Prognostic
values of magnetic resonance imaging and neurological staging in perinatal
hypoxic-ischaemic encephalopathy
Tse C, Khong PL*, Wong KY, Lam BCC
Department of Paediatrics, Department of
Diagnostic Radiology*, Queen Mary Hospital, The University of Hong Kong,
Hong Kong SAR, China
Objective: To evaluate the
potential use of Magnetic Resonance Imaging/Magnetic Resonance Spectroscopy
(MRI/MRS) in patients with hypoxic-ischaemic encephalopathy (HIE) and to
correlate the MRI findings and perinatal events with the neurodevelopmental
outcome.
Methods:
All neonates >36 completed weeks born with diagnosis of severe perinatal
asphyxia from December 1997 to January 2001 at Tsan Yuk Hospital and Queen
Mary Hospital were enrolled into the study. Clinical severity of
encephalopathy was assessed according to Amiel-Tison and Ellison’s staging.
Magnetic resonance imaging were performed in patients suffered from
HIE stage 2 or above. All clinical data were collected prospectively.
Results: Total thirty-three
neonates satisfied the inclusion criteria. The mean birth weight was 3.2 kg
± 0.46kg (range 2.5-4.5kg)
at a mean gestation age of 39 weeks (range 36-42). The median duration of
follow-up was 19 months (range: 2-39 months). 18/33 (54%) had normal development, 6/33 (18%) had mild
neurological sequel, 7/33 (21%) suffered from severe neurological sequel
and 2 (6%) neonatal death. All infants with stage 1HIE were normal. MRI brain examinations were
performed in infants with stage 2 or above (n=24). Fifteen infants (63%)
had abnormal MRI findings which included ischaemic changes in deep nuclei,
diffuse encephalomalacia with cystic changes and cerebral infarction.
MRI/MRS abnormalities were highly correlated with adverse neurological
outcome (P=0.0005, O.R. 52). Other perinatal events including low
Apgar score (£3)
at 5 minute, neonatal seizure, refractory seizure, prolonged assisted
ventilation (>24 hours) and failure of establishment of full oral
feeding within first week were risk factors for adverse neurodevelopmental
outcome.
Conclusions: Neurological staging
remains an effective tool to identify at risk infants with perinatal
asphyxia. Magnetic resonance neuroimaging is useful for better
prognostication of the neurodevelopmental outcome of these at risk infants.