Hepatobiliary imaging uses various modalities like ultrasound, CT, MRI and others to evaluate conditions of the liver, gallbladder and bile ducts. Ultrasound is the preferred first line imaging test due to its safety, low cost, and ability to evaluate in real-time. It can detect abnormalities of the liver, gallbladder and bile ducts like cysts, masses, stones, thickening, and blockages. Characteristics seen on ultrasound help to differentiate benign from malignant conditions. Additional modalities like CT, MRI and others provide further detail when needed. Together imaging plays a key role in the evaluation and management of hepatobiliary diseases.

1. Hepatobiliary Imaging
Pushpa Lal Bhadel
FCPS Resident
Department of Surgery
Kathmandu Model Hospital
Moderator:
Dr. Udaya Koirala
HOD
Department of General Surgery

2.  Acute conditions are often inflammatory
 Pain is a predominant syndrome
 Jaundice: benign and malignant HPB disease
 Thorough and complete history and clinical examination
 Avoid ‘scan first, clinic later’

3. Imaging modalities
 X-ray
 Ultrasound
 Computed Tomography (CT)
 Magnetic Resonance Imaging(MRI) and Magnetic Resonance
Cholangiopancreatography (MRCP)
 Endoscopic Retrograde Cholangiopancreatography (ERCP)
 Hepatic Iminodiacetic acid (HIDA) scan
 Percutaneous Transhepatic Cholangiography (PTC)
 Nuclear Medicine
 Direct cholangiography
 Intraoperative diagnostic techniques

4. Plain abdominal X-ray
Used in past, but has been widely replaced by US
Can be used to visualize:
oCalcified stones
oEmphysematous cholecystitis
oBiliary fistula (gas within biliary system)
oPorcelain gall bladder

5. Gall stones

6. Fig. Abdominal radiograph (frontal projection) shows
intraluminal air (arrow) with air– fluid levels –
Emphysematous cholecystitis
Fig. Plain x-ray showing air in the biliary tree

7. Well defined globular coarse calcification of gall bladder wall in right hypochonrium with an oval calcified area adjacent to it suggestive
Fig. Well defined globular
coarse calcification of gall
bladder wall in right
hypochonrium with an oval
calcified area adjacent to it
suggestive of GB calculus.

8. Ultrasound
 Favored imaging modality
oVersatility
oLow cost
oReal-time capability and portability
oNo harmful biologic effects on operator or patient
oDoppler US – assessment of blood flow dynamics
 Limitations:
oWaves unable to penetrate bone/air
oOperator dependent
oInfluenced by skill and experience

9. Ultrasound cont…
Principles:
oPulse-echo principle
 Lower-frequency transducer:
oPoor resolution, greater
penetration
oDeeper structures
 Higher-frequency transducers:
oBetter spatial resolution, poor
tissue penetration
oSuperficial soft tissues

10. Ultrasound cont…
 Echogenicity: reflection of transmission of
US waves relative to surrounding tissue
 Based on gray scale imaging, structure
displayed characterized as:
oAnechoic (uniformly black)
oHypoechoic (dark gray)
oHyperechoic (light gray)
Fig. Transverse gray scale ultrasound image of
the liver shows the right hepatic vein (hv) as an
anechoic fluid-containing structure. Note that
the walls of the veins are hyperechoic.

11. Ultrasound cont…
Doppler ultrasound:
oTo identify and evaluate blood flow in vessels
oAssessment of vessel patency, direction of blood flow, flow velocity
 Doppler effect: change in frequency proportional to the velocity of
reflector relative to transducer
 Three different Doppler displays:
oColor doppler
oPower doppler
oSpectral doppler

12. Fig. Doppler ultrasound of the liver.
A, Color Doppler mode shows mean flow velocity and direction of flow
toward or away from the transducer, as indicated in the bar display at left
of the image. The portal vein (PV) indicates hepatopetal flow. The inferior
vena cava (IVC) shows flow away from the transducer. The hepatic artery
(arrowhead) has mixed signals due to high-velocity flow and aliasing.
B, Power Doppler shows amplitude of flow but not direction. It is useful for
small vessels and low flow, as shown in this image of vessels in the
gallbladder (GB) wall (arrowheads).
C, Spectral Doppler shows flow pattern over time; when angle corrected, it
can measure true velocity. A sample cursor is placed within the vessel, as
shown in this transverse image of the middle hepatic vein (MHV).

13. Liver ultrasound:
 Hepatic parenchyma is hypoechoic to spleen, either isoechoic or minimally
hyperechoic to renal parenchyma
 Commonly determined by longitudinal image of right lobe
Fig. Normal liver longitudinal ultrasound images.
A, Left hepatic lobe. Segments are numbered. LH, Left hepatic vein.
B, Left lobe segment IV. Hepatic segments are numbered. GB, Gallbladder; IVC, inferior vena cava; PV, portal vein.
C, Right lobe. Hepatic segments are numbered. RHV, Right hepatic vein; RK, right kidney.

14. Fig. Transverse images of the liver.
A, Transverse sonogram at the level of
the hepatic veins. Hepatic segments
are numbered. IVC, inferior vena cava;
L, left hepatic vein; M, middle hepatic
vein; R, right hepatic vein.
B, Transverse section of the left lobe
at the level of the portal
vein bifurcation. L, Left portal vein; M,
uppermost main portal vein; R, right
portal vein;.
C, Transverse image of the left portal
vein (LPV) and right portal vein (RPV)
at the bifurcation. Segments IVB and I
are indicated. A, Aorta; IVC,inferior
vena cava; L, left hepatic vein; R, right
hepatic vein; RK, right kidney;.
D, Transverse image of the inferior
right lobe segments V and VI. IVC,
inferior vena cava; K, Right kidney; RA,
anterior right portal vein; RP, posterior
right portal vein.

