Use of Tc-99m HMPAO brain SPECT to evaluate cerebral collateral circulation during Matas test

Five patients with traumatic carotid-cavernous fistulae and two patients with internal carotid artery aneurysms inside the cavernous sinus are presented. A quantitative method was used for the evaluation of brain collateral circulation in the anterior and middle cerebral artery territories by using Tc-99m HMPAO SPECT before and during the Matas test. It affords a more reliable quantitative measurement of reduced activity than conventional carotid angiography during the Matas test. In this study, a reduction of radioactivity of less than 15% during the Matas test did not reveal any postoperative neurological deficit after a carotid artery trapping procedure. This noninvasive method seems to be useful to determine the appropriate surgical treatment.