T2 at MR imaging is an objective quantitative measure of cerebral white matter signal intensity abnormality in preterm infants at term-equivalent age

Abstract

Purpose: To compare quantitative T2 relaxometry of cerebral white matter (WM) with qualitative assessment of conventional T2-weighted magnetic resonance (MR) images, to assess the relationship between cerebral WM T2 and region-specific apparent diffusion coefficient (ADC), and to examine WM T2 regional variation in preterm infants at term.

Materials and methods: The local ethical committee granted ethical permission for this study; informed parental consent was obtained for each infant. Sixty-two preterm infants born at less than 32 weeks gestation and nine control infants were examined at 1.5 T; T2-weighted fast spin-echo MR images, T2 relaxometry data, and diffusion-weighted MR images were acquired. Conventional T2-weighted MR images were assessed by a pediatric neuroradiologist for diffuse excessive high signal intensity (DEHSI) in WM. Regions of interest were positioned in frontal WM, central WM, and posterior WM at the level of the centrum semiovale.

Results: In preterm infants at term, T2 was longer in all WM regions than in control infants; in infants with DEHSI, T2 was longer than in infants without DEHSI and control infants, with posterior WM T2 being longer than central or frontal WM T2. In control infants, T2 was similar in all WM regions. Frontal and posterior WM ADCs were higher in preterm infants at term than in control infants.

Conclusion: Cerebral WM T2 is an objective quantitative measurement that can easily and rapidly be obtained during clinical MR imaging in preterm infants at term.