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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_5790_Библиотеки_им_академика_М_И_Перельмана.pdf
7.4 Biliary Tract and Gall Bladder
parenchymal heterogenicity. In periportal infi ltration periportal areas become
hypoechoic – may result in biliary obstruction. Hepatosplenomegaly is often present, but nonspecifi c.
Involvement in leukaemia commonly manifests as diffuse infi ltration = hepatosplenomegaly, nonspecifi c changes of echotexture, potentially some inhomogeneity.
NOTE : Look for secondary changes such as enlarged lymph nodes, ascites and
splenomegaly.
245
7.3.6.15 Role of US
Often detects/confi rms presence of tumour, allows fi rst assessment of position and
relation to surrounding structures, may suggest specifi c entity, particularly when
using ce-US. On follow-up, helpful for assessing tumour behaviour under chemotherapy, long-term recurrences and potential complications.
Histologic diagnosis unavoidable, biomarkers helpful and essential.
Additional sectional imaging mandatory for initial assessment, preoperative
planning and (re)staging according to various tumour study/treatment protocols
(SIOP, COG, etc.).
7.3.6.16 Additional Imaging
• Ce-MDCT, preferably dynamic ce-MRI
• For some queries scintigraphy and angiography
• Rarely (M)ERCP or PET – depending on tumour study protocol and underlying
entity
7.4 Biliary Tract and Gall Bladder
7.4.1 General Findings
Similar fi ndings noted in nearly all biliary tract diseases, particularly in chronic
conditions.
US Signs of Periportal Fibrosis :
• Prominent echogenic linear periportal area
• Dilatation or cysts of bile ducts
• Bile duct dilated and visible – then often irregularly shaped or narrow and not
depictable in echogenic periportal structures
• Wall thickening of large bile ducts (hepatic and common duct) with increased
echogenicity; also gall bladder can vary in size with thickened wall
• Secondary intrahepatic gall stone/sludge formation
• Signs of biliary cirrhosis
7.4.2 Congenital Conditions and Normal Variants of Biliary Tract
7.4.2.1 Intrahepatic Gall Bladder
Rare normal variant. No sequelae.
246
7 Liver and Bile System
7.4.2.2 Hypo-/Aplasia of Gall Bladder/Biliary Atresia/Neonatal
Hepatitis Syndrome
Rarely isolated, usually associated with other conditions (e.g. intra-/extrahepatic
biliary atresia, a-/hypoplasia).
Defi nition
Biliary atresia/neonatal hepatitis caused by fetal damage/insult to developing
liver biliary tract. Typical biliary atresia develops if main bile duct + hilus
affected.
Neonatal hepatitis – nonspecifi c infl ammation secondary to different causes,
such as infection or metabolic defects.
Differentiation important, as treatment differs – defi nitive diagnosis only achievable by biopsy.
US Findings
• Nonspecifi c change of liver texture, US morphology depends on severity of man-
ifestation/already manifest biliary cirrhosis
• Bile ducts usually invisible
• Potentially central triangular cord sign (triangular echogenic spot in liver hilus
as fi brotic remnant of hilar biliary tract – rather specifi c sign but can also be seen
in relatively normal central bile duct or hypoplastic biliary system, not
diagnostic)
• Small or missing gall bladder (“ghost gallbladder”, less than 1 cm length, normal
wall layers absent)
NOTE : Importance of US is to exclude other conditions that may cause similar
clinical appearance and cannot replace histology.
Sometimes US used for percutaneous gall bladder puncture for diagnostic percutaneous cholangiography.
Subgroups
Intrahepatic biliary hypoplasia (rarely isolated, often combined with syndromatous
extrahepatic pathology) and neonatal hepatitis syndrome have similar appearance,
but usually lack triangular cord sign.
Often no bile ducts visible – not only because of developmental defi cit, but also
because of decreased bile production and thus collapse of main bile ducts.
