Paediatric cranial ultrasound: abnormalities of the brain in term neonates and young infants

Abstract

Cranial ultrasound is a critical screening tool in the detection of cerebral abnormalities in term neonates and infants, and is complementary to other imaging modalities. This pictorial review illustrates the diverse central nervous system pathologies which can affect the term neonatal and infantile brain, including vascular abnormalities (hypoxic ischaemic injury, perinatal arterial ischaemic stroke, cerebral sinovenous thrombosis, vein of Galen aneurysmal malformations, subpial haemorrhage, and dural sinus malformations); infections (congenital (cytomegalovirus and toxoplasmosis) and bacterial meningoencephalitis); genetic disorders and malformations (callosal agenesis, tuberous sclerosis, developmental megalencephaly, lissencephaly-pachygyria, and grey matter heterotopia); tumours (choroid plexus papilloma, atypical teratoid/rhabdoid tumour, and desmoplastic infantile glioma) and trauma (birth-related, inflicted injury). Each condition is explored with a focus on its sonographic characteristics-some have rarely, if ever, been described on ultrasound. CRITICAL RELEVANCE STATEMENT: Through this case review, we illustrate various pathologies affecting the term neonatal and infantile brain, including vascular lesions, infection, genetic disorders/malformations, tumours and trauma: some of these pathologies have rarely, if ever, been described on CUS. KEY POINTS: Cranial ultrasound (CUS) is a critical screening tool for the term brain. Many term neonatal and infantile pathologies can be detected on CUS. Some of the pathologies illustrated in this paper have rarely been described on US.

Keywords: Brain; Head; Infant; Pathology; Ultrasonography.

Fig. 1

Hypoxic ischaemic injury. Day 1 ultrasound in a term neonate with cord prolapse, poor APGAR scores, and seizures at birth. a, b Coronal images demonstrate “slit-like” lateral ventricular frontal horns (dashed arrows), diffuse effacement of extra-axial CSF spaces (white arrowheads), and bilateral, symmetrical increased echogenicity of the basal ganglia (a) and thalami (b) (solid arrows). c Parasagittal image demonstrates an effaced lateral ventricle (dashed arrow) and increased echogenicity and swelling of the thalamus (solid arrow). d Coronal and (e) axial T2WI, (f) axial trace DWI and (g) ADC map demonstrate corresponding bilateral, symmetrical T2 hyperintensity and swelling (d, e) and restricted diffusion (high signal on DWI, low signal on corresponding ADC map) (f, g) involving the caudate nuclei, lentiform nuclei (globi pallidi and putamina), and thalami

Fig. 2

Perinatal arterial ischaemic stroke. Day 2 ultrasound in a 36 + 1-week gestation neonate with seizures. a–c Coronal images at the level of the third ventricle (a), lateral ventricular trigones (b), and occipital lobes (c) demonstrate ill-defined, wedge-shaped increased echogenicity in the left cerebral hemisphere (dashed lines), sparing the medial left frontal lobe (FL) and cingulate gyrus (CG); there is associated brain swelling with loss of sulcation. d Coronal T2WI demonstrates corresponding hyperintensity in the left cerebral hemisphere, involving both cortex and subcortical white matter, with loss of normal grey-white matter differentiation (dashed lines). e Axial trace DWI demonstrates restricted diffusion (ADC map not shown) in the left cerebral hemisphere corresponding to the left middle cerebral artery territory (solid arrows)

