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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_5795_Библиотеки_им_академика_М_И_Перельмана.pdf
5 Paediatric Limited Field of View US/Point of Care US (POCUS) and Emergency US…
85
All diagnostic testing has risk and limitation of both false positive and false negative results.
• False positive results usually get less attention, since with additional testing false
positive results usually are resolved. However, this can expose patients to addi-
tional unnecessary tests and procedures that bring potential risk of complications
and added expense.
• False negative results may lead to delayed and errant diagnoses to the detriment
of patient care.
• A potential pitfall of having the clinical examiner also be the one performing and
interpreting the US examination: This can promote falling into cognitive biases
(such as anchoring, blind spot, conrmation and availability biases) that can
limit thinking and lead to worse care. When the clinical and imaging information
do not align well, the practitioner must re-evaluate. Partnership and collaboration
with other clinical and imaging colleagues will help to minimise this and lead to
better patient care.
Some additional thoughts concerning these aspects:
• Important to coordinate POCUS and limited eld/focused US/sonoscope with
other services in an institution to reduce overlap and duplication of resources and
effort as much as possible.
• Vital to have standards of training for all specialists who perform POCUS and
guidelines around scope of practice.
• Images and reports must be available to all—for proper patient care and coordi-
nation, as well as increasingly medico-legal issues, and as a tool for quality
assurance.
• Conicts among those performing POCUS to answer a specic clinical query
and those using US as an extension of the physical exam (sonoscope). Both can
have role in patient care and both should require same level of training and
expertise.
• Like any US exam, false positive and false negative studies occur—even more
prone to bias if clinical picture and expectation drive investigation and interpre-
tation. Particularly this latter restriction has always to be kept in mind. Always
remember that POCUS does not replace a detailed US study—may have serious
implications (Fig.5.5).
• For a negative POCUS or sonoscope study: important to consider other diagno-
ses and broader imaging inquiry—possibly starting with detailed and extended
US before indicating, e.g. a CT study.
86
abc
def
gh
M. Riccabona et al.
Fig. 5.5 Examples for serious consequences of suboptimally performed POCUS biased by clinical expectation: Sonoscope at paediatric admission ward to “rule out appendicitis”—no pathology
detected (a, b). Rescanned for query persistent unclear abdominal symptoms. Detailed US reveals
obvious neuroblastoma of right adrenal gland (c, d)—in retrospect already documented (though
poorly) in initial examination. Girl with voiding complaints and pelvic pain. Initial US was read as
residual urine in a voiding disorder (e) and an urodynamic study was requested. A detailed scan
with proper transducer positioning (initially it was too high—one does not nd the bladder just
below the umbilicus! Do not be shy and move the transducer down to the supra-symphyseal location) reveals a normal urinary bladder, but a cystic teratoma (+ … +) of the ovary (f). 4 years old
child presented for suspicion of renal tumuor based on initial “sonoscope” (g). When rescanned
and longitudinal section added, the “tumour” can be identied as just (though slightly hyperechoic) cortical renal parenchyma at the upper renal pole (h)—initially viewed in an oblique angle
only in an axial section (….)
Part II
Diagnostic Flow Charts, Imaging Algorithms,
and Graphs
Imaging andImaging Algorithms
forCommon Queries inChildhood
MichaelRiccabona
Definition
Imaging algorithms are simplied recommendation on how to image what in which
condition, with a stepwise hierarchy of different imaging modalities depending on
(clinical) presentation, query and condition, availability and clinical course-also
considering therapeutic implications and needs.
6.1 Introduction
Imaging algorithms and diagnostic ow charts have become a routine tool in clinical every day practice. In paediatric imaging US plays key role in many queries.
However, there is a tendency to overuse imaging for many reasons—particularly
US as it is easily available and relative inexpensive (although US is becoming one
of the most expensive imaging tools in overall healthcare market, simply by its wide
distribution, as everybody is doing numerous scans and charging for imaging; and
even if not charged, still it is expensive as it takes quite some time of costly dedicated and specialized medical personnel, particularly doctors).
Another problem with imaging algorithms: everybody aims at having evidencebased suggestions and recommendations—but hardly achievable for many queries in
childhood, simply because of small individual cohorts in various paediatric age groups
and constant changes in medicine that make long-term assessment on higher evidence
levels impossible. Furthermore, this evidence-based approach is increasingly under
discussion and medicine in general is moving towards a more personalized approach.
