title: Periventricular echodensity measured with the integrated backscatter system: from a qualitative assessment to a quantitative approach.
abstract: BACKGROUND
  The degree of periventricular white matter echodensity in preterm infants has been utilized as a sign of the early ultrasonographic appearance of periventricular leukomalacia, and this has been called periventricular echodensity (PVE).
  
  
  OBJECTIVE
  The aim of this study was to quantitatively measure PVE utilizing a new method which is called calibrated integrated backscatter (calibrated IB).
  
  
  METHODS
  Eighty-eight preterm infants (extremely low birth weight infants, n = 17; very low birth weight infants, n = 26; low birth weight infants, n = 45) without any CNS abnormality were enrolled. IB is the returned sound pressure against supersonic waves sent from an ultrasonographic machine. The IB of the choroid plexus and periventricular white matter in the subrolandic area were measured on a parasagittal cerebral image. The degree of PVE was defined by subtracting the IB of the choroid plexus from that of the periventricular white matter in the subrolandic area (calibrated IB of PVE).
  
  
  RESULTS
  The intraobserver and interobserver correlations were both excellent (between 0.87 and 0.98 as correlation coefficients). There was a trend for the calibrated IB of PVE to decrease in accordance with time after birth, with a significant difference in very low birth weight and low birth weight infants.
  
  
  CONCLUSIONS
  The objectively measured brightness of PVE was comparable to that of the choroid plexus irrespective of the size of the infants. Measurement of the calibrated IB of PVE might be a reliable method to assess PVE.
authors.affiliation: Department of Pediatrics and Developmental Medicine, Gunma University Graduate School of Medicine, Maebashi, Japan.
authors.forename: Yukihiro
authors.initials: Y
authors.lastname: Yoshizawa
authors.forename: Masayuki
authors.initials: M
authors.lastname: Watanabe
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Ohki
authors.forename: Kenichi
authors.initials: K
authors.lastname: Tokuyama
authors.forename: Hiroo
authors.initials: H
authors.lastname: Mayuzumi
authors.forename: Yukiko
authors.initials: Y
authors.lastname: Takahashi
authors.forename: Akihiro
authors.initials: A
authors.lastname: Morikawa
mesh_terms: D001724:Birth Weight; D002138:Calibration; D002552:Cerebral Ventricles / Q000000981:diagnostic imaging*; D002831:Choroid Plexus / Q000000981:diagnostic imaging / Q000473:pathology; D004453:Echoencephalography; D005260:Female; D005865:Gestational Age; D006801:Humans; D007091:Image Processing, Computer-Assisted; D052577:Infant, Extremely Low Birth Weight; D007231:Infant, Newborn; D007969:Leukomalacia, Periventricular / Q000000981:diagnostic imaging*; D008297:Male