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2.5 Vascular Access
73
fl uoroscopic- sonographic access with CM instillation to clearly demonstrate
absence of fi stulae or leak may be necessary.
• CT: more reluctantly used to guide procedures in children due to radiation bur-
den, however, helpful alternative (as is sometimes fl uoroscopy) if US cannot
grant safe access or suffi cient visibility of access pathway and target/
structure.
2.5 Vascular Access
US can be used to guide puncture of vessels after demonstrating their patency, not
only at site of puncture but also further downstream by either following vessel or
indirectly by proving normal fl ow profi les.
How to do : Usually freehand technique better, but avoid high transducer pressure
which might compress vessel lumen complicating successful puncture:
• Positioning manoeuvres sometimes helpful to properly fi ll vessel. After
needle insertion guide wire is placed and catheter is advanced per standard
techniques.
• Low angle between transducer surface and needle path improves needle visibility –
decision on axial versus longitudinal view depends on personal preference/handling
options/location and size (Fig. 2.16 ).
Assessment of catheter tip sometimes diffi cult – radiograph or fl uoroscopy may
become necessary.
• Always assure proper position at end of procedure: that catheter lies within vessel
lumen, that the tip is placed appropriately and that the line functions properly.
• US also used to assess tip of catheters placed without US guidance, catheter-
related vascular complications (such as catheter-induced thrombosis) or compli-
cations of other drainage tubes, feeding lines, etc. (Fig. 2.17 ).
Fig. 2.16 US-guided
vascular access. Longitudinal
US of basilic vein shows 21G
needle with tip within vessel
lumen
74
ac
ed
Fig. 2.17 US for catheter/tube position. ( a ) Thick femoral catheter placed for ECMO ending in
proximal iliac vein. ( b ) CDS demonstrates high fl ow and patency of the catheter. ( c ) Malposition
of an umbilical vein catheter in the venous sinus ( arrow ) – obviously ductus venous too narrow to
be passed. ( d ) Malposition of gastric feeding tube in a neonate – its tip is seen in the retroperitoneal
para-oesophageal soft tissue adjacent to pre-vertebral aorta. ( e ) After instillation of new tube tip
( arrow ) now seen correctly placed in stomach fi lled with saline
b
2 Ultrasound-Guided Interventions
2.6 Lumbar Puncture
Usually done without any image guidance.
In complicated cases (e.g. after unsuccessful attempts), US may be helpful to
show cause or consequences of unsuccessful attempts (Fig. 2.18a ).
US may guide needle to area where CSF can be tapped successfully (may be at
higher or lower level than performed clinically) (Fig. 2.18b ).
US technique: same as for diagnostic spinal US, although useful to have patient
semi-upright for lumbar puncture.
TIP : US also used to locate dorsal processes for counting vertebral bodies in obese
patients.
2.7 Foreign Body Removal
a b
Fig. 2.18 US for lumbar puncture. ( a ) Longitudinal US in an infant after failed blind lumbar puncture
attempts. Thecal sac ( T ) below conus medullaris ( C ) completely decompressed – with no cerebrospi-
nal fl uid seen around nerve roots of cauda equina in collapsed thecal sac. Echogenic dura ( arrow-
heads ) surrounded ventrally and dorsally by complex hypoechoic material representing haematoma
and leaked CSF. ( b ) Longitudinal US in an infant with fever: echogenic 22G spinal needle passing
between hypoechoic cartilaginous spinous processes ( P ) – needle tip ( arrowhead ) within thecal sac
2.7 Foreign Body Removal
US is ideal to localise foreign bodies (see Chap. 11 ).
How to do (Fig. 2.19 ):
• Localisation using high-frequency transducer.
• Proper/extensive local anaesthesia helps to outline foreign body.
• Small incision.
• Small haemostat inserted towards foreign body with closed teeth under US
monitoring.
• With gentle opening foreign body is grabbed – then slowly removed.
• Thereafter rescanning is essential – ensure complete removal of foreign body.
Alternative: US can be used to localise foreign body and mark it by guide wire to
enable conventional surgical retrieval.