Therefore these algorithms and recommendations have to be seen as a general proposal that needs to be individually adapted—to patient and local options and needs
6
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_6
89
90
and approaches, also depending on referring physicians, available equipment and
expertise (e.g., is high quality dedicated paediatric US available 24/7/365?).
Note Remember that if a certain condition is clinically obvious and treatment can
be decided without any imaging you do not have to do imaging—even if there is an
algorithm. So always question the impact of a study on therapy (e.g., an obvious
respiratory tract infection is treated depending on clinical symptoms and laboratory
signs of bacterial infection—US or radiographs for pneumonia or effusion only
needed in complicated course, with no response to treatment, or in an inammatory
condition without known focus).
The following suggestions and recommendations are based on available literature (e.g., example the ESPR Abdominal Imaging Taskforce), and constitute a condensed shortened summary statement focusing on the role of US. Only most
common queries listed.
M. Riccabona
6.2 How toApproach Common Urogenital Conditions
inChildhood
Urogenital tract queries compose a common query in paediatric US; in some ofces
these indications constitute the majority of examinations. More information can be
found in the listed literature references, often as open access papers (e.g., by the
ESPR abdominal imaging task force in Pediatr Radiol as open access statements or
the textbook on Pediatric Urogenital Radiology, Springer 2019).
6.2.1 Urinary Tract Infection (UTI)
Diagnosis made by urine sample and not US.
• US indicated in rst years of life in UTI particularly with fever or septicaemia,
or a history of pathologic ndings either on foetal or neonatal urinary tract US
(e.g., signicantly distended pelvi-calyceal system, complicated duplex kidney).
• US indicated in prolonged or complicated UTI or with insufcient response to
treatment; also in recurrent (upper) UTI.
• In older children with known normal urinary tract anatomy (=without signs of any
malformation on previous imaging) no US required initially—US indicated only
if no response to treatment or with clinically obvious/suspected complications.
• After UTI with renal involvement: follow-up study (not earlier than 4–6weeks
after infection) may be considered for assessment of scaring and later on for
monitoring renal growth (here renal volume calculations are better than just
length measurements).
Additional/complementing imaging may become necessary depending on ndings and clinical course.
6 Imaging andImaging Algorithms forCommon Queries inChildhood
91
• Particularly in rst years of life or with sonographic signs of dilatation/indirect
signs for vesicoureteral reux (VUR) or recurrent UTIs a contrast-enhanced
voiding uro-sonography (ce-VUS) or a (modied functional) VCUG can be per-
formed to asses for VUR (see respective chapter).
• For monitoring scaring Tc
99m
DMSA scintigraphy presently is considered the
gold standard (wait 6–9months after infection before scan); increasingly MRI is
advocated for this query too.
• MRI (with diffusion weighted sequences) may be an alternative (e.g., abscess,
DDx tumour), if US is unable to answer the therapeutically or prognostically
relevant question.
6.2.2 Foetal andNeonatal Urinary Tract Dilatation
Initially every visible collecting system in the foetus was considered to be
potentially dilated and pathologic, and the term “hydronephrosis” was introduced
(term now replaced by urinary tract dilatation = UTD, or pelvi-calyceal
distention = PCD), with thorough assessment of all neonates after birth.
With improved resolution of modern US equipment, normal foetal pelvis can
often be visualized and therefore “low-grade dilatation” in the range of some millimetres (even with visible, but normal congured calices) is not a strong indicator
of pathology and does not warrant postnatal assessment. Different algorithms exist
to indicate postnatal imaging—also vary over time and try to include prenatal ndings for decision making and streamlining/guiding postnatal imaging (see respective chapter)
Indications for postnatal evaluation focus on differentiating underlying
cause/entity and grading dilatation (American UTD classication, European PCD
grading system—see respective chapter):
• High-grade dilatation, particularly of calices with or without parenchymal
changes and/or narrowing will need neonatal assessment and further follow-up.
• Due to physiologic neonatal renal immaturity, the initial scan should be postponed to 7–10days after birth to allow a potentially collapsed collecting system
to increase again; studies done too early may miss or underestimate degree of
dilatation.
