AJR 2004; 183:163-170
© American Roentgen Ray Society
CT of the Gallbladder: Spectrum of Disease
David Grand1,
Karen M. Horton and
Elliott Fishman
1 All authors: Department of Radiology, Johns Hopkins Hospital, 601 N Caroline
St., JHOC 3253, Baltimore, MD 21287.
Received October 1, 2003;
accepted after revision November 19, 2003.
Address correspondence to K. M. Horton
(kmhorton{at}jhmi.edu).
Introduction
Traditionally, CT has not played a significant role in the evaluation of
gallbladder disease. Clinicians have instead relied on sonography or nuclear
medicine studies when gallbladder disease is suspected. However, CT has
emerged as the undisputed initial imaging technique for evaluating the acute
abdomen; CT allows routine visualization of the gallbladder whether or not
gallbladder disease is suspected. Additionally, advancements in CT scanner
technology have improved the ability to visualize the gallbladder and a range
of conditions including gallstones, cholecystitis, and cancer. This pictorial
essay reviews the current role of CT in the evaluation of gallbladder
disease.
Anatomy and Variation
The normal gallbladder is subjacent to the inferior surface of the liver in
the plane of the interlobar fissure (Fig.
1A,
1B). However, various anomalous
positions of the gallbladder have been reported, including inferior to the
left hepatic lobe and intrahepatic, transverse, and retrohepatic
[1]. A left-sided gallbladder
may be seen in situs inversus, or even, in extremely rare cases, in normal
situs. The normal gallbladder may exhibit folds, including the common and
asymptomatic folding of the gallbladder fundus termed a "phrygian
cap." Less commonly seen are true septa that can lead to stasis and
stone formation. Anomalies in the number of gallbladders— ranging from
absent to duplications—are rare but have also been reported
[1].
Cholecystitis: Acute and Chronic
The clinical signs and symptoms of acute cholecystitis are nonspecific, and
in 60–85% of patients evaluated for cholecystitis, symptoms are found to
result from other causes [2].
Therefore, despite the excellent sensitivity and specificity of sonography,
CT—the study of choice for evaluation of the acute abdomen—may be
a more helpful initial imaging technique.
The diagnosis of acute cholecystitis via abdominal CT requires attention to
a constellation of findings. Ninety-five percent of patients with acute
cholecystitis have gallstones, but the sensitivity of CT for detection of
these stones is only approximately 75%. Calcium-containing stones tend to be
well seen; however, cholesterol stones may be isoattenuating or
hypoattenuating compared with the attenuation of bile, making their detection
difficult (Figs. 2 and
3).
The CT features of acute cholecystitis include gallstones, thickening of
the gallbladder wall, pericholecystic fluid, stranding of the pericholecystic
fat, high-attenuation bile, and blurring of the interface between the
gallbladder and the liver [3]
(Figs.
4,5,6A,
6B). In addition, transient
increases in attenuation of the portion of the liver adjacent to the
gallbladder in patients with acute cholecystitis have been reported
[4]. This finding has been
attributed to hepatic arterial hyperemia and is likely equivalent to the rim
sign seen on hepatobiliary scintigraphy (Fig.
7A,
7B). This transient increased
attenuation is an important sign of acute cholecystitis, but it should not be
mistaken for a primary intrahepatic process. Chronic cholecystitis is a
difficult diagnosis to make on imaging, regardless of the technique used.
Findings include gallstones and thickening of the gallbladder wall; however,
correlation with the clinical findings is critical
(Fig. 8). Surrounding
inflammatory changes in the pericholecystic fat may be absent. Specific
diagnosis often requires nuclear medicine techniques, particularly to evaluate
the gallbladder ejection fraction.
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Fig. 4. —On CT scan obtained in 50-year-old man with acute
cholecystitis, gallstones are seen in dependent portion of gallbladder.
Thickening of gallbladder wall and stranding of pericholecystic fat are
evident.
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Fig. 7B. —57-year-old man with acute cholecystitis. Contrast-enhanced
CT scan reveals increased liver enhancement (arrows) surrounding
inflamed gallbladder. Calcified gallstone is also visible.
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Fig. 8. —Contrast-enhanced CT scan obtained in 65-year-old woman with
right upper quadrant pain reveals gallstone and minimal thickening of
gallbladder wall without pericholecystic inflammation, findings that are
compatible with chronic cholecystitis.
