Clinical Implications of MR Imaging Findings in the White Matter in Very Preterm Infants: A 2-year Follow-up Study
ABSTRACT To explore the association between diffuse excessive high signal intensity (DEHSI), punctate white matter (WM) lesions, and ventricular dilatation around term-equivalent age (TEA) and at clinical follow-up at 2 years in very preterm infants and the effect on neurodevelopment.
Ethical approval for this prospective study was given by the institutional review board, and informed parental consent was obtained. An unselected cohort of 110 preterm infants (gestational age, < 32 weeks) was imaged around or after TEA. Clinical follow-up was performed at a corrected age of 2 years and consisted of a neurologic examination and a mental and developmental assessment (Bayley Scales of Infant Development). Univariate analyses and logistic and linear regression were performed to examine the relationships between variables.
DEHSI was found in 58 of 65 (89%) infants imaged around TEA. DEHSI was never detected in infants imaged after postmenstrual age of 50 weeks and showed no association with neurodevelopmental outcome. Punctate WM lesions and ventricular dilatation were significantly associated with mental (P = .02 for punctate WM lesions) and psychomotor developmental delay (P < .001 and P = .03, respectively), motor delay (P = .002 and P = .02, respectively), and cerebral palsy (P = .01 and P = .03, respectively).
Because of its high incidence in preterm infants around TEA, its absence after a postmenstrual age of 50 weeks, and its association with normal neurologic outcome at a corrected age of 2 years, DEHSI should not be considered part of the spectrum of WM injury, but rather a prematurity-related developmental phenomenon.
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ABSTRACT: Hyperintense white matter signal abnormalities, also called diffuse excessive high signal intensity (DEHSI), are observed in up to 80% of very preterm infants on T2-weighted MRI scans at term-equivalent age. DEHSI may represent a developmental stage or diffuse microstructural white matter abnormalities. Automated quantitative assessment of DEHSI severity may help resolve this debate and improve neonatal brain tissue segmentation. For T2-weighted sequence without fluid attenuation, the signal intensity distribution of DEHSI greatly overlaps with that of cerebrospinal fluid (CSF) making its detection difficult. Furthermore, signal intensities of T2-weighted images are susceptible to magnetic field inhomogeneity. Increased signal intensities caused by field inhomogeneity may be confused with DEHSI. To overcome these challenges, we propose an algorithm to detect DEHSI using T2 relaxometry, whose reflection of the rapid changes in free water content provides improved distinction between CSF and DEHSI over that of conventional T2-weighted imaging. Moreover, the parametric transverse relaxation time T2 is invulnerable to magnetic field inhomogeneity. We conducted computer simulations to select an optimal detection parameter and to validate the proposed method. We also demonstrated that brain tissue segmentation is further enhanced by incorporating DEHSI detection for both simulated preterm infant brain images and in vivo in very preterm infants imaged at term-equivalent age.NeuroImage 09/2012; 64C:328-340. DOI:10.1016/j.neuroimage.2012.08.081 · 6.36 Impact Factor
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ABSTRACT: BACKGROUND: Widespread white matter (WM) pathology in preterm children has been proposed. OBJECTIVE: The purpose of this study was to investigate maturational differences of WM between preterm infants with thinning of the corpus callosum and full-term infants. MATERIALS AND METHODS: A total of 18 preterm children and 18 full-term children were divided into three subgroups according to the corrected age at the time of diffusion tensor imaging scanning. Tract-based spatial statistics was used for assessing differences in fractional anisotropy (FA) between preterm and full-term children, and between each age-related subgroup in preterm and in full-term children. RESULTS: In the preterm group, FA values of overall WM showed an increase with age. This trend indicates that WM maturation is a gradual occurrence during a child's first 2 years. In the full-term group, most WM structures had reached maturation at around 1 year of age; however, centrum semiovale level showed sustained maturation during the first 2 years. CONCLUSION: Results of our study demonstrate radiologic maturational differences of WM and provide evidence of the need for therapeutic intervention within 2 years of birth to prevent specific functional impairment and to improve clinical outcome in preterm children.Pediatric Radiology 11/2012; 43(5). DOI:10.1007/s00247-012-2545-5 · 1.65 Impact Factor
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ABSTRACT: AIM: The aim of this study was to determine whether tractography of white-matter tracts can independently predict neurodevelopmental outcome in very preterm infants. METHOD: Out of 84 very preterm infants admitted to a neonatal intensive care unit, 64 (41 males, 23 females; median gestational age 29.1 weeks [range 25.6-31.9]; birthweight 1163g [range 585-1960]) underwent follow-up at 2 years. Diffusion tensor imaging (DTI) values obtained around term were associated with a neurological examination and mental and psychomotor developmental index scores at 2 years based on the Bayley Scales of Infant Development (version 3). Univariate and logistic regression analyses tested for associations between DTI values and follow-up parameters. Cut-off values predicting motor delay and cerebral palsy (CP) were determined for fractional anisotropy, apparent diffusion coefficient (ADC), and fibre lengths. RESULTS: Infants with psychomotor delay and CP had significantly lower fractional anisotropy values (p=0.002, p=0.04 respectively) and shorter fibre lengths (p=0.02, p=0.02 respectively) of the posterior limb of the internal capsule. Infants with psychomotor delay also had significantly higher ADC values (p=0.03) and shorter fibre lengths (p=0.002) of the callosal splenium. Fractional anisotropy values of the posterior limb of the internal capsule independently predicted motor delay and CP, with sensitivity between 80 and 100% and specificity between 66 and 69%. ADC values of the splenium independently predicted motor delay with sensitivity of 100% and specificity of 65%. INTERPRETATION: Diffusion tensor imaging tractography at term-equivalent age independently predicts psychomotor delay at 2 years of age in preterm infants.Developmental Medicine & Child Neurology 02/2013; DOI:10.1111/dmcn.12099 · 3.29 Impact Factor