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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_5790_Библиотеки_им_академика_М_И_Перельмана.pdf
52
a
b
Fig. 1.28 Neonatal brain
3DUS: hydrocephalus. Three
orthogonal views and
segmented-inverted rendered
view of dilated ventricles
(right lower box) in a baby
with supratentorial
hydrocephalus
Fig. 1.29 Brain 3DUS in a preterm: brain surface assessment.
This surface- weighted rendered view of brain surface in a
preterm baby nicely demonstrates jet reduced and physiologically
immature gyration
1 Theory and Basics
Fig. 1.30 3DUS kidney for volume calculation: two views of a stepwise segmentation process.
(a) Entire kidney has been manually extracted from data volume, with demarcation of semiautomatically segmented dilated collecting system (threshold and gray scale inversion approach,
collecting system seen white). (b) After deduction of colleting system, only renal parenchyma
left – volume can then be calculated, and thus renal parenchymal volume calculation (including
split renal size estimates) can be performed even in hydronephrotic kidneys
1.9 Modern and Future US Methods and Techniques
Fig. 1.31 3DUS in hydronephrosis. Three orthogonal and segmented-inverted rendered view of
dilated collecting system (right lower box) in a baby with pelvi-ureteric junction obstruction
Fig. 1.32 Bladder 3DUS.
Three orthogonal views of
urinary bladder and surface
rendered view (right lower
box) of inner bladder surface
conspicuously depicting
position of the two ureteric
ostia and some bladder
trabeculation in an infant
with recurrent UTI
53
• Using threshold-based and inversion-rendering techniques, conspicuous IVU- or
MRU-like display of dilated collecting system and its anatomy is provided
(Fig. 1.31).
Urinary Bladder 3DUS
Ideal for automatic volume calculations, particularly valuable in bladders with
irregular shape.
Using surface rendering, inner surface information is extracted and displayed
improving depiction of trabeculation, bladder wall/bladder neck pathology, as well
as enabling viewing of ureteral ostium/ostium changes (Fig. 1.32)
• 4DUS of the bladder using surface rendering allows performing real-time virtual
cystoscopy.
54
Fig. 1.33 3DUS of the inner genitalia: uterine
dublication. Coronal reconstructed thick slab and
mucosa-weighted rendered view of two uterine
cavities (baby girl with Wunderlich syndrome)
Fig. 1.34 3DUS of skull
fracture. Three orthogonal
views of skull and surface
rendered view (right lower
box) of outer skull bone
surface conspicuously
demonstrating skull fracture
and its shape
1 Theory and Basics
3DUS of the Paediatric (Female) Genitalia
As shown in adults, 3DUS is particularly valuable for assessment of uterine malformations (e.g. DDx of didelphis/arcuate uterus) (Fig. 1.33).
NOTE: This application only can be performed with sufficient diagnostic accuracy
within the first months of life (fetally stimulated enlarged inner genitalia) or again
after onset of puberty (when uterus, vagina and ovaries are stimulated again – get
reasonable size).
Musculoskeletal 3DUS Applications
3DUS helpful in depiction of fractures and analysis of fracture shape enabling differentiation of simple versus complex fracture or a suture from a facture:
• Particularly valuable in skull fractures for differentiation of potential victims of
child abuse (Fig. 1.34).
Small Part 3DUS Applications
Assessment of tumours, neonatal spinal canal 3DUS and assessment of cutaneous
vascular malformation or vessel anomalies by enabling comprehensive overview of
ab
1.9 Modern and Future US Methods and Techniques
Fig. 1.35 Small part 3DUS. (a) Use of 3DUS in suspected rib anomaly – rendered view: due to
the cartilaginous nature of infant rib ends, plain film could not answer the query, whereas the
reconstructed rendered view after chest wall 3DUS acquisition conspicuously demonstrates the rib
anomaly obviating any other imaging. (b) Thyroid nodule in goiter – thyroid 3DUS (segmented
aCDS acquisition): a box view demonstrates the large nodule with its respective vessels
Fig. 1.36 Cardiac 3D-/4DUS in
neonate. Colour-coded 4DUS of
neonatal heart demonstrating blood
ejection from heart with open
communication (septal defect) between
right pulmonary system and left
systemic circulation
55
complex and tortuous vessels by aCDS rendering, as well as assessment of nodes,
cysts, lumps and bumps (Fig. 1.35).
