title: Punctate white matter lesions in infants: new insights using susceptibility-weighted imaging.
abstract: BACKGROUND
  Punctate white matter lesions (PWML) are recognized with magnetic resonance imaging (MRI) as hypersignal on T1-weighted imaging and hyposignal on T2-weighted imaging. Our aim was to assess how often a hemorrhagic component was present in PWML using susceptibility-weighted imaging (SWI).
  
  
  METHODS
  Seventeen preterm (gestational age, 25-34 weeks) and seven full-term infants (age at MRI, 37-42 weeks) with PWML were included. Seven preterm infants had sequential MRIs. PWML were diagnosed with conventional MRI and compared with SWI, where signal loss is suggestive of hemorrhage. The pattern of associated brain lesions was taken into account, and the percentage of lesions with signal loss on SWI was calculated for each infant.
  
  
  RESULTS
  A significantly higher percentage of signal loss on SWI (median, 93.9%) was found among infants with germinal matrix and intraventricular hemorrhage as the primary diagnosis (n = 8) compared to those with a primary diagnosis of white matter injury (n = 14; median, 14.2%; p < 0.01). In the infants with serial MRIs, a reduction in the number of PWML and/or signal loss on SWI was noted at term equivalent age. In the patient who died, cystic lesions, associated with hemorrhage and gliosis, were demonstrated on histology.
  
  
  CONCLUSIONS
  SWI can distinguish hemorrhagic and non-hemorrhagic PWML. Signal loss on SWI was more common when PWML were associated with an intraventricular hemorrhage. Longitudinal imaging showed a decrease in the number of PWML over time, with some PWML no longer showing signal loss on SWI, suggesting early gliosis.
authors.affiliation: Department of Radiology, University Medical Center Utrecht, Heidelberglaan 100, PO Box 85500, 3508 GA, Utrecht, The Netherlands. tniwa@kcmc.jp
authors.forename: Tetsu
authors.initials: T
authors.lastname: Niwa
authors.forename: Linda S
authors.initials: LS
authors.lastname: de Vries
authors.forename: Manon J N L
authors.initials: MJ
authors.lastname: Benders
authors.forename: Taro
authors.initials: T
authors.lastname: Takahara
authors.forename: Peter G J
authors.initials: PG
authors.lastname: Nikkels
authors.forename: Floris
authors.initials: F
authors.lastname: Groenendaal
mesh_terms: D001921:Brain / Q000473:pathology*; D002543:Cerebral Hemorrhage / Q000175:diagnosis* / Q000473:pathology; D005260:Female; D005865:Gestational Age; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007234:Infant, Premature; D008279:Magnetic Resonance Imaging; D008297:Male; D009413:Nerve Fibers, Myelinated / Q000473:pathology*; D011247:Pregnancy