Using transcranial duplex sonography for monitoring vessel patency during surgery for intracranial aneurysms

This article reports a method for reliable intraoperative monitoring of blood flow velocities in the basal cerebral arteries during clipping of intracerebral aneurysms. Transcranial color-coded duplex sonography provides practical integration of transcranial Doppler technology with real-time imaging capabilities through the intact human skull. With a computerized sonography system equipped with a 2.5-MHz probe in 50 healthy volunteers, the contralateral internal carotid artery, A1 and A2, as well as M1 and P1 vessels were identified and measured in most patients. In 13 patients undergoing dipping of intracranial aneurysms, the technique successfully imaged 12; it allowed definitive identification of vessels potentially threatened by clipping and not fully visible to the surgeon. Data were easily comparable to preoperative data. This noninvasive, repeatable neuroimaging technique provides useful intraoperative information about intracranial hemodynamics during dipping of intracranial aneurysms.