Abstract
Purpose: To clarify the usefulness of carotid ultrasonography for evaluation of cross-filling through the anterior communicating artery (ACoA) of the circle of Willis, which is regarded as the primary collateral pathway in patients with trial occlusion of the internal carotid artery (ICA). Methods: Cross-filling on the angiogram was determined by contrast filling of the ACoA following an injection of contrast medium into the carotid artery with temporary manual occlusion of the contralateral common carotid artery (Matas test). The appearance of cross-filling was graded on the following 3-point scale: grade 1, there was no apparent cross-filling on the angiogram; grade 2, slight but definite collateral distribution, often with dilution, e.g. to the anterior cerebral artery alone or to both the anterior cerebral and middle cerebral arteries; grade 3, complete cross-filling, i.e. to the middle cerebral artery. On carotid ultrasonography, we measured the blood velocity in the ICA (VICA) before and during the Matas test. Correlation between the grade of cross-filling and the VICA in carotid ultrasonography was investigated in each case. Results: In grade 3 patients, the VICA increased immediately during Matas test, while that of other patients remained unaffected by occlusion test. Consequently, increased VICA (≥20%) on carotid ultrasonography during the Matas test suggested that cross-filling via the ACoA is a more effective pathway compared with unchanged VICA (‹20%) during the Matas test. Conclusion: A combination of carotid ultrasonography and the Matas test seemed to be useful and minimally invasive in predicting cross-filling via the circle of Willis.
