Application of technetium-99m hexamethylpropylene amine oxime single-photon emission tomography to neurologic prognosis in patients undergoing urgent carotid surgery

In this study we aimed to work out a quantitative prognostic index for preoperative assessment of brain technetium-99m hexamethylpropylene amine oxime (HMPAO) single-photon emission tomography (SPET) in patients referred for urgent carotid endarterectomy due to acute obstructive disease of the internal carotid artery (ICA) and neurological deficit. To this end we compared data from preoperative SPET studies with the postinterventional changes in neurological status in 20 patients (17 males, three females; mean age 53 years, SD 4 years) with acute ischaemic cerebral disorders induced by obstruction of the ICA. Carotid obstruction was diagnosed by ultrasound B-mode study. All patients underwent urgent carotid endarterectomy from the ICA. Patients were divided into two groups in accordance with the results of postoperative follow-up: group A comprised patients with significant (more than 3 points) postoperative improvement in neurological condition as quantified by the Canadian Neurological Scale (11 patients); group B consisted of patients with minimal improvement or deterioration (nine, three of whom died). All patients were studied preoperatively by^99mTc-HMPAO SPET. The volume of nonperfused tissue (VS, cm³) was quantified using the Mountz technique. Hypoperfused volume (V _hypoperf, cm³) in the affected hemisphere was calculated as the total volume of voxels with^99mTc-HMPAO uptake <90% of the contralateral symmetric voxels. Discriminant prognostic function was calculated by discriminant analysis as:PF = 0.072×VS + 29.46×(VS/V _hypoperf). Patients with preoperativePF values <8.20 demonstrated postoperative improvement in neurological status, while the group withPF>8.90 comprised patients who demonstrated minimal improvement or deterioration. PF values in the range 8.20–8.90 carried an indefinite prognosis. We conclude that the preoperative^99mTc-HMPAO SPET can be used for the selection of patients in whom improvement in neurological status may be expected after urgent surgical correction of acute extracranial obstruction of the ICA.     

Analysis of changes in the electroencephalogram power spectrum on a new model of brain ischemia in rats

The bioelectrical activity is studied in the left and right parietal cortex by recording the power spectrum of the electroencephalogram in brain ischemia caused by complete ligation of the left common carotid artery and 50% reduction of the blood flow in the right common carotid artery in experiments carried out on nonnarcotized Wistar rats. Ischemia results in marked and stable disorders in the bioelectrical activity manifested in a decrease of the total EEG power, depression of the dominating frequency in the Θ-range, increase of the δ-range power, and interhemispheric asymmetry of some spectrogram parameters. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny Vol. 118, N ^o 12, pp. 565–567, December, 1994 Presented by E. D. Gol'dberg, Member of the Russian Academy of Medical Sciences     

Hemorheological and antioxidant effects of Ascovertin in patients with sclerosis of cerebral arteries

The clinical trials on 31 patients with arteriosclerosis and I-II stage discirculatory encephalopathy to assess an ability of Ascovertin to limit hemorheology abnormalities were carried out. In patients with discirculatory encephalopathy was a distinct increase in blood viscosity which was induced by disturbances of cell rheological factors: increase in aggregation of erythrocytes and decrease in their deformability were observed in comparison with indices in the group of healthy volunteers. No difference in plasma viscosity and fibrinogen was found. The treatment with Ascovertin in patients with discirculatory encephalopathy improved their attention, memory, mental performance, normalized sleep, releaved headache, decreased fatiquebility, led to the decrease in blood viscosity values, the reduction of pathological erythrocyte hyper aggregation and the improvement of erythrocyte deformability. We partly connect this clinical effect and hemorheology activity of Ascovertin with its antioxidant property--there was found impressive lipid peroxidation suppression. No significant changes in hemorheological and lipid peroxidation indices were observed in patients without Ascovertin.