NASCET Stenosis Research Articles

Usefulness of “AcT ratio” in diagnosis of internal carotid artery stenosis: a multicenter, retrospective, observational study

PurposeThe ratio of the internal carotid artery (ICA) to the common carotid artery (CCA), especially the “AcT ratio,” which is a modified measurement method of acceleration time, is useful for diagnosing ICA-origin stenosis. However, previous studies were single-center studies. Therefore, this multicenter, retrospective, cross-sectional study aimed to determine whether a method using the AcT ratio is useful for estimating stenosis rates.MethodsThis study included 461 vessels subjected to carotid artery ultrasonography and evaluation for ICA-origin stenosis via NASCET at four hospitals. The duration from the steep rise point to the inflection point or the first peak was defined as AcT on pulsed wave Doppler. The AcT ratio was calculated as AcT of ICA/AcT of ipsilateral CCA. The AcT ratio and rate of ICA-origin stenosis were analyzed using Pearson's correlation coefficient, simple regression analysis, and ROC curve.ResultsA significant positive correlation was observed between the AcT ratio and NASCET stenosis. NASCET stenosis of ≥ 50% had a sensitivity, specificity, and negative predictive value (NPV) of 70.2%, 71.6%, and 91.5%, respectively, when the cut-off value of the AcT ratio was 1.17. NASCET stenosis of ≥ 70% had a sensitivity, specificity, and NPV of 70.5%, 72.1%, and 95.9%, respectively, when the cut-off value of the AcT ratio was 1.22.ConclusionsThe findings of this multicenter, retrospective, cross-sectional study suggest that the AcT ratio is useful for diagnosing ICA-origin stenosis, especially for diagnosis by exclusion. NASCET stenosis of ≥ 50% was considered unlikely if the Act ratio was ≤ 1.17, whereas NASCET stenosis of ≥ 70% was considered unlikely if it was ≤ 1.22.

Clinical risk factors and features on computed tomography angiography in high-risk carotid artery plaque in patients with type 2 diabetes.

High-risk carotid artery plaque (HPR) is associated with a markedly increased risk of ischemic stroke. The aims of this study were: 1) to examine the prevalence of HRP in a cohort of asymptomatic adults with type 2 diabetes (T2D); 2) to investigate the relationship between HRP, established cardiovascular risk factors and computed tomography angiography (CTA) profile; and 3) to assess whether the presence of HRP is associated with an increased risk of major adverse cardiovascular events (MACE). This was a retrospective cohort study of T2D asymptomatic patients who underwent carotid endarterectomy (CEA) from January 2018 to July 2021. The carotid atherosclerotic plaque (CAP) was assessed for the presence of ulceration, the presence of lipids, fibrosis, thrombotic deposits, hemorrhage, neovascularization, and inflammation. A CAP presenting at least five of these histological features was defined as a HRP (Group A); in all other cases it was defined as a mild to moderate heterogeneous plaque and no-HRP (Group B). CTA features included the presence of rim sign consisting of thin peripheral adventitial calcification (<2 mm) and internal soft plaque (≥2 mm), NASCET percent diameter stenosis, maximum plaque thickness, ulceration, calcification, and intraluminal thrombus were recorded. Binary logistic regression with Uni- and Multivariate was used to evaluate possible predictors for HRP while multivariable Cox Proportional Hazards was used to assess independent predictors for MACE. One hundred eighty-five asymptomatic patients (mean age 73±8 years, 131 men), undergoing carotid endarterectomy, were included. Of these, 124 (67%) had HRP, and the 61 (33%) did not. Diabetic complications (OR 2.4, 95% CI: 1.1-5.1, P=0.01), NASCET stenosis ≥75% (OR 2.4, 95% CI: 1.2-3.7, P=0.02) and carotid RIM sign (OR 4.3, 95% CI: 3.9-7.3, P<0.001) were independently associated with HRP. However, HRP was not associated with a higher risk of MACE (freedom from MACE at 5 years: HRP 83.4% vs. non HRP 87.8%, P=0.72) or a reduction of survival (5-year survival estimates: HRP 96.4% vs. non HRP: 94.6%, P=0.76). A high prevalence of HRP (67%) was observed in asymptomatic and elderly T2D patients. Independent predictors of HRP were diabetic complications, NASCET stenosis ≥75% and carotid RIM sign (OR 4.3, 95% CI: 3.9-7.3, P<0.001). HRP was not associated with an increased risk of MACE during a mean follow-up of 39±24 years.