Fig. 3

Cerebral sinovenous thrombosis. Day 2 ultrasound in a 36-week gestation neonate with difficulty feeding after a complicated (failed forceps) delivery. a Coronal and (b) left parasagittal images demonstrate bilateral, slightly asymmetrical (left > right) increased echogenicity of the medial thalami (solid arrows). c Coronal and (d) left parasagittal colour Doppler images demonstrate flow in the internal cerebral veins (dashed arrows), suggesting patency. e Coronal image demonstrates echogenic material in the right frontal horn, partially effacing it (white arrowhead). f Right parasagittal image confirms echogenic material in the caudothalamic groove (white arrowhead), consistent with germinal matrix haemorrhage. This constellation of findings—bilateral thalamic increased echogenicity, presumed haemorrhagic infarction, and right grade 1 intraventricular haemorrhage—is suggestive of cerebral sinovenous thrombosis. g Coronal T2WI demonstrates corresponding bilateral hypointensity in the medial thalami, confirming haemorrhage (solid arrows). Note the subgaleal collection secondary to traumatic delivery (black arrowhead). h Axial T2WI demonstrates linear low signal in bilateral perforator veins of the thalamus, consistent with thrombosis (dashed arrows), which was not evident on CUS. i Axial trace DWI and (j) ADC map demonstrate restricted diffusion in bilateral thalami (left > right) (black arrowheads), consistent with acute thalamic haemorrhagic venous infarction

Fig. 4

Vein of Galen aneurysmal malformation. Day 1 ultrasound in a term neonate with high-output cardiac failure. a Coronal image demonstrates a central, ovoid, anechoic mass (solid arrow). b Midline sagittal image confirms that the anechoic mass (solid arrow) is centred on the pineal recess, lying posterior to the tectal plate (TP) and superior to the tentorium cerebelli (TC). c Coronal and (d) midline sagittal colour Doppler images demonstrate marked vascularity within the sac, with aliasing artefact suggesting turbulent flow. e Midline sagittal T2WI and (f) contrast-enhanced CT demonstrate a vascular mass, with T2 low signal flow voids (e) and avid contrast enhancement (f). Large arterial feeders (A) and draining venous channels (V) are evident. g Midline sagittal digital subtraction angiography (DSA) demonstrates arteriovenous shunting of blood from a large anterior cerebral artery (A) to an enlarged/aneurysmal median prosencephalic vein (VoG)

Fig. 5

Subpial haemorrhage and haemorrhagic venous infarction. Day 1 ultrasound in a 35-week gestation neonate with non-immune hydrops fetalis, screening for congenital infection or ischaemia. a Coronal and (b) parasagittal transfontanellar, and c transmastoid images demonstrate an ovoid/ellipsoid hypoechoic extra-axial collection in the left posterior temporal/occipital region, which buckles the adjacent cortex (solid arrows). There is increased echogenicity of the adjacent white matter (dashed arrows). The sonographic “yin yang” sign is illustrated here. d Coronal and (e) axial T2WI confirm the large left temporo-occipital subpial haemorrhage buckling the adjacent cortex (solid arrows). f Axial trace DWI and (g) ADC map demonstrate diffusion restriction in the surrounding haemorrhagic venous infarction (dashed arrows). h Axial SWI demonstrates pronounced susceptibility artefact related to the haemorrhage

Fig. 6

Congenital cytomegalovirus infection. Day 1 ultrasound in a 31 + 6-week gestation neonate, to assess for intraventricular haemorrhage. a Coronal image demonstrates multiple, bilateral septated subependymal/caudothalamic groove cysts (solid arrows) of mixed echogenicity. b Right parasagittal image shows a subependymal cyst extending posterior to the foramen of Monro (solid arrow), as well as periventricular cysts adjacent to the temporal and occipital horns (dashed arrows). c Coronal and (d, e) axial T2WI confirm multiple subependymal/caudothalamic groove (solid arrows) and periventricular (dashed arrows) cysts. Companion case: Day 1 ultrasound in a different 32-week gestation neonate. f Coronal image demonstrates bilateral echogenic subependymal/caudothalamic groove cysts (white arrowheads). g Right parasagittal image reveals linear, branching echogenicity within the basal ganglia/thalami, consistent with lenticulostriate mineralisation (black arrowhead). h Axial T2WI demonstrates bilateral polymicrogyria (brackets)