75
abc
Fig. 2.19 US-guided foreign body removal. ( a ) US of lower extremity shows (echogenic) piece
of glass in the soft tissues. ( b ) With US guidance, needle directed along planned path of foreign
body removal, local anaesthetic placed. ( c ) The haemostat jaws seen to be surrounding the foreign
body, after which it was gently grasped and removed
Neurosonography in Neonates, Infants and Children
Michael Riccabona
Contents
3.1 Requisites ........................................................................................................................ 78
3.1.1 Equipment and Transducer Needs ..................................................................... 78
3.1.2 Indications for Brain US.................................................................................... 79
3.1.3 How to Investigate ............................................................................................. 79
3.2 Normal Findings ............................................................................................................. 81
3.2.1 Transfontanellar Access .................................................................................... 81
3.2.2 Alternate Access Findings ................................................................................. 83
3.2.3 Colour Doppler Sonography (CDS) .................................................................. 84
3.2.4 Normal Variances in Preterm Babies................................................................. 87
3.3 Pathologic Findings ......................................................................................................... 92
3.3.1 Neural Tube Defects .......................................................................................... 92
3.3.2 Migration and Gyration Alterations and Disturbances...................................... 94
3.3.3 Phakomatoses .................................................................................................... 98
3.3.4 Cerebral Cysts ................................................................................................... 98
3.3.5 Ischemic Encephalopathy .................................................................................. 100
3.3.6 Infl ammation ..................................................................................................... 105
3.3.7 Dilatation of CSF Spaces: Hydrocephalus ........................................................ 107
3.3.8 Cerebral Haemorrhage ...................................................................................... 114
3.3.9 Tumours and Space-Occupying Lesions ........................................................... 119
3.3.10 Cerebral Calcifi cations ...................................................................................... 122
3.4 Ultrasound of the Skull ................................................................................................... 122
3.4.1 Introduction ....................................................................................................... 122
3.4.2 Haematoma ........................................................................................................ 122
3
M. Riccabona
Division of Pediatric Radiology, Department of Radiology,
University Hospital Graz, Auenbruggerplatz 3,
Graz 8036, Austria
e-mail: michael.riccabona@klinikum-graz.at
M. Riccabona, Pediatric Ultrasound,
DOI 10.1007/978-3-642-39156-9_3, © Springer Berlin Heidelberg 2014
77
78
3.4.3 Space-Occupying Lesions and Tumours ........................................................... 123
3.4.4 Skull Fracture .................................................................................................... 123
3.5 Additional Imaging ......................................................................................................... 123
3.5.1 Plain Film .......................................................................................................... 123
3.5.2 CT ...................................................................................................................... 123
3.5.3 MRI ................................................................................................................... 124
3.5.4 Catheter Angiography ....................................................................................... 124
3.5.5 Additional Supporting Procedures .................................................................... 124
3.6 Ultrasound of the Eye and the Orbit ............................................................................... 124
3.6.1 Introduction ....................................................................................................... 124
3.6.2 Normal Findings ................................................................................................ 124
3.6.3 Sonographically Depictable Pathology ............................................................. 125
3.7 Ultrasound of the Spinal Canal ....................................................................................... 127
3.7.1 Requisites .......................................................................................................... 127
3.7.2 Transducers and Technique ............................................................................... 127
3.7.3 Indications ......................................................................................................... 127
3.7.4 Normal Findings ................................................................................................ 128
3.7.5 Pathologic Findings of the Spinal Cord ............................................................ 130
3.7.6 Trauma ............................................................................................................... 134
3.7.7 Tumours ............................................................................................................. 134
3.7.8 Other Spinal and Vertebral Pathology ............................................................... 135
3.7.9 Additional Imaging............................................................................................ 135
3.7.10 Value of US ....................................................................................................... 136
3 Neurosonography in Neonates, Infants and Children
3.1 Requisites
3.1.1 Equipment and Transducer Needs
Any system-operating high-resolution sector, vector, micro-curved and linear transducers, + CDS capabilities.
Transfontanellar Access :
• Basic US scan performed using sector (vector) or micro-curved transducers, fre-
quency of 10–5 MHz in neonates, 5–2 MHz in older infants – until the fontanel
is closed.
