2. ANATOMY
The gallbladder is a long oval-shaped organ that is positioned
beneath the liver immediately adjacent to the interlobar
Fissure.
The fissure can be a useful landmark for locating small
contracted gallbladders or gallbladders filled with stones.
Gallbladder can be used as a landmark for identifying the
junction between the left and right hemiliver.
The upper limit of normal for transverse dimension of the
gallbladder is 4 cm.
It's length does not exceed 10 cm.
The normal wall thickness is 3 mm.
3.
4.
When the gallbladder contracts,the wall may appear
thickened more than 3 mm thick.
Fig.:
Relationship of gallbladder (GB) to interlobar fissure.
A,Transverse view of the liver shows the ligamentum
teres (white arrow)
and the interlobar fissure (black arrow).
5. B, Transverse view slightly inferior to A shows the GB
located immediately inferior to the interlobar fissure.
6. Contracted gallbladder.
A, Magnified longitudinal view shows a contracted
gallbladder with a lumen that measures less than 3 ×
1 cm. Thus the wall appear thick, although it measures only
2.7 mm.
B, Corresponding transverse view.
Both views show the echogenic mucosal layer and the
hypoechoic muscular layer.
7. Variations in the shape of the gallbladder are common.
There are frequently one or more junctional folds in the
gallbladder neck and throughout the gallbladder.
Fig,; A, Typical junctional folds near the gallbladder neck.
B, Subtle folds in the neck of the gallbladder.
8. C, Larger folds in the gallbladder neck.
D, When the gallbladder fundus folds on itself, it is
referred to as a Phrygian cap.
Typical Phrygian cap in the fundus of the gallbladder.
9. Gallbladder folds may mimic septations.
Septations are rare and generally appear thinner than folds.
Fig.: Septated gallbladder. A,Longitudinal view shows a thin
septation in the body of the gallbladder with little
deformation of the outer gallbladder contour.
B,Transverse view through the septation shows a small, round
defect in the periphery of the septation
10. Congenital variations in the location of the gallbladder are
rare; intrahepatic gallbladders are probably the most
frequently Recognized and are located immediately above
the interlobar fissure.
Fig.,, Longitudinal view of the liver shows a gallbladder
completely surrounded by hepatic parenchyma.
11. Ectopic gallbladder.
Variations in the shape or size of the liver may cause
variations in the configuration or location of the
gallbladder.
Fig., Longitudinal view of the right upper quadrant in a
patient with a small liver due to cirrhosis. The gallbladder
body and fundus are interposed between the liver and the
abdominal wall.
12. Gallbladder duplication is another rare congenital anomaly
that may be complete or partial duplication. Agenesis of the
gallbladder has also been reported.
Fig., A, Complete duplication of the gallbladder into two
separate structures.
B, Partial duplication of the gallbladder into two separate
fundal segments.
13. TECHNIQUE
Patients should fast 8 hours after midnight before
gallbladder sonogram.
Fasting ensure adequate gallbladder distention and
reduce upper abdominal bowel gas.
Most gallbladder examinations start with the patient in
the
supine position.
Using a 3- to 5-MHz sector/curved transducer.
The gallbladder should be scanned from both subcostal and
intercostal approaches whenever possible.
14. When scanning from a subcostal view, a deep inspiration will
usually allow better visualization.
Scanning from a more lateral and superior approach (an
intercostal space) using more of the liver as a window.
Scans should routinely be obtained with the patient in a
variety of positions (left posterior oblique, left lateral
decubitus, prone, upright)
15. The prone position is most useful in patients in whom the
gallbladder is in a horizontal orientation with the fundus
located Anteriorly.
Stones that fall into the fundus when the patient is prone
can be seen falling back into the neck as the patient rolls
from a prone to a supine position.
16. The upright view is most useful in patients in whom the
gallbladder is in a vertical orientation with the fundus located
inferiorly.
Upright views can be obtained in the sitting position, although
it is usually easier to scan with the patient standing.
17. It is important to visualize the entire gallbladder, the
gallbladder neck is especially important, because stones can be
missed if the entire neck is not visualized.
If a stone is positioned behind a junctional fold, or if the stone
is impacted in the neck it'ld not be missed.
It is also important to ensure that abnormalities in the fundus
are not obscured by bowel gas.
18. 1. GALLSTONES
Gallstones are present in up to 10% of the population.
The majority (60% to 80%) of gallstones are asymptomatic.
The most common symptom of gallstones is acute right upper
quadrant (RUQ) or epigastric pain lasting for up to 6 hours and
ending when the stone disimpacts from the gallbladder neck.