Rapid Carotid Screening by Duplex: A Prospective Single Centre Assessment.

A novel carotid quick scan (CQS) protocol was developed to rapidly screen for carotid atherosclerosis greater than 50% stenosis in a vascular outpatient setting. This study assessed accuracy and time saved. The CQS was developed by consensus agreement between vascular surgeons and accredited clinical vascular scientists through a modified Delphi technique. The protocol comprised a rapid B-mode then colour flow transverse sweep of the common and internal carotid arteries, with internal carotid artery velocity assessment. One hundred outpatients attending with peripheral artery disease or abdominal aortic aneurysm were recruited. CQS sensitivity, specificity and accuracy was assessed against a conventional full carotid duplex study, performed to UK and ESVS guidelines. Twenty four percent of patients (n = 100) had >50% carotid NASCET stenosis. CQS achieved an excellent accuracy of 96.5% in detecting >50% stenosis when compared to full duplex; Cohen's ƙ = .88, (95%CI .79-.97; P < .001), sensitivity 91.4%, specificity 97.6%, positive predictive value (PPV) 88.9% and negative predictive value (NPV) 98.2%. Median (IQR) time to complete the CQS was 13 sec (±12) per side, compared to 151 sec (±78) per side for the full carotid duplex. In the presence of >50% carotid disease, median CQS time was 25 sec (±31) per side compared to 214 (±104) by full scan. CQS as a carotid screening tool is rapid, accurate and acceptable to the population and workforce. It would be simple to roll out in all vascular laboratories to reduce the time and cost burden of excluding significant carotid disease in any group.

Early Carotid Endarterectomy for Symptomatic Stenosis of Internal Carotid Artery in Patients Affected by Transient Ischemic Attack or Minor-to-Moderate Ischemic Acute Stroke: A Single-Center Experience

In the setting of carotid transient ischemic attack (TIA) or minor/moderate ischemic stroke, early surgical endarterectomy (CEA) seems to decrease the number of recurrences. The aim of the present study was to report a single-center experience with early surgical carotid revascularization in patients affected by TIA and minor/moderate ischemic acute stroke. A retrospective data collection was carried out on all consecutive patients surgically treated for an extracranial internal carotid artery (ICA) hemodynamic NASCET stenosis in the Vascular Unit of Foch Hospital, in Suresnes (France) between January 2011 and July 2016. All patients undergoing ICA endarterectomy for symptomatic carotid stenosis (SCS) within 48 hours and 14 days after the acute neurologic onset were included in the present study. Outcomes were evaluated by a prospective follow-up. Primary outcomes were the rate of postoperative ipsilateral stroke and myocardial infarction (MI) and the death/stroke/MI at 30-day and at the long-term follow-up. Secondary outcomes were local and systemic complications' rate. Outcomes were stratified according to NIHSS score and comorbidities, and a univariate analysis and multivariate analysis were performed to define any correlation between preoperative data and postoperative outcomes. A total of 249 consecutive patients (45.4%, 113 symptomatic vs. 54.6%, 136 asymptomatic) underwent CEA for hemodynamically significant ICA stenosis at our institution. According to inclusion criteria, 72 patients affected by SCS (27.7% women vs. 72.3% men; median age 71.9 years, range: 42-89; median preoperative NIHSS score 3, range 1-17) were enrolled in the present study. Median delay for surgery was 4 days (range: 2-14). No in-hospital stroke, nor myocardial infarction nor death were detected during in-hospital post-operative period. The combined death/stroke/MI rate was 0% and 5.5 % at 30-days at 6 years follow-up respectively. In-hospital NIHSS score improved post-operatively of more than 2 points (range 0-15) in 47.2% of cases. A total of 10 patients (13.8%) experienced a local complication (hematoma, permanent or regressive nerve injury). No systemic complications (renal/respiratory failure, urinary tract infection, pneumoniae) were registered. At long-term follow-up a total of four patients (5.5%) died and six patients (8.3%) were lost. The stratification of outcomes according to NIHSS status, sex, comorbidities and preoperative surgical procedure did not show any statistical relation neither at 30 days nor at the long term-follow up. Diabetes was statistically correlated to a higher rate of complication at the long-term follow-up (P 0.049). In properly selected patients affected by minor/moderate ischemic acute stroke and TIA early carotid endarterectomy can be performed without any worsening of neurological status.

