APPLICATION OF TC-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 a mine oxime (HMPAO) single-photon emission tomography (SPET) in patient s 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 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 pat ients underwent urgent carotid endarterectomy from the ICA, Patients w ere divided into two groups in accordance with the results of postoper ative follow-up: group A comprised patients with significant (more tha n 3 points) postoperative improvement in neurological condition as qua ntified by the Canadian Neurological Scale (11 patients); group B cons isted of patients with minimal improvement or deterioration (nine, thr ee of whom died), All patients were studied preoperatively by Tc-99m-H MPAO SPET, The volume of nonperfused tissue (VS, cm(3)) was quantified using the Mountz technique. Hypoperfused volume (V-hypoperf, cm(3)) i n the affected hemisphere was calculated as the total volume of voxels with Tc-99m-HMPAO uptake <90% of the contralateral symmetric voxels, Discriminant prognostic function was calculated by discriminant analys is as: PF = 0.072xVS + 29.46x(VS/V-hypoperf). Patients with preoperati ve PF values <8.20 demonstrated postoperative improvement in neurologi cal status, while the group with PF>8.90 comprised patients who demons trated minimal improvement or deterioration, PF values in the range 8. 20-8.90 carried an indefinite prognosis, We conclude that the preopera tive Tc-99m-KMPAO SPET can be used for the selection of patients in wh om improvement in neurological status may be expected after urgent sur gical correction of acute extracranial obstruction of the ICA.