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Complications of cholecystitis include gangrenous cholecystitis,
gallbladder rupture, and formation of abscesses and fistulas. Gangrenous, or
emphysematous, cholecystitis occurs most commonly in diabetic patients via
gas-forming organisms such as Clostridium perfringens (C. welchii),
Escherichia coli, and Klebsiella organisms
[5]. CT is the most specific
imaging technique for establishing the diagnosis of emphysematous
cholecystitis, which carries an overall mortality rate of up to 15%
[6]. Findings include air in
the gallbladder wall or lumen, intraluminal membranes, irregular or absent
gallbladder wall, irregular enhancement, and pericholecystic abscess (Figs.
9 and
10). Diagnosing emphysematous
cholecystitis is critical, for although it no longer precludes a laparoscopic
approach to cholecystectomy, emphysematous cholecystitis is an imaging feature
that may be used to predict a higher likelihood of an intraoperative
conversion from laparoscopic to open cholecystectomy. Other features that may
complicate the surgical approach include a pericholecystic collection and
evidence of Mirizzi's syndrome, which is the obstruction of the extrahepatic
bile duct by a stone impacted within the cystic duct and subsequent extrinsic
compression or inflammation. This syndrome may be suggested on CT by
identification of a stone within the cystic duct with concurrent biliary
ductal dilatation [7] (Fig.
11A,
11B). As with emphysematous
cholecystitis, patients with Mirizzi's syndrome have an increased incidence of
requiring intraoperative conversion to open cholecystectomy; however, an
initial laparoscopic approach is not contraindicated
[8]. However, open
cholecystectomy is required for patients with a porcelain gallbladder
(diagnosed by the presence of gallbladder wall calcification) because of its
association with gallbladder carcinoma in 30% of cases
(Fig. 12).
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Fig. 9. —Contrast-enhanced CT scan obtained in 65-year-old man with
diabetes and who presented with right upper quadrant pain shows air in wall of
gallbladder as well as wall thickening and pericholecystic inflammation,
characteristic of emphysematous cholecystitis.
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Fig. 11A. —65-year-old man with right upper quadrant pain.
Three-dimensional volume-rendered CT scan in coronal projection reveals
intrahepatic ductal dilatation (arrows). Gallbladder is also
distended. Calcified stone (arrowhead) is identified in cystic
duct.
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Fig. 12. —Contrast-enhanced CT scan obtained in 47-year-old woman with
recurrent right upper quadrant pain reveals calcification (arrow) of
gallbladder wall, compatible with porcelain gallbladder.
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Gallbladder Carcinoma
Approximately 6,500 new cases of gallbladder carcinoma are reported
annually in the United States, with a 4:1 female-to-male ratio and the peak
incidence occurring in the sixth and seventh decades of life. Clinical and
radiologic features of gallbladder carcinoma overlap with those seen in
cholelithiasis and cholecystitis, which often causes a delay in diagnosis
until the disease is in the late stage.
The most common CT finding in gallbladder carcinoma is a mass that fills
most of an enlarged and deformed gallbladder
[9] (Fig.
13A,
13B). These masses are
typically low in attenuation with variable enhancement. Polypoid masses are
the second most common presentation; differentiation from benign polyps is
based on size, with the polypoid masses typically larger than 1 cm
(Fig. 14). Finally,
gallbladder carcinoma can present as a symmetric or an asymmetric gallbladder
wall thickening that may be difficult to distinguish from the scarred
gallbladder wall seen in chronic cholecystitis (Fig.
15A,
15B). A focal mass that is
less than half the size of the gallbladder has been reported to be a reliable
indicator of carcinoma rather than cholecystitis. Other signs are the result
of disease progression including biliary obstruction and liver involvement,
features that are commonly confused with carcinoma of the pancreas or even
liver [10].
Carcinoma of the gallbladder frequently spreads by direct extension to the
liver, although lymph node involvement is also common (Fig.
13A,
13B). Vascular metastases are
much less frequent but can occur. Involvement of the liver is commonly seen at
the time of diagnosis as is biliary obstruction, which can be due either to
lymphadenopathy or direct spread to the bile duct itself
[9]. Advanced-stage disease
spreads to the gastrointestinal tract, omentum, and pancreas. Preoperative
staging via CT has had an overall accuracy ranging from 83–86%; however,
although advanced disease is accurately and reliably detected on CT, the
ability to identify early-stage disease on CT remains disappointing
[11]. At least one article
suggested that dual-phase helical CT may improve assessment of resectability
[12].
