Sonographic detection of the optic radiation.
OBJECTIVE
To describe a region of hyperechoic white matter adjacent to the atrium of the lateral ventricle of preterms, and to speculate on the relevance of detecting preterm white matter injury.


METHODS
Cranial ultrasound images of 92 preterms of gestational age (GA) 32 wk or less were reviewed. For each infant, one first week standard coronal image was used for measurement of grey values around the para-atrial region of interest (PAROI) relative to the choroid plexus. For verification of the sonographic anatomy, MR images of an adult brain were used. For reference, neuro-anatomical images were compared in several atlases. In a group of nine preterms of similar GA with cystic periventricular leukomalacia (PVL) or MR-confirmed white matter disease, the disappearance of the PAROI was examined.


RESULTS
The hyperechoic para-atrial area, subjectively detected in 84% of the patients, was situated bilaterally between the inner end of the lateral fissure and the upper third of the choroid plexus. In white matter caudal to the atrium, the hyperechoic band could be pursued towards the calcarine area. The average ratio of grey value around the PAROI to the choroid plexus was 0.787 (SD = 0.072, median 0.791). There was no correlation between PAROI grey value and gestational age. At 26 wk gestational age, the average ratio was 0.781 (n = 14), and 0.789 (n = 17) at 31 wk. Location of the PAROI agrees with the angle of the upper loop of the optic radiation. None of the nine infants with white matter damage had PAROIs clearly distinguishable from flaring.


CONCLUSIONS
The symmetrical and unchanged acoustic character between 26 and 31 wk of gestational age argues in favour of the hypothesis that the PAROI is an anatomical structure. The localization of the hyperechoic band supports the hypothesis that it represents part of the optic radiation. Further study is needed to examine the absence of a hyperechoic para-atrial band as a prognostic marker of the extension and severity of white matter injury.
Boxma
Annemieke
A
Neonatal Intensive Care Unit, Sophia Children's Hospital, Rotterdam, The Netherlands.
Lequin
Maarten
M
Ramenghi
Luca A
LA
Kros
Max
M
Govaert
Paul
P
D000328:Adult; D001927:Brain Diseases / Q000175:diagnosis; D002821:Chorioamnionitis / Q000000981:diagnostic imaging*; D002831:Choroid Plexus / Q000000981:diagnostic imaging*; D015331:Cohort Studies; D003937:Diagnosis, Differential; D005260:Female; D047109:Fetal Development / Q000502:physiology; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature; D007235:Infant, Premature, Diseases / Q000000981:diagnostic imaging*; D007363:Intensive Care Units, Neonatal; D020547:Lateral Ventricles / Q000000981:diagnostic imaging*; D007969:Leukomalacia, Periventricular / Q000000981:diagnostic imaging* / Q000473:pathology; D008279:Magnetic Resonance Imaging; D008297:Male; D015588:Observer Variation; D011247:Pregnancy; D012680:Sensitivity and Specificity; D018608:Ultrasonography, Doppler