Fig. 7

Congenital toxoplasmosis infection. Day 13 ultrasound in a term neonate with seizures and a bulging anterior fontanelle. a Coronal and b parasagittal images demonstrate severe ventriculitis with intraventricular debris (solid arrows), septations (dashed arrows), ventriculomegaly and ependymal thickening/increased echogenicity (white arrowheads); there is also periventricular echogenicity with posterior acoustic shadowing indicating calcification (black arrowhead), as well as diffuse brain swelling and diffusely increased parenchymal echogenicity with reduced grey-white differentiation. c, d Coronal CT images demonstrate coarse bilateral periventricular calcifications (black arrowheads). e Axial T2WI demonstrates diffuse parenchymal high signal and brain swelling, consistent with cerebritis. f Axial post-contrast T1WI demonstrates diffusely thickened, enhancing ependyma indicating ventriculitis (white arrowheads), along with bilateral parietal rim-enhancing lesions, consistent with abscesses (*)

Fig. 8

Bacterial meningitis. Ultrasound at 4 months in a drowsy infant with a bulging anterior fontanelle. a Coronal image demonstrates increased echogenicity in the interhemispheric subarachnoid space (solid arrows). b Coronal image with a high-frequency linear probe reveals bilateral hypo-/anechoic parafalcine subdural collections (left > right) (dashed arrows), increased echogenicity of the right parasagittal subarachnoid space (solid arrow), and widening of left frontal sulci (black arrowhead) due to distension of the subarachnoid space by purulent material. Findings are consistent with bacterial meningitis—caused by Haemophilus influenzae in this case. Ultrasound at 3 weeks in a neonate presenting with septic shock. c Coronal image demonstrates ill-defined, bilateral (left > right), multifocal cortical, subcortical, and deep grey matter increased echogenicity (solid arrows). There is also echogenic material in the frontal horns of both lateral ventricles, suggesting purulent/infectious debris or intraventricular haemorrhage (dashed arrows). d Coronal colour Doppler image demonstrates absence of flow in the superior sagittal sinus (solid arrow). e Axial SWI reveals corresponding bilateral susceptibility artefact, consistent with haemorrhage, involving the right insular cortex, bilateral frontal and parietal subcortical white matter, and the right corpus striatum (solid arrows); linear susceptibility artefact represents cortical and medullary vein thrombosis (dashed arrows). f Coronal MRV demonstrates a lack of signal in most of the dural venous sinuses (superior sagittal, transverse, and sigmoid), consistent with extensive dural venous sinus thrombosis. Findings are consistent with meningoencephalitis—due to Group B Streptococcus sepsis in this case, with extensive secondary haemorrhagic venous infarction. Ultrasound at 28 days in a term neonate presenting with desaturations and cyanosis. g Coronal image demonstrates large, bilateral ovoid/“box”-shaped frontal lobe masses, right > left (*), with mixed internal echogenicity, consistent with abscesses. Minor leftward midline shift is present (curved arrow). h Coronal post-contrast T1WI details thick rim enhancement of bilateral frontal lobe abscesses (*). i Axial trace DWI and j ADC map show globular restricted diffusion within the abscesses, indicating pus (black arrowheads); note the effacement of the frontal horns of both lateral ventricles due to mass effect (solid arrows). Findings are consistent with bilateral frontal lobe abscesses, due to Citrobacter infection in this case

Fig. 9

Callosal agenesis. a Antenatal ultrasound demonstrates the absence of the septum pellucidum and enlargement of the right lateral ventricular occipital horn (labelled 1). b Coronal T2W fetal MRI confirms the absent septum pellucidum, with medially indented (solid arrows) and laterally convex (dashed arrows) frontal horns, and a high-riding third ventricle (3V) extending to the interhemispheric fissure (white arrowhead). c Axial T2WI MRI neonatally shows symmetrical enlargement of the lateral ventricular (LV) occipital horns, e.g., colpocephaly, which have a parallel “racing car” configuration; right frontal polymicrogyria is also noted (bracket). d Coronal ultrasound at term echoes the fetal MRI findings outlined in b above. e It also confirms colpocephaly and parallel orientation of the lateral ventricles. f Midline sagittal ultrasound demonstrates radially oriented cingulate gyri (black arrowhead) extending to the 3rd ventricle (3V), and no detectable corpus callosum or pericallosal artery

