Research on hemodynamics of cerebral arteriovenous malformation by Doppler ultrasound.

Combined extracranial and transcranial Doppler (TCD) instruments were used to study the hemodynamics of 20 patients with cerebral arteriovenous malformation (AVM) proved angiographically. It was discovered that the flow velocities in AVM-feeding arteries and their proximal arteries were increased; the increase of flow velocities in feeding arteries close to AVM was more remarkable than that in feeding-arteries proximal to extracranial internal carotid artery far from AVM; pulsating indexes of AVM-feeding arteries were decreased; increase of flow velocities in AVM-feeding arteries was related to the decrease of pulsating index; the flow velocities of nontapering feeding arteries were faster than those of tapering arteries; the greater the size of AVM, the faster the velocity in feeding artery; and the flow velocities and pulsating indexes of AVM-feeding arteries were gradually recovered to normal 3-5 weeks after resection of AVM. It is believed that increase of flow velocity in AVM-feeding artery is associated with distention and decreased resistance of flow in AVM-feeding artery. TCD combined with CT scans are helpful to the diagnosis of AVM. Combination of TCD and cerebral angiography (CAG) to evaluate comprehensively the preoperative hemodynamics of AVM and to monitor postoperative changes is helpful to detecting cerebral steal due to steal leakage in circle of Willis and preventing the hazardous postoperative complications caused by pressure breakthrough of normal perfusion.