CT angiographyPurpose: To explore the MDCTA findings and clinical values of carotid artery atherosclerotic plaque.Material and Methods: All the patients with the history of known or suspected carotid artery atherosclerotic disease underwent the 64 rows CT angiography. The patients with posterior circulation symptoms and stenosis of the intracranial artery which conformed by DSA or CTA or MRA were excluded from the study. The degree of the stenosis was defined by the criteria of the North American Symptomatic Carotid Endarterectomy Trial Collaborators. We retrospectively analyzed the type and distribution of carotid plaque, distribution and morphology of the calcium, and measured the degree of stenosis on the axial source and reconstruction images. The relationship between the MDCTA findings and the clinical symptoms was also investigated.Results: Three hundred and seventy-seven plaques (116 patients) were included in the study, including 138 soft plaques, 115 calcified plaques, 29 mixed plaques with obvious calcium and 29 mixed plaques with obvious lipid core. The distribution of the plaque was as following: the original part of the common carotid artery 23, the common carotid artery 105, carotid bifurcation 150, the internal carotid artery 81 and the external carotid artery 18. The incidence of the mild-, moderate- and high grade stenosis and occlusion were 57.56 %, 24.67 %, 11.94% and 5.83 % respectively. There was significantly statistical difference of the plaque type between lower than 50 year and higher than 70 year(p =0.005, p <0.01). The plaque type was significantly statistical difference between the common carotid artery and the carotid bifurcation(p =0.000, p <0.01), and between the common carotid artery and the internal carotid artery(p =0.000, p <0.01).The different type of plaque were distributed in the different vascular segments and resulted in the different degree of stenosis. The incidence of the calcium at the carotid bifurcation was 84% with slight and moderate degree of stenosis. There was no significantly statistical difference among the plaque type, the degree of stenosis and vascular segments. Plaque type, the degree of stenosis and vascular segment initially were identified as potentially significant variables of symptomatology for Backward logistic regression analysis. However, only the occlusion and simply calcified plaque was accepted in the model. The occlusion was a positive and significant association with the symptomatology (p=0.023, B=1.080) and the simply calcified plaque was significantly inverse associated with the occurrence of symptoms (p= 0.006, B=-0.688).Conclusion: MDCTA can accurately assess the characteristics of carotid plaque and measure the degree of stenosis. Our findings may have clinical value for the risk stratification of carotid atherosclerosis disease and could be used to predict the occurrence of symptom and the degree of stenosis.Partâ…¡The clinical value of carotid artery plaque calcification analyzed by 64 rows CT angiographyPurpose: To explore the relationship between the calcification of carotid artery plaque and the clinical symptoms.Material and Methods: All the patients underwent the 64 rows CT angiography. The degree of the stenosis was defined by the criteria of the North American Symptomatic Carotid Endarterectomy Trial Collaborators. We retrospectively analyzed the distribution of calcified plaque in the different age groups and different vascular segments, the degree of stenosis caused by calcification, distribution and morphology of intraplaque calcium. The relationship between the carotid calcification and the clinical symptoms was also investigated.Results: One hundred and sixteen patients with 377 plaques were included in the study, including 115 calcified plaques, 29 mixed plaques with obvious calcium and 95 soft plaques accompanied by calcification. The incidence of carotid plaque calcification was 63.40%.There was significant difference between the incidence of plaque calcification and different age groups and it was obvious that the prevalence is age dependent. The distributions of the calcification in different vascular segments were as following: the original part of the common carotid artery 60.87%, the common carotid artery 27.62%, carotid bifurcation 84%, the internal carotid artery 69.14% and the external carotid artery 77.78% respectively. The incidence of the calcium at the carotid bifurcation was higher than the other vascular segments. The incidence of calcification in the mild, moderate and severe degree of stenosis and occlusion were 46.51 %, 33.33 %, 26.67% and 0.00% respectively. However, there was significant difference of the incidence of calcification between the mild and severe degree of stenosis. There was no significant difference between distribution of calcification intraplaque in the symptomatic and asymptomatic group. Calcified plaque was negatively associated with symptomatology in backward logistic regression analysis (p<0.05).Conclusion: CT-angiography permits the reliable quantification and characterization of carotid calcium and may help noninvasively risk stratify patients with symptomatic and asymptomatic stenosis.Partâ…¢Combination of Agatston Calcium Score and Neuro DSA: quantification and characterization of carotid calciumPurpose: First, to quantify and qualities carotid calcification by MDCTA and Agatston calcium scores and determines whether the Agatston calcium scores and MDCTA appropriately evaluate calcified atherosclerotic burden and might be applied as a useful decision-making tool for treatment and, second to determine the relationship of carotid s calcium cores with luminal stenosis and ischemic symptoms.Materials and Methods: A total of 136 carotid arteries were examined with MDCT angiography (67.6±10.2 years; age ranges from 37-86 year; 1 woman, 