NOTE : If micro-curved array used, curvature should not be too narrow to avoid
compression of intracranial structures, particularly the brain surface and superior
sagittal sinus.
• Linear transducers for detailed study of brain surface using high frequencies
(10–17 MHz) + high-resolution imaging modes.
• Modern linear transducers with trapezoid/virtual convex mode helpful in entire
brain, not only for detailed surface analysis (Fig. 3.1 ).
Transtemporal Access :
• Transtemporal, transmastoid or other accesses such as occipital fontanel used in
neonates for detailed assessment of certain brain areas.
• In older children only transtemporal access with sector (vector) transducers (fre-
quency 7–1 MHz) is applicable.
3.1 Requisites
79
a
Fig. 3.1 Trapezoid view using high-resolution linear transducer for transfontanellar brain US.
Normal neonatal brain US in a coronal section through foramen of Monro ( a ) and sagittal section
in midline ( b )
b
3.1.2 Indications for Brain US
Indications in Neonates and Young Infants
Typical standard indications:
• Asphyxia and birth trauma, prematurity (screening, i.e. 3rd and 7th day).
• Macro- or hydrocephalus and (fetally) suspected cerebral malformations.
• Suspicion of brain haemorrhage.
• Clinical neurologic symptoms.
• Disease potentially associated with cerebral manifestations (e.g. septicaemia
with brain abscess, tuberous sclerosis and syndromic disease), meningeal empy-
ema, meningoencephalitis, brain abscess, etc.
• Some centres perform screening neonatal brain US.
Indications in Older Children :
• Hydrocephalus, also after shunting – using transtemporal access.
• Suspected cerebral perfusion alteration, such as with cardiac malformations,
after hypoxia or drowning, sickle cell disease, etc.
• Cerebral perfusion can be monitored at bedside in ICU for optimising ventilation
(“individual optimal PCO
• Assessment of (post-)haemorrhagic or tumorous midline shift, large vascular
malformations or brain death.
”).
2
3.1.3 How to Investigate
Positioning
Child in stable position – supine or lateral decubitus.
NOTE : Avoid pressure of transducer on fontanel.
80
3 Neurosonography in Neonates, Infants and Children
Fig. 3.2 Transfontanellar US – typical sections + respective images that should be documented.
Standard sections in scheme with corresponding respective images of normal US appearance. a
sagittal midline, b parasagittal, c anterior coronal, d median coronal and e occipital coronal
Transfontanellar Access :
• Assessment of entire visible brain in serial coronal and (para-)sagittal sections
(Fig. 3.2 ).
• Documentation of anterior, middle and posterior fossa as well as midline struc-
tures and lateral ventricles. Important features that need to be documented: cor-
pus callosum, ventricles including foramina of Monro with measurements if
enlarged, temporal and occipital horn of lateral ventricles, basal ganglia, periph-
eral parenchyma and interhemispheric fi ssure.
• In case of trauma or palpable bumps – assess calvarium using high-resolution
linear transducers.
• For special queries – add transmastoid, transtemporal or transoccipital access
(e.g. visualisation of aqueduct, posterior fossa structures and cerebellum particu-
larly in preterms, medulla oblongata), basal vessels.
• CDS: basal vessels, compare fl ow between left and right hemisphere.
NOTE : Use same routine for every investigation in order not to miss anything – sys-
tematic consistent approach.
Transtemporal, Transcranial, Mastoid Access, etc.:
• Every less ossifi ed part of the calvarium can be used, also osseous defects such
as after surgery.
• Axial and transverse sections acquired by rotating transducer.
• Coronal and oblique sections obtainable as needed.
3.2 Normal Findings
81
a
Fig. 3.3 Measurements on brain US. ( a ) Standard measurements of lateral ( 1 , 2 ) and third ( 3 )
ventricle diameter at level of the foramen of Monro in coronal section; sometimes area ( 4 ) and
circumference used (....) – more sensitive towards subtle changes. ( b ) Coronal section, hydro-
cephalus: ventricle measurements – diameters, circumference and area. ( c ) Standard depth
measurements of third ( 1 ) and forth ( 2 ) ventricle in sagittal midline section. ( d ) Coronal section,
linear transducer, near fi led view: extra-axial CSF size and interhemispheric fi ssure distance
measurements (↔)
b
c
d
Morphometry and Documentation :
• Standardised image orientation:
– Left side of US image = frontal (sagittal/axial view) and right side (coronal view).
