[Usefulness of three-dimensional CT angiography (3D-CTA) with a single bolus injection of contrast material for the examination of intracranial and cervical arteries in cerebrovascular disease screening].

Three-dimensional CT angiography (3D-CTA) has been gaining wide acceptance as a clinically useful tool in the field of neurosurgery. The great diagnostic value of 3D-CTA for cerebral aneurysm or other cerebrovascular diseases has been well established. However, images of the intracranial and cervical arteries have not been obtained simultaneously because of the limitation of the scanning area and the need for contrast material. In order to use 3D-CTA to screen for cerebrovascular disease, we used a helical CT scan with an intravenous single bolus injection of contrast material to perform 3D-CTA of the intracranial and cervical arteries simultaneously. A spiral computed tomographic scan was performed with a Hispeed Advantage RP (General Electric). After injection of 150 ml of nonionized contrast material at a rate of 3 mm/sec in an antecubital vein, an axial computed tomographic scan (120 kV, 200 mA) of the cranial region was performed with a delay of 20-25 seconds after starting the injection. Section thickness was 1 mm with table increments of 1 mm per rotation. The scan volume included 20-30 mm above and below the sella turcica. An axial computed tomographic scan (120 kV, 190 mA) of the cervical region was performed with a delay of 30 seconds after completion of cranial CTA. Section thickness was 3 mm with table increments of 3 mm per rotation. Image reconstruction was carried out through surface rendering and maximum intensity projection processing. From November 1995 to August 1998, we used this technique to screen 218 consecutive outpatients for cerebrovascular disease. Unruptured cerebral aneurysms were found in 20 cases (9.2%). Atherosclerotic diseases of the cervical carotid artery were found in 58 cases (26.6%), as follows: carotid artery occlusion in 2 cases, carotid bifurcation stenosis in 22 cases, and intramural calcification of the internal carotid artery in 50 cases. Atherosclerotic diseases of the intracranial artery were found in 99 cases (45.4%), as follows: middle cerebral artery occlusion in 2 cases, middle cerebral artery stenosis in 21 cases, internal carotid artery stenosis in 2 cases, and calcification of the carotid siphon in 78 cases. Although our method has various technical problems that require further improvement, we conclude that it is a useful and noninvasive diagnostic modality for screening patients for cerebral aneurysms and other cerebrovascular diseases.