3D black blood MR angiography of the carotid arteries. A simple sequence for plaque hemorrhage and stenosis evaluation

ObjectivesTo evaluate the diagnostic performance of a new three-dimensional T1-weighted turbo-spin-echo sequence (3D T1-w TSE) compared to 3D contrast-enhanced angiography (CE-MRA) for stenosis measurement and compared to 2D T1-w TSE for intra-plaque hemorrhage (IPH) detection. MethodsEighty three patients underwent carotid MRI, using a new elliptic-centric phase encoding T1-weighted 3D TSE sequence in addition to the clinical protocol.Two observers evaluated image quality, presence of flow artifacts, and presence of intra-plaque hemorrhage, and computed the NASCET degree of stenosis for CE-MRA and for the new sequence. Inter-observer agreement and correlation between 3D TSE and CE-MRA for NASCET stenosis was estimated using Cohen's kappa, and correlation using linear regression and Bland-Altman plots.Histology was performed on endarterectomy samples for 18 patients. Sensitivity and specificity of 2D and 3D TSE for IPH diagnosis were computed. Results3D TSE showed better image quality than 2D TSE (p<0.05). Interobserver agreement was good (kappa≥0.86). Correlation between 3D TSE and CE-MRA was excellent (R=0.95) for NASCET stenosis. Sensitivity and specificity for IPH diagnosis was 50% and 100% for 2D TSE and 100% and 83% for the 3D TSE. ConclusionsThe new 3D T1-w TSE allows both reliable measures of carotid stenosis, with a slight overestimation compared to CE-MRA (5%), and improved IPH identification, compared to 2D TSE.

Prediction of Carotid Intraplaque Hemorrhage Using Adventitial Calcification and Plaque Thickness on CTA.

Carotid intraplaque hemorrhage is associated with stroke, plaque thickness, stenosis, ulceration, and adventitial inflammation. Conflicting data exist on whether calcification is a marker of plaque instability, and no data exist on adventitial calcification. Our goal was to determine whether adventitial calcification and soft plaque (a rim sign) help predict carotid intraplaque hemorrhage. This was a retrospective cohort study of 96 patients who underwent carotid MRA and CTA within 1 month, from 2009 to 2016. We excluded occlusions (n = 4) and near occlusions (n = 0), leaving 188 carotid arteries. Intraplaque hemorrhage was detected by using MPRAGE. Calcification, adventitial pattern, stenosis, maximum plaque thickness (total, soft, and hard), ulceration, and intraluminal thrombus on CTA were recorded. Atherosclerosis risk factors and medications were recorded. We used mixed-effects multivariable Poisson regression, accounting for 2 vessels per patient. For the final model, backward elimination was used with a threshold of P < .10. Receiver operating characteristic analysis determined intraplaque hemorrhage by using the area under the curve. Our final model included the rim sign (prevalence ratio = 11.9, P < .001) and maximum soft-plaque thickness (prevalence ratio = 1.2, P = .06). This model had excellent intraplaque hemorrhage prediction (area under the curve = 0.94), outperforming the rim sign, maximum soft-plaque thickness, NASCET stenosis, and ulceration (area under the curve = 0.88, 0.86, 0.77, and 0.63, respectively; P < .001). Addition of the rim sign performed better than each marker alone, including maximum soft-plaque thickness (area under the curve = 0.94 versus 0.86, P < .001), NASCET stenosis (area under the curve = 0.90 versus 0.77, P < .001), and ulceration (area under the curve = 0.90 versus 0.63, P < .001). The CTA rim sign of adventitial calcification with internal soft plaque is highly predictive of carotid intraplaque hemorrhage.

Abstract TP136: Four-dimensionally Guided Three-dimensional Color-doppler Ultrasonography Quantifies Carotid Artery Stenoses With Equally High Reproducibility and Accuracy Compared to Catheter Angiography

