Noninvasive evaluation of extra-/intracranial anastomoses by dynamic CT and Doppler sonography.

In order to find a reliable noninvasive method of evaluating patency and function of extra-/intracranial arterial bypass, pre- and postoperative angiograms were compared with the results of pre- and postoperative dynamic computed tomographic (CT) scans and Doppler sonographic findings. Doppler sonography alone is a reliable method for determining patency and relative function of the anastomosis. Dynamic CT permits qualitative evaluation of cerebral perfusion and, by comparison of pre- and postoperative scans, assessment of the contribution of the extra-/intracranial bypass to the circulation of the affected hemisphere. Combined use of Doppler sonography and dynamic CT provides sufficient information about the postoperative status of cerebral perfusion to obviate the use of conventional angiography in routine cases.