Long-term outcome of preterm infants and the role of neuroimaging

Abstract

Preterm birth has been defined as one of the major public health problems of this decade, preterm neonates being at high risk for neurodevelopmental disabilities. As preterm survival rates increase, the next great imperative for perinatal medicine is to understand and prevent the serious adverse neurodevelopmental outcomes of preterm birth. The challenge for neonatologists and neurologists alike is identifying early markers of outcome in the prematurely born. This article reviews current trends in prevalence, mortality, and morbidity, and the present status of outcome data for cognitive and neurosensory neurodevelopmental dysfunctions in preterm infants. New neuroimaging modalities and analysis tools are contributing to the understanding of neurologic sequelae of preterm birth by providing microstructural evidence of injury sustained by the preterm brain.

Figure 1

Skranes has shown that the left posterior limb of the internal capsule (PLIC) is associated with visual motor and visual perceptual outcome of preterm infants at adolescence. In the newborn period, the left PLIC has been shown to correlate with Bayley MDI scores in infants exposed to the Newborn Individualized Developmental Care and Assessment Program (NIDCAP). Panel A shows an axial image of the left PLIC in preterm subjects scanned at age 12 years. Bayley scores for control and experimental groups at 9 months are shown in Panel B. Panel A courtesy of C. Lacadie, Magnetic Resonance Research Center, Yale University.

Figure 2

Skranes has also shown that the left external capsule is associated with lower IQ scores in preterm infants at adolescence. Panel A shows an axial image of the left external capsule in preterm infants scanned at age 12 years. Total IQ scores for preterm versus term control 12 year olds evaluated by Skranes is shown in panel B. Panel A courtesy of C. Lacadie, Magnetic Resonance Research Center, Yale University.

Figure 3

Gimenez employed voxel-based morphometry to demonstrate that prematurely-born subjects have less thalamic gray at age 14 years than term control subjects. These data correlate with verbal fluency scores in the preterm group. A VBM image of the thalamus of prematurely-born subjects scanned at age 12 years is shown in panel A, and verbal fluency scores for preterms versus term controls as evaluated by Gimenez is shown in panel B. Panel A courtesy of S. Kesler, Ph.D, Stanford University School of Medicine.