Tc-99m HMPAO brain perfusion imaging in young Down's syndrome patients

Down's syndrome (DS) is characterized by moderate mental retardation and a variety of abnormalities involving multiple organ systems. There is a high incidence of Alzheimer's disease (AD) type dementia beyond the age of 35. I n this study, single photon emission computed tomography (SPECT) brain perf usion imaging of young Down's syndrome patients was performed to define the perfusion pattern. Tc-99m HMPAO brain perfusion SPECT was performed on 17 young DS patients, aged 3-24 years (mean: 10.9 +/- 5.9 years). None of the patients had dementia symptoms. Brain perfusion scans were acquired 15 min after i.v. injection of 12 MBq/kg of Tc-99m HMPAO using a single head rotat ing gamma camera. Images were analyzed visually and semiquantitatively by d efining side-to-side asymmetry index. Nine DS cases showed normal brain per fusion. Eight of the 17 cases revealed mostly unilateral parieto-temporal, parieto-occipital and frontal hypoperfusions. The side-to-side asymmetry in dices for these visually interpreted regional brain perfusion abnormalities ranged from 6 to 15%, These findings revealing mostly unilateral parieto-t emporal and frontal hypoperfusions may not be considered as predictive patt erns of dementia related Alzheimer type perfusion deficits in DS. However, such findings may connect to other functional imaging studies related to th e higher cortical dysfunction in mental retardation. (C) 1999 Elsevier Scie nce B.V. All rights reserved.