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 arterioven ous malformation (AVM) proved angiographically. It was discovered that the flow velocities in AVM-feeding arteries and their proximal arteri es were increased; the increase of flow velocities in feeding arteries close to AVM was more remarkable than that in feeding-arteries proxim al to extracranial internal carotid artery far from AVM; pulsating ind exes of AVM-feeding arteries were decreased; increase of flow velociti es in AVM-feeding arteries was related to the decrease of pulsating in dex; the flow velocities of nontapering feeding arteries were faster t han those of tapering arteries; the greater the size of AVM, the faste r the velocity in feeding artery; and the flow velocities and pulsatin g 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 decre ased resistance of flow in AVM-feeding artery. TCD combined with CT sc ans are helpful to the diagnosis of AVM. Combination of TCD and cerebr al angiography (CAG) to evaluate comprehensively the preoperative hemo dynamics of AVM and to monitor postoperative changes is helpful to det ecting cerebral steal due to steal leakage in circle of Willis and pre venting the hazardous postoperative complications caused by pressure b reakthrough of normal perfusion.