– Always use proper labelling or pictograms.
• Standardised measurement of ventricular diameter and size, particularly if
enlarged (Fig. 3.3 ).
• Width of extra-axial CSF space: interhemispheric fi ssure, subfontanellar space,
fronto-temporal space (e.g. arachnoid cyst) and sylvian fi ssure – see also
hydrocephalus.
• Width of brain parenchyma (anterior, occipital, temporopolar) (Fig. 3.4 ).
• Size of the cerebellum (Fig. 3.5 , Table 3.1 ).
• Minimum documentation includes the following:
– Three to four coronal views (anterior, foramen of Monro, posterior horn, peri-
ventricular posterior parenchyma).
– Three to fi ve sagittal views (midline, left and right parasagittal through lateral
ventricles, periventricular parenchyma on both sides).
– Every abnormality documented in two orthogonal planes, reproducible mea-
surements helpful.
– Additional views helpful: brain surface with linear transducer, mastoid view
for posterior fossa, and CDS images with respective duplex trace (ICA, ACA,
MCA, circle of Willis, BA, major veins).
3.2 Normal Findings
3.2.1 Transfontanellar Access
Ventricular System :
• Slim lateral ventricles with symmetric confi guration, <10 mm diameter at level
of foramen of Monro.
82
a
3 Neurosonography in Neonates, Infants and Children
b
1
2
c
Fig. 3.4 Additional measurements. Measurement of parenchymal width (↔), particularly impor-
tant in hydrocephalus. ( a ) Parasagittal scheme: measurement of ventricular distance ( 1 ) and occipi-
tal parenchymal width ( 2 ). ( b ) US image in parasagittal section: hydrocephalus with severely
narrowed frontal and occipital parenchyma (+1, +2). ( c ) Coronal section: parenchyma (↔) to ven-
tricle ratio can be calculated, useful for follow-up incorporating physiological growth with stable
relations in spite of increasing values. ( d ) Normal values for ventricular size (mm, circumference
of lateral ventricle at level of foramen of Monro) related to head circumference (cm)
d
Fig. 3.5 Planimetric measurement of cerebellar
size. Cerebellum ( dotted line ) outlined for
planimetry – age adapted normal values see
3.1
Table
3.2 Normal Findings
83
Table 3.1 Cerebellar
size in preterm and term
neonates
Gestational age (week)
26 600 0.75
28 820 1.30
30 1,330 1.95
32 1,580 2.43
34 1,900 2.66
36 2,220 3.18
38 2,840 3.56
40 3,100 3.98
Body weight (g)
Cerebellar
area (cm 2 )
• Normal CSF: without any echoes.
• Choroid plexus: echogenic structure partially outlining ventricle, in posterior
parts fl oating within CSF.
• Ventricular system used as landmark for most parts of brain.
Other Physiologic Cavities to Visualise :
• Various cisterns.
• Various embryologic remnants such as cavum septi pellucidi, cavum vergae,
cavum velum interpositum.
• Extra-axial CSF space (interhemispheric fi ssure).
Brain Parenchyma :
• More or less homogeneous, of medium echogenicity, slight difference between
darker cortex and more echogenic white matter, identifi ed echogenic sulci (may
be inverted with immaturity, oedema etc.).
• Basal ganglia and internal capsule identifi ed by different echogenicity with high-
resolution transducers.
• Major vessels appear as echogenic pulsating tubular or nodular structures.
3.2.2 Alternate Access Findings
Image appearance varies with access; usually important basal and central structures
can easily differentiated:
• Lateral ventricles, foramen of Monro, third and fourth ventricle, connecting
aqueduct of Sylvius, crura cerebri, major parts of basal ganglia, tentorium, parts
of cerebellum, basal vessels and contralateral extra-axial CSF spaces.
• Mastoid access: occipital horn with choroid plexus, adjacent parenchyma
(Fig. 3.6 ) and cerebellum.