Carotid Artery Involvement Of Multiple Aorto Arteritis Ultrasound Study

Objective1. To investigate the ultrasonographic characteristics of involved carotid arteries in Takayasu’s arteritis (TA) systematically2. To evaluate the usefulness of carotid wall thickness in the assessment of disease activity3. To analyze the hemodynamic changes in involved carotid arteries with different degrees of stenosisMaterials and methodsFrom October2011to March2013,58consecutive patients with TA in our hospital were examined by carotid ultrasonography. The sonographic features were investigated and various parameters were taken, mainly including wall thickness, inner diameter, peak systolic velocity (PSV), end diastolic velocity (EDV) and resistance index (RI).58healthy controls were also studied. The different parameters were compared between TA group and control group using Student t test, χ2test and Mann-Whitney-Wilcoxon test. Pearson and Spearman correlation analysis were performed to analyze the relationship between two variables.Activity was defined according to the National Institutes of Health criteria (1994). The wall thicknesses were compared between active group and inactive group, and the receiver operating characteristic (ROC) curve was performed to evaluate wall thickness of carotid artery as a marker of active inflammation.Results1. Of the116common carotid arteries (CCAs) in58patients, a total of106CCAs were affected. The CCAs in82.7%(48/58) patients were bilaterally involved.81CCAs were entirely involved and22CCAs were involved in the proximal section. Other3CCAs had only middle or distal sections involved. Carotid bifurcation and internal/external carotid artery (ICA/ECA) involvement were uncommonly seen, accounting for26.4%(28/106) and8.5%(9/106),respectively.2. A characteristic homogeneous, circumferential thickening was shown in76(71.7%) involved CCAs, while irregular thickening was shown in25CCAs. Other two CCAs showed a kind of local eccentric thickening. There was a clear boundary between involved and normal parts in59(55.7%) CCAs, and a gradual thickening was seen in the edge of the involved carotid walls with a rat-tail shaped, isoechoic layer outside the tunica media.3. The echogenicity of involved CCAs was equal to or slightly lower than that of the normal thyroid parenchyma, manifested as an isoechoic or hypoechoic thickening.35CCAs showed homogeneous echogenicity in the thicken walls with a "macaroni" sign. However, the echogenicity in67(63.2%) CCA walls showed quadri-layer changes, with strong echo, hypoecho, isoecho and strong echo from within in the longitudinal section, while the cross section showed a "target" sign. Usually the isoechoic layer was the thickest, and the inner echogenic line was the thinnest.15CCAs displayed a smooth, continuous bright line along the lumen, representing the lumen-intima interface. Calcification was found in7CCAs.The target sign was more likely seen in thicker walls. The artery wall in target sign positive group was thicker than that in negative group (P<0.05). There was no significant difference between different TA activity groups and between different TA courses (≥1year and<1year), but in patients with TA course of3months to6months, the target sign was not found.4. The CCA wall was distinctly thicker in TA patients than that in control group (P<0.001), and it was also thicker in active group than in inactive group, whenever stenosis existed (P<0.05).When the ROC analysis was performed with2.25mm taken as the cutoff value of wall thickness to evaluate TA activity, the sensitivity was71%and specificity was66%. In stenosis group, the sensitivity was90%and specificity was58%, using2.40mm as the cutoff value, while in non-stenosis group, the sensitivity was55%and specificity was81%, using2.25mm as the cutoff value. 