联合应用Neuro DSA、Agatston Calcium Score和CTP技术对颈动脉粥样硬化患者的综合影像评价
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摘要
目的:应用64层CT血管造影对颈动脉粥样硬化斑块的类型、分布及所致血管狭窄等影像特征进行初步分析,探讨64层CT血管造影对颈动脉斑块影像特征评价的价值及临床意义。
材料和方法:对临床可疑颈动脉粥样硬化的患者行64排CT血管造影检查,后循环及颅内血管病变均排除在外(经CTA、DSA或MRA证实);狭窄程度的判断采用NASCET标准。分析不同类型颈动脉斑块在各年龄组及各血管节段的分布、斑块类型与临床症状与狭窄程度的关系、钙化的临床意义以及斑块的并发改变。
结果:116例患者中共发现377个斑块,其中软斑块138个,钙化性斑块115个,以钙化为主的混合性斑块29个,以软组织为主的混合性斑块95个,软斑块发生率36.60%,斑块钙化发生率63.40%;发生于颈总动脉起始部23例,颈总动脉105例,颈动脉分叉部150例,颈内动脉81例,颈外动脉18例。轻、中、重度狭窄及闭塞的发病率分别为57.56%、24.67%、11.94%及5.83%。＜50岁与＞70岁年龄组间发生的斑块类型具有统计学差异(P=0.005,P＜0.01);颈总动脉与颈总动脉分叉部及颈内动脉发生斑块类型具有统计学差异(P=0.000,P＜0.01)。颈动脉狭窄程度与斑块类型及发生血管节段相关,但无统计学意义(P＞0.05);将斑块类型、狭窄程度、发生血管节段等因素进行逐步回归分析,发现血管闭塞与临床症状正相关(B=1.080,P＜0.05),而钙化性斑块与临床症状负相关(B=-0.688,P＜0.05);对颈动脉分叉部的逐步回归分析发现也得出相同结论。
结论:64层CT血管造影不仅可初步评价颈动脉斑块的影像特征,还可以准确测量斑块所致的血管狭窄;联合评价斑块类型、狭窄程度及发生血管节段、斑块内钙化可对临床脑血管事件作出预测。
目的:应用64层CT血管造影对颈动脉钙化的影像学特征进行分析,探讨钙化在不同年龄组及不同血管节段的分布趋势以及钙化所致的血管狭窄的程度,并探讨64层CT血管造影对颈动脉钙化评价的临床意义。材料和方法:116例患者行64排CT血管造影检查,后循环及颅内血管病变均排除在本研究之外(经CTA、DSA或MRA证实),回顾性分析颈动脉斑块钙化的影像特征及临床意义。
结果:116例患者共发现377个斑块,其中钙化性斑块115例,颈动脉斑块钙化的发生率为63.40%。不同年龄组间斑块钙化率有统计学差异(P=0.004,P＜0.01),小于50岁年龄组斑块钙化发生率很低,随年龄增加,斑块钙化比率明显上升。不同血管节段钙化的发生率如下:颈总动脉起始部60.87%,颈总动脉27.62%,分叉部84%,颈内动脉和颈外动脉分别为69.14%和77.78%,颈动脉分叉部钙化率明显高于其他血管节段;颈总动脉、分叉部及颈内动脉斑块钙化率有明显统计学差异(P=0.000,P＜0.01)。在轻度、中度、重度狭窄及闭塞组中钙化的发生率分别为46.51%、33.33%、26.67%及0.00%,但仅有轻度与重度狭窄组间斑块钙化率有统计学差异(P=0.013,P＜0.05);斑块钙化与狭窄程度非线性相关,钙化常引起轻中度狭窄。钙化在斑块内的分布与临床症状相关但无明显的统计学差异。单纯钙化性斑块在症状组与无症状组中分布有明显的统计学差异,斑块钙化率在两组间也有统计学差异(P=0.013,P＜0.05)。将斑块类型、狭窄程度、发生血管节段等因素进行逐步回归分析,发现钙化与临床症状负相关(B=-0.688,P＜0.05)。
结论:总之CTA可清晰显示斑块内钙化的形态、分布及其导致血管狭窄程度,同时可定量测量血管狭窄;对钙化的颈动脉斑块是否引发临床症状应综合考虑患者年龄、发生的血管节段、引起的狭窄程度及钙化的程度及分布方能做出准确预测。通过钙化的定性分析有助于临床对颈动脉斑块进行筛查并预测脑缺血事件发生。
目的:联合应用Agatston Calcium Score和Neuro DSA技术定量、定性分析颈动脉钙化,探讨二者联合应用是否可作为一个有效工具指导治疗及颈动脉钙化积分的临床意义。