15. Hepatic masses:
 On gray scale US liver masses differentiated by internal architecture
and described as cystic, hypoechoic or hyperechoic
 Hypoechogenicity: feature of malignancies
 Hyperechoic masses: benign etiologies like hemangioma, focal fat,
HCC, metastases

16. Role of contrast-enhanced US(CEUS) in evaluation of focal liver lesion:
 Non-invasive real-time imaging
 US contrast agent:
o Microbubbles that are highly echogenic and oscillate in US field
o Enhance US signal in gray scale, color and spectral Doppler
o Bubbles capable of transpulmonary passage
 Improves characterization of focal liver mass and liver lesion
 Improved ability to see greater number and smaller lesions
 Diagnostic performance is similar to CT and MRI in recognition of
malignancy.
(Trillaud et. al, 2009)

17.  Vascular phases:
oArterial (10-40 seconds)
oPortal venous (40-120 seconds)
oLate parenchymal (>120 seconds)
(Wilson & Burns, 2006)

18. Benign liver lesion:
 Cystic masses:
o Demonstrate smooth, barely perceptible walls,
posterior acoustic enhancement and no internal
echoes
o Partial septation, thin septation or puckered wall may
be present
 Lymphomatous mass:
o Markedly hypoechoic, may mimic simple cyst,
demonstrate internal vascularity on color doppler
 Abscess:
o Solid initially, then cystic with debris, wall is usually
vascular
 Echinococcal cyst:
o Variable appearance, simple fluid-filled cyst, may
contain wavy membranes from rupture and detached
endocyst, may contain daughter cysts or may show
calcification
(Lewall & McCorkell, 1985)
Fig. Benign hepatic cyst with a thin,
smooth wall. Note the posterior acoustic
enhancement (arrows) that is a
characteristic feature of a cystic lesion.
Fig. Hepatic abscess in a patient after embolization
for hepatic neuroendocrine metastases
(arrowheads). The abscess (asterisk) contains
complex fluid and has posterior acoustic
enhancement (arrows).

19.  Cystic neoplasm:
oBiliary cystadenoma and cystadenocarcinoma
oMay be multilocular with cystic locules
demonstrating different echogenicities depending
on fluid content
(Levy et. Al, 2002)
 Focal nodular Hyperplasia:
oSmooth lobulated contour and variable
echogenicity
oCharacteristic Doppler appearance off a central
feeding artery with tortuous spoke wheel
vascularity
Fig. The images show a large and well-defined
multiloculated cystic lesion in the IV-hepatic-
segment with enhancing septations without any
solid pole or calcifications in the wall.
Fig. Focal nodular hyperplasia (FNH). Gray scale image of a
hypoechoic FNH. FNH lesions are often subtle.

20.  Malignant liver neoplasm:
oSensitivity 58-89%
(Bolondi, 2003)
oHCC: solitary, multiple or diffuse extending to bile
ducts causing biliary obstruction or hemobilia
(Kojiro et. Al, 1982)
oSmall HCC(<5cm): hypoechoic, may be hyperechoic
d/t fatty metamorphosis
(Caturelli et. Al, 2001)
oLarger HCC: heterogeneous d/t liquefaction necrosis
and fibrosis
(Tanaka et. Al, 1983)
oCEUS improves HCC characterization
oRegional lymphadenopathy is common
Fig. Hepatocellular carcinoma (HCC) with
portal vein thrombosis. A, Transverse image
shows a hypoechoic HCC in the right hepatic
lobe (arrows).

21.  Liver metastases:
oVary according to primary malignancy
oCommon appearance is hypoechoic lesions or lesions
with peripheral hypoechoic halos
oHypoechoic halo: fibrosis, compressed sinusoids,
tumor neovascularity surrounding the metastatic
deposit
(Kruskal et. Al, 2000)
oHypoechoic mets: metastatic breast, lung,
pancreatic, gastric and esophageal carcinoma,
lymphoma and HCC
oEchogenic mets: HCC or GI malignancies
oHyperechoic mets: vascular mets, mets from RCC
islet cell tumor, carcinoids and cholangiocarcinoma
(Tanaka et. Al, 1990, Marchal et. Atl, 1985)
Fig. Liver metastases with hypoechoic
halo. Metastatic neuroendocrine tumors
(arrows) in the liver have a hypoechoic
halo peripherally and a target
appearance. A hypoechoic halo usually
indicates malignant lesion or, less
commonly, an infectious etiology.

22. Sonography of diffuse liver disease
 Fatty liver disease:
o Fat deposition within hepatocytes results in increased
echogenicity of liver, decreased acoustic penetration and loss
of echogenic borders of portal vessels
 Viral hepatitis:
o Hepatomegaly, peripheral edema
 Cirrhosis:
o Neither sensitive nor specific
o Surface nodularity- reliable sign
o Nodularity along the deep surfaces or liver- more sensitive
sign
(Filly et. Al, 2002)
o Coarsened echotexture and heterogeneous parenchymal
echogenicity
(Caturelliet. Al, 2003)
Fig. Diffuse liver disease. A, Hepatic
steatosis, longitudinal right lobe. Hepatic
parenchyma of fatty liver is very
echogenic relative to the right kidney.
Fig. Cirrhosis. The liver is small with
coarsened echogenicity and a nodular
surface (arrows). a, Aorta.

23. US of gall bladder and biliary tree
 Sonographically GB is best visualized from the
right intercostal approach with patient supine or
left lateral decubitus
 Best evaluated when distended, thus patient
should fast before scan
 CBD best seen from right intercostal approach
with the patient in left lateral decubitus position
 The right and left hepatic duct lie anterior to
portal vein confluence and are best visualized on
transverse subcostal US image
Fig. Gallbladder. A, Normal longitudinal
gallbladder image with visualization of the
gallbladder neck.