Other Potential 3D-/4DUS Applications
Many other options, e.g. other abdominal/oncologic 3DUS and (neonatal) heart
3D-/4DUS (Fig. 1.36):
• However – have not yet been thoroughly evaluated, partially still struggle with
methodical problems, but promise to become more important and interesting in
near future.
1.9.8.3 Benefits of 3D-/4DUS
• Complete coverage of entire structure with improved information for analysis
and DDx, particularly reconstructed planes which are inaccessible for 2DUS but
essential for diagnosis or DDx.
56
1 Theory and Basics
• Comprehensive documentation: ideal for comparison during follow-up as well as
for comparison with other sectional imaging – as any desired plane can be
reconstructed.
• 3DUS allows for accurate volume calculations – even in objects with irregular
shape difficult to assess by 2DUS.
• Using rendering and surface viewing, new diagnostic areas can become available
that have been inaccessible to conventional 2DUS.
• Furthermore these tools enable conspicuous and comprehensive display of struc-
tures difficult to demonstrate on standard 2D image.
• aCDS data can be incorporated for anatomic vessel display, helpful particularly
in complex anatomy or pathology (Fig. 1.15).
• Superior data for medical-legal issues as well as for image analysis, counselling,
second opinion consultations or teaching and training, as all the information are
present in data set and can be retrieved whenever needed (without need of patient
being present).
1.9.8.4 Restrictions of 3D-/4DUS
• Restricted resolution – particularly in reconstructed plane. Presently limits
3DUS, particularly in small structures.
• Very few dedicated paediatric transducers available for all applications (e.g.
brain 3DUS).
• Handling of often clumsy transducers may be difficult particularly in non-coop-
erative patients causing motion artefacts and image deterioration.
• At present directional Doppler information cannot be included in 3D data: flow
information cannot be incorporated.
• Time necessary for post-processing/reading, however, at benefit of potentially
shorter investigation at patient (i.e. acquiring data set) – shortening investigation
at patient’s bedside.
• Hardware and viewing facility demands – may also increase costs of US device
(as long as no reimbursement established for 3DUS).
1.9.8.5 Potential Future Paediatric 3DUS
Applications
Besides increasing use of 4DUS for neonatal echocardiography, some other aspects
on horizon:
• Combining 3DUS with ce-US.
• Using 4DUS for functional assessment.
• Combining 4DUS with multidirectional US-elastography throughout entire
imaging field and all planes/directions.
• Interventional 4DUS.
• Image fusion (3DUS information combined with information retrieved from
other sectional imaging (e.g. 4DUS-based intraoperative/biopsy guidance)).
1.9 Modern and Future US Methods and Techniques
57
1.9.9 Potential Future for Other Modern
Paediatric US Applications
A number of potential applications on horizon: US-guided drug delivery, opticacoustic imaging, etc.
Most presently under preclinical research conditions, some starting in human
trials:
• US-guided drug delivery: US-CM is used as carrier for attached drugs. Arrival of
drug-loaded US-CM at desired location is detectable by ce-US, then high-energy
sound pulse is activated to destroy US-CM/carrier molecule, thus deliver drug
locally to targeted area – reducing systemic drug interactions/adverse advents.
– Foreseen for oncology but also potential for any other focal disease (e.g.
inflammatory).
• Image fusion techniques for diagnostic and interventional procedures.
• Opto-acoustic imaging, US thrombolysis, etc. – many future applications on
horizon but beyond scope of booklet.
