Transcranial Doppler diagnostic criteria in the evaluations of arteriovenous malformations.

In order to get a better insight in hemodynamic occurrence of intracranial arteriovenous malformations (AVM), 31 patients with AVM, documented by CT and angiography, were investigated by Transcranial Doppler (TDC). Although the angiography provides definite diagnosis of AVM, its size, position, type feeders and involvement of various vascular segments, TCD provides more information about collateral circulation, intracerebral shunts or functional stenosis due to high blood velocities within the blood vessels involved by AVM. The parameters obtained by TCD: mean cerebral blood flow velocities (MCBFV) in middle and internal carotid artery (MCA, ICA), pulsatility index (PI), MCA/ICA ratio and (S-D)/S ratio were introduced. Results have shown that TCD findings in non-feeding arteries were normal in all patients. TCD finding of MCBFV in MCA and ICA, PI and MCA/ICA ratio in feeding arteries has shown a significant difference from normal arteries (p less than 0.01). These parameters are shown to be AVM size dependent. MCBFV in MCA on the feeder side was statistically significant higher in those patients with large AVM (greater than 4 cm) size (p less than 0.01). For assessment of AVM and its improved and advanced analysis the potential advantages of parameters: (S-D)/S ratio and 3D hemodynamic mapping has been emphasised.