An MRI study was performed in 34 preterm infants who were clinically and neurologically
normal and whose cranial ultrasound revealed no or only mild abnormalities. The postconceptional
age at MRI varied between 30.6 and 37 weeks. The purpose of the study was to evaluate
the significance of periventricular changes in signal intensity on MRI, comparing
MRI with ultrasound. T1-weighted and T2-weighted images were assessed for changes
in signal intensity of the periventricular white matter relative to the remainder
of the cerebral hemispheric white matter. Cerebral MRIs of 13 postterm infants were
additionally investigated. In all preterm infants small localized areas of high signal
intensity on T1-weighted images and low signal intensity on T2-weighted images were
seen adjacent to the frontal horns of the lateral ventricles. They faded with increasing
age and were no longer seen one month after term in the group of postterm infants.
The areas were considered normal before term age and probably represent remnants of
the germinal matrix. Periventricular echoden-sities corresponded with a zone of changed
signal intensity within the periventricular white matter on MRI. MRI signal change
correlated with the presence and location of echo-densities; the MRI signal changes
slowly faded away after the echodensities disappeared.
Ultrasound - MRI - Periventricular abnormalities - Preterm infants