DDx
Intrahepatic cholestatic syndromes – e.g. Alagille syndrome, Byler disease (progressive familiar intrahepatic fi brosis).
Typical for Byler disease – central dot sign in saccular cystic periportal lesions
(periductal cyst noncommunicating with biliary tract, thus to be differentiated from
Caroli disease). See also Table 7.5 .
CDS
Enlarged hepatic artery, subcapsular arteries with inverted fl ow, signs of portal
hypertension, potentially with secondary persistent ductus venosus – all these
secondary to increased liver vascular resistance and cirrhotic changes.
7.4 Biliary Tract and Gall Bladder
Table 7.5 DDx in neonatal jaundice
Disease US criteria
Neonatal hepatitis Often gall bladder >1.5 cm with changes in size after feeding
Biliary atresia Small lumen gall bladder, triangular cord sign, potentially biliary
cirrhosis
Choledochal cyst Circumscribed cystic dilatation of some segment of enlarged bile ducts
Liver fi brosis Echogenic periportal area with narrow or potentially irregularly shaped
bile ducts + signs of arterial hyperperfusion (DDx cholangitis)
Caroli syndrome Multiple peripheral intrahepatic saccular dilatations of peripheral bile
ducts, signs of liver fi brosis, biliary cirrhosis
Bile obstruction/
inspissated bile
Dilated bile ducts and gall bladder, stone formation, either due to
obstruction or functional impairment (e.g. intensive care treatment/
parenteral nutrition, cystic fi brosis, Hirschsprung disease, posttraumatic
with haemobilia)
247
7.4.2.3 Choledochal cyst
Defi nition
Congenital malformation of bile ducts, may gradually develop and increase – diagnosis may be delayed.
Several types with different classifi cations – most commonly Todani classifi cation
used:
• Type I = dilatation of common hepatic duct
• Type II = true diverticulum of common bile duct
• Type III = choledochocele (cystic dilatation of common duct at intraduodenal
portion, pancreatic duct drains into it)
• Type IV = Type I and multiple cysts (A = intrahepatic and extrahepatic, B = only
extrahepatic)
• Type V = Caroli disease: segmental non-obstructive dilatation of hepatocholedochal duct and multiple purely intrahepatic peripheral cysts arising from
and connected to peripheral bile ducts (Fig. 7.21 )
NOTE : Choledochal cysts may coexist with biliary atresia or hypoplasia.
US Findings
• Depends on type
• More or less biliary ductal dilatation
• Sometimes only fusiform shape of affected portion
• Wall can be thickened and echogenic
• Within cysts there may be sludge and sedimentation – due to cholestasis, secondary infection, haemorrhage, etc.
• Often underlying/associated condition – “common channel” of pancreatic and choledochal duct before entering sphincter mechanism, usually not depictable by US
• Secondary changes depend on severity and duration/time of diagnosis, may
range from normal liver appearance to liver fi brosis or biliary cirrhosis
• Long list of DDx, particularly in neonatal hyperbilirubinemia/jaundice (see
Table 7.5 )
248
a db c
Fig. 7.21 Choledochal cysts: ( a ) Fusiform ectasia of hepato-choledochal duct (+ +) – choledochal
cyst Type I. ( b ) Severe dilatation of common choledochal duct – choledochal cyst. ( c ) Ruptured
choledochal cyst – septation below liver due to bilious peritonitis, cyst still seen covered by
infl amed echogenic mesentery. ( d ) Multiple cyst-like ectatic intrahepatic bile ducts (+ +) with
small bile lakes in Caroli syndrome (choledochal cyst Type V)
7 Liver and Bile System
Complications :
• Large cysts can rupture – cause biliary peritonitis
• Choledochoceles may protrude into duodenum
• Associated recurrent pancreatitis – may cause changes in echogenicity and size
of pancreas + prominent margin of slightly irregular pancreatic duct
• Stone formation
• Thickened wall of (enlarged) gall bladder with secondary cholecystitis
• Ascending cholangitis
• Intrahepatic abscess
• Neoplastic transformation – most commonly adenocarcinoma
NOTE : In Caroli disease both types are possible and associated with cystic renal dis-
ease (ciliary complex) – saccular dilatation + fi brotic type with portal hypertension.
