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Purpose: To evaluate in a proof-of-concept study the feasibility of Simultaneous Noncontrast Angiography and intraPlaque hemorrhage (SNAP) imaging as a clinical magnetic resonance angiography (MRA) technique for measuring carotid stenosis. There is a growing interest in detecting intraplaque hemorrhage (IPH) during the clinical management of carotid disease, yet luminal stenosis has remained indispensable during clinical decision-making. SNAP imaging has been proposed as a novel IPH imaging technique that provides carotid MRA with no added scan time. Flowing blood shows negative signal on SNAP because of phase-sensitive inversion recovery.Materials and Methods: In all, 58 asymptomatic subjects with 16-79% stenosis on ultrasound were scanned at 3T by SNAP with 0.8 mm isotropic resolution and 16 cm longitudinal coverage. Two readers measured luminal stenosis of bilateral carotid arteries (n = 116) on minimum intensity projections of SNAP using the NASCET criteria. In the subset (48 arteries) with contrast-enhanced (CE) MRA available for comparison, luminal stenosis was also measured on maximum intensity projections of CE-MRA.Results: Intraclass correlation coefficients (ICCs) with 95% confidence intervals were 0.94 (0.90-0.96) and 0.93 (0.88-0.96) for intra- and interreader agreement on stenosis measurements, respectively. Corresponding kappas for grading stenosis (0-29%, 30-69%, 70-99%, and 100%) were 0.79 (0.67-0.89) and 0.80 (0.68-0.90). Agreement between SNAP and CE-MRA was high (ICC: 0.95 [0.90-0.98]; kappa: 0.82 [0.71-0.93]).Conclusion: As a dedicated IPH-imaging sequence, SNAP also provided carotid stenosis measurement that showed high intra- and interreader consistency and excellent agreement with CE-MRA. Further comparisons with digital subtraction angiography and other noninvasive techniques are warranted.Level Of Evidence: 2 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2017;46:1045-1052. [ABSTRACT FROM AUTHOR]

Abstract: Purpose: NASCET and ECST systems to quantify carotid artery stenosis use percent diameter ratios from conventional angiography. With the use of Multi-Detector-Row CT scanners it is possible to easily measure plaque area and residual lumen in order to calculate carotid stenosis degree. Our purpose was to compare NASCET and ECST techniques in the measurement of carotid stenosis degree by using MDCTA. Methods and material: From February 2007 to October 2007, 83 non-consecutive patients (68 males; 15 females) were studied using Multi-Detector-Row CT. Each patient was assessed by two experienced radiologists for stenosis degree by using both NASCET and ECST methods. Statistic analysis was performed to determine the entity of correlation (method of Pearson) between NASCET and ECST. The Cohen kappa test and Bland–Altman analysis were applied to assess the level of inter- and intra-observer agreement. Results: The correlation Pearson coefficient between NASCET and ECST was 0.962 (p <0.01). Intra-observer agreement in the NASCET evaluation, by using Cohen statistic was 0.844 and 0.825. Intra-observer agreement in the ECST evaluation was 0.871 and 0.836. Inter-observer agreement in the NASCET and ECTS were 0.822 and 0.834, respectively. Agreement analysis by using Bland–Altman plots showed a good intra-\inter-observer agreement for the NASCET and an optimal intra-\inter-observer agreement for the ECST. Conclusions: Results of our study suggest that NASCET and ECST methods show a strength correlation according to quadratic regression. Intra-observer agreement results high for both NASCET and ECST. [ABSTRACT FROM AUTHOR]

