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8 Spleen and Pancreas
ab
Fig. 8.8 Splenic cyst. ( a ) Axial and ( b ) longitudinal view of spleen with dysontogenetic cyst in an
infant. Note physiologically prominent adrenal gland and typical appearance of neonatal kidney in
( b )
US Findings
• Simple cyst : smooth margins, sharp border, thin membrane, no central structures,
anechoic fl uid, often solitary (Fig. 8.8 )
• Epidermoid cyst : may contain some echoes, sedimentation phenomena occur
• Complex cysts : polylobulated with septae, some irregular margin or thick mem-
brane, potentially nodular components – large variety of underlying conditions
to be considered (history? Echinococcosis or other unusual infection?)
NOTE : Use CDS to differentiate vascular pathology from cysts.
Potentially US-guided puncture of cyst for aspiration/diagnosis and therapeutic
instillation of various agents.
8.1.11.2 Abscess
Defi nition
Rare condition in childhood, most commonly observed in immunocompromised
patients or posttraumatically.
Most common cause: staphylococcus, salmonella, fungus, and hydatid
disease.
US and CDS Finding :
Similar to complicated cyst – spheric space-occupying lesion, some irregular and
hazy margin, variable (often hypoechoic) echotexture depending on duration and
underlying condition (Fig. 8.9 ). Usually no proper capsule visible; sometimes peri-
focal hyperemia seen on aCDS. Potentially halo-like surrounding hypoechogenicity
(target sign).
May cause secondary infarction of dependent area.
NOTE : Multiple abscesses may be confusing, sometimes cannot be differentiated
from necrotic changes after infarction – if no systemic proof for infectious cause
found, US-guided puncture and drainage may be an option. But splenic punctures
have considerable risk of haemorrhage – take proper precautions.
8.1 Spleen
Fig. 8.9 Splenic abscess/infi ltration. Multiple hypoechoic spheric/round parenchymal lesions in
slightly enlarged spleen – in this case these were fungal abscesses during chemotherapy; however,
any other small abscess or infi ltration (e.g. in lymphoma or granulomatous disease) may exhibit
similar images and is sonographically indistinguishable
267
Fig. 8.10 Spleen haemangioma. Two focal round hyperechoic areas within spleen parenchyma
consistent with splenic haemangiomas
8.1.11.3 Tumours and Space-Occupying Lesions
Defi nition
• Rare. Haemangioma, hamartoma, and lymphangioma/lymophangiomatosis (e.g.
Gorham-Stout disease) occur
• Malignant solid tumours other than infi ltration in lymphoma/leukaemia
extremely rare (e.g. angiosarcoma)
• Infl ammatory pseudotumour may exhibit calcifi cations
• Involvement in storage disease or systemic granulomatous disease as well as rare
(tropical) infection may be diffi cult to distinguish from tumorous condition
US Finding
Very commonly hypo- or hyperechoic, nodular, space-occupying lesions, sometimes with hyperperfusion (Fig. 8.10 )
NOTE : Multinodular irregularities also seen in splenic infi ltration by metastatic or
systemic disease (e.g. metabolic disease, leukaemia, lymphoma, Langerhans cell
histiocytosis and Gorham-Stout disease). Manifestation of other systemic granulomatous disease should be considered for DDx (e.g. tuberculosis, cat scratch disease
and sarcoidosis).
268
8 Spleen and Pancreas
8.1.11.4 Role of US
Ideal method for diagnosis and follow-up:
• Particularly if ce-US available
Restrictions : in early posttraumatic setting, defi nition of underlying entity.