材料和方法:收集一侧或两侧颈动脉钙化患者68例(年龄67.6±10.2岁;男:女=57:1),所有病例均行Siemens 64 CTA检查,参考NASCET标准,应用NuroDSA技术对血管狭窄分析,增强前数据被传入Agaston Calcium Score软件行钙化分析。
结果:无论是否考虑狭窄和年龄的协同作用,症状组患者与无症状组患者相比具有更高的总钙化体积、钙化当量及钙化积分,但症状组患者与无症状组患者间总钙化体积、钙化当量及钙化积分未达到统计学差异。三个狭窄组间和三个年龄组间总钙化体积、钙化当量及钙化积分均有统计学差异;在重度与轻度狄窄组间、中度与轻度狭窄组间均具有明显的统计学差异(P＜0.001);50-69岁与大于70岁年龄组间上述钙化参数具有明显的统计学差异(P＜0.001)。将总钙化体积、钙化当量、钙化积分、一侧颈内动脉狭窄程度及年龄和性别进行逐步回归分析,仅有一侧颈内动脉狭窄程度与临床症状正相关(B=0.568,P=0.010)。一侧颈动脉球部及同侧颈内动脉的狭窄程度均与总钙化体积具有轻度但明显相关性(r_(bifurcation)=0.322,r_(ICA)=0.418,P＜0.01)。无症状组发现217个独立钙化,而症状组仅发现120独立钙化。在症状组和无症状组间所有独立钙化的特性均无统计学差异,但症状组钙化特性显示其更不均质。对钙化在斑块内的分布分析发现,在症状组和无症状组间钙化的分布形式无统计学差异。
结论:颈动脉钙化积分可作为一个无创性的新方法评价颈动脉粥样硬化负荷,帮助临床决定治疗方案,对斑块内钙化的定量和定性分析可帮助临床评价斑块的稳定性、预测临床症状的发生及对高危病人进行危险分层。
目的:单侧颈内动脉狭窄或闭塞患者是否存在脑血流灌注异常及其在随后发生的脑缺血事件中的作用尚不清楚,应用CT灌注成像对上述患者脑血流灌注改变的评价较少且结论不一。本研究应用64层CT灌注成像对单侧颈内动脉狭窄(大于50%)或闭塞患者的脑灌注改变进行评价;探讨不同解剖部位及不同灌注参数对灌注异常改变的意义及CT灌注成像对可能发生脑缺血事件的高危人群的筛查价值。
材料和方法:25例一侧颈内动脉狭窄(大于50%)或闭塞患者进行了64层螺旋CT灌注检查,所有病例均经CTA、DSA或MRA证实且颅内动脉无明显狭窄及闭塞。参照北美症状性颈动脉内膜切除术(NASCET)标准在本研究中将患者分为中度狭窄(50%-69%)、重度狭窄(70%-99%)及闭塞组。按颅内动脉血流分布手动镜面测量两侧大脑半球8个解剖部位的绝对灌注值并计算两侧半球的相对灌注值。对组内两侧的绝对灌注值比较采用Student's t-test和Mann-Whitneytest,组间相对灌注值比较采用One-way ANOVA和Kruskal-Wallis test。
结果:(1)彩色参数图显示,闭塞组、重度狭窄组、中度狭窄组所有解剖部位两侧脑组织的CBF图和CBV图均无明显差异。闭塞组TS图、TP图两侧均显示不同程度的差异;而在重度狭窄组仅有4例(4/9)TS图、TP图显示两侧脑组织存在不同程度的差异;中度狭窄组所有病例TS图、TP图两侧脑组织均无明显差异。(2)闭塞组、重度狭窄组、中度狭窄组所有解剖部位两侧脑组织的CBF和CBV均无统计学差异(P＞0.05)。(3)闭塞组:闭塞侧前分水岭区灰质及白质的TS与对侧相比有明显的统计学差异(P＜0.01),闭塞侧前分水岭区白质的TP与对侧相比有统计学差异(P＜0.05);闭塞侧后分水岭区灰质及白质的TS(P＜0.01)、TP(P＜0.05)与对侧脑组织相比均有统计学差异。(4)重度狭窄组,仅有颞叶(P＜0.01)、后分水岭区白质(P＜0.05)狭窄侧的TS与对侧相比有统计学差异。(5)中度狭窄组所有解剖部位两侧脑组织的TS、TP均无统计学差异(P＞0.05)。(6)颞叶、基底节区、前分水岭区灰质及白质、后分水岭区灰质及白质的rCBF、rCBV均无统计学差异(P＞0.05)。(7)颞叶的rTS、rTP三组间有统计学差异(P_(rTS)=0.0090,P_(rTP)=0.0104),闭塞组和中度狭窄组间的rTS、rTP具有统计学差异;基底节区的rTS、rTP三组间有明显的统计学差异(P_(rTS)=0.0281,P_(rTP)=0.0017),闭塞组和中度狭窄组间的rTS具有统计学差异,闭塞组和中度、重度狭窄组间的rTP具有统计学差异;前分水岭区灰质及白质的rTS、rTP三组间有明显的统计学差异(灰质:P_(rTS)=0.0173,P_(rTP)=0.0397;白质:P_(rTS)=0.0482,P_(rTP)=0.00321);后分水岭区灰质的rTS、rTP三组间有统计学差异(P_(rTS)=0.0203,P_(rTP)=0.0049);后分水岭区白质的rTS三组间有统计学差异(P_(rTS)=0.0015),但三组间rTP无统计学差异。