Introduction: Clinical stratification in patients with ICAS largely depends on symptomatic status and stenosis grading. The purpose was to analyze the agreement and binary accuracy for the degree of internal carotid artery stenoses (ICAS) as determined by four-dimensional (4D) real-time guided three-dimensional color-Doppler (3DC) ultrasonography (4D/3DC-US) compared to catheter angiography (CA). Hypothesis: We hypothesized that 4D/3DC-US is non inferior to CA in grading ICAS in selected patients. Methods: Screening with 4D/3DC-US was performed in 93 patients (122 ICAS) admitted to our vascular center.Main exclusion criteria were insufficient image quality, previous revascularization and contraindications to CA. Eighty patients were prospectively examined in optimal planes with 4D-US assisted static 3DC-US color-Doppler (10MHz) followed by blinded multiplanar off-line rendering to determine %-NASCET stenosis. Multiplane selective CA of the same ICAS were quantified with dedicated software in a blinded fashion. Results: Quantitative CA of 103 stenoses with a mean degree of 65 ± 17% were compared to 4D/3DC-US resulting in a Pearson correlation coefficient of 0.89 and a standard deviation of differences (SDD) of 8.1% at a bias of +1.7%. Binary 50, 60 and 70%-stenosis detection with 3DC-US revealed an accuracy of 96, 89, 85%, a sensitivity of 97, 92, 87% and a specificity of 92, 83 and 84%. Interobserver SDD for CA of 52 stenoses (7.2%) did not differ from SDD between 3DC-US and CA (P = 0.274). Conclusions: 4D/3DC-US allowed good metric stenosis quantification and accurate binary classification with high reproducibility in a selected cohort.

Abstract 98: Bilateral Carotid Intraplaque Hemorrhage Association With Simultaneous Bilateral Stroke

Introduction: Bilateral ischemic strokes are often attributed to central or cardiac embolic sources, especially in the absence of severe bilateral carotid stenosis. Carotid MRI detects carotid intraplaque hemorrhage (IPH), a marker of stroke risk independent of stenosis. Hypothesis: MRI-detected carotid IPH better identifies bilateral carotid source strokes compared to stenosis alone. Methods: In this retrospective cross sectional study, patients undergoing stroke workup were imaged with carotid and brain MRI. Stroke was determined by the AHA definition of CNS infarction. Patients with non-carotid stroke sources (e.g. cardiac sources), occluded or near-occluded carotids were excluded. A total of 425 patients were analyzed. Carotid imaging findings were recorded, including IPH and NASCET stenosis along with clinical cerebrovascular risk factors and medications. Receiver operating characteristic (ROC) analysis was performed to determine the predictive value (area under the curve, AUC) of carotid imaging findings. Results: Carotid IPH was present in 89/425 of cases, and was bilateral in 24/89 (27.0%). Bilateral carotid IPH was a good predictor of bilateral stroke (AUC=.808), performing better than bilateral stenosis with ≥50%, ≥60% or ≥70% cutoffs (AUC=.565 p=.001, AUC=.550 p&lt;.001, AUC=.523 p&lt;.001, respectively) but not significantly better than average bilateral stenosis (AUC=.800 p=.90). The combined predictive value of bilateral IPH and average bilateral stenosis was excellent (AUC=.891) and performed better than bilateral IPH alone (p=.07) or average bilateral stenosis alone (p=.002). Conclusions: Bilateral carotid IPH is associated with bilateral stroke, and adds significant discrimination of bilateral carotid stroke sources compared to stenosis. In the setting of bilateral stroke, carotid MRI may help uncover potential stroke sources undetected by lumen imaging alone.

Abstract T P49: Diagnosis of Carotid Artery Near-Occlusion in Computed Tomography Angiography Compared to Catheter Angiography - Validation of Criteria and Implications for Clinical Practice

BACKGROUND/PURPOSE: Patients with near-occlusion (NO) of the internal carotid artery (ICA) are suggested to benefit from an exclusive therapeutic stratification. We intended to verify computertomography angiography (CTA) criteria for NO-detection by the catheter angiography (CA) reference and to investigate the impact of NO upon diagnosis of 70%-NASCET stenosis. We hypothesized, that selected CTA-criteria are non-inferior to detect NO compared to CA. METHODS: Two independend observers analysed DICOM-images of 115 ICA stenoses obtained by multislice CTA and selective CA. Reference-NO’s were identified in CA by applying established criteria. Lumen measures and indizes previously applied to CTA , the minimal luminal diameter (MLD), the distal ipsilateral ICA (diICA) and the ratios between diICA and distal contralateral ICA (diICA : dcICA) and the diICA and ipsilateral external carotid artery (diICA : iECA) were validated against the CA-defined NO by receiver operator characteristic analysis (ROC). RESULTS: The ROC-curves showed AUC for criteria MLD, dICA, dICA:dcICA and dICA:dICE of 0.867, 0.952, 0.919 and 0.957 at cutpoints of ≤1.1mm, ≤2.7mm, ≤0.64 and ≤0.90 for detecting CA defined NO. For the CTA-detection of NO a sensitivity and specificity of ≥93% was achieved with dICA and dICA:dcICA criteria. PPV values could be augmented by a combination of two criteria. Correlation of CTA with CA %-NASCET-degree of stenosis revealed a relevant amount of false negatively categorized stenosis &lt;70% in part due to underestimation of NO stenoses by CTA. CONCLUSIONS: CTA is an accurate modality for the detection of NO compared to CA. The detection of NO in CTA is important for correctly diagnosing severe stenosis.