Miscellaneous
Gallbladder wall thickening is not a specific sign for cholecystitis and
can occur in other conditions such as hepatitis, cirrhosis, or ascites (Fig.
16A,
16B). In rare cases,
gallbladder varices also are identified on CT, usually in patients with
cirrhosis and portal hypertension or portal vein thrombosis
(Fig. 17). In these cases, no
surrounding inflammation or clinical signs of acute cholecystitis are
present.
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Fig. 16A. —55-year-old man with AIDS. Contrast-enhanced CT scans reveal
moderate circumferential gallbladder wall thickening. No stone or inflammation
was noted. Moderately thickened gallbladder wall was confirmed on sonography
(not shown) with no evidence of cholecystitis. Nonspecific gallbladder wall
thickening can be seen in patients with AIDS.
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Fig. 16B. —55-year-old man with AIDS. Contrast-enhanced CT scans reveal
moderate circumferential gallbladder wall thickening. No stone or inflammation
was noted. Moderately thickened gallbladder wall was confirmed on sonography
(not shown) with no evidence of cholecystitis. Nonspecific gallbladder wall
thickening can be seen in patients with AIDS.
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Fig. 17. —Contrast-enhanced portal venous phase CT scan obtained in
62-year-old man with history of portal vein thrombosis reveals enhancing
vessels (arrows) around gallbladder, compatible with varices.
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Conclusion
Although traditionally the domain of sonography and scintigraphy, routine
evaluation of the gallbladder is increasingly performed with CT because of its
widespread use as the first-line technique in the evaluation of acute
abdominal pain. Radiologists must therefore be keenly aware of the CT features
of acute gallbladder disease and its complications. Additionally, CT is an
excellent technique for the detection and staging of gallbladder carcinoma.
The accurate assessment of both acute and chronic gallbladder disease that CT
provides further cements its role as the primary technique for evaluation of
abdominal pathology.
References
- Meilstrup JW, Hopper KD, Thieme GA. Imaging of gallbladder
variants. AJR1991; 157:1205
–1208[Abstract/Free Full Text]
- Paulson EK. Acute cholecystitis: CT findings. Semin
Ultrasound CT MR 2000;21:56
–63[Medline]
- Mirvis SU, Vainright JR, Nelson AW, et al. The diagnosis of acute
acalculous cholecystitis: a comparison of sonography, scintigraphy, and CT.
AJR 1986;147:1171
–1175[Abstract/Free Full Text]
- Yamashita K, Jin MJ, Hirose Y, et al. CT finding of transient focal
increased attenuation of the liver adjacent to the gallbladder in acute
cholecystitis. AJR1995; 164:343
–346[Abstract/Free Full Text]
- Gore RM, Yaghmai V, Newmark GM, et al. Imaging benign and malignant
disease of the gallbladder. Radiol Clin North Am2002; 40:1307
–1323[Medline]
- Grayson, DE, Abott RM, Levy AD, et al. Emphysematous infections of
the abdomen and pelvis: a pictorial review.
RadioGraphics2002; 22:543
–561[Abstract/Free Full Text]
- Turner MA, Fulcher AS. The cystic duct: normal anatomy and disease
processes. RadioGraphics2001; 21:3
–22[Abstract/Free Full Text]
- Targarona EM, Andrade E, Balague C, Ardid J, Trias M. Mirizzi's
syndrome: diagnostic and therapeutic controversies in the laparoscopic era.
Surg Endosc1997; 11:842
–845[Medline]
- Kumar A, Aggarwal S. Carcinoma of the gallbladder: CT findings in
50 cases. Abdom Imaging1994; 19:304
–308[Medline]
- Smathers RL, Lee JK, Heiken JP. Differentiation of complicated
cholecystitis from gallbladder carcinoma by computed tomography.
AJR 1984;143:255
–259[Abstract/Free Full Text]
- Yoshimitsu K, Honda H, Shinozaki K, et al. Helical CT of the local
spread of carcinoma of the gallbladder: evaluation according to the TNM system
in patients who underwent surgical resection. AJR2002; 179:423
–428[Abstract/Free Full Text]
- Kumaran V, Gulati MS, Paul SB, et al. The role of dual-phase
helical CT in assessing resectability of carcinoma of the gallbladder.
Eur Radiol2002; 12:1993
–1999[Medline]
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Introduction
Anatomy and Variation
