[Quantitative assessment of carotid stenosis: comparison between Doppler ultrasound, spiral computed tomography angiography, magnetic resonance angiography and digital angiography]. / Quantification du degré de sténose carotidienne. Comparaison entre l'échographie Doppler, le scanner hélicoïdal, l'imagerie par résonance magnétique et l'angiographie numérise.

BACKGROUND: The North American Symptomatic Carotid Endarterectomy Trial has confirmed the benefit of carotid endarterectomy in comparison to medical treatment in stroke prevention in symptomatic patients having a carotid stenosis of 70% or more. The Asymptomatic Carotid Atherosclerosis Study has concluded that the benefit of surgical treatment remains significant in asymptomatic patients with 60% (or more) stenosis of the ipsilateral internal carotid artery, when mortality rate remains inferior to 3%. In these two trials, angiography has been used to quantify the stenosis. Though this test is carrying some neurological and renal risks, replacing the angiography stenosis grading for a non or less invasive test, seems to be permissible. METHODS: In our retroprospective study, the assessments of the carotid stenosis by several non-invasive tests findings were compared to the angiography results. Nineteen carotid arteries of fifteen patients, both symptomatic and asymptomatic, having a carotid stenosis at least 60% or more and being detected by the Doppler ultrasound were explored either by magnetic resonance angiography (MRA), spiral computed tomography angiography (SCTA) and angiography. RESULTS: The ultrasonography and angiography findings were well correlated (r=0,88; p<0.002) according to the Spearman test. The assessments of the MRA were better correlated to the angiography than to the SCTA (respectively r=0.91, p<0.0001 and r=0,68, p<0.001). Using both ultrasonography and MRA as a confirmatory test, the rate of injustified carotid endarterectomy was 25%. And this rate rose up to 33% when the ultrasonography was used with the SCTA. It is noteworthy that negative predictive value of ARM was 100%. To reduce the mortality rate, several surgical teams managed the carotid stenosis without angiography. CONCLUSION: MRA could replace angiography, on condition that the rate of unjustified carotid endarterectomy lowers and becomes acceptable. Far reaching complementary studies are necessary to confirm the fiability of those non-invasive tests. In order to raise the benefit to carotid endarterectomy, the research studies should turn to the predictive score determination of a surgical international risk and towards the "High benefit" patients groups after endarterectomy.