[en] Digital subtraction angiography (DSA) has been widely used in recent years in the field of neurosurgery. Compared with conventional angiography, intravenous DSA (IVDSA) has several advantages. Firstly, it is less invasive, since the contrast media is injected intravenously. It is safe even for a patient with severe atherosclerotic changes in the cervical arteries. Secondly, hemodynamic study can be performed by means of the computed post-processing procedure because the contrast media flows physiologically into all the vessels. In this report, we studied the effectiveness of IVDSA for the evaluation of hemodynamics as compared with Xe-133 single-photon-emission CT (SPECT). The patients examined were those who had stenosis or occlusion of the middle cerebral artery, as diagnosed by IVDSA, and those who were submitted to a SPECT study simultaneously. Regions of interests (ROIs) were placed symmetrically in the territory of the middle cerebral artery in the anteroposterior view. The ROI is not the artery itself, but a wider area, 3 x 4 cm in size. The chronotropical changes in the density of the contrast media were demonstrated as the time-density curve. The time to the peak, the height of the peak, and the area defined by the curve and horizontal axis, which seems to correlate to the cerebral blood volume (CBV), are compared on both sides. By this method, the hemodynamics could be evaluated semi-quantitatively. Several representative cases are demonstrated. While Xe-133 inhalation SPECT measures the regional CBF, this method evaluates the change in the CBV. IVDSA and SPECT are correlative in a majority of the cases. In determining the indications for vascular reconstruction, such as EC-IC anastomosis and/or carotid endoarterectomy, both CBF and CBV should be examined. For this purpose, the hemodynamic study by IVDSA is a useful method, especially when it is combined with SPECT study. (author)