Clinical Risk Factors and CT Imaging Features of Carotid Atherosclerotic Plaques as Predictors of New Incident Carotid Ischemic Stroke: A Retrospective Cohort Study

Parameters other than luminal narrowing are needed to predict the risk of stroke more reliably, particularly in patients with <70% stenosis. The goal of our study was to identify clinical risk factors and CT features of carotid atherosclerotic plaques, in a retrospective cohort of patients free of stroke at baseline, that are independent predictors of incident stroke on follow-up. We identified a retrospective cohort of patients admitted to our emergency department with suspected stroke between 2001-2007 who underwent a stroke work-up including a CTA of the carotid arteries that was subsequently negative for acute stroke. All patients also had to receive a follow-up brain study at least 2 weeks later. From a random sample, we reviewed charts and imaging studies of patients with subsequent new stroke on follow-up as well as those who remained stroke-free. All patients were classified either as "new carotid infarct patients" or "no-new carotid infarct patients" based on the Causative Classification for Stroke. Independently, the baseline CTA studies were processed using a custom, CT-based automated computer classifier algorithm that quantitatively assesses a set of carotid CT features (wall thickness, plaque ulcerations, fibrous cap thickness, lipid-rich necrotic core, and calcifications). Univariate and multivariate statistical analyses were used to identify any significant differences in CT features between the patient groups in the sample. Subsequent ROC analysis allowed comparison to the classic NASCET stenosis rule in identifying patients with incident stroke on follow-up. We identified a total of 315 patients without a new carotid stroke between baseline and follow-up, and 14 with a new carotid stroke between baseline and follow-up, creating the main comparison groups for the study. Statistical analysis showed age and use of antihypertensive drugs to be the most significant clinical variables, and maximal carotid wall thickness was the most relevant imaging variable. The use of age ≥ 75 years, antihypertensive medication use, and a maximal carotid wall thickness of at least 4 mm was able to successfully identify 10 of the 14 patients who developed a new incident infarct on follow-up. ROC analysis showed an area under the ROC curve of 0.706 for prediction of new stroke with this new model. Our new paradigm of using age ≥ 75 years, history of hypertension, and carotid maximal wall thickness of >4 mm identified most of the patients with subsequent new carotid stroke in our study. It is simple and may help clinicians choose the patients at greatest risk of developing a carotid infarct, warranting validation with a prospective observational study.

Abstract 3772: High Precision and Accuracy of B-flow Ultrasound Morphometry of Internal Carotid Artery Stenosis: Improved Non-invasive Stenosis Grading

Background: Evaluation of various imaging modalities for grading internal carotid artery (ICA) stenosis can be performed by comparison of minimal lumen diameters (MLD) as well as percent ICA-stenosis calculated with a healthy distal reference segment (NASCET method). The new B-Flow (BF) ultrasound (US) imaging method displays stenosis in a similar fashion as reference methods like catheter angiography (A) and multi-slice CT-angiography (MS CTA). Aim: to evaluate the accuracy of MSCTA by using multiplanar reformation (MPR) for measuring ICA stenosis compared with of A as well as accuracy and precision of BF-US compared with MSCTA at corresponding projections and locations. Methods and patients: CTA of ICA were compared with A in 37 low to high grade ICA stenoses of patients screened by doppler US velocity criteria. CTA were compared with US in 80 ICA stenoses of 63 patients in a similar fashion at identical projections. Diameters of stenosed ICA were rendered coaxial on CTA. A was made with AXIOM (Siemens, Germany), MSCTA with SOMATOM (Siemens, Germany); Ultrasound Logic 9 with 6-8 Mhz linear scanner, GE, USA. All readings were by two independent observers for each technique. Quantitative A was done with MEDIS software (Netherlands), Bland-Altman analysis and statistics with SPSS (Germany). Identical planes were confirmed by overlay technique. Results: MLD was slightly overestimated by CTA compared with angiography with mean differences (±SD) of 0.093 ± 0.25 mm for longitudinal sections. Pearson correlation coefficient (PCC) was 0.95. NASCET stenosis grade showed no bias between CTA and A (-0,5%±6.23% SD) and resulted in a PCC 0.93 for MPR's compared with A. MLD was slightly underestimated by parasaggital section (PSS) BF-US (0.031mm ± 0.23mm SD) compared with CTA, PCC = 0.96. NASCET ICA-stenoses were slightly underestimated by CTA, with mean differences of 1,16% ± 6,04% (SD), PCC was 0.92. In this cohort, discrimination of binary 50% NASCET stenosis with PSS BF-US had a 87%sensitivity, 86% specifity and an accuracy of 86%; discrimination of binary 70% NASCET stenosis with PSS BF-US had a sensitivity of 92%, specifity of 90% and an accuracy of 90%. Conclusion: diagnostic performance of CTA proved to be excellent compared with angiography and PSS 2D BF-US was highly accurate, when using corresponding projections. 2D BF-US may be a valuable additional tool for screening and confirmation of CAS for therapeutic stratification.

