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CHAPTER 6 Liver Scanning Protocol 119
18. The common bile duct and the hepatic artery follow a/an _______
course to the portal vein within the liver.
a) medial
b) anterior
c) posterior
d) superior
19. Just anterior to the portal vein within the liver lies the common
bile duct and the hepatic artery.
a) True
b) False
Left hepatic artery
Middle hepatic artery
Right adrenal gland
IVC
Main pancreatic duct
Left hepatic duct
Common hepatic duct
Right hepatic duct
Right portal vein
Cystic duct
Right hepatic artery
Gallbladder
Neck
Body
Fundus
Left portal vein
Proper hepatic artery
Celiac trunk
Common hepatic artery
Splenic artery
Pancreas
Right kidney
Duodenum
Gastroduodenal artery
Common bile duct
Aorta
Gallbladder and Biliary Tract Anatomy
CHAPTER 7
Gallbladder and Biliary Tract
Scanning Protocol
Betty Bates Tempkin
Key Words
Ampulla of Vater
Common bile duct (CBD)
Common duct
Common hepatic duct (CHD)
Cystic duct
Hepatic artery
Intraperitoneal
Objectives
At the end of this chapter, you will be able to:
• Define the key words.
• Distinguish the sonographic appearance of the gallbladder and
biliary tract and the terms used to describe it.
• Describe the transducer options for scanning the gallbladder and
biliary tract.
• List the various suggested breathing techniques for patients when
scanning the gallbladder and biliary tract.
• List the suggested patient positions (and options) when scanning
the gallbladder and biliary tract.
• Describe the patient preparation for a gallbladder and biliary tract
study.
• Distinguish the gallbladder and biliary tract normal variants.
• Name the survey steps and explain how to evaluate the entire
length, width, and depth of the gallbladder and biliary tract.
• Explain the order and exact locations to take representative
images of the gallbladder and biliary tract.
• Answer the review questions at the end of the chapter.
Left intrahepatic duct
Main lobar fissure (MLF)
Main pancreatic duct
Porta hepatis
Portal triad
Retroduodenal CBD
Right intrahepatic duct
Overview
Location
• The gallbladder (GB) and biliary tract are intraperitoneal struc-
tures (enclosed in the sac formed by the parietal peritoneum).
• The gallbladder is located in the fossa on the posteroinferior por-
tion of the right lobe of the liver. The gallbladder fossa is closely
121
122 PART III Abdominal Scanning Protocols
related to the main lobar fissure (MLF) of the liver, one of the
normal folds throughout the liver that typically form the spaces
that contain various blood vessels or ligaments. The MLF runs
obliquely between the neck of the gallbladder and right portal
vein. It contains the middle hepatic vein and separates the right
and left hepatic lobes. Its course is short and variable.
• The gallbladder is extremely variable in position and location as
a portion of it is attached by long mesentery, allowing for movement. The neck or narrow portion of the gallbladder, however, is
fixed in its position at the main lobar fissure.
• The biliary tract or “tree” runs between the liver and the
duodenum.
Anatomy
• The right and left intrahepatic ducts exit the liver at the porta
hepatis (area of the hilus/opening where the portal vein and
hepatic artery enter the liver and the common duct exits) and meet
to form the common duct. The superior or proximal portion of the
common duct is referred to as the common hepatic duct (CHD).
The CHD runs slightly inferomedially where it is joined by the cys-
tic duct (directs bile from the CHD into the neck of the gallblad-
der) to form the distal portion of the common duct, the common
bile duct (CBD). The CBD courses inferior and medial, all the way
to the duodenum.
• As the CBD courses inferomedially, it is referred to as the retro-
duodenal CBD, as it passes behind the first part of the duodenum
en route to the head of the pancreas. At the head of the pancreas
the CBD either passes through the pancreatic head or runs along a
groove on the posterior surface of the head to meet with the main
pancreatic duct (or duct of Wirsung, which transports and dis-
charges pancreatic enzymes into the duodenum). Joined together
or separately, the CBD and duct of Wirsung course slightly to the
right to enter the second portion of the duodenum at the ampulla
of Vater, a dilatation of the duodenum, where they empty bile and
pancreatic juices to aid the digestive process.
CHAPTER 7 Gallbladder and Biliary Tract Scanning Protocol 123
• Normal common duct size is variable according to the amount of
bile it contains and patient age. The common duct is known to
enlarge with age. CHD is considered normal in size up to 4 mm;
the CBD up to 6 mm. Following loss of GB function (as a result
of cholecystectomy or gallbladder disease), the common duct
assumes bile storage function and is considered normal in size up
to 10 mm.
• The gallbladder is a muscular, membranous sac that has been
described as pear-shaped, conical, or like a partially filled water balloon. Its narrow end is called the neck, a tube-like structure that
joins the cystic duct. Its rounded “bottom” is called the fundus.
The portion between the neck and fundus is called the body.
• The gallbladder serves as a storage site for bile; it is not essential to
life. Without the gallbladder, the biliary tract (ducts) continues to
transport bile from the liver to the duodenum.
• The size of the gallbladder is variable according to the amount of bile
it is storing. It is considered normal up to 3 cm wide and 7 cm to
10 cm long. In a fasting patient, the gallbladder wall measurement
is considered normal up to 3 mm.
Physiology
• The gallbladder and biliary tract are considered accessories to the
digestive system because they store and transport the bile that is
manufactured in the liver to the duodenum to help digest fat.
• The hepatic and biliary ducts passively transport bile directly to
the second portion of the duodenum or by way of the gallbladder
where bile is stored and concentrated.
