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114
3 Neurosonography in Neonates, Infants and Children
velocities (cause some jet phenomenon, where one may fi nd intermittent undulating jets that vary with respiration or with other forms of increased thoracic
pressure, such as crying, breath hold and ventilation manoeuvres).
NOTE : For any measurements of CSF spaces, standardised approach with repro-
ducible measurements should be applied; CSF overdrainage can cause ventricular
collapse and secondary subdural haemorrhage/effusion which may clinically mimic
shunt dysfunction and increased brain pressure.
• 3DUS particularly valuable: complete documentation, reproducible measurement
at comparable section and comparison to other sectional imaging (any desired
section may be reconstructed from 3DUS data set) (Figs. 3.34c , 1.26 , and 1.27 ).
3.3.8 Cerebral Haemorrhage
Various forms of haemorrhage need to be differentiated in terms of location and
aetiology: intra- and extracranial, intra- or extraventricular, parenchymal, extracerebral (sub-galeal haematoma, subcutaneous haematoma, subdural, epidural, subarachnoid, etc.). etc. (Fig. 3.35 ). Type of haemorrhage varies with age: preterms
have different haemorrhages than term neonates or infants.
3.3.8.1 Haemorrhage in Preterm Babies – IVH Grades I
to III, PVH (Fig.
3.36 )
Typically occur in germinal matrix near head of caudate nucleus, where immature
vessels tend to rupture with only mild trauma, unstable blood pressure and intravascular volume changes, etc.
IVH I : on US echogenic round or oval-shaped area below plexus and head of
caudate nucleus (intraventricular haemorrhage grade I = IVH I ) – to be differentiated
from swollen choroid plexus (also echogenic, but usually entire plexus affected) or
choroid plexus bleeds (occur at any location of plexus, but commonly close to
a b
Fig. 3.35 Scheme: cranial haemorrhages. Typical extra- ( a ) and intracranial ( b ) haemorrhages –
site and respective appearance. Abbreviations: SEB/SEH sebependymal bleed/haemorrhage, EDH
epidural haematoma, SDH subdural haematoma, ICH intracerebral haemorrhage, IVH intra–ven-
tricular haemorrhage, SAH subarachnoid haemorrhage and PVH periventricular haemorrhage
3.3 Pathologic Findings
115
a
b
f
Fig. 3.36 Images and schematic drawings demonstrating classifi cation and image appearance of
brain (intra-ventricular) haemorrhage in preterms. ( a ) Scheme plexus bleed and IVH grade I° (sub-
ependymal bleed/haemorrhage = SEB/SEH ), IVH intraventricular haemorrhage. ( b ) Parasagittal
view: IVH I°/SEB, clot seen as somewhat echogenic nodular structure (may be diffi cult to differentiate from plexus haemorrhage). ( c ) Scheme IVH grade II°, III° and IVH + periventricular haem-
orrhage (=PVH, older term IHV IV°). ( d ) Parasagittal view: IVH II°, huge clot in the plexus, a little
bit of blood in the posterior horn. ( e ) Coronal view: fresh haemorrhage with blood fi lling the entire
ventricle lumen = IVH grade III°. ( f , g ) Coronal view: haemorrhage with periventricular haemor-
rhagic infarction/PVH on right ( f ) or left ( g ) (+ +) side
c
d
e
g
frontal attachment, located within plexus). For differentiation – axial section or
axial 3DUS reconstruction helpful.
IVH II : if grade I haemorrhage increases, it ruptures into ventricle – some blood
seen in ventricle (grade II haemorrhage). Initially ventricles not dilated, only little
blood or some clotting in ventricle.
IVH III : with progression of haemorrhage ventricles get dilated, increasingly
fi lled with blood (grade III haemorrhage) Blood also seen in third and fourth
116
3 Neurosonography in Neonates, Infants and Children
a
c
Fig. 3.37 Examples for other cerebral haemorrhages and DDx. ( a , b ) Basal ganglia haemorrhage
(echogenic mass) in term infant ( a ) coronal and ( b ) (para-)sagittal section. ( c , d ) DDx in haemor-
rhage: Echogenic swollen plexus ( b , sagittal section) with hypervascularity on CDS ( c , coronal
view) in a plexus papilloma
b
d
ventricle due to physiological CSF drainage pathways. Due to dilatation of ventricle
paraventricular draining veins get compressed/obstructed/congested – cause venous
infarction of periventricular respective areas ⇨ haemorrhagic infarction.
IVH III + PVH : combination of periventricular haemorrhagic infarction with
grade III haemorrhage (initially called type IV haemorrhage, now classifi ed as
haemorrhage grade III + periventricular haemorrhage = PVH) – attributing new
insight into aetiology and pathophysiology.
