Syoji Asari

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.

Towne (Half-axial) and semisagittal computed tomography in the evaluation of blow-out fractures of the orbit

Three cases of blow-out fractures of the orbit were evaluated by Towne and semisagittal computed tomography (CT). The Towne CT well delincated the inferior rectus muscle, the orbital floor, and the entrapped orbital contents, including a bony fragment in the maxillary sinus. The semisagittal CT plane was optimal for lateral delineation of the orbit, although their is need for improvement in the head positioning and gantry width. Postoperative recovery of impaired eye movements was related to CT findings.

Normal anatomy of cerebral vessels by computed angiotomography in the coronal, Towne, and semisagittal planes.

This report presents a detailed analysis of the normal cerebrovascular anatomy on the modified coronal, Towne (half-axial), and semisagittal computed tomographic (CT) images. Direct multiplane CT scans were obtained from fresh cadavers injected with gelatinous iodine solution. The modified coronal plane is optimal for delineation of the internal carotid bifurcations and the anterior and the middle cerebral arteries, and for identification of the lenticulostriate arteries and the angiographic sylvian point. The Towne plane is optimal for delineation of the vertebrobasilar arterial system. Thorough knowledge of the normal appearance of cerebral blood vessels in biplane or multiplane computed angiotomography is a prerequisite for understanding the spatial relationships of the abnormal cerebrovascular anatomy.

Normal anatomy of cerebral vessels by computed angiotomography in the axial transverse plane

A detailed analysis of normal cerebrovascular anatomy on axial transverse computed tomographic (CT) images is presented. Fresh cadavers were injected with gelatinous iodine solution for clear visualization of cerebral blood vessels. A detailed knowledge of the normal cerebrovascular anatomy on the axial transverse CT image in relation to other intracranial structures is a prerequisite for the interpretation of cerebral computed angiotomograms.

Fast overlapping scans in cerebral computed angiotomography.

Three to four overlapping cerebral CT scans were obtained after the injection of a single bolus of contrast medium. The rapid sequential dynamic scanning was carried out with table increments, while there was peak iodine density in the carotid artery. The demonstration of cerebral vessel lesions (aneurysms, moyamoya disease, arteriovenous malformations, arterial narrowing, etc.) is easier and safer with this method as compared with the conventional multiple injection technique.