Gallstones appear as mobile, echogenic, intraluminal structures
that cast acoustic shadows. Demonstration of shadowing is
important.
19.
20. Stones smaller than 3 mm may not cast a detectable shadow.
Calcification is not necessary for shadow Production.
Fig,
A,Typical small stone with distinct clean acoustic shadow. B,
Large Stone C, Multipple small stones
21. Wall–echo–shadow complex (WES) is a reliable sign of a
stone-filled gallbladder.
Fig.,
The complex varies from a very distinct series of
arcshaped lines.
22. Floating stones
When the density of bile is unusually high, stones may float.
It indicates that the floating stones are cholesterol in nature.
23. Faceted stones.
Gallstones are generally either round or ovoid. Faceted stones
are also fairly common it looks like a turtle back and has
flattened sides.
Fig., A, A single large stone with angular margins. B, Multiple
smaller stones with angular margins.
A
B
24. 2. SLUDGE
Sludge consists of calcium granules and cholesterol crystals often
in the setting of thick, viscous bile.
It appears as low- to high-level, nonshadowing reflectors in
the gallbladder. It may fill the entire gallbladder lumen.
Sludge may form mass-like aggregates called sludge balls.
Stones may coexist with sludge, and in this case shadowing will be
seen.
The lack of shadowing distinguishes the different forms of sludge
from gallstones, and it's mobility distinguishes sludge from polyps
and tumors
25.
26. A, Typical echogenic sludge. Two stones are also
present. B, Sludge completely filling the gallbladder
lumen. C, Sludge ball (cursors) partially filling the
gallbladder lumen.
A B C
27. 3. ACUTE CHOLECYSTITIS
It occurs from persistent obstruction of the cystic duct or
gallbladder neck by an impacted gallstone.
Surgery is performed at presentation if the duration of
symptoms is less than 48 to 72 hours.
28.
29.
30. Acute cholecystitis in different patients.
A, Longitudinal view shows wall thickening (5.7 mm) and a stone
in gallbladder neck (arrow). B,Transverse view shows stones,
sludge, and gallbladder wall thickening. C,Longitudinal view
shows an enlarged gallbladder (116 × 51 mm) with a stone in the
neck and sludge.
A B C
31. Fig.,A, Longitudinal view shows wall thickening, sludge, stones,
and a small collection of pericholecystic fluid near the
gallbladder fundus.
B, Longitudinal view shows a gallstone impacted in the cystic duct
in addition to multiple stones in the gallbladder lumen.
32. 4. CARCINOMA
Gallbladder cancer is the fifth most common
gastrointestinal
malignancy. It probably occurs because of chronic irritation
of the gallbladder wall by stones. More commonly in women
than in men.
Patients with gallstones larger than 3 cm have a tenfold
increased risk of cancer. Appearance for gallbladder cancer
is a soft-tissue mass centered in the gallbladder fossa that
completely or partially obliterates the lumen. Gallbladder
wall thickening is irregular, asymmetric, and eccentric.
34. Fig.,
Both A and B, showing a homogeneous hypoechoic mass (cursors)
obliterating the gallbladder lumen and engulfing a gallstone.
C, Large polypoid mass in the gallbladder fundus.
A
B C
35. 5. POLYPS
Cholesterol polyps are by far the most common type of
gallbladder polyp.
They are usually 5 mm or less in size and only rarely get
bigger than 10 mm.
They can be distinguished from gallbladder stones by their
lack of a shadow and nonmobile nature,
and from sludge balls by their lack of mobility and to a lesser
extent by their spherical shape.
37. Gallbladder (GB) polyps in different patients.
Fig., A, Longitudinal upright view shows a small (<5 mm)
nonshadowing polypoid defect along the nondependent portion of
the GB typical of a cholesterol polyp.
B, Longitudinal view shows multiple small polyps.
38. 6. METASTASES
Metastatic disease to the gallbladder is a rare cause of
polypoid masses. Sonographically detectable metastatic disease
in the liver, lymph nodes, bowel, or peritoneum will accompany
gallbladder Metastases.
FIG., Transverse (A) and longitudinal (B) views of the
gallbladder show a large polypoid mass in the neck
39. 7. ADENOMYOMATOSIS
It is characterized by mucosal hyperplasia and thickening of
the muscular layer of the gallbladder.
It is unrelated to gallstones.The three most common forms of
adenomyomatosis are shown in fig.
40. Adenomyomatosis with severe wall thickening.
Fig., A, Transverse view shows severe wall thickening.
B, Longitudinal view shows a comet-tail artifact (arrow).
C, Color Doppler view shows twinkle artifact in several
areas (arrowheads).
A B C