Additional / alternate imaging :
• Ce-MRI/PET, rarer ce-CT – complementary imaging – optimal for lesion
detection (contrast enhanced techniques), also restricted for lesion characterisation/entity defi nition
• Scintigraphy
8.2 Pancreas
8.2.1 Requisites
Preparation :
• Fasted patient helpful for easier acoustic access
• Measures to avoid gaseous bowel and shadowing by stomach content
Positioning :
• Commonly accessed in patient lying supine
• Positioning manoeuvres (if tolerated) may be helpful – decubitus and
semi-upright
Transducers
• Usually curved array for general assessment
• Sometimes sector transducer if very small sonographic window
• Linear array for detailed assessment, standard in neonates and infants
• Frequencies vary with age/necessary penetration depth
8.2.2 Indication
Various conditions that either involve or affect pancreas:
• Malformation
• Infl ammation
• Trauma
• Obstruction
• Cysts, rarely tumours
8.2.3 Course of Investigation
Access via median upper abdomen:
• Use left liver lobe as window for head of pancreas and body
• Access via left upper quadrant
8.2 Pancreas
abc
269
Fig. 8.11 Normal pancreas. ( a ) Normal neonatal pancreas with homogeneous echogenicity,
measurement of head (+ +
compression and large left liver lobe as US window. ( b ) Normal pancreas ( P ), axial view accessed
via full stomach ( M ) after feeding to improve visualisation. ( c ) Axial transsplenic view to promi-
nent pancreatic tail
1
), tail (+ + 3 ) and common bile duct (+ + 2 ). Axial view using graded
• Use spleen as window to tail (see Fig. 8.11c )
• Potentially fi ll stomach with tea/water/formula (see Fig. 8.11b )
• Asking patient to take a deep breath sometimes helpful
TIP : Graded compression and scanning while patient standing upright (allows
transverse colon to descend) improves access.
Try to localise pancreas in midline, use coeliac trunk and abdominal aorta as well
as origin of mesenteric artery as reference structures.
Pancreas assessed in axial and sagittal sections, position may be slightly oblique
(more cranial to left):
• If only small access window, angulated transducer from this window to see head,
body and tail
• Use splenic vessels as landmark for assessing tail (see Fig.
8.11c )
• Use high-resolution imaging for visualising pancreatic duct and details of
parenchyma/contour
Try to visualise common bile duct and surrounding anatomy (PV, fl uid, retroperi-
toneal area, neighbouring vessels, adjacent stomach, etc.).
8.2.4 Normal Findings
Echogenicity of pancreas changes with age:
• Newborn: pancreas rather hypoechoic, more spheric head, homogeneous echogenicity, smooth contours (Fig. 8.11 )
• Children: with age pancreas becomes increasingly echogenic with slightly stippled appearance, otherwise homogeneous parenchymal echoes
• Commonly pancreatic echogenicity similar to liver – little higher than spleen. If
echogenicity increased – think of fi brosis, lipomatosis, haemosiderosis,
medication and congestive changes. Shape of head and body similar to adults;
tail often slightly pronounced
270
Table 8.3 Orienting values for size of pancreas, and where to take measurements
(a) Table for normal values of pancreas size during childhood for orientation
Age Head (cm) Body (cm) Tail (cm)
Newborns 0.5–1.0 0.5–1.1 0.5–0.8
0–6 years 1.0–1.9 0.4–1.0 0.8–1.6
7–12 years 1.7–2.0 0.6–1.0 1.3–1.6
13–18 years 1.8–2.2 0.7–1.2 1.3–19
(b) Schematic drawing illustrating standard sections for measurements of head, body and tail
thickness, chol.duct = choledochal duct
8 Spleen and Pancreas
Measurements may be diffi cult, particularly in standardised planes – given values
serve for orientation (Table 8.3 ).
Pancreatic duct often seen, should not measure more than 1.5 mm in older
children and 1 mm in early childhood.
8.2.5 Variations and Malformations
8.2.5.1 Annular Pancreas
Diffi cult to see, fi lling duodenum with fl uid helpful.
Specifi c fi nding: circular shape of pancreatic head surrounding the usually
compressed and stenotic duodenum, with signifi cant change in calibre at that site.
Often associated with intrinsic duodenal obstruction (duodenal web, atresia,
etc.).
8.2.5.2 Pancreas Divisum
Lack of fusion of ventral and dorsal part.
Rare normal variant.
Two different draining ducts that drain in papilla major/minor.
