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2.2 US-Guided Filling of Structures for Diagnostic or Therapeutic Purpose
a
bc
63
de
Fig. 2.3 Therapeutic saline enema: reduction of intussusception (or meconium ileus). ( a ) Typical US
image of intussusception (with entrapped fl uid). ( b ) Enema fl uid starts to push back the intussuscep-
tion, enema fl uid (saline) fi lling of colon from saline enema (80 cm H
Gradually fl uid is reducing the intussusception, increasing fl uid around head of invaginated bowel. ( e )
Intussusception successfully reduced – fl uid passes through somewhat swollen ileocoecal valve. ( f )
Enema has reached small bowel which is fi lled with enema fl uid from now unhindered refl ux into ileum
f
O water pressure). ( c , d )
2
– Success is seen if saline enters beyond point of obstruction: in intussusception
unhindered refl ux into ileum is mandatory; in meconium obstruction, mixing
of meconium with saline and mobilisation of plugs indicates success
(Fig. 2.3 ).
– Repeated attempts after a pause can be easily performed and increase success
rate.
• Mandatory to seal anal canal by taping or manual compression; use of balloon
catheters not recommended due to higher risk for perforation during uncon-
trolled pressure increase.
Benefi ts : Easily repeatable, furthermore, guided by US manual/transducer massage
can assist reduction in intussusception or mobilisation of meconium; procedure
applicable at bedside. Some only massage the intussusceptum out of the intussusciepiens manually through the abdominal wall (using same technique as surgions
would intra-operatively) without the enema procedure, with some reported success.
64
2 Ultrasound-Guided Interventions
Restrictions : Less overview; fl uid instead of air (as used for pneumatic reduction) –
less elastic – higher perforation risk.
2.2.4 US Genitography
Indications : Equivocal fi ndings on US in suspicion of genital malformations.
How to do : With full bladder (or after fi lling of bladder), vagina fi lled after gentle
catheterisation. Same saline infusion technique with constant drip and pre-fi lled
catheter as for ce-VUS (see below, Sect. 2.2.5 ):
• Distension, size/shape of vagina clearly delineated, potential fi stula visible,
atretic/double vaginas, cysts, uterine cervix much better delineated; improves
assessment of uterine malformations (Fig. 2.4 ).
• 3DUS with coronal reconstructions helpful and improves classifi cation (Fig. 1.33 ).
• Perineal approach + complementing upper abdominal/urinary tract study added
(Figs. 2.5 and 1.24 ).
• Eventually catheters removed, vagina observed during/after voiding for urine
infl ux into vagina.
• In case of suspected fi stulae – additional instillation of US-CM to enhance struc-
tures/clearly delineate connection between different cavities.
2.2.5 Contrast-Enhanced Voiding Urosonography (ce-VUS)
US method for detection of vesico-ureteric refl ux (VUR).
Although US-CM presently not licensed for paediatric use, thousands of investigations have been performed – high success rate, low complication rate and reliable
results well documented. (See also Fig. 1.23 .)
Indications : Recommended in girls and for follow-up investigations, as well as for
family screening. With increasing ability to properly assess urethra also applicable
to male infants.
NOTE : Initial thorough detailed comprehensive US investigation of entire urinary
tract including post-void assessment mandatory before performing ce-VUS.
How to do : After assuring sterile urine and initial US assessment performed, ure-
thral catheter placed (or suprapubic puncture) and bladder emptied:
• Then bladder gradually fi lled by drip infusion (infusion height <40 cm above
bladder level – physiologic fi lling pressure):
– Potential antibiotics added (or antibiotic prophylaxis).
• Alternating scanning of retrovesical space + bladder as well as both kidneys dur-
ing fi lling:
– Drip infusion may be used as manometer to see moments of increased bladder
pressure during fi lling – may indicate unstable bladder, helps to depict
moments of high pressure VUR.
• Fractional instillation of US-CM (at present mostly Sonovue
®
), concentra-
tion = 0.2–1.0 % of actual bladder fi lling volume (Fig. 2.6 ).
• Ongoing alternating assessment of bladder, retrovesical space/distal ureter and
both kidneys.