• US should be done in well hydrated babies/infants and should include a pre- and
post-void assessment of bladder and kidneys; a complementing sonographic
assessment of internal genitalia/scrotum is recommended in all patients with urinary tract malformations as early as possible.
• In severe bilateral dilatation, laboratory signs of renal failure, or with suspicion
of posterior urethral valve (severe bladder outow obstruction of any cause)
early imaging within 24–48h after birth is compulsory.
Further assessment depends on respective US nding and will have to include
functional studies, as US can only assess dilatation, but not grade obstruction.
92
M. Riccabona
Additional imaging if necessary:
• MAG3 diuretic scintigraphy commonly used for grading obstruction (only diagnostically reliable after3–4months of life)
• ce-VUS (particularly valuable in megaureters) or VCUG (particularly preoperatively) used for VUR assessment—to complete diagnostic work-up;
this must include assessment of bladder outow/urethra—particularly
in boys.
• IVU outdated, CT not used in children for radiation issues.
• MRU used for anatomic assessment (e.g., ectopic ureteral insertion, complicated
duplex kidney …) and—as dynamic contrast-enhanced study—for functional
assessment
6.2.3 Urinary Tract Dilatation Later inChildhood andFollow-Up
ofNeonatally Diagnosed PUJO, UVJO, High-Grade VUR,
Complicated Duplex Kidney
Main goal in all these conditions: preserve renal function and growth potential,
avoid UTI and scarring causing long-term sequalae. Nevertheless, presently impossible to offer a reliable predictive assessment, thus pragmatic indicators of potential
risks to kidney used for decision making/treatment and management decision and
indicating respective imaging.
Note If no treatment or management impact, avoid (particularly invasive or
irradiating) imaging!
Another important aspect: consistent standardized terminology—avoid
misunderstanding and confusion, as well as misleading terms and expressions.
Respective suggestions and recommendations exist.
6.2.3.1 Pelvi-Ureteric Junction Obstruction (PUJO)
Most common condition, may also manifest later in childhood, e.g. if associated
with crossing vessel or brous scaring after UTI.Even high-grade neonatal dilatation may resolve without treatment, and low-grade neonatal distention may eventually increase and decompensate. Therefore follow-up mandatory.
• Regular US (well hydrated—kids at risk of decompensating may avoid drinking
to protect themselves. One may have to urge them, and then sometimes already
clinically may notice an indication for surgery = PUJO with pain).
– Criteria for decompensation: increasing dilatation, decreasing parenchymal
width or differentiation, insufcient renal growth or contralateral compensatory hypertrophy (see respective chapter). Standardized measurements and
grading essential for comparison.
• Functional imaging: diuretic MAG3 Tc
99m
scintigraphy (or diuretic functional
ce-MRU) in any suspicion of decompensation.
6 Imaging andImaging Algorithms forCommon Queries inChildhood
93
6.2.3.2 Uretero-Vesical Junction Obstruction (=
UVJO)/“Megaureter” (MU)
Associated with dilated ureter, where different forms exist (may just be dysplastic
large ureter with insufcient peristalsis, but no real “obstruction”).
Task of imaging: monitor for silent infections, nd ectopic ureteric insertion or
prove normal ureteric opening into bladder, monitor impact on kidney (dilating
intrarenal collecting system? growth impairment?). Questions such as ureterocele
or duplex kidneys will have been answered in initial assessment.
• Regular US—again a full bladder and standardized good hydration essential;
post-void check at every investigation helpful to avoid overdiagnosis (“bladder
phenomenon”).
• Functional imaging: diuretic MAG3 Tc
99m
scintigraphy, potentially MRU (e.g.,
in duplex systems, for ectopic insertion)
6.2.3.3 Gross Vesico-Ureteric Reflux (VUR)
Mainly driven by clinical manifestation (UTIs, hypertension, renal impairment/
insufciency if severe and bilateral/single kidney), or in neonates with high grade
urinary tract dilatation seen foetally or neonatally – as a result of the respective
imaging work-up with US, ce-US or VCUG.
Task of imaging: monitor renal growth/scarring; potentially reassess for VUR
(e.g., after possibly unsuccessful treatment or reoccurrence), check for associated
bladder dysfunction/voiding disorders.
• Regular US: full bladder and post-void assessment mandatory.