Purpose: We previously demonstrated the validity of axial source (AxS) image quantification of computed tomographic angiography (CIA) visualized carotid stenosis. There is concern that AxS images may not accurately measure stenosis in patients with obliquely orientated stenosis and that measurements on axial oblique (AxO) multiplanar reformats (MPR), maximum intensity projections (MIP) images, or Doppler ultrasound (DUS) are superior. We tested the performance of AxS images against AxO MPRs, MIPs, and DUS techniques for stenosis quantification. Methods: A total of 120 consecutive patients with CIA and DUS detected carotid disease were enrolled; carotids with occlusion, near occlusion, or stenosis <40% were excluded. Proximal and distal carotid diameters and North American Symptomatic Carotid Endarterectomy Trial (NASCET) style ratios were measured independently by 2 neuroradiologists on AxS, AxO, and MIP images on separate occasions in a blinded protocol. Intra- and interobserver agreements were determined for all measurements. The performance of different image types to identify ≥70% stenosis was assessed against a NASCET-style reference standard. Results: Intra- and interobserver reliabilities for stenosis measurements were higher for both AxS (interclass correlation coefficients [ICCI, 0.87-0.93 and 0.84-0.89) and AxO images (ICCs, 0.82-0.89 and 0.86-0.92) than for MIPs (ICCs, 0.66-0.86 and 0.79-0.82), respectively. Intra- and interobserver agreements on the NASCET ratio tended to be lower than proximal stenosis measurements. AxS and AxO image proximal stenosis measurements most accurately distinguished patients with ≥70% stenosis (0.90), followed by DUS (0.83) and MIP images (0.76). Conclusions: A single AxS image stenosis measurement was highly reproducible and accurate in the estimation of carotid stenosis, which precluded the need for AxO MPRs. [ABSTRACT FROM AUTHOR]

Background.The generally accepted indications for carotid endarterectomy are the clinical picture and degree of per cent stenosis of the carotid artery. Despite the fact that stenosis measurement is defined, the methods vary considerably. The correlation of particular methods, especially angiography and duplex sonography, has been repeatedly demonstrated. However, the correlation between any technique and true anatomical stenosis, as evaluated on the surgical specimen, has been only anecdotally reported.Method.During carotid endarterectomy, the atherosclerotic plaque was removed in one piece and subsequently stored and histologically processed. The histological slides were evaluated under an optical microscope, scanned and the slide with maximum stenosis was determined using a planimetric program. Both the minimal lumen area and the area of the whole plaque were measured. The stenosis was calculated using the planimetric method. On the maximum stenosis slice, the minimal diameter and the diameter of the whole plaque were also measured. Angiographic images were scanned and the per cent stenoses were remeasured, according to the NASCET and ECST criteria. In total, of 147 cases, all above-mentioned parameters were obtained. Student’s t tests for paired samples were used to evaluate the results.Findings.The t-tests indicated significant differences between the per cent stenosis as measured on the anatomical specimen and on the angiogram (p<0.05). The results indicate that the angiographic measurement underestimates the degree of in-situ anatomical stenosis. The underestimation was more marked the less the degree of stenosis.Conclusions.Our study finds that per cent stenosis measurement obtained by angiography with NASCET or ECST methods does not reliably reflect the anatomical degree of per cent stenosis, which makes questionable the rigorous following of percentage stenosis using angiography as the sole indicator for carotid endarterectomy in all cases. [ABSTRACT FROM AUTHOR]

Atherosclerotic lesions of the extracranial cerebral arteries account for ischemic stroke in over half of all cases. The risk of stroke associated with symptomatic carotid artery disease is related to the severity of the stenosis. Results of the two major clinical trials, North American Symptomatic Carotid Endarterectomy Trial (NASCET) and European Carotid Surgery Trial (ECST), showed that patients with symptomatic carotid artery disease may benefit from carotid endarterectomy. Therefore, detection and quantification of stenosis are essential. Discrepancies in the angiographic criteria used in both NASCET and ECST trials resulted in continued controversy about the most accurate method of measuring carotid artery stenosis. Moreover, to avoid complications related to the angiography procedure, a good evaluation of vessel wall and plaque composition need to be considered. Both SCTA and CCDUS are non invasive techniques that could overcome angiographic complications and give detailed information on stenosis grading and plaque characteristics. They have been used to evaluate carotid stenosis as a single or combined methods. [ABSTRACT FROM AUTHOR]