2.2 US-Guided Filling of Structures for Diagnostic or Therapeutic Purpose
65
a
b
c
Fig. 2.4 US genitography. ( a )Axial transvesical section: vagina with catheter during fi lling with
saline infusion for US genitography. ( b ) Longitudinal transvesical view: nicely outlined uterine cer-
vix after distension and fi lling of vagina via saline infusion. ( c and d , or lower row) ce-US genitogra-
phy: additionally diluted US-CM added to see if there is a connection between the two vaginas in a
girl with uterus didelphis and hydrocolpos of atretic hemivagina; no contrast seen in right-sided
cystic- obstructed hemivagina, normally fi lled and distended echoic contrast-fi lled main left vagina
(double image technique, right side is dedicated contrast image, left side is fundamental image)
a
Fig. 2.5 Perineal US for vaginal pathology after fi lling with saline/during voiding. ( a ) Vagina
fi lled with saline after catheter is withdrawn, cervix lips nicely visualised. ( b ) Perineal sagittal US
depicts an obvious fi stula (+ +) to urine-fi lled distended vagina. ( c ) Additional diluted US-CM
instillation (ce-VUS + ce-US-genitography) demonstrates intact vagina and separated course of
urethra (during voiding) and vagina. ( d ) Distal common tract of urethra and vagina (urogenital
sinus tract) depicted on ce-US genitography by sagittal perineal access during voiding in a newborn girl with adrenogenital syndrome
b
cd
66
a
b
2 Ultrasound-Guided Interventions
c
Fig. 2.6 ce-VUS: bladder and ureter. ( a ) Filling of the bladder with saline drip infusion (30–
40 cm H
instilled – bladder lumen gets distended with echogenic material. Note the echoic CM-fi lled distal
right ureter behind the bladder, only clearly detectable by the contrast image. ( c ) Single contrast
image: echogenic contrast in a megaureter in dilating VUR (V°). ( d ) Single contrast image: con-
trast refl ux into narrow distal ureter, with gapping and pathologically shaped UVJ. ( e ) Voiding on
ce-VUS (transvesical sagittal access in an infant): only proximal urethra (+ +) seen from abdominal sagital approach/view
0 pressure) via catheter. ( b ) Dual image technique (left – contrast image): US-CM
2
d
e
NOTE : In fi rst years of life, cyclic fi lling (three cycles) recommended.
• Scanning continued when bladder is fi lled (urge or spontaneous voiding).
• Potentially assess urethra by perineal US.
• After voiding, check kidneys for potential refl uxed US-CM within collecting
system, CM drainage dynamics, and bladder for residual urine/diverticulae.
• At last cycle, catheter withdrawn for proper view of unobstructed urethra on
perineal US, unless same catheter used for complementing focused fl uoroscopic
VCUG.
Diagnosis : Any US-CM in upper urinary tract/ureters seen as echogenic bubbles –
indicative of VUR (Fig.
2.7 ). Also try to note potential CM infl ux into vagina.
Establish grading related to international VUR classifi cation system (see Table
1.3 ).
NOTE : ce-VUS tends to grade VUR slightly higher, particularly VUR I° on VCUG
often seen as VUR II°.
Benefi ts : Higher VUR detection rate, no radiation, additional information on non-
refl uxing structures and soft tissues, bedside applicability, etc.
NOTE : Modern US-CM visualisation techniques using low MI imaging preferred,
as US-CM stays stable much longer and VUR depiction improved. Urethra only
assessable if viewed during voiding (Fig.
2.8 ).
Limitations : Diffi cult handling for visualisation of urethra. Must have sono-
graphic access to kidneys, bladder and distal ureter area (limited e.g. in severe
scoliosis). Restrictions in visualisation of late, low-degree, high-pressure VUR at
2.2 US-Guided Filling of Structures for Diagnostic or Therapeutic Purpose
ab
Fig. 2.7 Typical renal appearance of VUR on ce-VUS. ( a ) Dual image technique ( left – contrast
image): contrast has refl uxed into kidney’s collecting system, with echogenic contrast fi lled pelvocaliceal system. ( b ) Dual image technique ( left – contrast image): slightly dilated collecting system
fi lled with contrast agent – not depictable on basic B-mode images without contrast detection
settings
acb
67
Fig. 2.8 Male urethra during voiding on ce-VUS. ( a ) Neonatal male urethra during voiding,
perineal access: voiding attempt before catheterisation, no US-CM; only the urine works as
physiologic CM – outlining the proximal urethra to the level of the pelvic fl oor. ( b , c ) Two
serial images of male neonatal urethra during voiding on ce-VUS; note the dynamic changes
of the shape of the proximal urethra and the better visualisation using the coloured contrast
image – particularly helpful if the room cannot be properly darkened such as in bedside examinations (e.g. in NICU)
end of voiding (no US access, as bladder is nearly empty), limited depiction of
intermittent diverticulae (for same reason). No panoramic overview. No clear
delineation of entire ureteral anatomy – therefore preoperatively always perform
conventional fl uoroscopic VCUG.
2.2.6 Other Intracavitary Contrast Applications
Saline and US-CM can be applied to any other cavity such as assessment of drains
(position and function), lines (patency), abscesses and collections (fi stulae?).
Same principle and concentration apply as above. CM concentration varies with
agent, for SonoVue (Bracco, Italy – the most commonly used agent) approx.
0.2–1 % solution.