• VUR reassessment: ce-VUS or VCUG.
• Renal function: DMDSA Tc
99m
scintigraphy.
6.2.4 Urolithiasis (and Nephrocalcinosis)
Urolithiasis exists in childhood (though rarer than in adults).
The rst (and often only) imaging study in a child is US (for details see respec-
tive chapter):
• US performed with sufciently full bladder to allow for visualization of the distal ureters.
• Most concrements can be seen by US, in slim children even those in mid-ureter
if examined meticulously.
• US also used for follow-up under treatment.
Additional alternative imaging only indicated in equivocal situations, with strong
indirect signs suggesting a concrement that cannot be visualized by US, or for therapy planning if US does not reveal all necessary information and data.
94
M. Riccabona
• Diagnostic standard if US equivocal: low dose unenhanced “stone CT”
• Potentially abdominal plain lm (e.g., if necessary for planning lithotripsy)
• Sometimes an individually focused/adapted IVU may be indicated.
Nephrocalcinosis may be cause for urolithiasis, but many different entities.
Imaging and grading based on US (generally no indication for radiographs or CT!).
Note Do not confuse physiologic transient medullary hyperechogenicities in new-
borns with medullar nephrocalcinosis or papillary calcications.
6.2.5 Cystic Kidney Disease (CKD)
Suspicion and diagnosis usually made clinically based on family history (and
genetics).
US = rst and commonly only imaging study can help to narrow down DDx (see
respective chapter).
• US may pick-up CKD as an incidentally nding.
• US used to monitor disease.
Rarely other imaging modality necessary:
• If needed, mostly MRI useful (see international consensus statement for example
from Gimpel etal. published in 2019).
6.2.6 Torsion (Ovary, Testis)
For both boys and girls, if torsion clinically is highly probable, do not waste time
with imaging and proceed to surgery.
• However, if clinically unclear US can be used for differential diagnosis—but
then as emergency study. CEUS might be valuable in equivocal situations (no
evidence yet available).
• Note: In testicular torsion Doppler is essential, whereas in ovarian torsion (due to
the dual arterial supply of the ovary) Doppler is less valuable and usually grey
scaled ndings suggest diagnosis.
• If unclear and readily available, or long history (such as “missed torsion”) or
underlying tumour, MRI (with DWI) may play a role.
• CT only used in situations with acute abdomen and unclear US; not a standard
indication.
6 Imaging andImaging Algorithms forCommon Queries inChildhood
95
6.2.7 Genital Malformations
Often these are picked-up incidentally, rarely (mostly in connection with ambiguous external genitalia) clinical signs indicate imaging assessment.
Basic US always in neonates/infants with newly detected urinary tract malforma-
tion; more dedicated (and invasive imaging such as genitography) only in respective
pathology on base line US or complex malformation/disorders (e.g., cloacal malformation, various disorders of sexual development = DSD, etc.).
• The rst study in neonates and infants is a detailed US study.
• The study should be done as early as possible to use the diagnostic window using
maternally stimulated neonatal internal genitalia in the rst month for reliable
assessment; studies done later are more difcult and may miss some conditions.
• As the urinary and genital tract develop in a common pathway, every patient
(particularly girls) with a freshly diagnosed urinary tract malformation should be
thoroughly checked for genital malformations to avoid missing conditions that
then only pose during puberty (e.g., hydrometrocolpos).
• For thoroughly assessing internal and external genitalia US is the rst study, and
US-genitography using lling techniques and most often reveals all necessary
questions.
• Fluoroscopic genitography and MRI are only used in complex situations or
before surgery if US cannot show all necessary structures and connections.
6.2.8 Renal Hypertension
Renal hypertension far less common query in childhood than in adults. Nevertheless,
in children with hypertension there potentially may be renal artery disease which
needs to be evaluated.
• US with meticulous Doppler of the major renal vessels (main artery, segmental
artery to the upper, the mid and the lower pole) is indicated.
In children the main renal artery is not as commonly affected as in adults with
Note
arteriosclerotic disease, much more commonly intrarenal arteries affected—thus
much more difcult to assess.
As peripheral intrarenal arteries also pose a challenge to MR- or CT-angiography,
often (with a strong suspicion of such an involvement) catheter angiography with
renal vein sampling is performed as the next diagnostic step.