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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_5795_Библиотеки_им_академика_М_И_Перельмана.pdf
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Inflammatory Changes
Meningitis: nonspecic US ndings, potentially echoes in lumbar CSF space (bacterial meningitis).
• US can be used to guide diagnostic lumbar puncture or successfully tap lumbar
CSF therapeutically (see chapter on interventional US).
Osteomyelitis, spondylodiscitis: consider ventral approach—may depict pre−/
paravertebral pseudotumorous inammatory collection at level of disc and difcult
to differentiate from tumorous inltration.
Note Spondylodiscitis usually manifests in ventral and the intraosseous parts ⇨
poorly accessible by US.
Periosteal/Subperiosteal Changes, subperiosteal abscess, cortical destruction, etc.
sometimes depicted—however, CT or MRI usually indicated.
M. Riccabona
9.10 Additional Imaging
Plain lm: for vertebral body malformations– entire spine mandatory. Focal views
in trauma.
Spinal MRI: method of choice for most queries– except for dysraphic changes in
rst months of life.
CT: used for acute trauma, exact assessment of complex fractures or complex
malformations, for planning surgery and for guiding biopsy.
Scintigraphy: spondylodiscitis, osteomyelitis, and metastases.
9.11 Value ofUS
• Ideal rst step imaging in neonates, in this group often sufcient.
• With increasing ossication less and less effective:
– Replaced/supplemented by other imaging (plain lm, CT, MRI).
Note US also valuable for assessing additional or secondary ndings in other body
regions (e.g. increasing hydrocephalus after closure of MMC, assessment of abdominal and cardiac malformations in syndromic disease, evaluation of secondary
pathology such as urinary tract disease in children with MMC).
Ultrasound oftheNeck inChildhood
10
MichaelRiccabona
10.1 Indications, Requisites andTechniques
10.1.1 Transducers
In general high-resolution high- and multi-frequency linear transducers
(18–4MHz) used:
• Small footprint transducers sometimes very helpful in neonates and infants, provided that they offer same resolution (e.g. intraoperative/“ngertip” probes,
micro-curved)—but eld of view restricted.
• Steering the linear transducers in trapezoid view helpful for better overview and
larger viewing eld in deeper compartments, alternatively for deeper structures
(retro-/parapharyngeal space) sector and convex arrays sometimes necessary.
• CDS: slightly lower frequencies applied, often helpful.
10.1.2 Positioning andHandling
Supine, potentially with pillow behind shoulders for slight extension:
• Sometimes lateral decubitus position necessary—then support head by pillow.
• For cervical vessels—avoid nonphysiologic rotation/bending.
Note Scanning techniques vary with query/targeted structure (e.g. lymph nodes or
glands, versus vessels).
M. Riccabona (*)
Department of Radiology, Division of Pediatric Radiology, Medical University Graz
and University Hospital Graz, Graz, Austria
e-mail: michael.riccabona@medunigraz.at
© Springer Nature Switzerland AG 2020
M. Riccabona (ed.), Pediatric Ultrasound,
https://doi.org/10.1007/978-3-030-47910-7_10
179
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M. Riccabona
10.1.3 Typical Examinations
10.1.3.1 Cervical Lymph Nodes
Usually start with submandibular space, work through all stations:
• Always start at unaffected side—less painful.
• Assess all nodes in longitudinal and axial sections.
• For extensive pathology—extended eld of view helpful.
• If feasible: (a)CDS helpful to assess vascular anatomy + ow pattern—
particularly helpful in necrosis/abscess, or inltration.
• Role of ce-US and US-elastography not yet dened, but promising-particularly
in larger nodes.
10.1.3.2 Glands
Image targeted gland in axial and longitudinal sections, compared to other/nonaffected glands:
• Supercial structures may benet from stand-off pads (or plenty US gel).
• Always compare left and right side; include surrounding structures:
– Particularly in pathology—assess deeper para-/retropharyngeal spaces when
possible.
• Always use proper labelling and/or pictograms to clearly indicate which site
has been documented; document all relevant ndings and standard normal
structures.