US Findings
• Two plate-like bars of typical echogenicity tissue separated by anechoic platelike layer
• Variation of pancreatic duct system – not reliably assessable by US
8.2.6 Inflammation: Pancreatitis
Pancreatitis usually primarily a clinical/serologic diagnosis.
Different entities.
8.2 Pancreas
271
ab
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Fig. 8.12 Acute pancreatitis. ( a ) Swollen, enlarged and hypoechoic pancreatic head in acute
(viral) pancreatitis, axial section. ( b ) Swollen and enlarged pancreatic head (+ +
pancreatitis, sagittal section. ( c ) Prominent and slightly irregular duct in tail and body of
enlarged and infl amed pancreas. ( d ) Exsudation along left kidney in severe exsudative
pancreatitis
1
) in acute (viral)
8.2.6.1 Oedematous or Reactive Pancreatitis
Commonly seen in viral infection.
US Findings :
• Enlargement and swelling with more spherical appearance (Fig. 8.12a, b )
• Can be restricted to just body or tail (Fig. 8.12c )
• Commonly slightly changed texture, often hypoechoic – may more prominently
delineate pancreatic duct. May also be of increased echogenicity (particularly if
combined with underlying or recurrent disease) (Fig. 8.12d )
• Depending on amount of exsudation, there can be peripancreatic fl uid (Fig. 8.12e )
• Hazy border to affected neighbouring mesentery and surrounding structures that
reactively become more hyperechoic
8.2.6.2 Haemorrhagic or Necrotising Pancreatitis
US Findings :
• Swelling, increased size
• Inhomogeneous, patchy, even hyperechoic echotexture
• Potentially focal lesions with hyper- or hypoechoic appearance (haemorrhage,
necrosis, etc.)
• Secondary pseudocyst formation (often later during course of disease)
272
8 Spleen and Pancreas
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Fig. 8.13 Chronic pancreatitis. ( a ) Parenchymal calcifi cations in pancreatic tail in chronic
recurrent pancreatitis with irregular and enlarged pancreatic duct, accessed via fl uid-fi lled stomach. ( b ) Echogenic swollen pancreatic head in chronic recurrent pancreatitis (CF-patient)
• Secondary abscess formation
• Calcifi cations and haemorrhage possible (Fig. 8.13 )
• Usually signifi cant exsudation with free fl uid around pancreas and other abdominal compartments (Fig. 8.12e )
• Pleural effusion
• Always assess ductal system including bile duct (bile obstruction as cause for
infection?)
• Consider trauma as potential reason
8.2.6.3 Chronic Pancreatitis
Rare in childhood.
Potentially secondary to systemic disease (e.g. CF, choledochal cyst, metachro-
matic leukodystrophy), also familial can be recurrent.
US Findings :
• Irregular contour, increased echogenicity
• Regional calcifi cation (Fig. 8.13 )
• Irregular size of potentially enlarged pancreatic duct/subducts (Fig. 8.14 )
• Potentially secondary stenosis
• With increasing duration – atrophy and lipomatosis, secondary necrosis, pseudocysts (Fig. 8.15 )
8.2.7 Trauma
In childhood possibly affected in blunt abdominal trauma:
• Particularly in accidents with bicycles (handlebar injury)
• Furthermore seen in abuse and vehicle trauma (seat belt injury)
US Findings
Vary with severity and kind of injury, grading see Table 8.4 :
• Nonspecifi c swelling in area of contusion with regionally altered echo-texture
• Superimposed fi ndings of reactive pancreatitis
8.2 Pancreas
ab
Fig. 8.14 Irregular dilated pancreatitic duct. ( a ) Enlarged and irregular pancreatic duct in body
1, 2
) in an infant with recurrent pancreatitis. ( b ) Hazy hypoechoic pancreatic parenchyma with
(+ +
irregular ductal ectasia in pancreatic tail as well as stippled calcifi cation in the body – in acute
exacerbation of recurrent pancreatitis
273
Fig. 8.15 Pancreas pseudocyst. Large complex (pseudo-)cyst (+ +) in body and tail of pancreas,
axial view
Table 8.4 Grading of pancreatic injury (according to Lucas)
Grade I Superfi cial contusion, no involvement of ducts
Grade II Peripheral rupture, rarely a peripheral duct involved, distal parts of pancreas
involved
Grade III Proximal rupture or even burst, duodenum not involved, pancreatic duct may be
involved
Grade IV Complex injury of pancreas, duodenum, pancreatic duct and potentially
choledochal duct
• Rupture/haematoma seen as disruption of contour/structure by focal initially
echogenic, later on anechoic or hypoechoic inhomogeneous structural disruption
(Fig. 8.16 )
• Potential leak of pancreatic exsudate if ducts involved
• Secondary necrosis, formation of pseudocysts
• Peripancreatic fl uid
274
8 Spleen and Pancreas
Fig. 8.16 Pancreas laceration. Subtle irregularity of pancreas contour at junction between head
and body ventrally after trauma
These changes often only depicted on follow-up, particularly increasing amount
of fl uid surrounding pancreas, delineation of necrosis and development of
pseudocysts – usually only after days.