68
2 Ultrasound-Guided Interventions
2.2.7 Intravenous ce-US
Increasingly advocated in children in spite of lack of approved US-CM. At present
no severe side effects reported in young children. Same principles apply as in adults.
Dose (for SonoVue@, Bracco, Italy – the most commonly used agent): usually
0.03–0.05 ml/1 kg, in the fi rst year (higher circulating relative blood volume) 0.1 ml/
kg, no offi cial dose-fi nding studies and recommendations available, some use
1 ml/10 kg as a rule of thumb (up to 25 kg body weight).
Indications :
• Visualisation of fl ow + vessels under poor scanning conditions/insonation angle
(deep structures, transcranial, etc.), assessment of vessel patency.
• Detection of parenchymal lesions (neoplastic, infectious, after trauma, etc.)
(Fig. 2.9 ).
• Lesion characterisation by using specifi c perfusion patterns (as known from CT /
MRI), particularly in liver (Fig. 1.25 , Table 1.4 ).
ab
cd
e
Fig. 2.9 Dynamic CEUS in a liver lesion (normal fi ndings see also Fig. 1.24 ). ( a ) Unenhanced US
shows two round liver lesions in a girl with a fatty liver. ( b – e ) Serial images during CEUS (dual
image technique, left – contrast image), same patient as in a: early vascular/arterial enhancement
of spoke wheel-like central vessels in the tumour, with increasing pronounced enhancement of the
lesions till portal phase – eventually homogenous enhancement of the lesion same as the surrounding liver in the late phase, consistent with FNH (focal nodular hyperplasia)
2.3 Biopsies and Punctures
69
• Assessment of perfusion in small peripheral areas, diffi cult to depict and assess
with conventional Doppler (joints, bowel wall, potentially also testis, etc.) –
these applications are not well established, use caution due to potential harm by
cavitation effects.
TIP : Avoid any fi lters at injection side; use largest possible calibre of venous
access. Decide before whether you need bolus injection or slow infusion. Initially
perform dedicated US and assure proper US access. Store contrast dynamic as
video clips of targeted area for later analysis; clock should be included in clips for
timing. Remember too, that US contrast is purely intravascular - enhancvement
pattern differs from CT/MRI due to different contrast agent behavior.
For further details see entry ce-US in Chap. 1 .
2.3 Biopsies and Punctures
Most common biopsy targets : Liver/kidney, rarely nodes, suspected tumours/unclear
masses and collections.
How to do :
• Initial pre-interventional US must be comprehensive and detailed – properly
assess anatomy and discover potential contraindications to US guidance.
• Preparation as described above (Sect. 2.1.2 ).
• For diffuse pathology (mostly liver): easily and safely accessible part of repre-
sentative parenchyma chosen, access usually from ventral or ventrolateral (liver).
Menghini needle still commonly used liver, (suction needle); multiple other
semiautomated core biopsy devices available (Fig. 2.10a, b ).
• For renal biopsy, lower pole of left kidney with dorsal approach commonly rec-
ommended, (cutting) needle direction steered towards area without major vessels,
biopsy depth defi ned to avoid pelvo-caliceal system (see also Chap. 10 ) (Fig. 2.12 ).
a
Fig. 2.10 Liver (image a , b ) biopsy in a teenager with unexplained elevation of liver enzymes and
node sampling ( c ). ( a ) Longitudinal US of right hepatic lobe: 16G biopsy needle with tip just under
liver capsule. ( b ) After “fi ring” biopsy device, needle tip now seen deeper within hepatic paren-
chyma. ( c ) US-guided node biopsy using a cutting needle in a child with persistent cervical adenop-
athy focusing an enlarged hypoechoic lymph node. A 21G cutting needle passed through node with
tip seen at far margin. The open specimen tract of cutting needle ( arrowheads ) clearly in centre of
node, outer cutting cannula visible ( arrow )
b
c
70
a
Fig. 2.11 Splenic biopsy with coaxial technique and tract embolisation. ( a ) US of spleen in leu-
kaemia and fevers – dominant hypoechoic mass, multiple smaller lesions. ( b ) A 17G guiding can-
nula placed into spleen ( arrowhead ) and an 18G biopsy needle ( arrow ) guided to edge of largest
mass. ( c ) After fi ring biopsy device, needle traverses lesion – needle tip ( arrow ) seen on the far side
of the mass. ( d ) After biopsy, Gelfoam pledgets placed through guiding cannula to prevent bleeding –
seen as very bright echogenic structure ( arrowheads ) due to entrapped air in material
b
2 Ultrasound-Guided Interventions
cd
• Punctures of focal lesions: commonly performed with freehand approach, though
sometimes needle steering devices maybe helpful and improve accuracy. Most
important in biopsy of suspicious nodules: maintenance of safe access without
upgrading tumour by passing through unaffected compartments (talk to surgeons
and oncologists before..); coaxial technique often helpful particularly if target
positioned deeper. Often cutting needles used to yield suffi cient tissue (Fig. 2.10c ).