Ultrasound-Guided Interventions
Michael Riccabona and Brian Coley
Contents
2.1 General Aspects .............................................................................................................. 60
2.1.1 Requisites ............................................................................................................ 60
2.1.2 Precautions and Preparations .............................................................................. 60
2.2 US-Guided Filling of Structures for Diagnostic
or Therapeutic Purpose ................................................................................................... 61
2.2.1 General Remarks for Assessing Physiologic Cavities
(e.g. Bladder, Vagina, Intestines and Stomach) .................................................. 61
2.2.2 Diagnostic Sonographic Enema .......................................................................... 61
2.2.3 Therapeutic Sonographic Enema ........................................................................ 62
2.2.4 US Genitography................................................................................................. 64
2.2.5 Contrast-Enhanced Voiding Urosonography (ce-VUS) ...................................... 64
2.2.6 Other Intracavitary Contrast Applications .......................................................... 67
2.2.7 Intravenous ce-US ............................................................................................... 68
2.3 Biopsies and Punctures ................................................................................................... 69
2.4 Drainage .......................................................................................................................... 71
2.5 Vascular Access ............................................................................................................... 73
2.6 Lumbar Puncture ............................................................................................................. 74
2.7 Foreign Body Removal ................................................................................................... 75
2
M. Riccabona ()
Division of Pediatric Radiology, Department of Radiology
University Hospital Graz , Auenbruggerplatz 36 , Graz , 8036 , Austria
michael.riccabona@klinikum-graz.at
e-mail:
B. Coley
Department of Radiology, ML5031 ,
Cincinnati Children’s Hospital Medical Center,
3333 Burnet Avenue , Cincinnati , OH 45229 , USA
M. Riccabona, Pediatric Ultrasound,
DOI 10.1007/978-3-642-39156-9_2, © Springer Berlin Heidelberg 2014
59
60
2 Ultrasound-Guided Interventions
2.1 General Aspects
Nearly all of common and important somewhat invasive techniques, i.e. biopsies,
punctures, drainages, foreign body removal, voiding urosonography, sonographic
enema, US guidance for catheter placement, and similar procedures are addressed.
2.1.1 Requisites
Select adequate transducer for target/organ:
• High-resolution linear transducer for superfi cial structures.
• Curved arrays for deep targets.
• Frequencies vary respectively.
2.1.1.1 Other Important Needs
High frame rate is helpful; CDS is practically mandatory for many procedures.
Cine-loop documentation recommended – still images taken retrospectively
from stored loops.
Core biopsy or cytology aspiration needles used – depending on target and necessary material.
Needle guide sometimes helpful – have to fi t selected transducer (check in
advance, also fi tting needles).
Biopsy gun or similar, partially semi-automated devices.
2.1.2 Precautions and Preparations
• Sterile conditions have to be maintained (except for saline enema):
– Sterile cover for transducer (and US keyboard), sterile needle guide (if used),
antiseptic skin cleanser and sterile cloths/drapes to cover surrounding area
• Important for both patient and operator to be positioned comfortably.
• Monitoring + resuscitation equipment must be present and readily available.
• In children procedures are often performed under general anaesthesia or con-
scious sedation – coordination with other providers is mandatory.
TIP : Place local anaesthetic paste at area of access well in advance.
• Prepare catheters, lines, tubes, materials for sample handling and all other sup-
plies well before; use standardised checklist.
• If possible, have an interventional suite equipped with all necessary material and
devices.
• Intervention procedures require a team approach – establish an interventional
team with clear structure and duties/responsibilities
• Pre-procedural assessment of case with defi nition of access needs, needle size
and calibre and kind of approach (needle guide versus freehand approach, coax-
ial technique or single needle, etc.) is recommended.
• Have microscope available for immediate inspection – helps to avoid unneces-
sary passes or unsuccessful biopsies.
• Useful to ask patient to empty bladder before procedure (exception: saline
enema, US genitography).
