Analysis of Cerebral Blood Circulation using Intravenous Digital Subtraction Angiography

Abstract

Digital subtraction angiography with intravenous injection of contrast medium was used to assess 10 patients with ischemic disease. The time-density curve (TDC) was evaluated for its usefulness in analyzing brain blood circulation (dynamics). Such other parameters as peak time (PT), mean transit time (MTT), and mode of transit time (MOTT) were also assessed. Particular attention was paid to high convexity, watershed, and perforator areas of the middle cerebral artery, which are regions of interest in the bilateral hemispheres. The dynamics of blood circulation demonstrated by this method were compared with those demonstrated by single photon emission computed tomography (SPECT). In patients with carotid artery stenosis, the TDC at the convexity area on the affected side showed both a gentle upward slope and a slow downward slope, and all parameters (PT, MTT, MOTT) were prolonged. After endarterectomy, the delay in all parameters decreased and the laterality of the TDC diminished. In patients with middle cerebral artery occlusion, the TDC at the convexity area on the affected side showed delay of attenuation, and all parameters were prolonged. After superficial temporal artery-middle cerebral artery anastomosis, the peak on the operated side was higher than that on the unaffected side and prolongation of MTT and MOTT on the affected side was decreased. In cases of moyamoya disease, none of the parameters could be calculated because the TDC showed no downward slope. In all of the evaluable cases, TDC data were superior to SPECT determinations in detecting laterality of the circulation. These results indicate that this method accurately demonstrates laterality of circulation time and volume as well as the degree of collateral circulation. The TDC and other parameters appear useful in determining whether or not surgery is indicated and in estimating the postoperative circulation in patients with ischemic disease.