3.3.8.2 Haemorrhage in Term Infants
Much rarer, usually do not occur as IVH but as intraparenchymal haemorrhages
(intracerebral haemorrhage – ICH).
Typical locations: basal ganglia and locations of haemorrhagic venous infarc-
tions (Fig. 3.37 ).
Rare other causes that defi ne locations – secondary haemorrhage into hypoxic areas
or trauma:
• Epidural haemorrhages – EDH (e.g. after forceps delivery or skull fractures), use
TCI (Fig. 3.38 ).
3.3 Pathologic Findings
Fig. 3.38 Epidural haemorrhage (+ +). Axial
view – TCI, magnifi ed section: subcalvarian complex
ovaloid fl uid space-occupying lesion in terms of
a subacute EDH
117
a
Fig. 3.39 Tentorial and cerebellar haemorrhage. ( a ) Coronal section, linear transducer: tentorial
and cerebellar haemorrhage. ( b ) Same patient as in ( a ) tilted mastoid-axial view: superior demon-
stration of bleed
b
• Subdural haemorrhages – SDH (consider shaken baby syndrome), linear transducer and TCI helpful (Figs. 3.29 and 3.20d ).
• Subarachnoid haemorrhages – diffi cult to see on US unless large.
• Tentorial bleeds (e.g. after complicated fetal repositioning manoeuvres or breach
delivery) (Fig. 3.39 ).
• Direct impact (trauma), by caesarean section (e.g. cutting too deep, thus injuring
brain through fontanel).
NOTE : Unexplained haemorrhages in neonates and young infants raise suspicion
of nonaccidental injury (NAI) – thorough workup.
US Appearance
All haemorrhages have similar US appearance and development:
• Hyperacute state: blood has similar echogenicity as surrounding tissue – not
seen.
• (Sub)acute state: bright echogenic spot.
• Further course – sedimentation and resorption: inhomogenous with some
hyperechoic areas and clot formation – usually inhomogenously echogenic,
tumour- like areas (Fig.
3.40 ).
118
3 Neurosonography in Neonates, Infants and Children
a
Fig. 3.40 Clot and hydrocephalus after IVH III. ( a ) Coronal section demonstrating inhomoge-
nously echogenic masses within lateral ventricles obstructing foramen of Monro. ( b ) Parasagittal
view: demonstrates clots in dilated lateral ventricle after IVH III
b
• Eventually resorbed – cystic remnants, hyperechoic ventricular wall and parenchymal defects (Fig. 3.20 ).
• Impairment of CSF circulation may cause hydrocephalus – careful monitoring
and assess need for CSF drainage:
– Early phase: drainage sometimes achievable by repeated lumbar punctures.
– Later phases: external drainage and shunt placement necessary.
NOTE : Every term neonate and young infants with haemorrhage may suffer from
rare underlying disease, e.g. coagulopathies, venous thrombosis, vascular anomalies, underlying tumours, hyperviscosity, hypoxia, ischemia, dehydration, septicaemia and meningoencephalitis. Differentiation by US often diffi cult or impossible
(e.g. haemorrhagic infarction diffi cult to differentiate from haemorrhage without
underlying infarction).
3.3.8.3 Role of CDS in Neonatal Haemorrhage
Doppler and CDS does not help in defi ning aetiology or predicting haemorrhage,
however, reduced fl ow velocities and large fl uctuation of fl ow spectra with repeated
examinations (due to lack of autoregulation) associated with higher risk of
haemorrhage:
• Only in severe active bleeding is increased particularly diastolic fl ow with
reduced RI seen in feeding vessel.
• Sometimes CDS depicts vascular anomaly that caused haemorrhage.
• CDS helpful for depiction of thrombosis of large venous pathways.
• aCDS is helpful to differentiate swollen choroid plexus (with existing perfusion)
from choroid plexus bleed or clot.
3.3.8.4 Haemorrhage in Infants and Older Children
After fontanel closure and increasing skull ossifi cation, US possibilities decrease;
particularly detailed assessment of small changes or exclusion of haemorrhage
becomes increasingly diffi cult and eventually impossible. CT and MRI are
mandatory.
3.3 Pathologic Findings
119
a
Fig. 3.41 US for skull fracture. ( a ) Linear transducer: skull fracture sees as disruption of skull
echo. ( b ) Linear transducer: skull fracture with subacute haematoma
b
US Findings :
• Haemorrhage as in transfontanellar view – initially echogenic, relatively sharp
margins.
• As long as US access and penetration possible, large parenchymal bleeds and
large SDH/EDH can be depicted, particularly if cause some mass effect and distort ventricles or midline structures.