124 PART III Abdominal Scanning Protocols
Gallbladder
n
Anterior
Sonographic Appearance
• Since the position of the gallbladder is variable depending on the
amount of bile it contains and/or the length of its mesenteric
attachment its orientation in the body is also variable. Therefore,
the gallbladder long axis can be visualized in any scanning plane.
• As demonstrated in the images below, A, the normal bile-filled gall-
bladder appears longitudinally as an anechoic, oblong structure
with bright, thin walls and B, axial sections appear as anechoic,
round or oval structures with bright, thin walls.
Anterior
Portal vein
Liver
Superior
Inferior
vena cava
A
Liver
Right
Diaphragm
Posterior
Small bowel
Inferior
vena cava
Spine
Increased
posterior
through
transmissio
Inferior
Gallbladder
fundus
Left
Increased posterior
through transmission
Right kidney
B
A, Longitudinal gallbladder section. B, Axial gallbladder section.
Posterior
CHAPTER 7 Gallbladder and Biliary Tract Scanning Protocol 125
Pancreas body
Left renal
Left
Posterior
• The following images show how A, the bile-filled common duct
appears longitudinally as an anechoic tubular structure with
bright, thin walls and B, axial sections of the duct appear as small,
anechoic, round structures with bright, thin walls.
Anterior
Superior
Hepatic
artery
Liver
Inferior
Bowel
Portal vein
Common
bile duct
A
Posterior
Liver
Gastroduodenal
Right
confluence
Pancreas
Common
bile duct
artery
Portal
splenic
head
Inferior
vena
cava
B
Right renal
artery
Anterior
Crus of
diaphragm
Splenic vein
Aorta
Spine
Superior
mesenteric
artery
Pancreas
uncinate
process
Left
renal vein
artery
Pancreas
tail
A, Longitudinal common duct section in a sagittal scanning plane.
B, Axial CBD section in a transverse scanning plane.
126 PART III Abdominal Scanning Protocols
Posterior
Anterior
Right Left
• When there is a question of dilated bile ducts, it is important to
make a distinction between the structures that comprise the portal
triad: the proper hepatic artery, common duct, and portal vein at the
level of the porta hepatis. The following oblique, transverse scanning plane image shows that at the level of the porta hepatis, the
portal vein (1) lies posterior to the proper hepatic artery (2), which
is on the left and the CBD (3), located on the right. The appearance of the axial sections of the portal triad is often referred to as
“Mickey’s sign” as they resemble a face and two ears.
PORTAL
TRIAD
23
(From Brant WE: The Core Curriculum: Ultrasound. Lippincott Williams & Wilkins, 2001.)
Normal Variants
Gallbladder
• Shape variations:
• Segmental contractions: These “segments” disappear when
the patient changes position or fasts.
• Phrygian cap: The fundus is folded over giving the gallbladder
a “capped” appearance.
• Position variations:
• The position and location of the gallbladder is variable because
it is suspended by long mesentery.
• Very rare, deep fossa, intrahepatic gallbladder.
• Septations:
• May partially or totally divide the gallbladder.
Biliary Tract
• Duplications:
• Although very rare, the common duct may be partially or com-
pletely duplicated.
1
CHAPTER 7 Gallbladder and Biliary Tract Scanning Protocol 127
• Level variations:
• The level of the junction of the cystic duct and common hepatic
ducts is variable.
• Septations:
• May partially or totally divide the cystic duct, producing various
degrees of double gallbladder.
Preparation
Patient Prep
• The patient should fast for 8 to 12 hours before the study. This
ensures normal gallbladder and biliary tract dilatation and reduces
the amount of bowel gas.
• If the patient has eaten within 4 to 6 hours, still attempt the
examination.
NOTE: A nonvisualized gallbladder is indicative of either gallbladder disease or the patient recently eating. Therefore, it is essential to determine
when a patient last ate.
Transducer
• 3.0 MHz or 3.5 MHz.
• 5.0 MHz for thin patients.
Breathing Technique
• Deep, held inspiration.
NOTE: Different breathing techniques should be used whenever the
suggested breathing technique does not produce the desired results.
Patient Position
• The gallbladder and biliary tract study is performed with the patient
in two different positions.
• Supine and left lateral decubitus.
• Left posterior oblique, sitting semierect to erect or prone as needed.
NOTE: Different patient positions are required when examining the
gallbladder to help differentiate certain abnormalities from each other.
For example, gallstones and sludge will move and change their position
within the gallbladder when the patient position is changed. Gallbladder
polyps and carcinoma remain stationary.
NOTE: Different patient positions should be used whenever the suggested positions do not produce the desired results.
128 PART III Abdominal Scanning Protocols
Patient’s right (RT)
Patient’s left (LT)
Gallbladder and Biliary Tract Survey Steps
NOTE: The gallbladder and biliary tract must be surveyed in two
different patient positions.
Gallbladder • Longitudinal Survey
Sagittal Plane • Transabdominal Anterior Approach •
First Patient Position
NOTE: Generally, the gallbladder tends to lie in the area between the
right medial angle of the ribs and the superior pole of the right kidney.
First Patient Position: Supine
1. Begin scanning with the transducer perpendicular, just inferior to
the costal margin at the right medial angle of the ribs. Have the
patient take in a deep breath and hold it. In most cases, the portal
vein and gallbladder neck should come into view. If the gallbladder is not visualized here, locate the bright main lobar fissure of the
liver that extends from the right branch of the portal vein to the
gallbladder neck.
Transducer
NOTE: If the gallbladder is still not visualized, try moving the transducer
slightly inferior and right lateral. Subcostal transducer angles can also
help locate the gallbladder. In some cases, intercostal scanning may be
necessary to view the gallbladder.