Qualitative brain MRI at term and cognitive outcomes at 9 years after very preterm birth.

OBJECTIVE: A prospective study was performed to assess the relationship between the appearance of cerebral MRI at term and the cognitive functioning at 9 years old in very preterm born infants. METHODS: Seventy-six very preterm born infants (birth weight <1500 g or gestational age ≤32 weeks) obtained cerebral MRI at term-equivalent period, which was assessed by using established composite scores for the white and gray matter; cognitive outcomes at 9 years old were assessed in 60 subjects by using Wechsler Intelligence Scale for Children, Third Edition. RESULTS: Mildly low scores on the different IQ indices (<85) were observed in 23.3% (verbal IQ), 41.7% (performance IQ), and 30.0% (full-scale IQ) of the cohort, whereas moderately low scores (<70) were noted in 3.3% (verbal IQ), 11.7% (performance IQ), and 11.7% (full-scale IQ); cerebral palsy was diagnosed in 10.0%, whereas special assistance at school was required in 56.7%. Abnormal white matter appearances predicted mildly low verbal, performance, and full-scale IQs; moderately low performance and full-scale IQs; cerebral palsy; and the requirement for special assistance at school. Abnormal white matter appearances predicted mild cognitive impairment even after the adjustment for known clinical risk factors. In contrast, abnormal gray matter appearances did not predict any of the outcome measures. CONCLUSIONS: In a cohort of very preterm born infants, abnormal white matter appearance on term MRI showed consistent associations with cognitive impairments at 9 years old, further supporting the benefit of obtaining term MRI for very preterm born infants.

Abnormal white matter appearance on term FLAIR predicts neuro-developmental outcome at 6 years old following preterm birth.

UNLABELLED: Preterm infants are at significant risk of neuro-developmental disorders at school-age. MRI is a potentially useful screening tool of such disorders. Using FLAIR imaging in the preterm infants at term, here we demonstrate that abnormal low-intensity signal in the white matter predicts the neuro-developmental outcome at 6 years. STUDY DESIGN: Clinical factors associated with white matter appearance on MRI obtained at term were investigated in 210 preterm infants. RESULTS: Low-intensity signal on FLAIR imaging was commonly observed (69%) at <2 months corrected-age. Its incidence correlated with corrected-age at scan, maternal pyrexia and cystic periventricular leukomalacia. Low-intensity signal on FLAIR significantly correlated with performance and full-scale developmental quotients, whereas diffuse high-intensity signal on T2-weighted imaging correlated only with the full-scale developmental quotient at 6 years (n = 75, WISC-R). FLAIR imaging, but not T2-weighted imaging, predicted mild neuro-developmental delay. CONCLUSIONS: FLAIR appeared to detect subtle white matter injury related with neuro-developmental disorders at school-age, whereas T2-weighted imaging seemed to identify relatively more severe injury. FLAIR is a potentially sensitive screening tool that is readily available and easily interpretable.

Periventricular low intensities on fluid attenuated inversion recovery imaging in the newborn infant: relationships to the clinical data and long-term outcome.

BACKGROUND: The author's previous study showed that it is possible to predict the severity of white matter injury in early infancy by using fluid attenuated inversion recovery (FLAIR) imaging. A follow-up study was performed in order to assess the correlation between the incidence of periventricular low intensities on FLAIR imaging (F-PVLI) and the clinical data including the physiological variables at birth and the long-term outcome of the infant. METHODS: The authors reviewed MRI of 328 newborn infants, which were obtained before 2 months corrected age. Abnormal findings in the periventricular white matter and other part of the brain were recorded. Periventricular abnormal intensities were sorted into four groups according to the FLAIR grade, which comprised normal, F-PVLI 1 (focal), F-PVLI 2 (extensive), cystic periventricular leukomalacia (C-PVL), and diffused leukomalacia. RESULTS: Significantly more periventricular abnormal intensities were detected by FLAIR imaging than by conventional T1 and T2 weighted imaging. In the groups of F-PVLI 2 and C-PVL, the birth weight (BW), gestational age (GA), blood pH and base excess at birth were significantly lower than in the normal group. However, when the study population was defined into very low birth weight infants, F-PVLI 2 had significantly larger BW and GA than normal. The FLAIR grade had a strong correlation with the developmental outcome at 12 and 36 months corrected age. CONCLUSIONS: F-PVLI is a silent but very important white matter injury, which has many features in common with C-PVL. FLAIR imaging could be a strong tool in screening newborn infants at high risk of neurological impairment.