NOTE : US can guide drainage of pseudocyst, but only advisable after solid and
well-formed cyst wall established.
8.2.8 Space-Occupying Lesions
8.2.8.1 Cysts/Pseudocysts
Most common – congenital (systemic cystic disease), posttraumatic and
postinfl ammatory.
US Findings
• Simple cysts – anechoic, spheric structure, thin and smooth wall
• Complicated (pseudo-)cysts: often contain anechoic fluid potentially with
some debris, echoes, sedimentations and septae. Wall often irregular,
polygonal – appearance varies with origin and age of cyst – may grow and
become very large (see Fig. 8.15 )
Cysts often accessible for US-guided puncture/drainage
8.2.8.2 Tumours
Extremely rare in children. Different entities:
• Adenoma, hamartoma and insulinoma:
– Focal tumour
– Diffuse “infi ltration” – nesidioblastosis – hyperplasia of insulin producing
beta cells
• Rarely adenocarcinoma
• Involvement in leukaemia/lymphoma
• Focal granulomatous pseudotumour – may be diffi cult to differentiate
(involvement in HIV, sarcoidosis, tuberculosis, etc.) (Fig. 8.17 )
8.2 Pancreas
Fig. 8.17 Pancreatic pseudotumour in HIV- infected girl (DDx: lymphoma). Hypoechoic
tumorous lesion in body of pancreas (axial view), which turned out to be an infl ammatory
pseudotumour in a girl with HIV
NOTE : Assess for secondary changes (e.g. obstruction of pancreatic/bile duct, local
spread to duodenum, regional lymph nodes and involvement of PV/coeliac trunk/splenic
vein/mesenteric artery). Also consider that US may miss small tumours, particularly if
of similar echogenicity as normal pancreatic parenchyma, or diffuse infi ltration.
US and (a)CDS Findings
• Focal tumorous disruption of typical echotexture with regionally increased size,
commonly anechoic or less echogenic than parenchyma
• Depending on aetiology – sharp or hazy, irregular margins
• CDS rarely helpful. May help differentiation of tubular ectatic ductal structures
from vessels or vascular pathology, or to assess patency of vessels (secondary
thrombosis – e.g. of splenic vein and aneurysm of adjacent arteries)
• Depiction can be improved by aCDS, ce-US, endoscopy/endoscopic US and
intraoperative US (helpful for location during surgery)
275
8.2.9 Role of US
Commonly used as fi rst imaging modality:
• Always evaluate pancreatic US in conjunction with laboratory fi ndings
NOTE : Morphologic changes may manifest later than disease onset.
Also used for follow-up, intraoperatively and for guiding interventions.
8.2.10 Additional Imaging
• Sectional imaging by MR (or CT) helpful, particularly in trauma or for tumorous
conditions
• CT mandatory in severe trauma for early depiction of frequent associated
injuries of bowel or bony structures
• Scintigraphy/PET in some tumours, infi ltration, nesidioblastoma, etc.
• ERCP offers best anatomic resolution for assessing pancreatic duct; MRCP (sometimes performed with secretin) presently useful only in obvious/gross dilatation