24. Gall stones and biliary sludge:
 Gall stones are mobile, echogenic and demonstrate
posterior acoustic shadowing
 Large stones or multiple stones filling the entire GB
lumen – ‘wall echo shadow’ (WES) sign
 Porcelain GB has calcification in GB wall - so no
hypoechoic crescent of bile separating the wall
from echo
 GB sludge:
o Viscous echogenic bile, nonshadowing and sometimes
takes on a rounded shape called tumefactive sludge
o Change with positional variation and moves slowly
Fig. Gallstones. A, Longitudinal view of the
gallbladder shows layering stones (numbered)
with acoustic shadow. A small amount of sludge
(arrow) is also seen in the dependent portion of
the gallbladder.
Fig. Gallstones fill the gallbladder lumen,
producing a Wall-Echo-Shadow (WES) sign from
the anterior gallbladder wall, the echogenic
anterior surface of gallstones, and posterior
acoustic shadowing by the gallstones.

25.  Cholecystitis:
o Sensitivity: 80-100%, specificity: 60-100%, PPV: 90-94%
(Harvey & Miller, 1999)
o GB wall thickening > 3mm, pericholecystic fluid,
positive sonographic Murphy sign
(Smith et.al, 2009)
 Emphysematous cholecystitis:
o Echogenic air bubbles in GB wall – produce
reverberation artifact
o GB necrosis, gangrene and perforation
 Gangrenous cholecystitis:
o Floating intraluminal membranes from sloughed
mucosa, shadowing foci from air in GB wall, disrupted
GB wall and pericholecystic abscess
(Jeffrey et.al, 1983)

26. Hyperplastic Cholecystoses and GB
polyps:
oFocal/polypoid GB wall thickening
Cholesterolosis:
oMultiple small (1-10 mm) nonshadowing
polyps arising from non-dependent wall with
echogenic speckles and lobular contour
Adenomyomatosis:
oGB wall thickening focal/diffuse, most
common in fundus
oIn body there is annular constriction
producing hourglass shaped GB
oRisk factor for malignancy:
• Age >60 yr, coexistence of gall stones, size > 10mm
Fig. Gallbladder polyps (arrows).
Note the lack of acoustic shadowing.

27. Gall bladder carcinoma:
 Sessile/polypoid mass, thickened GB
wall/infiltrative mass that fills the GB lumen and
extends into the adjacent liver
(Wibbernmeyer et.at, 1995)
 Secondary signs: discontinuity of echogenic
mucosal lining, absence of echogenic specks seen
in cholesterol crystals and high velocity arterial
flow greater than 60 cm/s
 Selective mucosal calcification is significantly
associated with GB cancer but diffuse intramural
calcification is not
(Stephen & Berger 2001)
Fig. Gallbladder carcinoma. A, Gray scale
longitudinal image of the gallbladder
shows a solid irregular mass in the
fundus.

28. Biliary Ducts:
 Biliary obstruction:
oExtrahepatic duct measurement performed near
crossing of hepatic artery
oIntrahepatic biliary dilatation - >2mm or greater than
40% of adjacent portal vein
oDouble track sign – caused by dilated bile ducts parallel
to the portal vein branches
 Bile duct calculi: appear as intraluminal filling
defects
Fig. Biliary obstruction from choledocholithiasis.
Transverse sonogram of the liver reveals the
“double-track” sign (circled areas), consistent
with intrahepatic biliary dilatation.
Fig. B, Longitudinal view of the common bile duct
(cbd) shows an echogenic stone (arrow) that
produces acoustic shadowing (arrowheads). gb,
Gallbladder; v, portal vein.

29. Cholangiocarcinoma:
 Intrahepatic peripheral form:
oFocal mass, peripheral biliary ductal dilatation(25%),
capsular retraction, lack of hypoechoic halo, lack
venous thrombosis
(Chung et.al, 2009)
 Hilar cholangiocarcinoma:
oSegmental upstream dilatation with abrupt cutoff
and nonunion of right and left dilated ducts at porta
hepatis
oIsoechoic, larger tumors have hypoechoic rim
(Hann et.al, 1997)
 Extrahepatic cholangiocarcinoma:
oInfiltrative spreading along the duct walls, nodular
mural thickening or papillary
(Hann et.al, 1997)
Fig. Hilar cholangiocarcinoma

30. Computed tomography (CT)
 Traditionally primarily been used for hepatic lesion
detection and characterization
 Identifies peritoneal disease involvement, distant
lymphadenopathy and other distant metastatic disease, key
vessel involvement
 Role in initial staging of patients with malignant disease and
preprocedural vascular evaluation
 Portal and hepatic veins can be identified as anatomic
landmarks to localize tumors to specific hepatic segments
 To assess the proximity of lesions to the inflow and
outflow vessels
Fig. Volume-rendered 3D model of the
liver created from axially acquired
computed tomographic data.

31. Noncontrast CT of Liver
oUnenhanced scan generally included in triphasic
liver scan
oNormal attenuation values between 54-60 HU
 Increased attenuation:
oHemochromatosis, glycogen storage disease,
Wilson disease, B-thalassemia, sickle cell
disease, drug (amiodarone, cisplatin)
 Decreased hepatic attenuation in steatosis
Fig. Nonenhanced computed tomography through
the liver of a patient with hemochromatosis
shows diffuse increased attenuation of the liver
compared with the spleen.
Fig. Nonenhanced computed tomography through
the liver of a patient with steatosis shows
hypoattenuation of the hepatic parenchyma
compared with the hepatic blood vessels, liver
capsule, and spleen.

