OBJECTIVETo study the clinical and imaging features demonstrated by conventional magnetic resonance imaging (MRI) and diffusion weighted imaging (DWI) in late preterm infants with white matter damage.

METHODSA total of 519 preterm infants (277 late stage, 242 early stage) from January 2005 to May 2008 at Shengjing Hospital of China Medical University were enrolled. They received the MRI scans with the sequences of conventional MRI and DWI.

RESULTSIn the 277 late preterm infants, 118 (42.6%) showed white matter damage, accounting for 71.9% of 164 cases of brain injury. In the 242 early preterm infants, 92 (38.0%) showed white matter damage, accounting for 69.2% of 133 cases of brain injury. There were no significant differences in the incidence of white matter damage between the late and early preterm infants. There were 61.9% (73/118) of late preterm infants with white matter damage had no obvious clinical symptoms, but 75% of infants with severe white matter damage (widespread and diffusive lesions on MRI-DWI) presented obvious clinical symptoms. Within the first week of white matter damage, DWI showed high signals, T1WI showed normal or slightly high signals, with or without high signals on T2WI. In the infants with diffuse injury, DWI showed high signals, but conventional MRI did not show obvious signal changes.

CONCLUSIONSWhite matter damage is common in late preterm infants. The majority of infants with severe white matter damage on MRI-DWI have obvious clinical symptoms. DWI can reflect the lesions ahead of conventional MRI.