Internal carotid artery stenosis: comparison of duplex scan and magnetic resonance angiography with digital subtraction angiography

Abstract

-Objective: We compare duplex scan (DS) and magnetic resonance angiography (MRA) with digital angiography (DGA) in respect to accuracy in measuring internal carotid artery (IC) stenosis in symptomatic patients. Method: Ten symptomatic patients with IC stenosis greater than 70% previously diagnosed by DS were submitted to another DS and to both MRA and DGA. Both ICs from each patient (total 20 ICs) were evaluated by physicians blinded for the results of other tests. DS and MRA were compared with DGA, using the intraclass correlation coeficient (r) and its 95% confidence interval (95% ci). .or each diagnostic test, the study group (20 Ics) was also divided in surgical patients (IC stenosis between 70 and 99%) and non surgical patients, using kappa concordance coeficient (k) to compare the results. KEY WORDS: carotid stenosis, diagnosis, cerebrovascular disease, comparative study.Estenose da artéria carótida interna extracraniana: comparação de duplex-scan e angio-ressonância com angiografia digital RESUMO -Objetivo: .oram comparados duplex scan (DS) e angio-ressonância magnética (AGRM) com angiografia digital (AGD) na avaliação da estenose da artéria carótida interna (CI). Método: .oram estudados 10 pacientes sintomáticos com estenose da CI superior a 70% em estudos de triagem com DS. Os pacientes foram submetidos a novo DS, AGRM e AGD para estudo de ambas as CIs (total 20 CIs). O DS e a AGRM foram comparados com a AGD utilizando-se o coeficiente de correlação intra-classe (r) e o seu intervalo de confiança a 95% (ic 95%). Para cada método diagnóstico, o grupo de pacientes (considerando as 20 CIs) foi também dicotomizado em casos cirúrgicos (estenose entre 70% e 99%) e não cirúrgicos, utilizando-se o coeficiente kappa de concordância (k). Resultados: Na comparação entre DS e AGD, obteve-se r = 0,71 (0,4 -0,87). Entre AGRM e AGD, r = 0,61 (0,25 -0,82). Após a dicotomização da amostra, obteve-se, entre DS e AGD, k = 0,857, p < 0,0001; e entre AGRM e AGD, k = 0,545, p = 0,003. A maioria dos erros de DS e AGRM ocorreu nos casos de suboclusão arterial. Conclusão: Os resultados sugerem que o DS e a AGRM, usados em conjunto, podem substituir a AGD na indicação da endarterectomia carotídea, exceto quando há discordância entre os dois ou quando algum dos métodos detecta suboclusão arterial.

Accuracy of Magnetic Resonance Angiography for Internal Carotid Artery Disease

“…Negative predictive value (95% CI) was 100% (74.7% to 100%) and 100% (69.9% to 100%) respectively. 2 Because of our small sample size, confidence intervals were large, but results are similar to those found in the meta-analysis by Debrey et al 1 A previous meta-analysis 4 found different results with 82% to 86% sensitivity and 98% specificity for duplex scan and MRA cases with total ICA occlusion. In stenosis Ն70%, sensitivity ranged from 83% to 86% and specificity ranged from 89% to 94%.…”

“…2 In conclusion, combining duplex scan and MRA results may prove more dependable than using MRA alone; when both methods are concordant, they may safely substitute invasive DGA.…”

Comparison between the NASCET method and subjective visual impression in the evaluation of internal carotid artery stenosis

“…Their clinical presentation and course have been fully described 13 . Table 2 shows the main numeric values obtained.…”

“…Using material generated in another study 13 , the authors made a direct comparison between SVI of an experienced neuro-radiologist (.SA) and a well established method to measure IC stenosis the NASCET method 5 . There was an excellent correlation between the obtained numeric values.…”

“…Ten consecutive patients from a university hospital selected to another study 13 -agreed to participate. In summary, the inclusion criteria were: age up to 80 years; history of transient ischemic attack (TIA) or mild stroke Rankin scale 14 up to grade two in the ipsilateral IC territory; a previous DS showing IC stenosis equal or greater than 70% in one or both extracranial IC; and informed consent.…”