Background.Long-term studies of the outcome of very prematurely born infants have clearly documented that the majority of such infants have significant moto r,cognitive,and behavioral deficits.However,there is a limited understanding of the nature of the cerebral abnormality underlying these adverse neurologic o utcomes.Aim.The overall aim of this study was to define quantitatively the alt erations in cerebral tissue volumes at term equivalent in a large longitudinal c ohort study of very low birth weight premature infants in comparison to term-bo rn infants by using advanced volumetric 3-dimensional magnetic resonance imagin g(MRI)techniques.We also aimed to define any relationship of such perinatal l esions as white matter(WM)-injury or other potentially adverse factors to the quantitative structural alterations.Additionally,we wished to identify the rel ationship of the structural alterations to short-term neurodevelopmental outcom e.Methods.From November 1998 to December 2000,119 consecutive premature infan ts admitted to the neonatal intensive care units at Christchurch Women’s Hospit al(Christchurch,New Zealand)and the Royal Women’s Hospital(Melbourne,Austr alia)were recruited(88%of eligible)after informed parental consent to underg o an MRI scan at term equivalent.Twenty-one term-born infants across both sit es were recruited also.Postacquisition advanced 3-dimensional tissue segmentat ion with 3-dimensional reconstruction was undertaken to estimate volumes of cer ebral tissues:gray matter(GM;cortical and deep nuclear structures),WM(myelinated and unmyelinated),and cerebrospinal fluid(CSF).Results.In comp arison to the term-born infants,the premature infants at term demonstrated pro minent reductions in cerebral cortical GM volume(premature infants [mean ±SD]:178 ±41 mL;term infants:227 ±26 mL)and in deep nuclear GM volume(prematur e infants:10.8 ±4.1 mL;term infants:13.8 ±5.2 mL)and an increase in CSF vo lume(premature infants:45.6 ±22.1 mL;term infants:28.9 ±16 mL).The major predictors of altered cerebral volumes were gestational age at birth and the pre sence of cerebral WM injury.Infants with signifi-cantly reduced cortical GM an d deep nuclear GM volumes and increased CSF volume volumes exhibited moderate to severe neurodevelopmental disability at 1 year of age.Conclusions.This MRI st udy of prematurely born infants further defines the nature of quantitative cereb ral structural abnormalities present as early as term equivalent.The abnormalit ies particularly involve cerebral neuronal regions including both cortex and dee p nuclear structures.The pattern of cerebral alterations is related most signif icantly to the degree of immaturity at birth and to concomitant WM injury.The a lterations are followed by abnormal short-term neurodevelopmental outcome. Background.Long-term studies of the outcome of very prematurely born infants have clearly documented that the majority of such infants have significant moto r, cognitive, and behavioral deficits.However, there is a limited understanding of the nature of the cerebral abnormality underlying these adverse neurologic o utcomes.Aim.The overall aim of this study was to define quantitatively the alt erations in cerebral tissue volumes at term equivalent in a large longitudinal c ohort study of very low birth weight premature infants in comparison to term-bo rn infants by using advanced volumetric 3-dimensional magnetic resonance imagin g (MRI) techniques. We also aimed to define any relationship of such perinatal l esions as white matter (WM) -injury or other potentially adverse factors to the quantitative structural alterations. Additionally, we wished to identify the reltionship of the structural alterations to short-term neurodevelopmental outcom e.Methods.From November 1998 to December 2000, 119 c onsecutive premature infan ts admitted to the neonatal intensive care units at Christchurch Women’s Hospit al (Christchurch, New Zealand) and the Royal Women’s Hospital (Melbourne, Austr alia) were recruited (88% of eligible) after informed parental consent to underg o an MRI scan at term equivalent. twenty-one term-born infants across both sitets were recruited also.Postacquisition advanced 3-dimensional tissue segment with 3-dimensional reconstruction was undertaken to estimate volumes of cer ebral tissues: gray matter (GM; cortical and deep nuclear structures, WM (myelinated and unmyelinated), and cerebrospinal fluid (CSF). Results in comp arison to the term-born infants, the premature infants at term demonstrated pro minent reductions in cerebral cortical GM volume (premature infants [mean ± SD]: 178 ± 41 mL; term infants: 227 ± 26 mL) and in deep nuclear GM volume (prematur e infants: 10.8 ± 4.1 mL; term infants: 13.8 ± 5.2 mL) and an increase in CSF vo lume infants: 45.6 ± 22.1 mL; term infant s: 28.9± 16 mL) .The major predictors of altered cerebral volumes were gestational age at birth and the pre sence of cerebral WM injury. Infants with signifi-cantly reduced cortical GM an d deep nuclear GM volumes and increased CSF volume copies of moderate to severe neurodevelopmental disability at 1 year of age. Conclusions. This MRI st udy of prematurely born infants further defines the nature of quantitative cereb ral structural abnormalities present as early as term equivalent. The abnormality ies particularly of cerebral neuronal regions including both cortex and dee p nuclear structures The pattern of cerebral alterations is related most signif icantly to the degree of immaturity at birth and to concomitant WM injury. A lterations are followed by abnormal short-term neurodevelopmental outcome.