The liver, gallbladder, and bile ducts make up the hepatobiliary system. The liver is the largest organ located in the right upper abdomen. It has two surfaces and receives 80% of its blood supply from the portal vein. The gallbladder stores and concentrates bile before it is released into the small intestine. Bile ducts drain bile from the liver and gallbladder and include the right and left hepatic ducts which join to form the common hepatic duct and eventually the common bile duct. Variations can occur in the anatomy of these structures. Ultrasound is useful for evaluating the normal anatomy and identifying any abnormalities.

1. RADIOLOGICAL ANATOMY OF
HEPATOBILIARY SYSTEM
DR.KAMAL ADHIKARI
1ST YAER RESIDENT
RADIODIAGNOSIS

2. LIVER
GALL BLADDER
BILE DUCT

4. LIVER
• The liver, the largest organ in the body, is found in the right upper
quadrant of the abdomen.
• It is relatively much larger in the fetus and child.
• Weighs about 1600 gm in males,1300 gm
in females.
• Occupies the right hypochondrium,epigastrium and left hypochondrium.
• Most of the liver is covered by ribs and costal cartilage.
• It is covered by network of connective tissue(Glisson’s capsule)
• It has two surfaces, the diaphragmatic surface and the visceral surface. A
depression between these marks the site of the central tendon and the
overlying heart.

5. Liver surfaces
1.Diaphragmatic surface
• smooth and dome shaped surface
• inferior to diaphragm
• separated from diaphragm by subphrenic recess and from posterior
organs[kidney and suprarenal gland] by hepatorenal recess
• covered by peritoneum except on the posterior surface of liver
which is not invested in peritoneum and is known as bare area of liver

7. 2.Visceral Surface
covered by visceral peritoneum except porta hepatis and gall bladder
bed
the visceral surface is related to :
• right side of the stomach i.e. gastric and pyloric areas
• superior part of duodenum i.e. duodenal areas
• lesser omentum
• gall bladder
• right colic flexure and right transverse colon;colic area
• right kidney and suprarenal gland ; renal area

8. Visceral relations

9. Normal liver size and echogenicity
• Liver extend from 5th intercostal space to or slightly below the Rt costal
margin in mid clavicular line
• Accurate assessment of size of liver with real-time ultrasound difficult
Gosink proposed measuring in mid-hepatic line (>15.5 cm
→Hepatomegaly)
In general practice normal upto 14.5 cm for female and 15.5 cm for male
• Liver : Homogenous with fine level echoes , minimally hyperechoic or
isoechoic compared to normal renal cortex, hypoechoic compared to
spleen

10. Fig Longitudinal scan showing normal homogenous liver

11. Fig normal liver echogenecity. Liver is more
echogenic then renal cortex and
less echogenic then spleen

12. PERITONEAL RELATIONS OF THE LIVER
THE LESSER OMENTUM
Encloses the portal triad[bile duct , hepatic artery and portal vein]
Passes from the liver to lesser curvature of the stomach + 2cm of
duodenum
Thick free edge – hepatoduodenal ligament
Sheet like remainder –hepatogastric ligament

14. Ligaments of the Liver
1.Peritoneal ligaments
Lesser omentum
Falciform ligament
Coronary ligaments
Triangular ligaments
2.Vascular remnants
Round ligament of the liver
(remnant of umbilical vein)
Ligamentum venosum
(remnant of ductus venosus)

15. FALCIFORM LIGAMENT
• It is a double fold of peritoneum from umbilicus to the liver
• Contains ligamentum teres, the remnant of umbilical vein,which
attaches to the left portal vein
• Falciform ligaments split into coronary ligament(which becomes the
right triangular ligament) and left triangular ligament, between which
lies the bare area of the liver

16. Hepatoduodenal ligament
Encloses the portal triad (bile duct, hepatic artery and portal vein )
Passes from the liver to lesser curvature of the stomach + 2 cm of
duodenum.