5.50stenotic CCAs with inner diameter decreased≥50%was diagnosed, accounting for47.1%, with9CCAs occluded. Among these CCAs,40%(20/50) showed a long-section, homogenous stenosis. Dilated lumen was found in10CCAs, including3CCAs dilated after stenosis and4aneurysms with inner diameter12.5mm-16.2mm.The inner diameter of involved CCAs was not reduced as the wall thickness increased. Some CCA walls were thickened outwards or both inwards and outwards. There was no negative correlation between inner diameter and wall thickness (r=-0.163, P=0.110).6. There were significant differences of CCA-PSV, CCA-EDV and CCA-RI between stenotic and non-stenotic groups (P<0.05). The average CCA-PSV increased as the stenotic degree increased, but when the CCA stenosis was≥70%, PSV of some CCAs would be decreased. Similarly, there were significant differences of ICA-PSV and ICA-RI between stenotic and non-stenotic groups (P<0.05), and when the CCA stenosis was≥70%, the ICA-PSV and ICA-RI were both decreased.Among the32severely stenotic (≥70%) or occluded CCAs, intramural arterioles were detected in7CCAs, while vein-like spectrum form detected in9ICAs, and reversed blood flow detected in20ECAs.ConclusionThe target sign may become a new sonographic feature for the diagnosis of TA in carotid ultrasonography. Different from traditional concept, our research promoted that the isoechoic layer in thicken CCA walls may not be the intima-media complex but intima-media-externa complex or media-externa complex.Ultrasonography is helpful for the early diagnosis of TA and increased wall thickness may be a useful marker of active disease. Objective1. To investigate the enhancement features of carotid artery in Takayasu’s arteritis (TA) with contrast-enhanced ultrasound.2. To evaluate the characteristics of carotid artery enhancement by drawing time-intensity curve (TIC).3. To analyze the correlation between carotid enhancement and wall thickness or disease activity.Materials and methodsFrom January2012to March2013,19patients with TA in our hospital were recruited and examined by carotid contrast-enhanced ultrasound. The enhancement features of involved carotid arteries were observed and the TICs were drawn by acoustic quantitative analysis software (QLAB). Four parameters were recorded and calculated, including arrival time (AT), time to peak (TTP), enhanced intensity (EI) and wash-out time when El dropped to1/2EI (WT1/2).Student t test, χ2test and Pearson correlation analysis were used to compare AT, TTP and El between carotid wall and lumen, and also used to analyze the correlations between carotid enhancement and wall thickness or disease activity.Results1. Of the38common carotid arteries (CCAs) in19patients,35CCAs were involved. Contrast enhancement can be observed in24involved CCA walls, manifesting as a large amount of a contrast signal within the lesions, as visualized by moving bright spots and linear flow of microbubbles within the vascular walls, especially along the outer layer. The appearance can’t be seen in the remaining3normal and11involved CCAs, which were classified into non-enhanced type.4CCAs showed intramural arterioles, appearing as small stripped enhanced signals in the thickened CCA walls. One CCA was occluded without enhanced signal in the lumen.2. According to the comparison of TICs between CCA walls and lumens in20arteries, the average AT and TTP of walls were longer than those of lumens (P<0.05), while the average EI of walls was smaller than that of lumens. Both AT and TTP between walls and lumens showed positive correlations (r=0.777and r=0.755, respectively, P<0.05), but there was no correlation of EI between walls and lumens (P>0.05).3. TICs displayed different enhanced patterns of CCA walls and lumens. The walls showed fast enhancement with average AT9.83±1.44s, and a single apex with steep ascending and descending branches was seen on TIC. The average WT1/2was22.73＋4.86s. In contrast, the lumens showed fast enhancement, but then slowly washed out with a slow descending branch on TIC.4. The wall thicknesses in enhanced arteries were remarkable thicker than that in non-enhanced ones (2.42＋0.63mm vs.1.76±0.46mm, respectively, P<0.05). Of the23arteries with wall thickness>2mm,20ones (87.0%) showed enhancement in the wall. However, there was no correlation between El and wall thickness.5. The enhancement rate in the active group was76.9%(10/13), while it is63.6%(14/22) in the inactive group. There is no significant difference between these two groups. Similarly, there is also no significant difference between ESR-elevated group and ESR-normal group, and the enhancement rate were75.0%and63.2%respectively (P>0.05).ConclusionsContrast-enhanced ultrasound can be used in the TA patients to evaluate the neovascularization in carotid arteries, and it may provide valuable information for assessing the disease activity and the response to immunosuppressive therapy.