7.4.3 Biliary Tract Diseases
7.4.3.1 Aerobilia
Defi nition
Air in intrahepatic bile ducts (postoperative, ileus, obstruction, etc.).
US and CDS fi ndings
• Echogenic material with reverberation artefacts in periportal fi eld
• Differentiation from portal venous air may be diffi cult
• DDx to portal venous gas: No gas bubbles depictable in central portal vein
(duplex-Doppler trace – see above, Fig. 7.17 )
• CDS: Twinkling sign – similar to calcifi cations/intrahepatic bile stones
7.4.3.2 Cholestatic Changes/Inspissated Bile/Gall \stone
Defi nition
Different causes, reactive either during infection due to medication (e.g. parenteral
nutrition, intensive care medicine, some antibiotics such as Ceftriaxon®), bile duct
7.4 Biliary Tract and Gall Bladder
ab c
Fig. 7.22 Dilated bile ducts: ( a ) Dilated main hepatic duct. ( b , c ) CDS helps differentiation of
portal vein from main hepatic duct
obstruction by compression or tumours, intrinsic bile duct obstruction (stone and
sludge), functional impairment (cystic fi brosis, haemolytic anaemia, Hirschsprung
disease, etc.).
US Findings
• Variable dilatation of affected part (Fig.
7.22 )
• Potentially site of obstruction visualised
• Sludge/stones within bile duct and gall bladder (Fig. 7.23 )
• Oedematous periportal fi eld, thickening of bile duct wall – if long standing or
chronic
• Typical fi ndings in gallstones : Echogenic formation with more or less shadowing
depending on composition. Sludge – no shadowing, but sedimentation + fl uid
levels. Cholesterol polyps are connected to gall bladder wall (DDx: gallbladder wall
polyps – polyposis, e.g. in metachromatic leukodystrophy) (Fig.
7.23e )
NOTE : In childhood, biliary stones are less common than in adulthood – should
prompt thorough search for underlying conditions (e.g. bile duct malformation,
papillary stenosis, metabolic disease, haemolytic anaemia).
249
7.4.3.3 Sclerosing cholangitis
Defi nition
Chronic cholestatic disorder, obliterative fi brosis of extrahepatic and intrahepatic
bile ducts, eventually leads to biliary cirrhosis associated with chronic infl ammatory
bowel disease and immune-defi ciency disorders.
US Findings
Typically thick-walled, dilated intrahepatic ducts with irregular shape and regionally secondary narrowing due to strictures.
Secondary cholelithiasis, intraductal stones, gallbladder wall thickening, devel-
opment of cirrhosis + portal hypertension.
NOTE : Cholangitis in AIDS appears similar, but may have papillary oedema caus-
ing hypoechoic nodule at distal end of common bile duct.
250
7 Liver and Bile System
a
b
c
d
Fig. 7.23 Sludge and bile stones: ( a ) Normal gall bladder with sludge balls. ( b ) Sludge-fi lled gall
bladder with several small stones (increased echogenicity, partially with shadowing). ( c ) Isolated
infundibular bile stone (+ +) with shadowing. ( d ) Echogenic sludge in a dilated intrahepatic bile
duct, some shadowing
7.4.3.4 Other Forms of Cholangitis and Cholecystitis
Rare in childhood, usually secondary to underlying condition or postoperative.
US Findings
• Enlargement of gall bladder, thick bile duct and gallbladder wall, oedematous
gallbladder bed, periportal oedema and sludge formation (Fig. 7.24 )
• In chronic, persistent or recurrent disease: complications from periportal fi brosis,
strictures, wall thickening, irregular contours and post infl ammatory
calcifi cations
• In tropic areas various parasites can ascend into bile ducts and cause infl ammation and obstruction – may sometimes be visualised moving within biliary tract
Trick : Validate obstruction + dilatation of bile ducts by US with valsalva- manoeuvre
(decrease of ductal diameter as positive response to manoeuvre in non- obstructed
biliary system) or by gall bladder size/duct size changes 30–60 min after fatty meal
helpful.
