[Modern imaging in cerebral XXXX ].

@entity2758 @entity548 @entity2695 @entity600 @entity6623 @entity2287 @entity1211 @entity1462
@entity6623 are @entity1462 of the brain which, before the advent of modern imaging, and in particular MRI, were thought to be rare. They have a specific angiographic aspect called "caput Meduse" as it corresponds to the description of a large draining vein to which converge numerous radial veins located in the white matter. These @entity1462 have characteristic histological features making it possible to differentiate them from other @entity1462 , notably cavernomas. These lesions are less scanty than classically believed, being the most frequent @entity600 encountered in post-mortem examination series. The circumstances in which cerebral @entity6623 are discovered vary considerably, and @entity548 can be the revealing sign. Some authors regard these @entity600 as "abnormalities" of white matter veins and not as pathological entities, since they derive from a change in development during embryogenesis, but this theory is not supported by any anatomical evidence. The same authors attribute the bleeding to an associated cavernoma. Whereas CT enables @entity6623 and possible associated cavernomas to be detected, only repeated MRI explorations performed after the finding of @entity6623 and @entity548 can permit, by analysis of signal changes, to confirm or invalidate the non-pathological theory of the @entity1211 and its tendency to bleed. Apart from hemorrhages, since @entity2287 is used MRI is the most reliable and least invasive means to diagnose @entity2695 and to detect associated occult angiographic @entity600 . For this reason, nowadays only hemorrhages require an angiography in search of an @entity2758 demanding prompt treatment. Moreover, MRI makes it possible to detect angiographically occult @entity600 .