结论:CT灌注成像能有效评价颈内动脉狭窄或闭塞患者脑灌注的改变,为临床治疗提供依据;在颈内动脉狭窄或闭塞患者中,灌注异常见于前后分水岭区,以分水岭区的白质最易受累,使用绝对及相对的TS能早期、敏感的发现灌注异常。
PartⅠAnalysis of CT characteristics for carotid artery atherosclerotic plaque by 64 rows CT angiography
Purpose: 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.
PartⅡThe clinical value of carotid artery plaque calcification analyzed by 64 rows CT angiography
Purpose: 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.
PartⅢCombination of Agatston Calcium Score and Neuro DSA: quantification and characterization of carotid calcium
Purpose: 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). Pearsonχ~2 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.
PartⅣCT Perfusion Study of Cerebral Hemodynamics in Patients with unilateral stenosis (> 50%) or occlusion of the ICA
Purpose: 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.
材料和方法:对临床可疑颈动脉粥样硬化的患者行64排CT血管造影检查,后循环及颅内血管病变均排除在外(经CTA、DSA或MRA证实);狭窄程度的判断采用NASCET标准。分析不同类型颈动脉斑块在各年龄组及各血管节段的分布、斑块类型与临床症状与狭窄程度的关系、钙化的临床意义以及斑块的并发改变。
结果:116例患者中共发现377个斑块,其中软斑块138个,钙化性斑块115个,以钙化为主的混合性斑块29个,以软组织为主的混合性斑块95个,软斑块发生率36.60%,斑块钙化发生率63.40%;发生于颈总动脉起始部23例,颈总动脉105例,颈动脉分叉部150例,颈内动脉81例,颈外动脉18例。轻、中、重度狭窄及闭塞的发病率分别为57.56%、24.67%、11.94%及5.83%。＜50岁与＞70岁年龄组间发生的斑块类型具有统计学差异(P=0.005,P＜0.01);颈总动脉与颈总动脉分叉部及颈内动脉发生斑块类型具有统计学差异(P=0.000,P＜0.01)。颈动脉狭窄程度与斑块类型及发生血管节段相关,但无统计学意义(P＞0.05);将斑块类型、狭窄程度、发生血管节段等因素进行逐步回归分析,发现血管闭塞与临床症状正相关(B=1.080,P＜0.05),而钙化性斑块与临床症状负相关(B=-0.688,P＜0.05);对颈动脉分叉部的逐步回归分析发现也得出相同结论。
结论:64层CT血管造影不仅可初步评价颈动脉斑块的影像特征,还可以准确测量斑块所致的血管狭窄;联合评价斑块类型、狭窄程度及发生血管节段、斑块内钙化可对临床脑血管事件作出预测。
目的:应用64层CT血管造影对颈动脉钙化的影像学特征进行分析,探讨钙化在不同年龄组及不同血管节段的分布趋势以及钙化所致的血管狭窄的程度,并探讨64层CT血管造影对颈动脉钙化评价的临床意义。材料和方法:116例患者行64排CT血管造影检查,后循环及颅内血管病变均排除在本研究之外(经CTA、DSA或MRA证实),回顾性分析颈动脉斑块钙化的影像特征及临床意义。
