The evolution of cerebral blood flow in the developing brain: Evaluation with iodine-123 iodoamphetamine SPECT and correlation with MR imaging

BACKGROUND AND PURPOSE: Although it is well established that brain maturati on correlates temporally with the functions the newborn or infant performs at various stages of development, the precise relationship between function and anatomic brain maturation remains unclear. The purpose of this study w as to investigate the developmental changes of regional cerebral blood flow (rCBF) in infants and children using iodine-123 iodoamphetamine (I-123-IMP ) and single-photon emission computed tomography (SPECT). These findings we re correlated with the MR imaging appearance of the brain and with known de velopmental changes. METHODS: Twenty-one I-123-IMP SPECT examinations of 17 patients, ranging in age from neonates to 2 years, were reviewed retrospectively. All children had had transient neurologic events in the neonatal period that did not sig nificantly affect subsequent neuropsychological development. MR studies wer e performed in 12 of these patients and the MR findings were correlated wit h the SPECT results. RESULTS: SPECT studies showed a consistent pattern of evolving changes in I -123-IMP uptake, most likely reflecting evolution of rCBF, From the 34th po stconceptional week until the end of the second month after term delivery, there was predominant uptake in the thalami, brain stem, and paleocerebellu m, with relatively less cortical activity. Radionuclide uptake in both the perirolandic and occipital cortices was well seen around the 40th postconce ptional week and increased rapidly thereafter, with a predominance of parie tal activity. By 3 months, radionuclide uptake in the cerebellar hemisphere s and parietofrontal cortices increased. Frontal and temporal activity incr eased by age 6 to 8 months. Uptake in the basal ganglia increased by 8 mont hs. By the beginning of the second year, rCBF showed a similar topographic pattern to that in adults. CONCLUSION: The time course of the changes in I-123-IMP uptake in the devel oping brain as detected by SPECT is similar to that of myelination and most likely reflects an overall topologic maturational pattern of the brain.