Evaluation of Cerebral Vascular Disease With Radionuclide Angiography

Abstract

Experience with radionuclide angiography (RA) utilizing radiosodium pertechnetate and the scintillation camera as a practical means of evaluating cerebral vascular disease (CVD) is presented. The normal RA patterns were established in more than 500 patients without clinical evidence of CVD. Detailed study of the arterial and venous perfusion patterns in cases of CVD showed that certain discrete changes can be classified. The RA patterns were evaluated in 143 patients with strokes and in 120 patients with transient ischemic attacks (TIA) and correlated with symptomatology, clinical hospital course and cerebral angiograms. Although static brain scanning in patients with strokes is reportedly positive in approximately 42%, such scans are rarely positive (3%) in patients with TIA. However, by using the RA in combination with static camera imaging, in those patients wth documented stroke, positive studies were obtained in more than 80%, a twofold increase compared to previous experience. In patients with TIA, a tenfold (33%) increase in positive studies was found related to CVD and, in addition, another 7% were positive as mass lesions. The data presented stress the importance of establishing specific criteria for analysis of RA as well as the greatly enhanced sensitivity of this combined approach in detecting CVD.

Radionuclide cerebral blood flow and carotid angiogram. Correlation in internal carotid artery disease.

“…5 Although glial swelling previously seemed to obstruct red cell passage through capillaries within 15 minutes of ischemia, we agree with others that this seems doubtful," as it is quite unlikely that the glial swelling and capillary luminal narrowing found in the present experiments would present an absolute barrier to the flow of red cells. We feel that the impaired flow noted in acute experimental ischemic models 1 " 3 -•• 10 therefore must be better explained by mechanisms other than pericapillary glial swelling, such as precapillary shunting, increased blood viscosity due to red cell settling' or vascular constriction.…”

“…Jhingram also found that if there was stenosis of the ICA, four of seven subjects had a positive radionuclide study. Fischer et al 5 noted that in 29 subjects with completed stroke, the cerebral angiogram corresponded with the radionuclide angiogram, but he did not mention the various types of carotid artery lesions. Meschan et al 7 noted that in 11 of 15 subjects with aortocranial atherosclerosis proved angiographically, the dynamic flow on the brain scan was abnormal.…”

“…Mann et al, 10 in their experiments with dogs, estimated that the area of the arterial lumen might be reduced 90% before 50% reduction in blood flow occurred. Fischer et al 5 estimated that the radionuclide angiography would be abnormal if the carotid stenosis was greater than 50%.…”

“…Despite perfusion pressures calculated at 110 cm H 2 O and less, we were unable to demonstrate profound capillary collapse, even in areas at high risk to the "noreflow phenomenon" such as thalamus and basal ganglia. In addition, Chiang et al 5 probably infused their fixative against a much higher cerebrovascular resistance because, in their experiments, the cerebral vasculature had been filled with blood during ischemia, the viscosity of which was undoubtedly increased as a result of the stasis. 4 Thus, it is highly likely that the fixative perfusions of Chiang et al occurred at pressures and flow rates considerably less than those of the present experiments.…”

Non-invasive external regional measurement of cerebral circulation time changes in supratentorial infarctions using pertechnetate.

“…1 *" 18 Although many regional cerebral perfusion studies using a brain helmet type of multi-detector device have been made, hardly any regional circulation time measurements have been From the Departments of Clinical Chemistry and Neurology, Oulu University Central Hospital, SF-90220 Oulu 22, Finland performed using pertechnetate. Previously the detectors were placed in 2 opposite planes in multiprobe devices but recent developments show a clear tendency towards helmet-type instruments.…”