结果:116例患者共发现377个斑块,其中钙化性斑块115例,颈动脉斑块钙化的发生率为63.40%。不同年龄组间斑块钙化率有统计学差异(P=0.004,P＜0.01),小于50岁年龄组斑块钙化发生率很低,随年龄增加,斑块钙化比率明显上升。不同血管节段钙化的发生率如下:颈总动脉起始部60.87%,颈总动脉27.62%,分叉部84%,颈内动脉和颈外动脉分别为69.14%和77.78%,颈动脉分叉部钙化率明显高于其他血管节段;颈总动脉、分叉部及颈内动脉斑块钙化率有明显统计学差异(P=0.000,P＜0.01)。在轻度、中度、重度狭窄及闭塞组中钙化的发生率分别为46.51%、33.33%、26.67%及0.00%,但仅有轻度与重度狭窄组间斑块钙化率有统计学差异(P=0.013,P＜0.05);斑块钙化与狭窄程度非线性相关,钙化常引起轻中度狭窄。钙化在斑块内的分布与临床症状相关但无明显的统计学差异。单纯钙化性斑块在症状组与无症状组中分布有明显的统计学差异,斑块钙化率在两组间也有统计学差异(P=0.013,P＜0.05)。将斑块类型、狭窄程度、发生血管节段等因素进行逐步回归分析,发现钙化与临床症状负相关(B=-0.688,P＜0.05)。
结论:总之CTA可清晰显示斑块内钙化的形态、分布及其导致血管狭窄程度,同时可定量测量血管狭窄;对钙化的颈动脉斑块是否引发临床症状应综合考虑患者年龄、发生的血管节段、引起的狭窄程度及钙化的程度及分布方能做出准确预测。通过钙化的定性分析有助于临床对颈动脉斑块进行筛查并预测脑缺血事件发生。
目的:联合应用Agatston Calcium Score和Neuro DSA技术定量、定性分析颈动脉钙化,探讨二者联合应用是否可作为一个有效工具指导治疗及颈动脉钙化积分的临床意义。
材料和方法:收集一侧或两侧颈动脉钙化患者68例(年龄67.6±10.2岁;男:女=57:1),所有病例均行Siemens 64 CTA检查,参考NASCET标准,应用NuroDSA技术对血管狭窄分析,增强前数据被传入Agaston Calcium Score软件行钙化分析。
结果:无论是否考虑狭窄和年龄的协同作用,症状组患者与无症状组患者相比具有更高的总钙化体积、钙化当量及钙化积分,但症状组患者与无症状组患者间总钙化体积、钙化当量及钙化积分未达到统计学差异。三个狭窄组间和三个年龄组间总钙化体积、钙化当量及钙化积分均有统计学差异;在重度与轻度狄窄组间、中度与轻度狭窄组间均具有明显的统计学差异(P＜0.001);50-69岁与大于70岁年龄组间上述钙化参数具有明显的统计学差异(P＜0.001)。将总钙化体积、钙化当量、钙化积分、一侧颈内动脉狭窄程度及年龄和性别进行逐步回归分析,仅有一侧颈内动脉狭窄程度与临床症状正相关(B=0.568,P=0.010)。一侧颈动脉球部及同侧颈内动脉的狭窄程度均与总钙化体积具有轻度但明显相关性(r_(bifurcation)=0.322,r_(ICA)=0.418,P＜0.01)。无症状组发现217个独立钙化,而症状组仅发现120独立钙化。在症状组和无症状组间所有独立钙化的特性均无统计学差异,但症状组钙化特性显示其更不均质。对钙化在斑块内的分布分析发现,在症状组和无症状组间钙化的分布形式无统计学差异。
结论:颈动脉钙化积分可作为一个无创性的新方法评价颈动脉粥样硬化负荷,帮助临床决定治疗方案,对斑块内钙化的定量和定性分析可帮助临床评价斑块的稳定性、预测临床症状的发生及对高危病人进行危险分层。
目的:单侧颈内动脉狭窄或闭塞患者是否存在脑血流灌注异常及其在随后发生的脑缺血事件中的作用尚不清楚,应用CT灌注成像对上述患者脑血流灌注改变的评价较少且结论不一。本研究应用64层CT灌注成像对单侧颈内动脉狭窄(大于50%)或闭塞患者的脑灌注改变进行评价;探讨不同解剖部位及不同灌注参数对灌注异常改变的意义及CT灌注成像对可能发生脑缺血事件的高危人群的筛查价值。
材料和方法:25例一侧颈内动脉狭窄(大于50%)或闭塞患者进行了64层螺旋CT灌注检查,所有病例均经CTA、DSA或MRA证实且颅内动脉无明显狭窄及闭塞。参照北美症状性颈动脉内膜切除术(NASCET)标准在本研究中将患者分为中度狭窄(50%-69%)、重度狭窄(70%-99%)及闭塞组。按颅内动脉血流分布手动镜面测量两侧大脑半球8个解剖部位的绝对灌注值并计算两侧半球的相对灌注值。对组内两侧的绝对灌注值比较采用Student's t-test和Mann-Whitneytest,组间相对灌注值比较采用One-way ANOVA和Kruskal-Wallis test。
