| The paper involved two aspects:(1)a feasibility study of three-dimensional ultrasonography in assessing the carotid atherosclerotic plaque vulnerability;(2)a study about relationship between CTA-defined calcification characteristics,intraplaque hemorrhage and ulceration in the carotid atherosclerotic plaque.Part I: A feasibility study of three-dimensional ultrasonography in assessing the carotid plaque vulnerabilityObjectiveTo investigate the feasibility and reliability of three-dimensional ultrasound in evaluating carotid artery vulnerable plaque.MethodsFrom February 2016 to March 2017,thirty-one consecutive patients(45 cases with 4 cases of bilateral)performed carotid endarterectomy(CEA)from Department of Neurosurgery at the First Affiliated Hospital of Soochow University were scheduled for conventional cervical vascular ultrasonography,three-dimensional ultrasonography(3D-US),CT angiography(CTA),CT perfusion imaging(CTP)and / or digital subtraction angiography(DSA)examinations respectively pre-operation.Observation of atherosclerotic plaque morphology and HE staining were employed post-operation.The results of preoperative 3D-US were compared with the corresponding postoperative pathologic findings.Scoring on plaque morphology,homogeneity,echo characteristics and degree of vascular stenosis in 3D-US,and calculated responsible plaque comprehensive score.According to the pathological results,the plaques were divided into vulnerable plaque group(n=35)and stable plaque group(n=10),application of independent sample t test,and score difference was calculated.Patients were classified into ischemic stroke group(ischemic group,n=27)and non-ischemic stroke group(non-ischemic group,n=14)according to whether ischemic stroke symptoms occurred during the last 6 months,application of the Pearson test by calculating the correlation coefficient,then analysis the correlation between ischemic events and the incidence of vulnerable plaques.Results(1)Plaque score was significant difference between vulnerable plaque group and stable plaque group(5.3±0.2 vs 3.4±0.3),the difference was statistically significant(t=5.339,p<0.05);(2)The accuracy of assessing vulnerable plaque by plaque score is higher: the area under the ROC curve is 0.907,the best cutoff is 4.5(the maximum Youden index is 0.671,the sensitivity is 77%,the specificity is 90%);(3)There is a significant positive correlation between the occurrence of ischemic events and plaque vulnerability: the correlation coefficient(r=0.858,p<0.05).Conclusion(1)3D-US can accurately and quantitatively assess vulnerability of carotid plaques;(2)carotid artery vulnerable plaque was significantly associated with ischemic stroke,which can provide the basis for clinical individualized treatment.Part II: Relationship Between CTA-defined Calcification Characteristics,Intraplaque Hemorrhage and Ulceration in the Carotid Atherosclerotic PlaqueObjectiveTo explore the relationship between CTA-defined calcification characteristics,intraplaque hemorrhage and ulceration in the carotid atherosclerotic plaque.MethodsOne hundred and thirty-seven consecutive symptomatic patients scheduled for carotid endarterectomy(CEA)were recruited.CT angiography(CTA)and CT perfusion imaging(CTP)were performed prior to CEA.Plaque samples were collected at surgery for histology to visualize IPH.According to the presence or absence of surface ulcer and IPH of CTA images and HE staining results,carotid artery plaques were divided into ulcer group(83 cases)and non-ulcer group(54 cases)or IPH group(71 cases)and non-IPH group(66 cases).According to the location,calcification nodules were categorized into superficial,deep and mixed type;and according to the size and number,calcification nodules were classified as thick and thin calcification,multiple and single calcification.Application of the pearson test by calculating the correlation coefficient,then analysis the correlation between IPH and the incidence of surface ulcer in carotid plaque.Student t test,Mann-Whitney U test and c2 test were used to compare baseline characteristics,CTP parameters and CTA makers between patients with and without IPH/ulceration.Multivariate regression analysis was used to explore associations between characteristic calcifications and IPH and ulceration adjusting for age,positive remodeling index,and high sensitivity C-reactive protein(hs-CRP).Sensitivity and specificity of the characteristics of calcification in identifying IPH and ulceration were calculated.Results(1)Among the 137 patients with carotid plaques,71(51.8%)had IPH,83(60.6%)had IPH,and 62(45.2%)had both IPH.None of them had 45(32.8%).There was a correlation between IPH and the occurrence of surface ulcer(r=0.49;p<0.001).(2)Comparison of clinical datas between groups: The incidence of hypertension in ulcer patients was significantly higher than that in non-ulcer groups(88.0% vs 57.4%,p<0.001);the age and C-reactive protein were higher in IPH and ulcer groups than non-IPH and non-ulcer groups(p<0.05).(3)The relationship between carotid plaque surface ulceration,IPH and cerebral perfusion: Mean transit time(MTT)and peak time(TTP)in ulcer group were longer than those in non-ulcer group(p<0.05).In addition,compared with non-IPH group,cerebral blood flow(CBF)decreased in the IPH group(p<0.05),and cerebral blood volume(CBV)has no significant difference in groups(p>0.05).Patients with lesions with both IPH and ulceration had a poorer CBF in the ipsilateral infarction area as compared to those containing one or neither of them(56.6 vs 54.6 ml/100 ml/min,p=0.034).(4)The relationship between CTA characteristics and surface ulcer and IPH: Compared to plaques without ulceration,those with ulceration showed less severe luminal stenosis(NASCET-defined stenosis,77.3% versus 81.9%,p=0.018).Lesions with IPH showed a higher prevalence of plaque surface ulcer than those without(87.3% versus 31.8%,p<0.001).The incidence of multiple calcifications,superficial calcification and thin calcification were significantly higher and the incidence of deep calcification was lower in lesions with IPH and ulceration compared with those without(all p<0.05).Moreover,the incidence of positive soft plaque,degree of stenosis and thick calcification showed no significant difference between the two groups.After adjusting for age,hs-CRP and positive remodeling,the presence of calcification(odds ratio(OR),2.4(1.0-5.7)(95% confidence interval),p=0.048),multiple calcification(OR,2.9(1.3-6.6),p=0.013),superficial calcification(OR,4.3(1.6-11.7),p=0.004)and thin calcification(OR,2.2(1.0-4.9),p=0.047)were all significantly associated with IPH.When further adjusting for ulceration,the above associations remained expect for thin calcification(OR,1.6(0.6-3.9),p=0.316).(5)The diagnostic efficacy of multiple calcification and surface calcification in defining surface ulcer and IPH: The specificity of multiple calcification and superficial calcification in identifying IPH is high(80.3% and 89.4%,respectively)with positive predictive values of 74.0% and 78.8%,respectively.However,the sensitivity is moderate(52.2% and 36.6%,respectively)with negative predictive values of 60.9 and 56.7%,respectively.Diagnostic performance of multiple calcification and superficial calcification for being associated with ulceration were as follows: high specificity of 79.6% and 88.9% with positive predictive values of 78.0% and 81.8,respectively;and moderate sensitivity of 47.0% and 32.5% with negative predictive values of 49.4% and 46.2%,respectively.Conclusions(1)Carotid plaque surface ulcer associated with plaque hemorrhage;(2)Superficial and multiple calcification were associated with carotid IPH suggesting that CTA-detected calcification may be a surrogate for higher risk lesions. |
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