Re-evaluation of Radioisotope Angiography as a Screening Test for Ischemic Cerebral Diseases

Abstract

Old patients need a non-invasive screening test instead of conventional angiography for diagnosis of cerebrovascular diseases (CVD). The availability of radioisotope (RI) angiography as a screening test was studied on ischemic cerebral diseases, and compared with computed tomography findings or conventional angiographic findings. RI angiography was performed with a bolus injection of 20 mCi 99mTcO4- via a cephalic vein using a scintillation camera and an on-line computer system. One hundred images were obtained during 50 seconds. RI angiography was found useful for detecting occluded major arteries and perfusion through collateral circulations in acute stage of the ischemic CVD. Sequential examinations of RI angiography were performed without complications even in old patients. Recanalization of the major arteries was also detected without the help of conventional angiography. Occlusion of an internal carotid artery with no cross circulation indicated a poor prognosis, whereas good collateral circulation such as the presence of the flip-flop sign indicated a good recovery. A patent extracranial-intracranial (EC-IC) bypass after an operation and a patent internal carotid artery after a carotid endarterectomy were well detected. Increased perfusion of the distal middle cerebral arteries from the EC-IC bypass was revealed. The intracranial non-filling phenomenon in patients with brain death was also well detected. RI angiography is suitable for screening of ischemic cerebral diseases, especially in old patients, reconstructive vascular surgery, and brain death.