结果:(1)彩色参数图显示,闭塞组、重度狭窄组、中度狭窄组所有解剖部位两侧脑组织的CBF图和CBV图均无明显差异。闭塞组TS图、TP图两侧均显示不同程度的差异;而在重度狭窄组仅有4例(4/9)TS图、TP图显示两侧脑组织存在不同程度的差异;中度狭窄组所有病例TS图、TP图两侧脑组织均无明显差异。(2)闭塞组、重度狭窄组、中度狭窄组所有解剖部位两侧脑组织的CBF和CBV均无统计学差异(P＞0.05)。(3)闭塞组:闭塞侧前分水岭区灰质及白质的TS与对侧相比有明显的统计学差异(P＜0.01),闭塞侧前分水岭区白质的TP与对侧相比有统计学差异(P＜0.05);闭塞侧后分水岭区灰质及白质的TS(P＜0.01)、TP(P＜0.05)与对侧脑组织相比均有统计学差异。(4)重度狭窄组,仅有颞叶(P＜0.01)、后分水岭区白质(P＜0.05)狭窄侧的TS与对侧相比有统计学差异。(5)中度狭窄组所有解剖部位两侧脑组织的TS、TP均无统计学差异(P＞0.05)。(6)颞叶、基底节区、前分水岭区灰质及白质、后分水岭区灰质及白质的rCBF、rCBV均无统计学差异(P＞0.05)。(7)颞叶的rTS、rTP三组间有统计学差异(P_(rTS)=0.0090,P_(rTP)=0.0104),闭塞组和中度狭窄组间的rTS、rTP具有统计学差异;基底节区的rTS、rTP三组间有明显的统计学差异(P_(rTS)=0.0281,P_(rTP)=0.0017),闭塞组和中度狭窄组间的rTS具有统计学差异,闭塞组和中度、重度狭窄组间的rTP具有统计学差异;前分水岭区灰质及白质的rTS、rTP三组间有明显的统计学差异(灰质:P_(rTS)=0.0173,P_(rTP)=0.0397;白质:P_(rTS)=0.0482,P_(rTP)=0.00321);后分水岭区灰质的rTS、rTP三组间有统计学差异(P_(rTS)=0.0203,P_(rTP)=0.0049);后分水岭区白质的rTS三组间有统计学差异(P_(rTS)=0.0015),但三组间rTP无统计学差异。
结论:CT灌注成像能有效评价颈内动脉狭窄或闭塞患者脑灌注的改变,为临床治疗提供依据;在颈内动脉狭窄或闭塞患者中,灌注异常见于前后分水岭区,以分水岭区的白质最易受累,使用绝对及相对的TS能早期、敏感的发现灌注异常。
PartⅠAnalysis of CT characteristics for carotid artery atherosclerotic plaque by 64 rows CT angiography
Purpose: 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.
PartⅡThe clinical value of carotid artery plaque calcification analyzed by 64 rows CT angiography
Purpose: 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.
PartⅢCombination of Agatston Calcium Score and Neuro DSA: quantification and characterization of carotid calcium
Purpose: 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). Pearsonχ~2 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.
PartⅣCT Perfusion Study of Cerebral Hemodynamics in Patients with unilateral stenosis (> 50%) or occlusion of the ICA
Purpose: 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.
引文
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