32. Contrast enhanced CT of Liver:
 Different enhancement of various types of
lesion relative to background hepatic
parenchyma dictates timing/phases
 Arterial phase imaging:
oHigher injection rate (4-6 ml/s) for early arterial
imaging
oImages acquired at ~20-30 seconds
oLate arterial phase used to evaluate
hypervascular lesion (about 40 seconds): HCC,
metastatic NET
Fig. A, Late arterial-phase image reveals
multiple hypervascular enhancing foci of
metastatic renal cell carcinoma (arrows).
B, Portal venous phase image at the same
level does not reveal the numerous masses.

33.  Portal venous phase imaging:
oNormal hepatic parenchyma enhances
maximally at approx. 70 sec
oMaximal contrast differential between typical
hypovascular liver lesion and surrounding
parenchyma is achieved
oClear delineation of portal and hepatic veins
 Delayed imaging phase:
oHypervascular tumors becomes
hypoattenuation after late arterial phase
oIf suspicious of HCC ~3-5 min delayed phase
(late venous/equilibrium phase) may be added
Fig. A, Arterial phase image through the inferior right
hepatic lobe reveals branches of the right hepatic
artery. Faint enhancement of a hypervascular mass is
seen in segment VI, which proved to be focal nodular
hyperplasia (arrow).
B, Portal venous phase image through the same
level reveals enhancement of the right portal vein
(long arrow) and the sectoral branches. The mass
(short arrow) is nearly hypointense to the liver.

34. Systematic approach to segmentation

35. Systematic approach to segmentation

36. Systematic approach to segmentation

37. Systematic approach to segmentation

38. Systematic approach to segmentation

39. Systematic approach to segmentation

40. Benign tumors and tumor like conditions
of liver
 Cysts:
oOn CT they are round or ovoid, sharply-marginated,
bounded by imperceptible wall and they do not
enhance after administration of IV contrast
 Hemangioma:
oHypoattenuating to surrounding liver, after IV
contrast on arterial phase - peripheral
discontinuous nodular enhancement
(Quinn & Benjamin, 1992)
oPortal and late phase demonstrate progressive
centripetal enhancement, a ‘filling in’ of
enhancement towards center of lesion
(Leslie et.al, 1995)
Fig. Multiple simple hepatic cysts in a
patient with polycystic kidneys.
Fig. Cavernous hemangioma of the right
liver showing typical enhancement
starting at the periphery of the lesion

41. Inflammatory conditions:
Pyogenic abscess:
oUnilocular cavities with smooth outer
margins to highly complex and septated
structures with internal debris and irregular
contour
Echinococcus:
oLarge solitary mass or multiple well-defined
cystic lesion often containing internal
daughter cyst
oCoarse calcification(50%)
Fig. Contrast-enhanced computed tomography of a
pyogenic liver abscess shows enhancement of the
walls and internal septa.
Fig. Contrast-enhanced axial CT reveals a
multiseptated echinococcal cyst in the right
hepatic lobe. Note eccentric calcifications along
the wall of one of the cysts (arrow).

42.  Cirrhosis:
oBands or regions of confluent fibrosis, relative
left lateral segment and caudate lobe
hypertrophy with right lobe and left medial
segment atrophy, nodular hepatic contour
oElevation of caudate-to-right lobe ratio >0.65
(Harbin et.al, 1980)
Malignant lesions
 HCC:
oLiver cirrhosis (70%)
oHypervascular in arterial phase, subsequently
becoming hypoattenuating to surrounding liver
in later phase (washout appearance)
Fig. Cirrhosis. The interlobar fissure, delineated by the
gallbladder, is deviated toward the right as a result of
atrophy of the right liver with hypertrophy of the left
liver and the caudate lobe.

43. Fig. Precontrast, arterial-phase, and portal venous phase images in a patient with a large hepatocellular carcinoma.
A, Unenhanced imaging reveals a hypoattenuating mass.
B, Arterial-phase images reveal the mass is heterogeneously hypervascular with supply from small arteries (arrow).
C, Portal venous phase image reveals the “washout appearance” with tumor now enhancing to a lesser degree than
surrounding parenchyma.

44.  Hepatic metastases:
oLesion morphology: round, ovoid or irregular and borders may be sharp,
poorly defined or nodular
oAttenuation lower than that of surrounding hepatic parenchyma
oAttenuation decrease as they undergo necrosis
Fig. Contrast-enhanced computed tomography in a patient with metastatic gastrointestinal stromal tumor.
A, Before treatment, heterogeneous solid enhancing masses are seen in the right and left hepatic lobes (arrows).
B, After treatment, lesions have lower attenuation and appear more cystic (arrows).

45.  Cholecystitis:
oCT not as a screening technique
oCT findings of GB distension, wall thickening and gall
stones
oPresence of ill-defined pericholecystic lucency within
hepatic parenchyma adjacent to GB
 Mirizzi syndrome:
oIdentification of impacted stone in adjacent
structures, associated dilatation of proximal biliary
system with a normal caliber downstream system
oIrregular cavity with surrounding edema and
inflammation adjacent to GB neck
Fig. Acute cholecystitis. CT shows a distended,
thick-walled gallbladder with pericholecystic
fluid. No gallstones are seen.
Fig. Mirrizi syndrome. CECT reveals a large
calcified gallstone associated with gallbladder
wall thickening and extensive pericholecystic
inflammatory change (arrowheads).

46. Choledocholithiasis :
oCT detection rate: 76%
(Baron, 1987)
oPresence of dense intraluminal
calcification or target sign
GB carcinoma
oMass replacing the GB (40-65%)
oFocal/diffuse GB wall thickening (20-30%)
oIntraluminal polypoid mass (15-25%)
Fig. target sign
Fig. Gallbladder carcinoma. The gallbladder is
distended and contains calcified stones.
Nodular soft tissue emanates from the GB
wall into the lumen (arrow).

