CLINICAL IMAGES

Delayed computed
tomography

appearances of
hypoxic ischaemie

•• •Injury In premature
neonates

Savvas Andronikon
MB BCh, FCRad(D), FRCR (Lond)

Chris Weiman
MBChB

Ebrahim Kader
MBChB

. Department of Paediatric Radiology
Umverslty of Cape Town and Institute of Child

Health
Red Cross War Memorial Children's Hospital,

Cape Town

Unlike full-term neonates, the
periventricular region of premature
neonates is considered at high risk for
ischaemia due to the immaturity of
the vascular supply. The end result of
an ischaemie insult in this region is
termed leukomalacia. The most com-
monly affected periventricular white
matter locations are those around the
trigone and those adjacent to the
foraminae of Monro. Cavitation

Fig. 1. Marked supratentorial white matter loss seen
as cystic (low-density) areas of liquefaction abutting
the ventncles. This area of leukomalacia is circum-
scribed by a thin ribbon of cortex (arrowheads). The
grey matter and cerebellum are both spared in
keeping with a hypoxic rather than a more severe
anoxic episode.

occurs only 2 - 6 weeks after injury
and the cystic change approaches the

Fig. 2. Leukomalacia affecting the centrum semio-
vale with prominent CSF spaces around the brain
and only a thin remaining rim of cortex (arrow-
heads).

ventricular walls until these can no
longer be identified on imaging. In
premature neonates, these cystic areas
represent liquefaction without glial
response. After an anoxic episode, e.g.
cardiovascular arrest, grey matter
nuclei and brain stem nuclei also
show low density.' Uliraso~d (US)
should be used when the anterior
fontanelle is open. Computed tomog-
raphy (CT) is indicated after
fontanelle closure and when there is
non-specific ventricular enlargement
found at US.

Reference
1. Barkovich AI. Paediatric Neuroimaging. 2nd ed.

Philadelphia: Lippincott-Raven, 1996: 113-145.

48 SA JOURNAL OF RADIOLOGY. March 2002