• (a)CDS helpful for viewing vascular architecture and perfusion—particularly
helpful in necrosis/abscess, or inltration.
Note Perform standardised measurements—try to use denable reference structure
to allow for comparison during follow-up.
10.1.3.3 Cervical Arteries
Initially assessed in cross section (orientation easier)—image up and down as far as
possible. Complementing longitudinal demonstration of course of vessel, include
carotid bifurcation. Avoid angulations and oblique views unless necessary.
(C)DS: spectral analysis mandatory, particularly of relevant vessel sections and
in stenosis/pathology/occlusion.
Typical vessels: common carotid artery (CCA), internal/external carotid artery
(ICA/ECA) and vertebral artery (VA) exhibit typical and specic ow patterns
(Fig.10.1):
• Rarely more peripheral vessels must also be assessed (e.g. query vascular
malformation, temporal arteritis).
Note For detailed spectral analysis with velocity measurements proper angle
correction mandatory, with angle <60°!
10 Ultrasound oftheNeck inChildhood
Fig. 10.1 Schematic drawing of relevant cervical vessels with respective ow patterns on Doppler
US, (a) arterial and (b) venous
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10.1.3.4 Cervical Veins
Assessed primarily in axial section, imaging upwards and downwards as far as possible, completed by longitudinal documentation:
• Compression manoeuvres (gentle) allow assessing for stiffness and thrombosis.
• Use (a)CDS and spectral analysis for conrmation of initial ndings (Fig.10.1).
Note For any vascular investigation transducer pressure may cause artefacts that mimic
pathology; same applies for wrong patient positioning with bending or kinking of vessels.
10.1.3.5 Intervention
US used to guide therapeutic procedures:
• Vessel and cyst puncture (IV line placement—e.g. jugular vein and sclerotherapy—see chapter “interventional US”).
• Biopsy/puncture/drainage of focal processes such as nodes, tumours or abscesses
(for further details see chapter “interventional US”).
10.2 Normal Findings
10.2.1 Lymph Nodes
Lymph nodes look similar throughout the body—will not be discussed in other
chapters.
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M. Riccabona
Typical lymph node locations in neck shown in Fig.10.2a.
US Findings
More or less homogeneous structure of low echogenicity with sharp margins and
ovoid conguration. Central echogenic hilar structure (Fig.10.2b):
• Usually measure <1cm diameter, length-to-diameter ratio <0.7.
CDS
Exhibit central/hilar vascular supply with regularly brunching vessels (Fig.10.2c).
a
b
e
Fig. 10.2 Cervical lymph nodes. (a) Scheme: typical cervical lymph node regions and distribu-
tion. Abbreviations: Level I submandibular space, Level II jugulodigastric space, Level III venous
group, Level IV jugular vein nodes, Level V lateral cervical triangle, Level VI prelaryngeal, P
parotid, N nuchal group and A extra-/para-auricular group. (b) Grey scale US (+ +), ovaloid,
>1cm, hilar structures. (c) Normal vascular architecture on aCDS (power Doppler). (d) Spherically
enlarged lymph node with focal inltration (dotted circle) depicted by reduced vascularity on
aCDS, (e) enlarged node with a kidney like appearance without obvious focal lesion, (f) same
lymph node as in (e): CDS delineates a focal inammatory process, but preserved hilar vasculature
c
d
f
10 Ultrasound oftheNeck inChildhood
183
aCDS more sensitive for low-ow velocities at high insonation angles—better
demonstrates peripheral vasculature (Fig.10.2d). Helps to depict small peripheral
inltrations even in normal-sized lymph nodes—alternatively ce-US improves
detection of focal inltration/disrupted vascular architecture; in future B-ow or
other new sensitive ow imaging techniques such as SMI might further improve
potential.
Note These criteria apply to all lymph nodes everywhere throughout the body;
some normal sized and shaped normal lymph nodes often seen physiologically.
10.2.2 Cervical Glands
10.2.2.1 Thyroid Gland
Composed of two lobes with central isthmus (Fig.10.3).