CDS
Helpful to differentiate vascular from biliary structures, but only if performed at
adequate Doppler angle, hyperaemia/hypervascularisation of gall bladder wall vessels and hyperaemia of HA.
NOTE : Arterial nature of vessel must be proven by spectral analysis – other conditions
may also cause increased vascularity of gall bladder wall (e.g. Henoch-Schoenlein purpura, Kawasaki disease, intensive care medicine with parenteral nutrition, cardiac
7.4 Biliary Tract and Gall Bladder
251
ab
Fig. 7.24 Thickened gall bladder wall: ( a ) Severely thickened gall bladder wall (+ +) – nonspe-
cifi c fi nding a can be seen in a variety of conditions (e.g. congestion, hepatitis, Kawasaki, cholecystitis). ( b ) CDS depicts wall vessels; spectral analysis confi rms its arterial nature with
high-diastolic hyperaemic fl ow and low resistance fl ow pattern, consistent with cholecystitis
congestion, portal hypertension, hepatic vein and obstruction). Typical pitfall in diagnosing calculi may be air in adjacent bowel with associated shadowing or reverberations, echogenic vessel walls with side loop artefacts. Some stones twinkle, some do not.
7.4.4 Tumour-Like Conditions
7.4.4.1 Polyps
Defi nition
Rare in childhood, associated with syndromes – particularly if multiple or
numerous.
Should always be evaluated and followed up.
US Findings
• Usually quite homogenous echogenic formation, adjacent to bile duct/gall bladder wall, protruding into lumen (Fig . 7.25 ). Stay at same side adjacent to wall
during positioning manoeuvres
• Potentially exhibit central vascular pedicle on (a)CDS
DDx: Concretion, fi brous, sludge/clot formation, “cholesterol polyps”, irregular
thickening or focal changes in infl ammation
NOTE: multiple gall bladder polyps in metachrome leucodystrophy, practically
pathognomonic
7.4.4.2 Tumours
Cholangiocellular Tumours
Cholangiocellular tumours extremely rare in childhood. Rhabdomyosarcoma of bile
duct may occur – may show similar growth as cholangiocarcinoma.
252
Fig. 7.25 Gall bladder polyp. Gall bladder polyp
(+ +) attached to wall, stable in this location during
positioning manoeuvres. Similar behaviour seen in
the more echogenic “cholesterin polyps” (DDx to
stone formation that move and fl oat with
manoeuvres)
7 Liver and Bile System
• Nonspecifi c. Tumorous lesion adjacent to central hilar structure, potentially
growing within dilated common bile duct, is causing intrahepatic dilatation of
bile ducts and cholestasis
• May compress or affect hilar vascular structures, particularly PV. For differentiation biological markers and sectional imaging as well as biopsy are
necessary
Granular Cell Tumour
Benign tumour, rare, anywhere along biliary tree.
US Findings
• Echogenic, intraductal mass with secondary dilatation of respective part of biliary tree. Cannot be differentiated without histology
7.4.5 Role of US
7.4.5.1 Cholestasis and Jaundice
Initial investigation to differentiate various entities and fi nd dilatation of bile ducts.
Method of choice for depicting calculi, particularly in gall bladder and main/central
bile ducts.
NOTE : If liver function and thus bile production impaired, even obstructed ducts
will not be dilated.
7.4.5.2 Malformations
Method of choice for fi rst investigation and follow-up.
Additional imaging depends on suspected condition.
7.4 Biliary Tract and Gall Bladder
253
7.4.5.3 Trauma
US restricted in early phase after trauma, but ideal for follow-up.