57 men). Pre-contrast data was transferred to coronary calcium score software and calcium scores were determined according to the method described by Agatston et al. Post-contrast data was transferred to NuroDSA and vessel analysis software for stenosis analysis by North American Symptomatic Carotid Endarterectomy Trial (NASCET) criteria.Results: Symptomatic patients had higher total calcium volume, total equiv mass and total calcium score than asymptomatic patients, but this difference did not reach statistical significance with or without age and stenosis taken into account. According to the stenotic degree of ipilateral ICA, there was a significant difference among the three stenotic subgroups of total calcium volume, total equiv mass and total calcium score. Pair-wise comparisons indicated there was a significant difference between high-grade and mild-grade stenotic vessels (p<0.001), moderate- grade and mild-grade stenotic vessels (p< 0.001) without interaction with patient age. There was a statistically significant difference among the three age groups (p<0.01) and a significant difference between group two and three (p<0.001). Multiple logistic regressions indicated there was a significant association between symptomatology and luminal stenosis of ipsilateral internal carotid artery in the model(B=0.568, P=0.010). Pearsonχ² test showed a mild but significant correlation between stenotic grade of carotid bifurcation and ipsilateral ICA and total calcium volume (r_bifurcation = 0.322 and r_ICA = 0.418 respectively, p < 0.01). There were 217 calcifications in asymptomatic group and 120 calcifications in symptomatic group. However, there was no significant difference for all the individual calcium property between symptomatic and asymptomatic patients. There was no difference in intra-plaque Ca distribution patterns between symptomatic and asymptomatic patients (p >0.05).Conclusions: Carotid calcium scores is likely to emerge as the noninvasive investigation of choice to accurately assess the severity of carotid atherosclerosis and provide valuable insights into plaque characterization and stability especially for the calcified plaque in view of its ability. More important, Carotid calcium scores is a potential independent risk marker for TIA and stroke that could be used to stratify patients on the basis of risk and to monitor the effects of therapy. Partâ…£CT Perfusion Study of Cerebral Hemodynamics in Patients with unilateral stenosis (> 50%) or occlusion of the ICAPurpose: first, to investigate hemodynamic changes in different cerebral anatomic areas in patients with unilateral stenosis (>50%) or occlusion of the internal carotid artery (ICA) using CT Perfusion (CTP) imaging and, second to evaluate its potential value in identifying higher risk patients for TIAs or strokes.Material and Methods: Twenty-five patients (21 men, 4 women; mean age, 56.72±11.07years) with unilateral internal carotid artery stenosis (>50%) or occlusion underwent 64-detector perfusion CT. Exclusion criteria were intracranial artery stenosis with DSA or CTA or MRA. Stenosis was graded in accordance to the NASCET criteria and patients were divided into three groups: patients with a unilateral ICA occlusion, patients with high-grade (70%～99%) and patients with moderate-grade (50% 69%). We manually drew the ROIs of eight different anatomic regions to outline various cerebral flow territories on bilateral hemisphere. Cerebral blood volume (CBV), cerebral blood flow (CBF) , time to start (TS) and time to peak ( TP) were calculated, and relative values based on the comparison between stenotic and contrlateral hemispheres—specifically, rCBV, rCBF, rTS and rTP were derived. The absolute and relative perfusion values analyses were performed for the group as a whole by using the Student's t-test and Mann-Whitney test; and after subdividing patients into three groups according to the degree of stenosisof ICA by using the One-way ANOVA and Kruskal-Wallis test.Result: (1) All the patients in occlusion group and 4 patients in high-grade group had abnormal perfusion characterized by TS or TP color perfusion maps. (2) Among the absolute perfusion values, the TS of the occlusive hemisphere in gray matter and white matter of the anterior and posterior washeld regions had significantly statistical significance compared to contraside (P_TS<0.01). But the TP of the occlusive hemisphere only in the white matter of the anterior washeld region and the gray matter and white matter of the anterior and posterior washeld regions had significantly statistical significance compared to contraside (P_TP <0.05). (3) In high-grade stenotic group, the TS of stenotic side only in temporal lobe (P_TS<0.01) and in the white matter of the posterior washeld region (P_TS<0.05) were significantly increased compared to contraside. (4) Among the relative values, there were significantly statistical significance in rTS and rTP of temporal lobe(P_rTS=0.0090, P_rTP=0.0104), basal ganglia region (P_rTS=0.0281, P_rTP=0.0017), the gray matter and white matter of the anterior washeld regions (GM: P_rTS=0.0173, P_rTP=0.0397; WM: P_rTS=0.0482, P_rTP=0.0032) and the gray matter of posterior washeld region (P_rTS=0.0203, P_rTP=0.0049) had significantly statistical significance among three groups. However, only the rTS in the white matter of posterior washeld region had significantly statistical significance among three groups (P_rTS=0.0015).Conclusion: CT Perfusion may provide valuable information of the cerebral hemodynamic status in patients with unilateral internal carotid artery stenosis (>50%) or occlusion. Abnormal cerebral perfusion is often present in anterior and posterior washeld regions, predominantly in the white matter region. Absolute and relative TS are the most sensitive parameters to detect the changes in cerebral perfusion.