[Computer tomographic diagnosis of a mega-dolicho basilar artery (author's transl)].

Four mega-dolicho basilar arteries are described, which were found by computer tomography and confirmed by angiography. Two patients showed additional abnormalities or anomalies of other vessels. The computer tomographic features are described. The elongated vessels can produce so-called normal pressure hydrocephalus by impressing the floor of the third ventricle, although the hydrocephalus cannot be confirmed by computer tomographic cisternography.