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 Printable version |
Consensual recommendations concerning the morphology and the cerebral risk of carotid stenosis |
Sang Thrombose Vaisseaux. Volume 10, Number 10, 623-30, Décembre 1998, Mini-revues
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 Résumé
Article gratuit
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Author(s) : Jean-Michel de Bray, Jean-Michel Baud, Michel Dauzat |
Summary : The risk of stroke is significantly related to the degree of carotid stenosis, but other factors appear to increase the risk. They are in order of descending importance: progressivity of the lesion, surface ulceration and low echogenicity. These parameters necessitate a standardisation of all investigations. This was the purpose of the International Consensus Conference that was held in Paris on December 13th-14th 1996. The authors emphasise the main aspect in routine and on the importance of comparison of the investigations. Arteriography identifies recent thrombi, large calcification and ulceration defined in two classes: simple, > 2 mm and complex with several craters, but this is not adapted to tissue analysis. MR angiography can also detect ulcerations > 2mm but remains limited because of turbulent flow, and by its common contra-indications. MRI studies in vitro suggest that this modality could be useful to the characterisation. Computerised tomographic angiography has the advantage of providing an image of walls and a tridimensional rendering of the extent of the plaque. It differentiates calcified and fatty densities and recognises ulcerations > 2 mm. Ultrasonic morphological analysis remains limited in cases of calcified stenosis. It is, however, the only means of describing the composition of stenosis. The best parameter is their echogenicity by taking into account their size and extension while having relevant images. It has to be standardised with reference to the flowing blood (anechoic), to the sternocleidomastoid muscle (isoechoic) and to the cervical vertebra (hyperechoic). Extreme aspects of echogenicity from anechoic to iso- or hyperechoic are the better validated. Ulcerations have to be defined by 3 parameters: their dimensions in width and in depth > 2 mm, colour Doppler injection and a well defined base. These recommendations provide semi-quantitative measurements routinely and could facilitate prospective studies and computerised examinations. |
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