| Abstract: | The present study was carried out in 12 patients (7 males and 5 females) aged 16-56 years (mean age 35.9) with arteriovenous malformation diagnosed in cerebral angiography. The examination was performed by means of ATL ULTRAMARK 9 with low-frequency (2MHz to 3MHz) transducer. Assessment was made of possibilities of imaging arteriovenous malformations by transcranial colour-coded duplex sonography and of blood flow values in the studied intracranial arteries. Statistical analysis was applied of the following blood flow parameters: mean velocity, peak systolic velocity, end diastolic velocity, pulsatility index (PI), resistance index (RI), pulsatility transmission index (PTI) and relative flow velocity (RFV). The malformations were imaged using TCCS in 9 (75%) patients. In two-dimensional B mode image the angiomas displayed echogenicity similar to the surrounding brain parenchyma and could not be precisely delineated. The colour-coded imaging made possible depicting the image of the vessel loops in the AVM nidus. In two other patients the presence of angiomas was confirmed by blood flow disturbances in the feeder vessel: increased blood flow, decreased pulsatility and resistance indices, and collateral circulation. Collateralization by the contralateral internal carotid artery via the anterior communicating artery was disclosed in 9 cases. The TCCS results corresponded closely to angiographic findings. Collateral circulation via the posterior communicating artery ipsilateral to the AVM was found in 3 of 5 patients in whom it was diagnosed in cerebral angiography. Doppler findings in the patients were similar to the conventional TCD examination. In the feeding vessels significant increase in blood flow velocity and decreased pulsatility and resistance indices was observed. RFV value for the end diastolic velocity was higher than RFV for the peak systolic velocity (p < 0.001) and mean velocity. These findings suggest that the increased end diastolic velocity in the feeding vessel is higher than the mean velocity and peak systolic velocity. It is thought that the TCCS can be successfully used in early diagnosis of cerebral arterio-venous malformations and as an instrument in follow-up examination. |