NOTE : Do not mistake repeating echoes from (contralateral) skull on transtempo-
ral images for haemorrhage.
• SDH may be recurrent – thus septae develop, with different echogenicity in various compartments. If chronic – hygroma.
NOTE : Usually brain surface fl attened and sulci narrow in area of haematoma – in
atrophy sulci enlarged without fl attening of brain surface. If SDH of different age
always think of NAI, try to assess near-fi eld cortex for depiction of typical teardrop
lesion (resorbed focal venous infarctions) in (sub)cortical area – may be missed if
only sector array used (Fig. 3.20 ).
• Cerebellar and tentorial haemorrhages rare, also bleeds of brain stem and other
posterior fossa structures. Diffi cult for US once skull ossifi ed. Usually have poor
prognosis.
• Transmastoid, -occipital and -temporal access mandatory when evaluating these
potential pathologies.
NOTE : In older children with appropriate history or symptoms, emergency imag-
ing by CT and/or MRI indicated.
• Helpful application: assessment of skull and galea by high-resolution linear
transducers. Haematoma seen, formation of seroma can be documented and
measured, skull fractures – even if only subtle – usually nicely depicted by showing disruption of skull surface echo (Fig. 3.41 ).
• Skull US also helpful for assessment of other skull or skin lesions; e.g. epithelial
cysts, histiocytosis, eosinophelic granuloma, metastases and in some places also
applied for assessment of craniosynostosis.
3.3.9 Tumours and Space-Occupying Lesions
Intracranial tumours represent 15 % of childhood tumours, most occurring beyond
fi rst year of life – therefore not ideally suitable for US diagnosis; in these ages
120
3 Neurosonography in Neonates, Infants and Children
Fig. 3.42 US appearance in a typical neonatal cerebral AVM – ectatic/aneurysmal vein of Galen
malformation. Midline sagittal view: large cystic formation fi lled with fl oating echoes – vein of
Galen malformation
only large tumours depicted particularly if they cause midline shift or
hydrocephalus:
• In infancy mostly teratoma, craniopharyngioma, medulloblastoma/PNET, choroid plexus papilloma and lipoma.
• Older children – larger variety of different tumours.
US Findings :
Tumour echogenicity and texture – nonspecifi c: homogeneous or heterogeneous,
cystic or necrotic areas, haemorrhage and may contain calcifi cations (only large
calcifi cations cause acoustic shadowing).
Secondary signs – consequences of space-occupying lesions – shift/compression
of surrounding structures, compression of ventricle and hydrocephalus.
Some specifi c appearances:
• Echogenic tumour typically in midline – rather specifi c for (callosal) lipoma.
• Choroid plexus papilloma – homogenously echogenic, within plexus, inhomogenous tumours may represent carcinoma; very vascular – CDS is helpful.
NOTE : Additional imaging by preferably MRI or – if not available – CT.
3.3.9.1 Vascular Malformations
Diffi cult to depict on US, particularly beyond fi rst months of life, contrast-enhanced
CDS may increase US potential.
Typical entity – phakomatosis (e.g. Klippel-Trénauny syndrome, Von Hippel-
Lindau syndrome and Bourneville-Pringle disease), tubers and gliomas manifest in
more central portions or at ventricular margins – more easily depicted than common
peripheral or meningeal lesions (particularly venous ectasia with calcifi cation and
thrombosis) as in Klippel-Trénauny, and easily missed → contrast-enhanced MRI.
US Appearance :
• Echogenic – if consisting of many small vessels.
• Tubular or cystic – if consisting of larger vessels and aneurysmal vascular portions (Fig. 3.42 ).
• Show vivid Doppler fl ow only with large or high fl ow shunts: feeding and draining vessels depictable.
3.3 Pathologic Findings
121
a
b
cd
Fig. 3.43 CDS in cranial and cerebral AVM. ( a ) Axial view by TCI-CD: fl ow in aneurysmatic
portion of a vein of Galen malformation, some feeding arteries seen as well as the enlarged draining vein (with high and turbulent fl ow causing aliasing). ( b , c ) Focal mass suspected to be a skin
haemangioma on the skull; CDS demonstrates vivid vascularisation. NOTE: Mirror image artefact
both on gray scale as well as on CDS caused by the highly refl ective skull bone. ( d ) Superior sinus
thrombosis, sagittal view: CDS demonstrates lack fl ow in the superior sagittal sinus which is also
somewhat inhomogenously echogenic; consequently dilated extra-axial CSF space
• Purely venous malformations have low fl ow – diffi cult to depict, particularly on
transcranial imaging.