47. Biliary cystic tumors (cystadenoma and
cystadenocarcinoma)
oMultiloculated cystic lesions with internal
septation, rarely unilocular
oAttenuation depends on its content
(hemorrhagic, mucinous, proteinaceous or
bilious)
oMultiple calcifications may be present
within wall or septa
Fig. Biliary cystadenoma. CECT reveals a
large cystic mass with a very subtle
internal septation (curved arrows).

48. Magnetic Resonance Imaging (MRI)
 Cross sectional multiplanar imaging technique
 Principle:

49. Factor
CT (CT abdo
used as
example)
MRI
X-ray (CXR
used as
example)
Ultrasound
Duration 3-7 minutes 30-45 min 2-3 min 5-10 minutes
Cost Cheaper Expensive Cheap Cheap
Dimensions 3 3 2 2
Soft tissue Poor detail Excellent detail Poor detail Poor detail
Bone Excellent detail Poor detail Excellent detail Poor detail
Radiation 10mSv None 0.15mSv None

50.  Free water has long T1 relaxation, is
low signal on standard T1-weighted
imaging and high signal on standard
T2-weighted imaging
 Diffusion weighted MRI(DWI):
alternative tissue contrast mechanism
that produce images dependent on
local magnitude of water diffusion
oTo detect focal hepatic lesions, esp.
mets.
oTo assess liver parenchyma like liver
fibrosis
Appearance
T1 Weighted
Image
T2 Weighted
Image
White
FatProtein
Rich Fluid
Water
Content E.g.
Inflammation,
Tumour,
Haemorrhage,
Infection
Intermediate
Gray Spinal
Matter darker
than White
White Spinal
matter darker
than gray
spinal matter.
Dark
BoneAir
Water
Content e.g.
Inflamation,
Tumour,
Haemorrhage
Bone, Air
Fat
It can help to remember that a T tWo weighted image shows Water as White.

51. Fig. Multiplanar T2-weighted images
through the liver in a patient with
multiple hepatic metastases. A,
Axial image. B, Sagittal image. C,
Coronal image.
A variety of techniques can be used
to obtain these images. Note that
fluid-containing structures, including
small bowel (curved arrow, A),
gallbladder, biliary tree, and
pancreatic duct (arrow, C), are
bright

52. Magnetic resonance Imaging
Cholangiopancreatography(MRCP)
 Imaging technique to evaluate the bile and pancreatic ducts
 Important role in imaging benign disorders
 Comprehensive evaluation of malignancies of biliary system
(Mandelia et.al, 2013; Singh et.al, 2014)
 Heavily T2-weighted images used to provide an overview of biliary and
pancreatic ductal anatomy
 Diagnose ductal dilatation, strictures and intraductal abnormalities
(Sandrasegaran et.al, 2010; Palmucci et.al, 2010)

53. Fig. "Normal hepatic ductal anatomy". Coronal
oblique MIP reformat image reveals the
confluence (circle) between the right posterior
duct (RPD) and the right anterior duct (RAD),
originating the right hepatic duct (RHD). Note
that the RPD has a more horizontal route while
the RAD is more vertical. By its turn the RHD
joins the left hepatic duct (LHD), originating the
common hepatic duct. The LHD results from the
confluence of the ducts of the left hepatic lobe
segments, here only represented by segments II
(S2) and III (S3). Cystic duct (CD), common bile
duct (CBD), main pancreatic duct (MPD),
gallbladder (GB).

54. Fig. Normal hepatic magnetic resonance
image.
A, T1-weighted. The liver is brighter
(hyperintense) relative to the signal of the
spleen.(straight arrow, intrahepatic portion
of the inferior venacava; curved arrow,
aorta).
B, T2-weighted image. Because of reversal
of the liver/spleen contrast, the normal
spleen is brighter than the liver (straight
arrow, intrahepatic portion of the inferior
vena cava; curved arrow, aorta).
C, Postcontrast T1-weighted gradient-echo
image. Normal enhancement in the liver
and spleen is evident, and the parenchyma
of both is about equal in this phase of the
injection. All the vessels are bright as a
result of the T1 shortening effect of
gadolinium (straight arrow, intrahepatic
portion of the inferior vena cava; curved
arrow, aorta).

55.  Fatty liver:
oFat accumulation in patient with alcohol intake, DM, medications and obesity
Fig. D, T1-weighted fat saturation precontrast image also shows mild signal loss in this area (arrow).
E, T1-weighted fat saturation postcontrast image. The area in question has normal vascularity coursing through it; no
mass was present—the typical appearance of fatty infiltration.

56. Cysts:
 Small cysts(<1cm) which are
difficult to characterize on CT are
easily diagnosed by MRI
 Simple cyst:
oNonenhancing lesion that is
homogeneously low in signal
intensity on T1-weighted
oHomogeneous very bright on T2-
weighted
Fig. Hepatic cysts associated with polycystic kidney
disease. A, Axial T2-weighted image at the level of
the kidneys shows bilaterally enlarged kidneys with
multiple hyperintense cysts. Little normal renal
parenchyma is present at this level, and multiple
small hepatic cysts (arrow) are seen

57. Hepatic metastases
 Mildly hypointense on T1-weighted image
 Mildly hyperintense on T2-weighted image
 Hypervascular mets from NET, HCC, RCC
o Best seen on arterial phase imaging
 Most mets are hypovascular having less well-defined borders
 Larger mets: thick irregular rim of enhancement with areas of central necrosis
Fig. Hepatic metastasis from colorectal
carcinoma.
A, T1-weighted image shows a low signal
intensity metastasis (arrow) within segment
IVB of the liver.
B, T2-weighted image shows the mass is
mildly brighter than background hepatic
parenchyma. C

58. Hepatocellular carcinoma
 Hypointense on T1-weighted
 Hyperintense on T2-weighted images
 Arterial phase hyperenhancement with delayed dynamic phase washout
Fig. Large hepatocellular carcinoma showing the mosaic pattern.
A, T1-weighted image shows a large heterogeneous mass (m) in the liver. Note the hypertrophied left hepatic lobe and caudate.
B, T2-weighted image also shows the mass (m) to be heterogeneous, with islands of tissue that are hyperintense with respect to
other portions of the same mass.

