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Byline: E. Facco (1), P. Zucchetta (2), M. Munari (1), F. Baratto (1), A. U. Behr (1), M. Gregianin (2), A. Gerunda (1), F. Bui (2), M. Saladini (3), G. Giron (1) Keywords: Key words Brain death; SPECT; Cerebrovascular circulation; Brain injuries; EEG Abstract: Objective: To evaluate the effectiveness of single proton emission tomography (SPECT) with 99m.sup.Tc-HMPAO in the diagnosis of brain death (BD). Design: Prospective study in comatose and brain-dead patients. Setting: Neurologic ICU. Patients and methods: Fifty comatose patients (age range: 10 days--75 years) were submitted to SPECT study. In 21 of them (42 %) reversible factors (e. g., influence of drugs affecting the central nervous system) were present. Thirty-eight patients were clinically brain-dead, while the remaining 12 were tested both in pre-terminal conditions and after the clinical onset of BD. Interventions: Brain SPECT following i. v. injection of 99m.sup.Tc-HMPAO (300--1100 MBq), using a 4-headed gamma-camera (20 min, 360 deg, 88 images). Measurements and results: All patients tested in pre-terminal conditions showed preserved brain perfusion. Two of them had flat EEGs despite the absence of any reversible cause of coma three patients survived, but remained in persistent vegetative states. SPECT confirmed the diagnosis of BD in 45 out of 47 patients (95.7 %), clearly showing the arrest of brain perfusion (picture of 'empty skull') in two clinically brain-dead children (aged 10 days and 12 months, respectively) weak perfusion of the basal ganglia, thalamus and/or brain stem was still present, precluding the diagnosis of BD both of them died a few days later. Conclusions: Our results confirm the reliability of SPECT in the diagnosis of BD. A problem arises about its effectiveness in brain-dead children, but this seems to be a matter of definition of BD and cerebral viability, rather than a limit of SPECT. Author Affiliation: (1) Lab. Neurophysiology -- Neuro ICU, Dept. of Anesthesiology and Intensive Care, University of Padua, via C. Battisti 267, I-35121 Padova, Italy Tel.: +39.49.8 21 30 90, or +39.336.42 06 04 Fax: +39.49.8 75 42 56 email: efacco@uxl.unipd.it, IT (2) Nuclear Medicine Service I, University of Padua, via C. Battisti 267, I-35121 Padova, Italy, IT (3) Dept. of Neurology, University of Padua, via C. Battisti 267, I-35121 Padova, Italy, IT Article note: Received: 6 October 1997 Accepted: 21 July 1998