• Needle length/size varies with application: in general small needle size has less
risk of complications or bleeding but may need coaxial technique for unhindered
access without distortion/twisting of needle. Furthermore – particularly in oncologic
procedures – smaller needles may not yield enough tissue for necessary analysis,
thus larger needles/repeated sampling may become necessary. Most commonly
18–20 gauge is suffi cient, rarely 14 gauge. Coaxial technique allows embolisation of biopsy tract (using gelfoam, fi brin glue or other agents) to minimise
bleeding complications, particularly in risky targets (e.g. spleen) (Fig. 2.11 ).
• Most commonly a biopsy gun or semiautomatic device is used – must become
familiar with device before taking it to patient. Make sure that appropriate guiding needles, etc. are available.
• Always monitor intervention by US, potentially by documenting video clips (Fig.
• Consider fi rst proceeding only to margin of target and only then retrieve sample
from tissue using biopsy device.
• Most commonly core biopsies obtained; sometimes aspiration for cytological
assessment suffi cient.
• Always send specimen or aspirated fl uid for histology or laboratory/microbial
workup. Make sure that specimen transport is well organised, and specimen kept
under appropriate conditions.
After every procedure :
• Check for potential complications, e.g. disruption or bleeding (Fig. 2.13 ).
• Particularly in areas/organs/clinical situations with high risk of complications or
bleeding: consider repeat follow-up at around 3–8 and 12–24 h.
• Always use CDS to examine for potential arteriovenous fi stula, etc.
2.12 ).
2.4 Drainage
a
Fig. 2.12 Renal biopsy. ( a ) US at start of renal biopsy (dorsal longitudinal image): the needle tract
outlined by dotted lines when using a guiding device; the distances (until reaching kidney, depth of
parenchyma till reaching central structures, + +1/2) measured for selecting the proper needle size.
( b ) Needle tip placed just at the renal outer border, before fi ring the biopsy gun. ( c ) Needle monitor-
ing during biopsy (image taken from a cine-loop clip): needle tip avoids central structures
acb
b
c
71
Fig. 2.13 Complication of renal biopsy. ( a ) Dorsal longitudinal image: haematoma around lower
pole of left kidney after renal biopsy. ( b ) aCDS improves early depiction of perirenal haematoma
which may initially appear isoechoic to renal cortex. ( c ) Post-biopsy arteriovenous fi stula depicted
by CDS ( arrow ), confi rmed by duplex analysis
2.4 Drainage
Same principles apply as above. Access similar for drainage or puncture.
How to do : Basically two techniques available (Fig. 2.14 ).
1. Trocar technique: relatively large needle with central perforation used to access
collection of fl uid-fi lled structure; drain then inserted through central lumen of
needle. Alternatively, drain with inner trocar advanced directly into collection,
and drain deployed.
2. Seldinger technique: small needle used to access collection, guide wire placed,
tract dilated and then drainage catheter inserted – less traumatic for tissue but
more cumbersome; may need fl uoroscopy to visualise proper wire placement
and safe handling during dilatation and drain insertion.
72
ab
Fig. 2.14 Schematic drawing demonstrates the two common puncture techniques: Seldinger ( a )
and trocar ( b ). ( a ) Seldinger technique: system accessed with thin needle; guide wire placed
through narrow needle lumen to secure access. Then dilatators used to widen access tract, before
eventually catheter passed over guide wire. ( b ) Trocar technique: large needle (trocar) introduced –
has wide lumen that allows placing of catheter through lumen of this access needle – usually no
guide wire needed, often preferred for US (as handling and visualisation by US is easier, less need
for complementing fl uoroscopy, etc.)
a
b
2 Ultrasound-Guided Interventions
c
Fig. 2.15 US-guided abscess drainage (Seldinger technique) in perforated appendicitis. ( a )
Longitudinal US shows large abscess ( A ) below liver ( L ). ( b ) Small aspiration catheter ( arrow-
heads ) placed into collection below liver edge. ( c ) Guide wire ( arrowheads ) passed into deepest
part of collection in Morrison pouch, then 12F drainage catheter placed over guide wire to drain
abscess
NOTE : After successful drainage, always assure proper placement of catheter tip and
proper function (Figs. 1.23 and 2.15 ) – postinterventional US check recommended.
Needle / tube size : Depends on location, patient size/age and composition of aspi-
rated fl uid:
• Larger bore drains (8–16 French) necessary in complicated or septated collec-
tions (e.g. abscess, pleural empyema).
• Smaller bore drains – used for clear fl uid (e.g. 5 or 6 French for infant urinary
drainage).
• If instillation of sclerosing/therapeutic agent considered, particular precaution
has to be taken to avoid leakage of injurious agent – sometimes combined