Abstract 3346: Design of Multi-center, Randomized, Open-label, Blind-endpoint Trial Comparing Effects of Cilostazol versus Other Anti-platelet Drugs for the In-stent Restenosis after Carotid Artery Stenting : The Carotid Artery Stenting with Cilostazol Addition for Restenosis (CAS-CARE) Trial

Background and Purpose: Carotid artery stenting (CAS) is increasingly used to treat high-grade carotid stenosis, but the impact of medication on carotid in-stent restenosis (ISR) has not been shown. The present study was conducted to evaluate the inhibitory effect of cilostazol on ISR, compared to that of other antiplatelet drugs, in patients scheduled to undergo CAS. Methods: The Carotid Artery Stenting with Cilostazol Addition for Restenosis (CAS-CARE) trial is a multi-center, prospective, randomized, open-label, blind-endpoint trial, designed to compare the efficacy of cilostazol versus other anti-platelet therapy on ISR after CAS. Main inclusion criteria are patients with diagnosis of carotid artery stenosis, scheduled for carotid artery stenting within 30 days of enrolment, and aged at 45 - 80 years at time of consent. Patients who suffered an ischemic stroke within 48 hours prior to enrolment or those with aortic arch syndrome, vasculitis, or collagen disease will be excluded from the study. Diagnosis of carotid artery stenosis is based on angiography (NASCET stenosis ratio &gt; 50% for symptomatic lesion or &gt; 80% for asymptomatic lesion), or carotid ultrasound (peak systolic velocity &gt; 130cm/sec for symptomatic lesion or &gt; 230cm/sec for asymptomatic lesion). Nine hundred patients will be randomized into 2 groups: the first group will receive cilostazol from at least 3 days before CAS and continue for 2 years. The second group will never receive cilostazol during the same period. Use of other antiplatelet agents and concomitant drugs is unrestricted in each group. The allocation adjusting factors are presence or absence of symptoms, presence or absence of diabetes mellitus, type of stent scheduled to be used (open cell vs. closed cell), and test center. Follow-up carotid ultrasound will be examined at 6, 12 and 24 months after CAS, and carotid restenosis ≥50% is diagnosed using velocity criteria. The primary outcome is occurrence of in-stent restenosis within 2 years after CAS and time to occurrence. Secondary outcomes include 1) occurrence of in-stent restenosis, new out-stent stenosis, or re-treatment, 2) occurrence of cardiovascular event or death from any cause, 3) occurrence of a hemorrhagic event, and 4) a composite endpoint of them. Conclusion: CAS-CARE will determine whether cilostazol can prevent restenosis after carotid artery stenting with an acceptable risk profile.

Assessment of carotid stenosis using three‐dimensional T2‐weighted dark blood imaging: Initial experience

To evaluate the use of a T2-weighted SPACE sequence (T2w-SPACE) to assess carotid stenosis via several methods and compare its performance with contrast-enhanced magnetic resonance angiography (ceMRA). Fifteen patients with carotid atherosclerosis underwent dark blood (DB)-MRI using a 3D turbo spin echo with variable flip angles sequence (T2w-SPACE) and ceMRA. Images were coregistered and evaluated by two observers. Comparisons were made for luminal diameter, luminal area, degree of luminal stenosis (NASCET: North American Symptomatic Endarterectomy Trial; ECST: European Carotid Surgery Trial, and area stenosis), and vessel wall area. Degree of NASCET stenosis was clinically classified as mild (<50%), moderate (50%-69%), or severe (>69%). Excellent agreement was seen between ceMRA and T2w-SPACE and between observers for assessment of lumen diameter, lumen area, vessel wall area, and degree of NASCET stenosis (r > 0.80, P < 0.001). ECST stenosis was consistently higher than NASCET stenosis (48 ± 14% vs. 24 ± 22%, P < 0.001). Area stenosis (72 ± 2%) was significantly higher (P < 0.001) than both ESCT and NASCET stenosis. DB-MRI of carotid arteries using T2w-SPACE is clinically feasible. It provides accurate measurements of lumen size and degree of stenosis in comparison with ceMRA and offers a more reproducible measure of ECST stenosis than ceMRA.

