Large Vascular Malformations of the Brain Not Visualized by Serial Angiography

IIT IS GENERALLY accepted that large symptomatic intracranial vascular malformations can be definitively demonstrated by angiography. Olivecrona and Riives1in 1948 stated: "Arteriograms, of course, always disclose the presence of an arteriovenous aneurysm" and pool,2in 1962, similarly stated: "Arteriography is, of course, the key test for the diagnosis of an arteriovenous malformation." Small vascular malformations which have not been demonstrated angiographically have been found at operation or autopsy in the walls of intracranial hematoma.3-6These have ranged in size from malformations found only in microscopic examinations to those just visible to the naked eye and at the limits of x-ray resolution. Partial destruction of the malformation, occurring at the time of hemorrhage and hematoma formation, has been invoked as the cause of lack of visualization of these smaller malformations. Five cases have been reported of large vascular malformations which theoretically should have shown on arteriography