18. Functional division of liver
Three lobes right, left and caudate
• Right and left lobes by Main lobar fissure which passes through GB
fossa to the IVC
• Right lobe- divided into anterior and posterior segments by Rt inter-
segmental fissure
• Left lobe- divided into medial and lateral segments by Lt inter-
segmental fissure

19. Caudate lobe: situated on posterior aspect of liver with anterior
border → fissure of ligamentum venosum and posterior border →IVC
• May receive branches of both Rt and Lt portal vein
• Has one or several hepatic veins that directly drain into IVC
• Due to a different blood supply the caudate lobe is spared from the
disease process and hypertrophied to compensate for the loss of
normal liver parenchyma
• Papillary process – anterior medial extension from caudate lobe
which may mimic lymphadenopathy

20. Segmental liver anatomy
Liver is now divided into segments as per Couinaud System.
Portal and hepatic veins used as landmarks to divide the remainder of
the liver into eight segment.
• Is of functional and pathological importance
• Each segment has its own blood supply( arterial, venous and biliary
drainage)
• In the center of each segment there is a branch of the portal vein,
hepatic artery and bile duct.
• In the periphery of each segment there is vascular outflow through
the hepatic veins.

21. • There are eight liver segments
• The numbering of the segments is in a clockwise manner .
• Segment 4 is sometimes divided into segment 4a and 4b.
• Segment 1 (caudate lobe) is located posteriorly. It is not visible on a
frontal view.

22. Couinaud’s segments

23. • Right hepatic vein divides the right lobe into anterior (segment V
and VIII) and posterior segments (segment VI and VII).
• Middle hepatic vein divides the liver into right and left lobes (or
right and left lobe liver). This is principal plane also known as
Cantlie’s line runs from the inferior venacava to the gallbladder fossa.
• Left hepatic vein divides the left lobe into a medial (segment IV)
and lateral part (segment II and III).
• Portal vein divides the liver into upper and lower segment.

25. I = Caudate lobe
II =Lateral Segment of left lobe
(superior)
III= Lateral segment of left lobe
(Inferior)
IV=Medial segment of left lobe
V =Anterior segment of Right
lobe(inferior)
VI= Posterior segment of Right
lobe(inferior)
VII= Posterior segment of Right
lobe(superior)
VIII= Anterior segment of Right
lobe(superior)

26. Vascular anatomy of liver
• The liver has dual blood supply : hepatic artery and portal vein.
• Hepatic artery : Provides 20% of hepatic blood supply. Branch of
coelic trunk
• Common hepatic artery passes over the head of the pancreas and
gives of right gastric artery, then gives off gastroduodenal artery at
the epiploic foramen to become the hepatic artery proper.
• Hepatic artery continues in the free edge of the lesser omentum ,
anterior to the portal vein and to the left side of the common bile
duct[CBD]
• Divides into left and right branches at the porta hepatis

27. • The proper hepatic artery ascends toward the porta hepatis to join
the portal vein in the portal triad.
Variations:
1.may be replaced by left hepatic artery originating from Left gastric
artery(10%)
2.Replaced by right hepatic artery origination from SMA(11%)
3.Replaced by common hepatic artery originating from SMA(2.5%).
4.Rarely originate from Aorta

28. Portal Vein :
• Provides 80% of blood suply to liver.
• Formed by the union of the splenic vein and superior mesentric vein
behind the neck of the pancreas at L1/L2.
• Runs at the posterior aspect of free edge of lesser omentum to the
porta hepatis; it lies posterior to hepatic artery and CBD

29. • Just before entering the liver in porta hepatis , the main trunk of
portal vein divides into Right portal vein (RPV) and Left portal vein
(LPV)
Intra-segmental
• RPV- anterior and posterior branch
• LPV- medial and lateral branch

31. • Venous Drainage
Majority of the liver is via the hepatic veins which unite to drain into
the IVC at T9 close to the diaphragmatic hiatus.
Caudate lobe drains directly into the IVC and may therefore be spared
in case of hepatic vein thrombosis
• Nerve supply
parasympathetic supply is by the preganglionic fibres of the vagus
nerve
sympathetic innervation is by the postganglionic fibres from the
coelic plexus