59. Gallbladder carcinoma:
 Improved characterization of GB cancer compared to
others
 Differentiation from inflammatory conditions is
difficult
 Shows irregular intermediate to high T2 signal
thickening of GB wall
 Early and prolonged heterogeneous enhancement
(Tan et.al, 2013)
 Evidence of liver invasion and spread to regional LN
(Dai et.al, 2009)
Bile duct cancer:
 May be intrahepatic, hilar or extrahepatic
 Seen as intermediate, mildly increased T2 signal
Fig. Hilar mass. A, Axial T2-weighted
image shows dilatation of the left hepatic
duct and a low to intermediate–intensity
mass expanding the right hepatic duct
(arrow).

60. Cholelithiasis and choledocholithiasis:
 Gallstones – well identified on T2-weighted images
 Appear as low signal intensity structures in fluid filled GB
 Coronal T2-weighted imaging – readily identifies CBD stones
Fig. Choledocholithiasis.
A, Coronal T2-weighted single-shot
fast spin-echo image through the
common duct in a patient after
cholecystectomy shows multiple
stones within the common bile
duct. Note the distal stone
impacted at the level of the ampulla
(arrow).
B, Axial T2-weighted image with
the same technique also shows a
stone, surrounded by bile, in the
distal common bile duct (arrow).

61. Choledochal cyst:

62. Thank you
To be continued…..

63. Hepatobiliary Imaging
Part II
Pushpa Lal Bhadel
FCPS Resident
Department of Surgery
Kathmandu Model Hospital
Moderator:
Dr. Udaya Koirala
HOD
Department of General Surgery

64. Imaging modalities
 X-ray
 Ultrasound
 Computed Tomography (CT)
 Magnetic Resonance Imaging(MRI) and Magnetic Resonance
Cholangiopancreatography (MRCP)
 Nuclear Medicine
 Direct cholangiography
 Endoscopic Retrograde Cholangiopancreatography (ERCP)
 Percutaneous Transhepatic Cholangiography (PTC)
 Intraoperative diagnostic techniques

65. Endoscopic Ultrasound
 Transducer in duodenum:
oPancreatic head and uncinate process, ampulla of Vater, pancreatic ducts,
common bile duct(CBD), surrounding vascular and nodal structures
 Transducer in stomach:
oPancreatic body and tail, gallbladder, left lobe of liver
 Celiac, splenic, hepatic and SMA as well as splenic, SMV and portal
veins are seen in detail
 Cysts differentiated from vascular structures using doppler flow

66. Detecting benign causes of biliary
obstruction like CBD stones:
 Sensitivity 89-94%; specificity 94-100%
(Garrow et.al, 2007)
 If biliary stricture visualized, malignancy
suggested by presence of irregular, thickened
(>3mm) bile duct wall
 EUS guided FNA in diagnosis of bile duct
strictures sensitivity: 43-86%
(De witt et.al, 2006, Rosch et.al, 2004)
Fig. Common bile duct stone with sludge
seen on linear endoscopic ultrasound from
the duodenal bulb

67. Diagnosis and staging of
cholangiocarcinoma
 Sensitivity 73%
 EUS determined resectability: sensitivity
53%; specificity 97%
 Staging on basis of depth of invasion,
maximal longitudinal extent of lesion,
presence of invasion into other organs and
major blood vessels esp. portal vein
invasion with accuracy of 60-80%
(Inui & Miyoshi, 2005)
Fig. Hypoechoic mass appearance of
cholangiocarcinoma of the common bile duct
(solid arrow) with biliary stent visible (open
arrow).

68. Novel therapeutics:
oEUS-guided ethanol ablation of cysts
(DeWitt et.al, 2009)
oIn cases with duodenal and biliary obstruction associated with
abdominal malignancies:
• EUS-guided transduodenal or transgastric biliary drainage
(Yamao et.al, 2008, Park et.al, 2009)
oEUS guided biliary drainage equally effective with fewer adverse
events, reduced cost as compared to ERCP

69. Nuclear Medicine
 Radiopharmaceuticals:
oRadioactive compound containing a radionuclide, also referred as
radioisotope
 Energy decay
oMakes elemental atom either a different isotope of same element (e.g., the
radioisotope of technetium 99m decays to stable isotope of technetium 99)
oOr become different element by transmutation (e.g., the radioisotope 18F
decays to elemental oxygen)
 Can be placed into three major categories of application:
oDetection and evaluation of HPB tumors
oTreatment of HPB cancers
oEvaluation of HPB organ function

70. Fluorodeoxyglucose Positron Emission Tomography
 FDG (2-deoxy-2-fluoro-D-glucose): analogue of glucose
 Blood FDG concentration decreased to low levels (45-90 mins after
injection)
 Most tissues have relatively minor FDG uptake whereas most tumors have
relatively stable uptake
 Liver concentration of FDG begin to decline approx. 1 hr. after injection
 In tissues affected by infectious or inflammatory disease, concentration of
tracer often decline significantly with time
 Warburg effect: In cancer cells, glucose metabolism occurs predominantly
by glycolysis in cytosol, regardless of whether or not the tumor cells were
well oxygenated