Concordance rates of Doppler ultrasound and CT angiography in the grading of carotid artery stenosis: a systematic literature review

Physicians have been increasingly relying on noninvasive imaging methods to grade carotid stenosis. The accuracy of Doppler ultrasound (DUS) and CT angiography (CTA) versus intra-arterial angiography (IA) has been assessed in many studies and at least two meta-analyses. Here, we performed a systematic review of studies that compared DUS to CTA. In a PubMed review of the literature from 2000 to 2009, we found 12 studies that compared DUS and CTA-based grading of carotid stenosis. Only 4 of them included at least 20 patients and provided data to classify the diseased arteries into the following categories: mild, moderate or severe NASCET stenosis or occlusion. We extracted 431 arteries from 244 patients (range per study: 48-164). It was not possible to distinguish symptomatic from asymptomatic stenoses. Nearly half arteries had severe stenosis (46% based on DUS and 43% based on CTA). The weighted kappa was 0.85 (95% CI 0.76-0.94), and the accuracy was 0.78. When the arteries were classified into medical and potentially surgical groups, the kappa was 0.76 (95% CI 0.70-0.83), and the accuracy was 0.89. Overall, 17% of the stenoses classified as medical based on DUS were reclassified as surgical based on CTA and 14% of the stenoses classified as medical based on CTA were reclassified as surgical based on DUS. The sparse available data comparing DUS and CTA suggest that the grading of a carotid stenosis as medical or potentially surgical remains uncertain in a relatively high proportion of patients.

Morphometry of Carotid Arteries with B-Flow Ultrasound: High Precision and Accuracy for 50% NASCET Stenosis Grades by Comparison with Computer Tomography-Angiography

Morphometry of Carotid Arteries with B-Flow Ultrasound: High Precision and Accuracy for 50% NASCET Stenosis Grades by Comparison with Computer Tomography-Angiography

PS70. Carotid Artery Plaque Burden and Calcification in ≥ 50% NASCET Stenosis in Relation to Symptomatic Outcome

Carotid arteriography provides an accurate assessment of luminal narrowing but may inherently fail in assessing plaque burden, composition, and structure. In this study we investigate whether a) carotid plaque burden correlates with NASCET stenosis and b) quantitative measures of in vivo carotid plaque burden and calcification are different in symptomatic and asymptomatic patients.

Comparison Between Quantification Methods of Carotid Artery Stenosis and Computed Tomographic Angiography

The purpose of this study was to compare 3 percentage carotid artery measurement methods (the North American Symptomatic Carotid Endarterectomy Trial [NASCET], the European Carotid Surgery Trial [ECST], and the Carotid Stenosis Index [CSI]) and 1 millimeter method (direct millimeter measurement) to evaluate the difference and correlation between them. Seven hundred ninety-two patients (591 men; age: mean, 63 years; range, 32-91 years) studied by using a multi-detector row computed tomographic scanner for a total of 1584 carotid arteries were retrospectively analyzed. Each carotid stenosis was measured according to 4 measurement methods (the NASCET, the ECST, the CSI, and the direct millimeter measurement). Carotid arteries with near-occlusion condition were excluded. The Kolmogorov-Smirnov Z test was used to test the normality of continuous variable groups. Comparison of derived ratio-percent methods was performed by using the Bland-Altman plots, and receiver operating characteristic curves were calculated. Correlation coefficients were also calculated by using a nonparametric Spearman correlation. A P < 0.05 was considered to mean statistical significance. Four hundred sixteen carotid arteries were excluded, and in the remaining 1168 ones, a strength correlation according to quadratic regression between the NASCET and ECST methods was observed (Spearman rho coefficient, 0.948; P < 0.0001). An inverse correlation according to linear regression was observed between the NASCET and the direct millimeter measurement (Spearman rho coefficient, -0.972; P < 0.0001); the CSI shows a quadratic regression with the NASCET, a linear regression with the ECST, and an inverse linear regression with the direct millimeter measurement (Spearman rho coefficient, 0.946, 0.932, and -0.939 respectively). The cutoff values for 50% and 70% NASCET stenosis were 2.36 and 1.51, respectively. Our study results indicate that the direct millimeter measurement of stenosis, by using appropriate equations, can reliably predict NASCET-, ECST-, and CSI-type percent stenoses. The use of direct millimeter measurement may remove the pitfalls and the discrepancies deriving from the use of different ratio-percent methods.

