Minimum dose contrast bolus in computed angiotomography of the brain.

We have carried out basic investigations of an intravenous minimum dose bolus (MinDB) injection method for cerebral computed angiotomography by comparing blood iodine concentrations with high resolution computed tomography (CT) images of cerebral blood vessels. With the GECT/T 8800 scanner, a MinDB injection of 1 ml/kg of 60% Conray at a rate of 2 ml/s made it possible to increase the blood iodine concentration in the carotid artery to more than 15 mg/ml for about 20 s. Computed tomography performed during this period enabled us to obtain clear images of the circle of Willis, including other main cerebral arteries, deep veins, and cortical and lenticulostriate arteries. Cerebral computed angiotomography using this method should be useful for noninvasive screening or detection of cerebrovascular lesions themselves, such as cerebral aneurysms, cerebrovascular obstructions, arteriovenous malformations, and moyamoya disease, and should also be useful for determining the anatomical relationship between the cerebral blood vessels and other parenchymal or space occupying lesions.