MR flow measurement using RACE before and during the Matas test seems to be a noninvasive method for evaluating cerebral collateral circulation via the circle of Willis. Increased blood volume is thus thought to maintain the blood supply of a cerebral hemisphere affected by compression of the common carotid artery via the anterior communicating artery. The anterior communicating artery was visualized in all subjects. The relative mean ratio was 1.74 with a standard deviation of 0.36.
Six out of the 10 common carotid arteries were sufficiently compressed to stop blood flow. Additionally, using a head coil, 3 dimensional time-flight MR angiograms of the brain were obtained for each subject order to evaluate the anterior communicating artery. The relative flow ratio of the contralateral carotid artery (flow velocity during the Matas test divided by that before the Matas test) was calculated. Flow velocity of the common carotid artery was evaluated using the RACE technique before and during a Matas test. The total acquisition time is about 10 seconds without need for electrocardiographic synchronization. RACE is a one-dimensional projective flow measurement technique using fast low angle shot (FLASH) without phase encoding gradient (FLASH sequence: TR=20 ms, TE=6 ms, FA=90 degrees, FOV=220 mm, slice thickness=8 mm). Five normal subjects were studied with a 1.5 T superconducting imager (Siemens, Erlangen) using a neck coil. The purpose of our study was to evaluate the flow velocity of the contralateral common carotid artery using Renal Time Acquisition and Velocity Evaluation (RACE) before and during a Matas test and to estimate brain collateral circulation. Prior to the temporary or permanent therapeutic occlusion of the carotid artery, evaluation of the cerebral collateral circulation via the circle of Willis is necessary in order to prevent complications. Isoda, Haruo Masui, Takayuki Takahashi, Motoichiro Mochizuki, Takao Kaneko, Masao Ohta, Atsuko Shirakawa, Toyomi.
International Nuclear Information System (INIS) Matas test combined with MR flow measurement
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