CDS usually helpful, particularly, when assessing HV/PV/HA complications,
aneurysms, fi stula, etc.
US-potential signifi cantly enhanced by ce-US.
7.4.5.4 Postoperative Conditions
Particularly after Kasai-/Y-Roux Anastomosis – used to assess further course of
disease. Cystic ectasia/dilatation of bile ducts may indicate some obstruction and
stenosis at anastomotic site.
Secondary cholangitis, periportal fi brosis and aerobilia can be seen.
7.4.5.5 Metabolic Disease
Used to screen for liver involvement, insensitive for entity – usually shows unspecifi c changes of liver parenchyma and size. Multifocal inhomogenous patchy appearance may have irregular distribution, as also after various therapies (e.g. oncology).
7.4.6 US-Guided Biopsy (See also Entry
Interventional US, Chap.
Helpful to reduce complications or for targeted biopsies of individual lesion.
Essential to secure safe needle tract with suffi cient healthy liver tissue between
peritoneal cavity/skin and core biopsy site.
Helps reduce risk of complications: avoid major vessels, increase tissue harvest,
reduce number of passes, avoid injuring diaphragm/entering chest, penetrating into
abdominal cavity, etc.
2 )
7.4.7 Additional Imaging
• ERCP/MRCP: technically challenging in neonates and small infants; in narrow
bile ducts MRCP has insuffi cient resolution for visualisation/demonstrating
detailed anatomy
• CT/MRI: for assessment of focal liver lesions that secondarily cause obstruction.
MR helpful in cholangitis, fi brosis and assessment of secondary liver tumours in
biliary cirrhosis. At present restricted role in diagnosing biliary atresia, not necessary for uncomplicated stone disease
• Scintigraphy: Tc
• Interventional radiology: Punctures and drainages performed under US, fl uoroscopic or CT guidance. Used for relieve of obstruction, for cholangiography in
complex anatomy/biliary atresia, after trauma (bile leaks, collections, vascular
problems/embolisation), after transplantation (dilatation and stenting), for targeted biopsies of equivocal lesions or for abscess drainage
99m
HIDA used in biliary atresia + liver function assessment
254
7 Liver and Bile System
7.5 US in Liver Transplantation
7.5.1 Pretransplant US
7.5.1.1 Recipient Evaluation
• Assessment of liver/focal lesions/initial diagnosis of liver disease
• Documentation of patency of PV by CDS + spectral trace
• Assessment of ascites and spleen (size)
• Demonstration of abdominal vascular anatomy, assessment of portosystemic
shunts
• Assessment of potentially associated renal disease
7.5.1.2 Donor US (Split Liver Transplant,
Related Living Donor – Deceased Donor)
• In living donor: replaced by ce-CT or MRI, which allows reliable assessment of
parenchyma and (vascular) anatomy for exact planning
• In deceased donor: US (to assess anatomy of PV, HV, vascular anatomic variations, presence of liver disease…) or ce-CT (e.g. at same session with brain CT/
CTA when used for assessing brain death)
• Potentially 4Dce-US may widen US potential in future
7.5.2 Intraoperative US
Not commonly used – sometimes for assessing vascular complications (diffi cult surgery, atypical anatomy, etc.) immediately before or shortly after abdominal closure.
7.5.3 Postoperative Assessment
US – mainstay of imaging, both in early and late stage.
Tasks of US :
• Demonstrate anatomy and patency of vascular anastomosis (PV, HA, HV, IVC),
CDS + spectral analysis mandatory
• Assessment and follow-up of focal collections (e.g. haematoma, haemorrhage,
biloma, secondary abscess formations)
• Assessment of bile ducts commonly only achievable in early phase after transplantation or with dilated ducts (stenosis, sludge, etc.). Otherwise periductal
fi brosis, aerobilia and calcifi cations reduce US potential
• US-guided drainage/biopsy potentially helpful
NOTE : Always include surrounding structures such as spleen, abdominal IVC (for
patency and size), ascites, etc.