Correlation between US-PSV and MDCTA in the quantification of carotid artery stenosis

Purpose Stroke is a major cause of death and serious long-lasting neurological disability and the severity of carotid artery stenosis is one of the most important determinants of cerebrovascular events. The purpose of this paper is to evaluate the correlation between multi-detector-row CT angiography (MDCTA) and ultra-sound peak-systolic-velocity (US-PSV) in the quantification of carotid artery stenosis. Methods and material 52 patients were retrospectively studied by using four-detector row CT and ultra-sound. Each patient was assessed for stenosis degree by using NASCET method when studied by using MDCT and by using PSV when studied by using US. Statistic analysis was performed to determine the entity of correlation (method of Pearson) between MDCTA and US-PSV. The Bland-Altman analysis was applied to assess the level of inter-technique agreement. Results Sonographic PSV measurements ranged from 70 to 589 cm/s. Distal ICA velocities ranged from 29 to 238 cm/s. Linear regression analysis showed a good correlation ( r 2 = 0.613) between MDCTA-NASCET linear percentage stenosis and PSV and measured. PSV value that corresponded to a NASCET linear percentage stenosis of 70% was 283 cm/s and with this values sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were 75%, 88.6%, 90.7% and 70.5%, respectively. Conclusions Results of our study suggest that NASCET stenosis measured in MDCTA and PSV values have a good correlation. The use of a threshold of 283 cm/s allows obtaining good value of sensitivity and specificity.

Ultrasound Based Measurement of ‘Carotid Stenosis >70%’: An Audit of UK Practice

Objectives To determine velocity thresholds for diagnosing ‘carotid stenosis >70%’ and whether Vascular Studies Units in the United Kingdom used ECST or NASCET measurement methods. Design Questionnaire to 102 members of the Society of Vascular Technology of Great Britain and Ireland. Results One quarter (26%) of respondents reported that their unit used the NASCET measurement method, 31% used the ECST method, while 43% did not know. When all velocity criteria were pooled and compared, an almost equal proportion of ECST, NASCET and ‘do not know’ respondents used a peak systolic velocity threshold of >230 cm/s as being diagnostic of a ‘stenosis >70%’. Interestingly, this velocity is now the threshold proposed by a North American consensus group for diagnosing a NASCET stenosis of >70%. Conclusions This audit suggests that there is considerable confusion about what constitutes an ultrasound based diagnosis of ‘stenosis >70% in the United Kingdom.

Carotid stenosis measurement on colour Doppler ultrasound: Agreement of ECST, NASCET and CCA methods applied to ultrasound with intra-arterial angiographic stenosis measurement

Purpose: Carotid stenosis is usually determined on Doppler ultrasound from velocity readings. We wondered if angiography-style stenosis measurements applied to ultrasound images improved accuracy over velocity readings alone, and if so, which measure correlated best with angiography. Materials and methods: We studied prospectively patients undergoing colour Doppler ultrasound (CDU) for TIA or minor stroke. Those with 50%+ symptomatic internal carotid artery (ICA) stenosis had intra-arterial angiography (IAA). We measured peak systolic ICA velocity, and from the ultrasound image, the minimal residual lumen, the original lumen (ECST), ICA diameter distal (NASCET) and CCA diameter proximal (CCA method) to the stenosis. The IAAs were measured by ECST, NASCET and CCA methods also, blind to CDU. Results: Amongst 164 patients (328 arteries), on CDU the ECST, NASCET and CCA stenosis measures were similarly related to each other (ECST = 0.54 NASCET + 46) as on IAA (ECST = 0.6 NASCET + 40). Agreement between CDU- and IAA-measured stenosis was similar for ECST ( r = 0.51), and CCA ( r = 0.48) methods, and slightly worse for NASCET ( r = 0.41). Adding IAA-style stenosis to the peak systolic ICA velocity did not improve agreement with IAA over peak systolic velocity alone. Conclusion: Angiography-style stenosis measures have similar inter-relationships when applied to CDU, but do not improve accuracy of ultrasound over peak systolic ICA velocity alone.