32. • Lymphatic drainage
lymphatics from upper surface drain into nodes in the posterior
mediastinum
lymphatics from lower surface drain into hepatic nodes and celiac
nodes

33. Distinguishing Portal veins and Hepatic veins
• Portal Veins
• Very echogenic walls
• High collagen content
• Course transversely
• Size upto 13 mm
• Hepatic Veins
• Less echogenic walls( almost imperceptible)
• Low collagen content
• Course longitudinally
• Get larger as they course towards the IVC
• Size upto 10mm

35. •In oblique cranially-angled sub
xiphoid view, Left portal venous
system can be well appreciated
•A “recumbent H” is formed by
main left portal vein, the
ascending branch of left portal
vein, and the branches to
segments II, III and IV.
•Similar “recumbent H” shape can
also be appreciated in right lobe
of liver in sagittal or oblique
sagittal view formed by branches
of right portal vein

36. Variations in anatomy and development of liver
• Agenesis: Failure of development most commonly affects the left lobe –
segments II and III – with subsequent compensatory hypertrophy of
segment IV and the right lobe
• Anomalies of position : situs inversus totalis (viscerum)liver is found in left
hypochondrium
• Accessory fissures: inferior hepatic accessory fissure stretches inferiorly
from right portal vein to inferior surface of right lobe of liver, diaphragmatic
slips etc
• Vascular anomalies: hepatic artery anatomy variations , congenital portal
vein anomalies like atresia, stricture, obstructing valves etc, absence of
right portal vein.

37. • Left lobe variations
• Riedel’s lobe- tongue like extension of inferior tip of right lobe of
liver (frequent in asthenic women)

39. Some congenital abnormalities
• Liver cyst
• Peribilliary cysts
• Adult polycystic disease
• Biliary hamartomas

40. Biliary Apparatus
• It collects bile from the liver ,stores in the gallbladder & transmits to
2nd part of duodenum.
• Gall bladder.
• Cystic duct.
• Right and left hepatic ducts which unite to form Common Hepatic
Duct.
• Common Bile duct formed by the union of cystic duct and common
hepatic duct.

42. Gall bladder
A pear shaped sac and reservoir of bile and is responsible for
concentration of bile. It can hold upto 30-50 ml.
• 9-10 cm long , 3 cm in diameter.
• Wall thickness < 4mm.
• Hangs from inferior surface of liver – fundus usually anterior and
inferior to body and neck.
• Cystic duct arises from the neck of the gallbladder.

43. • Neck and cystic duct has spiral appearance to the mucosal folds
(spiral valve of Heister); on ultrasound it is highly echogenic and may
be mistaken for gallstones.
• In the region of the neck, there may be an infundibulum called
Hartmann’s pouch
• Covered by peritoneum on fundus and inferior surface , occasionaly
hangs on its own mesentry

44. Anatomical Relations
• Anterosuperiorly: Gallbladder bed of liver and layer of peritoneum
• Posteroinferiorly:Lesser omentum,1st part of duodenum and
transverse colon

47. • Blood Supply
cystic artery , a branch of right hepatic artery
cystic vein , drains into portal vein
• Nerve Supply
parasympathetic supply is by pre-ganglionic fibers from the vagus nerve
sympathetic innervation is by post-ganglionic fibers from the coeliac plexus
• Lymphatic Drainage
Lymphatics drain into cystic nodes,hepatic nodes and coeliac nodes

48. Ultrasound of GB
•The normal gallbladder has the
typical sonographic features of a
cyst
• The lumen is an echofree
space, bounded by smooth
regular walls, with posterior
wall enhancement (more
echogenic than surrounding
tissue)
•The cystic duct carries bile to and
from the gallbladder and common
bile duct into the duodenum. It is
up to 5 cm long, and it joins the
common hepatic duct to create
the common bile duct (CBD)

50. Sonographyically non visualisation of gall bladder
• Previous cholecystectomy
• Physiological contraction
• Emphysematous cholecystitis
• Agenesis of gall bladder
• Tumefactive sludge
• Ectopic location

51. Normal variants of Gall Bladder
•Phrygian cap: The
gall bladder often
folds on itself, at
the junction of the
fundus with body.