2.2 US-Guided Filling of Structures for Diagnostic or Therapeutic Purpose
61
2.2 US-Guided Filling of Structures for Diagnostic
or Therapeutic Purpose
2.2.1 General Remarks for Assessing Physiologic Cavities
(e.g. Bladder, Vagina, Intestines and Stomach)
Filling of structures with saline (or tea/formula for stomach) is very helpful – e.g. to
replace air, for distension:
• Additionally US-CM can be added for improved depiction of various phenom-
ena (e.g. refl ux, fi stulae).
• Filling usually needs catheter – except for upper intestines where fl uid can be
ingested.
TIP : Rinse catheter with fl uid before insertion (to avoid infusing air).
• All investigations need justifi cation but often can help to replace other invasive
methods using radiation.
• Consider sedation (rectally/orally) in anxious children – as proposed for VCUG
(e.g. Midazolam, choral hydrate).
2.2.2 Diagnostic Sonographic Enema
Usually no precautions are necessary unless evaluating potential polyps – then evacuation by conventional enemas before investigation is helpful.
Indications : Unclear large bowel fi ndings – particularly stenosis, polyps, unclear
tumorous lesions, suspected fi stula tracts, equivocal suspicion/US fi ndings (intussusception, meconium plug, small left colon, megacolon, etc.).
How to do :
• Rectal tube/catheter inserted – use fl exible tubes to prevent perforation, particu-
larly risky in preterm neonates.
• Tube is gently inserted after lubrication – in neonates under constant saline infu-
sion until well positioned; try to insert at least to the height of recto-sigmoid
junction.
• Tube taped to prevent early fl uid evacuation and dislocation (particularly useful
in older children).
TIP : Drip infusions preferred where height of infusion bottle can be used as
manometer to avoid overly high pressures; rarely gentle rinsing by syringe can be
an alternative option, mostly for therapeutic approaches. Saline should be
pre-warmed.
• After starting enema, US surveillance of gradual fi lling of recto-sigmoid, then
descending colon, left fl exure, transverse colon and eventually ascending
colon + coecum. Always monitor by US (Fig. 2.1 ). Fluid infl ux into distal ileum
fl uid distension of appendix is often seen.
• Tube removed after suffi cient fi lling and distention of entire colon, assess in
longitudinal + axial sections.
• Perineal US can be applied to observe defecation, particularly observe shape of
rectum and transition zone to anal canal as well as respective angulations second-
ary to pelvic fl oor activity after withdrawing the catheter (Fig. 2.2 ).
62
a
Fig. 2.1 Diagnostic US saline enema. ( a ) Tube inserted, colon fi lled and distended with saline.
( b ) Increasing fi lling of more proximal bowel loops after advancing tube under constant saline
irrigation. ( c ) The soft feeding tube advanced further – no distension can be achieved, no saline
passes to more oral loops, no meconium plugs seen at that level – indicative for atresia
b
2 Ultrasound-Guided Interventions
c
a
Fig. 2.2 Perineal US for defecation. ( a ) Perineal US demonstrates bladder, urethra, narrow and
atypical anal canal and fl uid-fi lled rectal pouch. Note no distal opening of the anus and no proper anal
canal in a neonate with anal atresia. ( b ) Still image from a video clip during defecation after saline
enema, perineal sagittal view (neonate): open short rectal canal, atypical shape of recto- pubic angle
b
2.2.3 Therapeutic Sonographic Enema
Same procedure as above can be used for reduction of intussusception or meconium plug.
How to do : Basically same technique as described above:
• Dedicated precautions are recommended: analgesia/sedation, IV infusion for
hydration and electrolyte balance, sometimes antibiotic prophylaxis, physiologi-
cal monitoring.
• For successful reduction, higher pressures have to be applied, thus larger tubes
are necessary. Filling pressure = 80–100 cm H 2 O (less in preterms/neonates):