Fig. 10

Tuberous sclerosis. Day 1 ultrasound in a 32-week gestation neonate with a paternal history of tuberous sclerosis and an antenatally detected cardiac rhabdomyoma. a, b Coronal and (c, d) parasagittal images from day 1 (postnatal) ultrasound demonstrate multiple confluent areas of increased echogenicity in the cortical/subcortical and deep white matter of both cerebral hemispheres (solid arrows), without posterior acoustic shadowing; subependymal nodules are also evident (dashed arrows). e Coronal and (f) parasagittal T1WI shows the corticosubcortical tubers as subtle, ill-defined T1 hyperintense, radially oriented lesions (solid arrows); the T1 hyperintense subependymal nodules (dashed arrows) are more conspicuous than on CUS. g Antenatal ultrasound demonstrated an echogenic intracardiac lesion (measured), consistent with a rhabdomyoma

Fig. 11

Dysplastic right hemimegalencephaly. Term neonate with antenatal ventriculomegaly, macrocephaly, and an abdominal wall haemangioma evident postnatally. a, b Coronal images demonstrate unilateral enlargement of the right cerebral hemisphere (CH) and right lateral ventricle (LV), with reduced grey-white matter differentiation in the affected (right) hemisphere. c, d Coronal and (e) axial T2WI confirm unilateral enlargement of the right cerebral hemisphere (CH) (and to a lesser extent the right cerebellar hemisphere (CerH)) and of the right lateral ventricle (LV), with asymmetric T2 low signal in the (dysplastic) white matter of the right cerebral hemisphere (solid arrows) and periventricular nodular heterotopia adjacent to the right frontal horn (dashed arrows). There is also asymmetrical enlargement of the right skull

Fig. 12

Choroid plexus papilloma. Ultrasound at 2 months in an infant with rapidly increasing head circumference and sun-setting eyes. a Coronal image demonstrates a large, lobulated/cauliflower-like, echogenic, non-shadowing mass (solid arrows) occupying the lateral (LV) and third ventricles (3V), with associated hydrocephalus. b Coronal colour Doppler image demonstrates a vascular pedicle centrally within the mass (dashed arrow), which had an arterial waveform on spectral Doppler. c Coronal post-contrast T1WI shows avid enhancement within the large solid intraventricular mass (solid arrows), with associated hydrocephalus. This lesion proved to be a choroid plexus papilloma. Atypical teratoid/rhabdoid tumour. Ultrasound at 4 months in an infant with reduced feeding, vomiting, and increasing head circumference. The patient had a normal head ultrasound on day 1 of life. d Coronal image demonstrates a large, ill-defined, and heterogeneous posterior fossa mass (solid arrows), with obstructive hydrocephalus involving the lateral ventricles (LV). e Coronal post-contrast T1WI confirms the large, solid, heterogeneously enhancing and obstructing posterior fossa mass (solid arrows). This lesion proved to be an atypical teratoid/rhabdoid tumour. Desmoplastic infantile ganglioglioma. Ultrasound at 2 weeks in a neonate presenting with floppiness and increasing head circumference. The patient had a normal MRI brain on day 1 of life. f Coronal image demonstrates a large, heterogeneous mass occupying most of the right cerebral hemisphere, with anechoic cystic (solid arrow) and echogenic solid (dashed arrows) components. There is an associated leftward midline shift (curved arrow). g Coronal oblique colour Doppler image demonstrates marked vascularity within the mass. h Coronal T2WI confirms the large mixed cystic (solid arrow) and solid (dashed arrows) mass, with obstructive hydrocephalus. This lesion proved to be a desmoplastic infantile ganglioglioma