• Ce-US may improve differentiation from other lesions.
aCDS : helpful particularly in neonates and young infants for :
• Vascular pathology: malformations and aneurysms (intra- and extracranial):
– Particularly typical arteriovenous malformation/fi stula of vein of Galen
(Figs. 3.43a–c and 1.15 ).
NOTE : In vascular malformations, CDS can be misleading, particularly after haem-
orrhage or with thrombotic components, often differentiation from tumours and
other mass lesions impossible.
• Venous thrombosis – poor insonation angle and low fl ow may impair conventional CDS potential (Fig. 3.43d ).
• Signifi cantly hyperperfused tumours (e.g. plexus papilloma – see Fig.
3.37d ):
– Otherwise aCDS not particularly useful for cerebral tumours.
– Potentially for DDx of necrotic parts or compartments containing compli-
cated fl uid (e.g. abscess).
CDS in older children : to some extent transcranial ce-CDS may improve sonographic
potential in depicting vascular malformations or differentiating clots, necrotic areas
or haemorrhages and subacute infarctions from tumours. Atypical fl ow patterns may
indicate shunt fl ow and allow rough estimation of hemodynamics.
122
3 Neurosonography in Neonates, Infants and Children
3.3.10 Cerebral Calcifications
Introduction
Various causes: prenatal infection, peri- and postnatal meningitis, vascular malformations, posthaemorrhagic, neoplastic, phakomatoses, postthrombotic, etc.
Localisation :
• Commonly in supratentorial brain, mostly in basal ganglia and also
hemispheres.
• Commonly in vicinity of vessels and in choroid plexus.
• Calcifi cation-like echoes in cysts or abscess-like formations – suspicion for
parasitic or fungal infection, if in cyst wall – hint at unusual origin (infectious,
posthaemorrhagic, tumorous, etc.).
NOTE : Meningeal calcifi cations diffi cult to depict on US.
US Findings (see Fig. 3.27a ):
• Usually echogenic formations with sharp borders can be scattered and may vary
in size and echogenicity.
• Small calcifi cations lack typical acoustic shadowing.
• Differential diagnosis of calcifi cations diffi cult by US:
– Aetiology can only be assumed in combination with other imaging and par-
ticularly clinical information.
3.3.10.1 Non-calcifying Vasculopathy
(Lenticulostriate Vasculopathy)
Band-like echogenic stripes along vessels, mostly in the basal ganglia (see
Fig. 3.27b ).
3.4 Ultrasound of the Skull
3.4.1 Introduction
US can be used for assessment of subcutaneous pathology as well as disruption of
skull surface.
Always use linear high-resolution high-frequency transducer and plenty US
gel.
3.4.2 Haematoma
Types of haematoma – see Fig. 3.36 . US helpful in differentiating entity:
• Echogenicity and US appearance may help estimate age:
– Acute bleed – rather hyperechoic.
– Older bleed – hypoechoic with sedimentation.
– Chronic bleed or remnants/seroma – anechoic, capsule formation.
3.5 Additional Imaging
123
3.4.3 Space-Occupying Lesions and Tumours
US – resembles fi nding in other small parts (see respective chapter), may visualise
cysts, tumours, metastases, etc.
3.4.4 Skull Fracture
• US depicts disruption of echogenic calvarial bone surface – helpful for assessing
suspicious fi ndings on plain fi lm (Fig. 3.41 ).
• US may help analyse amount of displacement.
• US may help in follow-up – e.g. if growing fracture suspected.
US used to assess sutures and their ossifi cation + differentiating sutures from
fractures:
• Fracture – typically sharp border.
• Suture – dentates shape of borders, similar to plain fi lm; US also used to assess
craniosynostosis in some places.
• 3DUS with surface rendering helpful for differentiation, conspicuously visual-
ises shape of fracture (Fig. 1.33 ) .
3.5 Additional Imaging
3.5.1 Plain Film
Used for visualisation of osseous structures
• Particularly when looking for fractures, calcifi cations, skull defects, skull anom-
alies, etc.
– Dedicated projections used for assessment of premature synostosis.
• Assess continuity of shunt drains.
3.5.2 CT
Indicated for emergency imaging, particularly in older children
• After trauma, suspected haemorrhages and for complicated fractures (always
with surface rendering).
• Hydrocephalus/follow-up after shunt (use specifi c low-dose protocols) – if no
MRI available or contraindicated/unsuitable.
• Stroke (if MRI not available).
• Tumours (if MRI not available).
• CT-Angiography used for vascular assessment:
– Modern volume CT and CT-DSA allow for angiography-like subtraction
images as well as perfusion studies.
NOTE : Considerable radiation burden – try to replace by MRI whenever possible.