Novel early structural MRI scoring system for use at 29-35 weeks postmenstrual age in infants born <31 weeks gestation

Abstract

Background and Objective(s): Magnetic resonance imaging (MRI) earlier than term equivalent age is becoming more readily available and is important for developing an understanding of very early brain injury and brain development. There are limited scoring systems validated for use in this early period. A comprehensive scoring system which includes evaluation of deep gray matter and the cerebellum is validated for use from 36 to 42 weeks postmenstrual age (PMA) (Kidokoro et al. New MR imaging assessment tool to define brain abnormalities in very preterm infants at term. AJNR Am J Neuroradiol. 2013;34(11):2208-2214.). We aimed to validate a similar scoring system at 29-35 weeks PMA by examining associations with 12 month motor and cognitive outcomes. Study Design: Prospective cohort study. Study Participants & Setting: Eighty-three infants (49 males) born at mean gestation 28+1day (±1+6weeks) and birthweight 1076 g (±317g). Materials/Methods: Infants underwent early 3T MRI between 29-35 weeks postmenstrual age (mean 32+1wk; SD ±1+3wks). A second MRI at term equivalent age (TEA; 40+6d; ±1+3wk) was performed in 78 of the infants. Structural MRIs were scored generating white matter, cortical grey matter, deep grey matter, cerebellar and global brain abnormality scores, with higher scores indicating greater brain abnormality. Outcome at 12 months corrected age (12mo, 4d; ±1+2wks) consisted of the Bayley Scales of Infant and Toddler Development III (Bayley III) and Neurosensory Motor Developmental Assessment (NSMDA). Multivariable regression analyses included social risk and sex as covariates. Results: Early MRI global scores were negatively associated with Bayley III motor (regression coefficient ß=-1.26; 95% confidence interval CI=-2.36, -0.16; p=0.03) and NSMDA (ß=-1.72; 95%CI=-3.17, -0.28; p=0.02), deep gray matter scores negatively associated with Bayley III motor (ß=-5.80; 95% CI=-9.57, -2.03; p<0.01) and NSMDA outcomes (ß=-5.87; 95%CI=-10.95, -0.80; p=0.02), and cerebellar scores negatively associated with NSMDA outcome (ß=-5.96; 95%CI=-11.82, -0.11; p=0.046). Results were reconfirmed at TEA MRI. Early MRI global (regression coefficient ß=-1.50; 95% confidence interval CI=-2.38, -0.61; p<0.01), white matter (ß=-2.00; 95%CI=-3.47, -0.53; p<0.01) and deep grey matter scores (ß=-4.46; 95%CI=-7.63, -1.28; p<0.01) were negatively associated with the Bayley III cognitive composite score. Results were reconfirmed at TEA MRI, and in addition, TEA cerebellar scores also demonstrated negative associations with the Bayley III cognitive composite score (ß=-5.20; 95%CI=-8.80, -1.60; p<0.01). Conclusions/Significance: To our knowledge this is the first validated structural MRI scoring system for Early MRI that a) includes evaluation of deep gray matter and the cerebellum, and b) includes regional brain measurements which aim to capture the effect of secondary brain growth impairment following very early brain injury.L6184696942017-09-29 <br />