US Findings
Parenchyma of slightly high, but homogenous echogenicity, potentially with tubular
anechoic structures representing vessels (particularly in slightly older age).
Echogenicity increases slightly with age.
Anterolateral border convex shaped (concave shape indicates increase in size and
may only occur regionally inlocal inltration):
Some mild cystic changes and nodular-patchy parenchymal irregularities may
normally be present in older children.
Size calculated using ellipsoid equation (L×W×T×0.48) for each lobe: entire
volume=sum of left+right lobe, volume of isthmus negligible in normal thyroid.
Note Thyroid volume changes with age (see respective growth charts) and shows
geographic regional variation (depending on iodine supply in water and food,
Fig. 10.3 Normal thyroid
gland. (a) Longitudinal
(length, ++) and (b) axial
section, both images using
dual image technique.
SD=thyroid gland,
L=lobe, I=isthmus
(→, ××) and T=trachea
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M. Riccabona
endemic goitre, etc.) (Table10.1). 3DUS more accurate, but 3DUS-based normal
value charts presently not available.
Also note: irregular shape of the gland will obviate use of the volume calculation
equation, as respective correction factor based on normal thyroid shape and
appearance.
• Sometimes nodular areas up to 1cm size of low echogenicity depicted—particularly close to outer borders in posterior part of gland—represent parathyroid
glands (alternatively positioned next to thyroid gland, then difcult to depict
particularly in infants).
aCDS
• For demonstration of vascular architecture, vessel identication (DDx cysts) or
displacement (as seen in tumours).
Table 10.1 Thyroid US
(a) Normal thyroid size/volume (in Austria):
Till 6years>4mL
6–10years 7.1±3.5mL
10–13years 9.7+± 6.6mL
13–15years 13.0±8.9mL
15–17years 14.1±10.2mL
Grown-up male<18mL
Grown-up female<25mL
(b) DDx of thyroid lesions
Diagnosis US ndings
Simple cyst Anechoic, sharp margin, thin wall, no central echoes
Complicated cyst (regressive,
abscess, haemorrhage, etc.)
Adenomatous nodule Echoic nodule, echo-poor rim-like border
Adenoma Focal nodule with sharp margins, usually of higher
Regressive nodule Often irregular shape and border and complex
Fibrous nodule Very low-level echostructure, may be part of adenoma,
Tumour (carcinoma,
metastasis, lymphoma, etc.)
Parathyroid gland and
respective adenoma
(a) Normal thyroid size/volume (values from Austria): vol (mL)= l × d×w× 0.48, signicant
gender differences only occur with puberty and manifest in adulthood/adolescence
(b) Table to list DDx and kind of typical thyroid lesions
Cyst with often prominent, irregular or thickened wall,
central echoes, potentially septet and levelling
(seldom less) echogenicity than thyroid parenchyma
inhomogenous content
often with calcication
Nonspecic echostructure, may grow rapidly, often with
low echogenicity, show micro-calcication and some
inhomogenicity, unclear and irregular border, may exhibit
penetrating-inltrating behaviour, irregular vascular
architecture
Usually hypoechoic nodules close to dorsal capsule, or
positioned cranially/caudally to thyroid gland
10 Ultrasound oftheNeck inChildhood
185
• Necessary for judging (hyper)vascularisation (e.g. in hyperthyroidism or thyroiditis) and focal vessel disruption/aneurysm (trauma).
Ce-US and US-elastography
• Promising tool but not sufciently evaluated in children. May help conrm or
delineate necrotic/inltrated areas (ce-US) or demonstrate altered tissue stiffness
in diffusely inltrated organ or a focal node helping to differentiate underlying
entity (US-elastography).
10.2.2.2 Parotid, Submandibular andSublingual Glands
US Findings
Parotid gland: slightly patchy, somewhat inhomogenous, echogenic parenchyma
with lobules and hilar vascular supply (Fig. 10.4). Parotid duct only visible if
enlarged, particularly in children.
Assessment of duct continuity difcult/impossible.
Submandibular/sublingual gland: echogenicity similar to parotid, but without
lobules, potentially less patchy. Hilar structures less prominent than in parotid.
