Vascular reactions after cerebral angiography have not been hitherto extensively explored due to the lack of a simple, easily available, and safe method for the measurement of cerebral circulation. We attempted to study cerebral circulation with color Doppler transcranial sonography (TCCS) in consecutive patients before and immediately after digital subtraction angiography (DSA).TCCS examination of the major cerebral arteries was carried out in 52 patients (25 females and 27 males), mean age 50.3+/-11.5 years, before and 10-20 minutes after cerebral angiography. A Toshiba Aplio SSA 770A system with a 2.5-MHz sector transducer was used.In general terms, there was a tendency after DSA towards a slight decrease in peak systolic blood velocity and an increase in mean and end-diastolic velocity in all the major cerebral arteries which, in turn, led to a decrease in the impedance index (pulsatility index, PI). In 19 patients, the impedance index as measured in the middle cerebral artery decreased after DSA, in 29 it did not change, while in 4 patients PI increased. Discriminant analysis showed that the factors predisposing individuals to these adverse reactions were a low score on the Glasgow Coma Scale, etiological diagnosis of intracerebral bleeding, and a high value of the impedance index prior to the procedure.Contrast cerebral angiography may affect the tonus of cerebral vessels. In the majority of patients it caused vasodilatation to varying degrees and in a small sub-group vasoconstriction.