Brain imaging is an integral part of the diagnostic work-up for metabolic disorders, and the bedside availability of cranial ultrasonography (
cUS) allows very early brain imaging in symptomatic neonates. Our aim was to investigate the role and range of abnormalities seen on
cUS in neonates presenting with metabolic disorders. A secondary aim, when possible, was to address the question of whether brain MR imaging is more informative by comparing
cUS to MR imaging findings.
MATERIALS AND METHODS: Neonates with a metabolic disorder who had at least 1
cUS scan were eligible.
cUS images were reviewed for anatomic and maturation features,
cysts,
calcium, and other abnormalities. When an MR imaging scan had been obtained, both sets of images were compared.
RESULTS: Fifty-five infants (35 also had MR imaging) were studied. The most frequent findings were in oxidative phosphorylation disorders (21
cUS and 12 MR imaging): ventricular dilation (11
cUS and 6 MR imaging), germinolytic
cysts (GLCs; 7
cUS and 5 MR imaging), and abnormal white matter (7
cUS and 6 MR imaging); in peroxisomal biogenesis disorders (13
cUS and 9 MR imaging): GLCs (10
cUS and 6 MR imaging), ventricular dilation (10
cUS and 5 MR imaging), abnormal cortical folding (8
cUS and 7 MR imaging), and
lenticulostriate vasculopathy (8
cUS); in
amino acid metabolism and
urea cycle disorders (14
cUS and 11 MR imaging): abnormal cortical folding (9
cUS and 4 MR imaging), abnormal white matter (8
cUS and 8 MR imaging), and hypoplasia of the corpus callosum (7
cUS and 6 MR imaging); in organic
acid disorders (4
cUS and 2 MR imaging): periventricular white matter echogenicity (2
cUS and 1 MR imaging); and in other disorders (3
cUS and 1 MR imaging): ventricular dilation (2
cUS and 1 MR imaging).
cUS findings were consistent with MR imaging findings.
cUS was better for visualizing GLCs and calcification. MR imaging was more sensitive for subtle tissue signal intensity changes in the white matter and abnormality in areas difficult to visualize with
cUS, though abnormalities of cortical folding suggestive of
polymicrogyria were seen on
cUS.
CONCLUSION: A wide range of abnormalities is seen using
cUS in neonatal metabolic disorders.
cUS is a reliable bedside tool for early detection of
cysts,
calcium, structural brain abnormalities, and white matter echogenicity, all suggestive of metabolic disorders.