Ducts usually not identied. Vessels depictable by aCDS.
10.2.3 Other Cervical Soft Tissues
10.2.3.1 Muscles
Resemble normal skeletal muscles throughout body (see respective chapter). Use
same scanning technique and observe same phenomena (anisotropy, etc.).
a
Fig. 10.4 Glands and tonsils. (a) Normal parotid gland, note the normal slightly prominent
hypoechoic, nodular-shaped tonsil below the echogenic triangular gland as often observed in
infants and children, adjacent normal homogenously echogenic tongue. (b) Cross section demonstrating parotid (P), tonsils (T) and tongue (asterix)
b
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M. Riccabona
10.2.3.2 Tonsils
Usually seen as hypoechoic lobulated nodular structures in respective location and
may show echogenic bands representing air-lled crypts or vessels (see Fig.10.4).
• Physiologically often prominent in childhood.
• Tree-shaped or stripe-like vascular architecture on CDS.
10.2.3.3 Tongue
Nicely seen from submental access and best in axial section.
Has homogeneous structure of muscle-like appearance, potentially with some
slightly higher echogenicity than muscles elsewhere.
10.2.3.4 Para- andRetropharyngeal Spaces
Only meaningfully assessable in case of pathology, such as parapharyngeal abscess
or paravertebral tumour. Otherwise not a routine target of US investigation, retropharyngeal space is difcult to visualise.
10.2.3.5 Larynx
Especially in infant/younger children, laryngeal US often difcult due to limited
patient cooperation.
Cartilaginous structures nicely assessable—helpful for assessing congenital mal-
formations (e.g. cysts, haemangioma), posttraumatic changes (e.g. haematoma of
vocal cord) and similar queries (Fig.10.5).
Note It is important to know age-dependent anatomic appearance (varies with pro-
gressive calcication).
Fig. 10.5 Larynx US.Normal US appearance
of yet non-ossied larynx
10.2.4 Cervical Vessels
Normal anatomy with respective US and Doppler ndings of major vessels shown
in Fig.10.1.
US Findings
Vessel—anechoic tubular structure
• Artery—multilayered thick wall.
10 Ultrasound oftheNeck inChildhood
187
• Vein—usually thin wall, valves may be visible and more easily compressible:
– Veins show signicant variation in diameter depending on respiratory cycle
and intrathoracic/transducer pressure—used for assessing patency.
Note Physiologic venous ectasia may be present, particularly during valsalva
manoeuvre.
CDS (Fig.10.6)
• In arteries—biphasic unidirectional ow towards head.
• In (jugular) veins—usually three-phase modulated ow, inspiratory and expiratory velocity variations can be bidirectional.
Spectral Analysis
Essential—typical ow patterns can be demonstrated in individual arteries (see Fig.10.1):
• CCA—intermediate resistive ow pattern, relatively low antegrade diastolic
velocity and RI=0.7–0.9.
• ICA—low-resistant ow pattern, higher diastolic velocity and RI=0.6–0.7.
• ECA—ow prole resembles any peripheral high-resistance vessel with low,
potentially missing or inverted end-diastolic ow, RI=0.9–1.1.
• VA—may resemble CCA or ICA ow, depending on area of measurement and
head position as well as dominant/nondominant vessel; ow velocities usually
slightly lower than CCA; ow prole may change with altered head position
(particularly in rst year of life—see chapter on neurosonography).
• All vessels: sharp systolic upstroke, short acceleration time and narrow Doppler
envelope (i.e. narrow band of velocities, no spectral broadening).
• Flow velocities: vary with age (peak systole=40cm/s in newborn, 150cm/s in
adolescents), vessel part and head position (particularly VA).
Note
Flow prole and velocities also depend on many other systemic factors.
Venous ow pattern is described above.
Fig. 10.6 Cervical vessels. Anatomy+typical US appearance of carotid artery (a) using aCDS
and the vertebral artery with accompanying vein (b) on CDS (note shadowing from transverse
process of cervical vertebra)