Retinal Wada test.
نویسندگان
چکیده
The interventionist needs precise information about the tissue supplied by an artery that is to be embolized. With intracranial arteriovenous malformations (AVMs), Amytal* can be used to challenge cerebral arteries and their branches [1]. Cranial nerves are physiologically and histologically like peripheral nerves, so external carotid artery branch embolization can be controlled by challenge with intraarteriallidocainet [2]. Doppman [3] has reported that the spinal cord , like the brain , is exquisitely sensitive to Amy tal. We recently had occasion to embolize an ophthalmic artery whose branches fed an extremely vascular frontal meningioma (Fig.1). It was necessary to ascertain in advance whether this could be done safely by using the more preferred agent, gelfoam powder, ~ which can pass into the capillary bed of the tumor (Kerber CW, personal communication), or the alternative, large particles of polyvinyl alcohol (PVA) foam,§ which stop short of that point and occlude the arterioles. We knew that if our slowest injection rate would be likely to result in flow to the globe, then it would be necessary to use particles larger than the lumen of the retinal artery to prevent embolization of the retina. This is exactly analogous to the particlesize strategy for embolizing spinal cord AVMs [4]. The right ophthalmic artery was selectively catheterized by transfemoral approach . The feeder vessels themselves were as large as the ophthalmic artery trunk, but could not be individually catheterized. We determined that a small artery was supplying the retina beyond the origin of these feeder vessels. Since near-exsanguination had occurred on an earlier attempt to operate, the desirability of tumor devascularization was obvious. Amy tal in a dose of S mg was injected through the catheter without causing a loss of visual acuity . After S min, O.S ml of 1 % lidocaine (S mg) mixed with a like volume of iohexol was injected, and an irregular but definite scotoma was grossly detectable. This resolved in 2 min. As in the case of testing external carotid artery branches before embolization, we opacified the lidocaine so that we could be certain that it would not reflux into the internal carotid system and possibly precipitate a seizure.
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عنوان ژورنال:
- AJNR. American journal of neuroradiology
دوره 9 6 شماره
صفحات -
تاریخ انتشار 1988