71. Colorectal cancer metastasis to Liver:
 FDG PET/CT diagnostic adjunct to dedicated
structural CT and MRI
 Sensitivity 90-92%
(van de Velde et.al, 2014)
Cholangiocarcinoma
 FDG-avid PET-positive disease
 Sensitivity 82%, specificity 75%
 Sensitive for intrahepatic and extrahepatic
metastases Fig. (FDG) PET scan of colon cancer patient
with liver metastases Two known liver
metastases demonstrate focal
hypermetabolic activity (arrowheads)

72. Hepatobiliary scintigraphy/
Cholescintigraphy
 Diagnostic imaging of radiotracers that
assess hepatic perfusion, hepatocellular
function and hepatobiliary drainage
 Detection of cholecystitis:
oAcute d/t cystic duct obstruction and
oChronic d/t impaired GB contractility
 Sensitivity and specificity of 90-95%

73.  Cholescintigraphy uses iminodiacetic acid (IDA)- derivative
pharmaceutical labelled with 99mTc: HIDA scan
o99mTc disofenin or mebrofenin
 Marked decrease in IDA radiotracer and bile excretion and associated lack
of bile (tracer) flow through biliary tree: sign of severe hepatic
dysfunction

74. Fig. Normal hepatobiliary iminodiacetic acid study. Serial images of the liver, in anterior projection, acquired beginning immediately after
tracer injection; each image is 5 minutes in duration. The serial images show prompt systemic clearance of radiotracer (e.g., disappearing
cardiac blood pool, gray arrowhead) via hepatic uptake, followed by prompt hepatobiliary excretion of tracer. Excreted tracer flows promptly
through the extrahepatic biliary tree, including into the gallbladder lumen (large arrow). Excreted tracer passes from biliary tree into the
duodenum, carried away into distal bowel loops by peristalsis (black arrowhead). One atypical incidental finding is enterogastric reflux of the
biliary tracer (small arrow).

75. Pathology in hepatobiliary scintigraphy is indicated by one or
more of following
oAn abnormally low amount of hepatic tracer uptake
oAn abnormally prolonged hepatic retention of tracer
oAn abnormally delayed appearance of excreted tracer in biliary
tree
oAn abnormally delayed appearance of excreted tracer in the
intestines

76. Acute cholecystitis:
 Sensitivity 87-98%; specificity 81-100%
(Ziessman, 2003)
 Nubbin sign (cystic duct sign): focal accumulation of biliary tracer
within proximal cystic duct
Chronic cholecystitis:
 Hallmark: GB dyskinesia, abnormally low GB ejection fraction of
<38%
(Ziessmann, 2014)

77.  Acute high-grade extrahepatic bile duct obstruction diagnosed if:
oPatient has good hepatic function, as indicated by blood test and in
Cholescintigraphy by rapid hepatic tracer-uptake and rapid tracer clearance
from the blood pool
oExcreted biliary tracer is not detectable or scantly present in extrahepatic
biliary tree by 1 hour after injection
 Partial obstruction of extrahepatic bile duct is associated with:
oHepatic uptake is normally prompt
oExcreted-tracer appears promptly within extrahepatic biliary tree
oClearance of excreted tracer from extrahepatic biliary tree is absent or scant
during the 1st hour after injection
oFurther clearance of excreted tracer from the extrahepatic biliary tree into
bowels, after Sincalide administration or at delayed time points, is less than
expected.

78. Direct cholangiography
 Introduction of contrast medium into the biliary system
 Can be performed under fluoroscopic guidance percutaneously,
endoscopically or intraoperatively
 Nonoperative techniques:
oPercutaneous transhepatic cholangiography (PTC)
oEndoscopic retrograde Cholangiopancreatography (ERCP)

79. Percutaneous Transhepatic Cholangiography
History:
 First reported fluoroscopic imaging of biliary tree: Burckhardt and
Muller (1921)
 First reported PTC by Huard and Do-Xuan-Hop (1937)
 Transhepatic cholangiography by Carter and Saypol’s (1952)
 Fine needle technique developed at Chiba university, Ohto and
Tsuchiya (1969)

80. Preprocedural preparation:
All patients should undergo prior CECT or MRI
oDepicting the level of obstruction
oPosition of liver
oPortal vein patency
oRelationship of liver and bile ducts to other structures
oPresence of tumors or lobar atrophy
Coagulation parameters and platelets count
Informed consent
Broad spectrum antibiotics 1 hour prior

81. Procedure:
Right-sided puncture:
 Site: right mid axillary line, 1-2 interspace below costophrenic angle
 1% lidocaine infused s/c, f/b small dermatotomy with no. 11 scalpel
 21- or 22-gauge, 15- to 20-cm Chiba-style needle advanced under
fluoroscopic guidance
 Care taken to avoid puncture of GB or extrahepatic bile duct
 Small amount of water-soluble contrast is injected while slowly
withdrawing the needle until bile duct is identified
 Appearance of oil being dropped in water
 Failed to enter bile duct, needle withdrawn and reintroduce in a
slightly different direction

82. Left-sided puncture:
 Considerable variation in size and anatomic position of left lateral
segments of liver
 Site: subxiphoid approach to a bile duct in segment II or III
 Through right liver via anterior axillary line approach to segment IV
 Percutaneous access can be simplified by using real time US guidance
 Success rate:
o95-100% for biliary obstruction
(Mueller et.al, 1981)
o60-95% for non-dilated system
(Wetter et.al, 1991)

83. Pitfalls:
Lack of opacification:
oFailure to inject adequate volume
of contrast agent
Ductal dilatation:
oAbsence of duct dilatation doesn’t
exclude biliary obstruction
• Sclerosing cholangitis, AIDS,
chemotherapy induced biliary
sclerosis
oPresence of dilatation not imply
presence of obstructed biliary
system
• Caroli disease, choledochal cyst
Fig. Ampullary carcinoma.
A, With the patient supine, contrast pools proximally, giving a
false impression of a high bile duct obstruction. The spurious
nature of the level is suggested by the hazy inferior margin to
the contrast column.
B, With the patient sitting semierect, the contrast pools at the
true point of obstruction, which is sharply defined.

