Brain white-matter analysis using diffusion tensor imaging in retinopathy of prematurity

Abstract

Purpose : Visual impairment in children born very preterm is caused by cerebral white matter injury affecting the visual pathways, in addition to retinopathy of prematuriy. Diffusion tensor imaging (DTI) of magnetic resonance imaging (MRI) provides indirect quantitative measures of brain white matter (WM) integrity, with the various diffusivity parameters. Tractography analyses can reconstruct in vivo the trajectories of WM fasciculi connecting different brain areas, providing information regarding structural networks. We aimed to perform tractography analyses on diverse areas of the brain in patients with retinopathy of prematurity (ROP) and explore the areas associated with the disease.

Methods : In this prospective study, 63 preterm with or without ROP and 26 full-term infants were enrolled and underwent MRI at near-term (35-42 weeks in gestational age). For 48 regions of interest, DTI analyses were performed. Fractional anisotropy (FA) and mean diffusivity (MD) values for diverse white matter areas were calculated and compared between the preterm and patient and control groups. For evaluation of the effect of preterm, we compared FA and MD values between preterm and full-term infants. For that of ROP, we compared the values between preterm with and without ROP. Multiple regression analyses were performed to identify the white matter areas asscoaited with ROP.

Results : FA values were significantly different between the patient and control groups in 20 white matter areas, including retrolenticular part of internal capsule (0.228 ± 0.050 in preterm infants and 0.263 ± 0.081 in full-term controls, P = 0.015) and optic radiation (0.208 ± 0.031 in preterm and 0.243 ± 0.073 and full-term infants, P = 0.029). However, subgroup analyses between ROP and no ROP showed only 4 of 48 areas, mostly related to motor function, were significantly different. Multiple regression analyses revealed 3 areas associated with ROP, corpus callosum, putamen, and caudate nucleus.

Conclusions : Compared to full-term control, preterm infants showed decreased cerebral white matter microstructural integrity in multiple areas. However, from subgroup analyses and multiple regression analyses, most of the differences were mainly associated with preterm birth, rather than ROP.