ARTERIOVENOUS MALFORMATION HEMODYNAMICS - A TRANSCRANIAL DOPPLER STUDY

CONGENITAL ARTERIOVENOUS MALFORMATION (AVM) of the brain represents a defect in capillary development resulting in a high flow fistula betwe en arterial and venous systems. In this study, AVM hemodynamics were r elated with clinical findings. Volume flow was calculated based on tra nscranial Doppler (TCD) and angiographic data. Forty patients admitted to the Massachusetts General Hospital for proton beam therapy (33 +/- 10 yr old; mean +/- SD) were studied. Four symptoms were considered: intracranial bleeding, progressive neurological deficit, seizures, and headache. Fourteen control subjects aged 30 +/- 7 years (mean +/- SD) were normal volunteers. Angiography with calibrated markers permittin g magnification correction was available for all patients. Lateral and medial depth limits of the intracranial basal arteries in relation to the TCD temporal window were determined by TCD and angiogram with exc ellent correlation. Selected depth for data acquisition was determined independently in the angiogram and by TCD. The difference between the two techniques was less than 4 mm. Mean flow velocity, pulsatility in dex, and vessel diameter were studied. Flow volume was calculated from these data. Mean flow velocity, pulsatility index, vessel diameter, a nd flow volume were significantly different among AVM feeders, non-fee ders, and control arteries. The non-feeding middle cerebral artery, an terior cerebral artery, and posterior cerebral artery flows were 254 /- 13, 136 +/- 14, and 79 +/- 8 ml/min, respectively. Accordingly, the estimated cerebral flow volume was 938 ml/min. The feeding middle cer ebral artery, anterior cerebral artery, and posterior cerebral artery flows were 552 +/- 47, 369 +/- 70, and 484 +/- 67 ml/min, respectively (P < 0.001). The mean flow volume to the AVMs was 913 +/- 227 ml/min, and patients having hemorrhage had significantly lower flow volume (6 24 +/- 117 ml/min, P < 0.01) than patients having other symptoms. TCD accurately determined the depth limits of the basal cerebral arteries measured against the angiographic determinations. The evaluation of fl ow volume with vessel diameter measured in the angiogram and flow velo city was close to that reported by authors using other techniques. Ana lysis of these data disclose important hemodynamic patterns related to AVM symptomatology. These patterns may have therapeutic implications.