85. Complications:
 Bile leak (1-2%)
 Sepsis (2-3%)
 Hemorrhage (0.2-0.4%)
 Pneumothorax
 Biliothorax
 Injury to colon
 Abscess formation

86. Endoscopic Retrograde Cholangiopancreatography (ERCP)
History:
 First described in 1968
(McCune et.al, 1968)
 Rapidly became accepted as diagnostic modality for pt with
hepatobiliary and pancreatic diseases
(Freeney, 1988; Oi et.al, 1970)
 Improvement of side-viewing duodenoscope with elevator: facilitated
cannulation of papilla of Vater
(Takagi et.al, 1970)
 Development of therapeutic application: sphincterotomy
(Soehendra et.al, 1980)

87. Indications:
 Obstructive jaundice,
 Biliary or pancreatic ductal system disease treatment or
tissue sampling,
 Suspicion for pancreatic cancer,
 Pancreatitis of unknown cause,
 Manometry for sphincter of Oddi,
 Nasobiliary drainage,
 Biliary stenting for strictures and leakage,
 Drainage of pancreatic pseudocysts,
 Balloon dilation of the duodenal papilla and ductal
strictures.
 Sphincterotomy is indicated in cases of the sphincter of
Oddi dysfunction or stenosis
Fig. Side viewing endoscope.

88. Fig. A: Normal biliary and pancreatic ducts during an ERCP;
B: ERCP image

89. Contraindications:
 Lack of evidence for biliary or pancreatic disease,
 Safer diagnostic tools are available,
 Cases of abdominal pain of unknown cause,
 ERCP would not change the plan of action
Complications:
 Associated with endoscopic procedures
 Pancreatitis (3-5%) (Andriulli et.al, 2007)
 Infection (1.4%) (Andriulli et.al, 2007)
 Bleeding
 Perforation (0.5-2.1%) (Cotton et.al, 1991)

90. Cholangioscopy:
 Miniature endoscopes through
the channel of duodenoscope:
direct visualization of the bile
ducts
 Diagnostic cholangioscopy:
evaluate indeterminate biliary
stricture and filling defects
Fig. Peroral cholangioscopy

91. Direct cholangiography by PTC or ERCP:
 Knowledge of common variation of ductal
branching essential
 In right lobe:
oPosterior segments lie more laterally than anterior
segments
oMost lateral ducts on cholangiogram are segments VI
inferiorly and VII superiorly
oConfluence of right and left duct takes the form of
trifurcation rather than bifurcation in 12%
 In left lobe:
oSuperior and inferior lateral segment ducts (segment
II & III) unite in line of or to the right of umbilical
fissure (92%)
Fig. Standard intrahepatic ductal anatomy. The
segments are numbered according to
Couinaud’s description (see CHD, Common
hepatic duct; LHD, left hepatic duct; RASD, right
anterior sectoral duct; RHD, right hepatic duct;
RPSD, right posterior sectoral duct.

92.  Left hepatic duct (ave. length 17 mm) considerably longer than right
hepatic duct (ave. length 9 mm)

93. Interpretations:
 Bile leaks: extravasation of contrast agent at the site of bile duct
injury
 Filling defects: air bubbles, blood clots, calculi, primary and
secondary bile duct cancers and parasitic diseases
oAir bubbles: perfectly circular and distribution to non dependent structures
oBlood clots: cast like and mask other filling defects
oCalculous disease: seen as discrete filling defects/ cast like structures filling
entire ducts
oDifferentiating GB stones and bile duct stones: faceted appearance and
disposition to move to gravity dependent positions
oPrimary bile duct cancers: T-shaped filling defects
oParasitic infections: intraductal filling defects, widely dilated extrahepatic bile
ducts, filled with sludges and stones

95. Intraoperative diagnostic technique
Intraoperative Ultrasonography (IOUS)
 Both open and laparoscopic procedures
 Assessment of (Jakimowicz, 1993)
o Hepatic and biliary anatomy
o Localization of tumors
o Determination and extent of and /or resectability of disease
o Determination of the extent of mesenteric vasculature involvement of pancreatic
tumors

96. Intraoperative cholangiography:
First described by Mirizzi in 1937
To assess (Sotiropoulos et.al, 2004)
oCholedocholithiasis
oProvide clarification of the biliary anatomy
oAssess extent of biliary tumors and hepatic resection

97. Indications:
 Choledocholithiasis: suspicion on clinical grounds or after serologic testing for
elevated liver enzymes, preop visualization in US, ERCP or MRI
 Bile duct injuries
 Clinical history of jaundice, pancreatitis, increased amylase levels, high lipase
level
 Dilated CBD on preoperative US
 Unclear anatomy during laparoscopic dissection
 Unsuccessful preoperative ERCP for choledocholithiasis

98. Fig. Intraoperative cholangiography showing
cystic duct (white arrow) draining in the right
hepatic duct
Fig. No filling defect within the extra-hepatic
bile ducts. Free passage of contrast into the
duodenum. No contrast extravasation to
suggest bile duct injury.
Fig. T-tube cholangiogram

99. Reference
 Blumgarts Surgery of the Liver, Biliary Tract and Pancreas; 6th edition
 Internet sources