조영증강 경두개 도플러 검사를 이용한 Willis씨 환을 경유한 측부혈류의 반정량적 평가 : 디지탈 감산 혈관조영술과의 비교

Abstract

PURPOSE: The preoperative evaluation of the collal flow through the circle of Willis is necessary for the certain cases such as intracranial aneurysms or head and neck tumors which sometimes need ligation of internal carotid artery. So we intended to evaluate collateral flow through the circle of Willis semi-quantitatively by transcranial Doppler ultrasonography (TCD) using Levovist(R) for the purpose of replacing invasive digital subtraction abgiography(DSA). MATERIALS & METHODS: Twenty-two TCD examinations with bolus injection of Levovist (Schering AG, Germany) on 20 patients with central nervous system diseases were undertaken with color Doppler machine(128XP/10, Acuson, USA). All of them had taken DSA. We compared the results of TCD with those of DSA in finding out the presence and the amount of collateral flow through the circle of Willis. We also compared the change(minimal decrease, marked decrease, complete loss) of color Doppler signal intensities(SI) with decrease ( < or > or =65%) of mean middle cerebral artery (MCA) flow velocity before and during compression of ipsilateral common carotid artery (CCA) on TCD. RESULTS: TCD coincided with DSA in finding out the presence of collateral flow through anterior communicating artery (AcoA) except 2 patients with extremely poor transmittance of acoustic window. TCD, however, could not detect collateral flow through posterior communicating artery (PcoA) execpt 1 patient with fetal type PcoA. TCD depicted 4 cases with insufficient amount of collateral flow from 12 cases which showed good collateral flow through AcoA in DSA. On TCD, the cases with minimal decrease of color Doppler SI(n=8) during compression of ipsilateral CCA also showed decrease of mean MCA flow velocity less than 65% which means sufficient amount of collateral flow. CONCLUSION: Semi-quantitative assessment of the amount of collateral flow could be done by checking the changes of mean flow velocity and color Doppler SI of MCA by TCD, and TCD can replace DSA for the functional evaluation of collateral flow through the circle of Willsi.