52. SEPTATE GALL BLADDER

53. Others variants
• Location may be suprahepatic or retrohepatic
• Location may be intrahepatic
• Location may be left sided.
• Absent gallbladder
• Double gallbladder

54. Intrahepatic Bile duct
• It consists of the right hepatic duct and left hepatic duct and drains
the right and left lobes of the liver, respectively.
• The right duct branches into the right posterior hepatic duct, draining
posterior segments VI and VII and the right anterior hepatic duct,
draining anterior segments V and VIII.

55. • Segmental tributaries draining segments II–IV are form the left
hepatic duct.
• The fusion of the right and left hepatic ducts gives rise to the
common hepatic duct at porta hepatis usually.
• RHD and LHD have a diameter of upto 3mm each.

57. Variants in the biliary ducts
• The RPD may drain into the LHD before its confluence with the RAD.
This is the commonest variant.
• The RAD , RPD and LHD may join in a triple confluence of the ducts.
• The RHD and LHD may fail to unite , giving rise to a ‘double’ hepatic
ducts
• Accessory hepatic ducts may arise in the liver, particularly in the right
lobe of liver

58. Variants in the Cystic duct
• A low insertion where it fuses with the distal CHD
• A medial insertion where it passes posterior to the CHD and drains
into its left side
• A parallel course where it adheres closely to the CHD for at least 2cm

60. Extrahepatic Bile Ducts (CBD)
• It includes Cystic duct and common bile duct.
• CHD is joined by the cystic duct at a variable position (usually) 3.5 cm
to form the CBD.
• Diameter of CBD is variable : i.e up to 6mm till 50 yrs of age then
1mm/decade after that age.
• Diameter can be larger in postcholecystectomy patients i.e up to
10mm.

61. Divisions and Relations of CBD
• Upper: Above duodneum within the lesser omentum, anterior to
portal vein and to the right of hepatic artery.
• Middle: Posterior to 1st part of duodneum with the gastroduodenal
artery, sloping away to the right from the portal vein.
• Lower: Grooves the posterior part of head of pancreas anterior to the
right renal vein. It joins the MPD at Ampulla of Vater and opens into
2nd part of duodneum.

63. Arterial Supply
1.Supraduodenal part
from retroduodenal , right hepatic , cystic and gastroduodenal artery
majority of this supply (60%) runs upward from the major vessels,with
38% descending from the intrahepatic divisions of the right hepatic a
artery , while 2% from the main trunk of hepatic artery.
2.Retropancreatic part
is supplied by retroduodenal artery

64. Localization of CBD• The CBD is most easily
identified through its
association with the portal vein
and the portal vein is most
easily identified in the long axis
of the gallbladder.
• It is the ‘point’ of the
exclamation point that is
created with the gallbladder in
the long-axis. The main lobar
fissure is followed from the
neck of the gallbladder to the
porta hepatis.
• The portal vein will appear as a
large, hypoechoic circle with
echogenic walls.

65. • The CBD and hepatic
artery will appear as
two smaller circles
anterior to the portal
vein. Often times, it
gives the appearance of
a face with two ears –
also called a ‘Mickey
Mouse’ sign
• The right ear will be the
common bile duct and
the left ear the hepatic
artery.

66. References
• DIAGNOSTIC ULTRASOUND CAROL M RUMAK 4TH EDITION
• ANATOMY FOR DIAGNOSTIC IMAGING STEPHANE RYAN 3RD EDITION
• TEXTBOOK OF RADIOLOGY AND IMAGING D.SUTTON

67. • THANK YOU