Diagnostic Ultrasound - Abdomen and Pelvis

Approach to Biliary Sonography
hospitalized patients and may be mass-like. It is important to
distinguish tumefactive sludge from mass by using color
Doppler to detect flow in a mass. Spectral Doppler can also
distinguish twinkling artifact caused by microcalculi from true
blood flow in a mass. The gallbladder wall should be evaluated
for focal wall thickening and signs of malignancy such as
adjacent wall thickening or retraction and invasion into liver.
The majority of gallbladder polyps are small and have a
characteristic appearance. Gallbladder adenomyomatosis is
characterized by polypoid lesions with "comet tail" artifacts
and diffuse or segmental wall thickening.
Right Upper Quadrant Pain
Ultrasound is the modality of choice for the evaluation of a
patient with right upper quadrant pain, and is the highest
rated modality in the ACR appropriateness criteria. The well
known advantages of ultrasound include the high sensitivity
and specificity for gallstones and acute cholecystitis as well as
availability, lower cost, lack of ionizing radiation, repeatability,
and short duration. The ability to derive a diagnosis in real time
while interacting with the patient and determining the site of
maximal tenderness is unrivaled.
The presence of the sonographic Murphy sign allows a
definitive diagnosis of acute cholecystitis when added to
other findings of gallstones, wall thickening, pericholecystic
fluid and distension which may otherwise be secondary to
other confounding factors. Diffuse gallbladder wall thickening
in isolation is often caused by secondary causes such as
hypoalbuminemia, cardiac, renal or hepatic failure, sepsis,
pancreatitis, hepatitis, and trauma. When the Murphy sign
cannot be elicited in obtunded or sedated patients or after
opiate administration, the performance of ultrasound is
inferior for the diagnosis of acute cholecystitis.
Cholescintigraphy has a higher accuracy, sensitivity, and
specificity than ultrasound for acute cholecystitis, but the
availability, ionizing radiation, length of study, and
dependence on hepatic function promote ultrasound as the
first-line modality. Ultrasound also has the advantage of
determining alternative pathology, presence of gallstones,
and status of the bile ducts; however, cholescintigraphy is
extremely useful after equivocal or nondiagnostic ultrasound,
especially in sick, septic patients at high risk for acalculous
cholecystitis.
In patients with acute cholecystitis, detection of complications
can influence the surgical approach. Gangrenous, perforated,
or emphysematous cholecystitis may be diagnosed with
ultrasound. However CT or MR should be considered given
the wider field of view and fewer limitations regarding body
habitus and acoustic window. The bile ducts should be
carefully evaluated for bile duct stones; the biliary duct stones
will definitely influence surgical management, requiring
preoperative ERCP or intraoperative bile duct clearance.
In chronic cholecystitis, the gallbladder wall is thick but
noninflamed and the gallbladder is not distended.
Confirmation requires clinical correlation and HIDA scan.
Obstructive Jaundice, Elevated Liver Function Tests
The main role of ultrasound is to determine if there is biliary
dilatation and the level and cause of biliary obstruction. The
bile duct lumen, caliber, and walls should be evaluated in
addition to the liver and gallbladder. Ultrasound may be
sufficient for benign obstruction from bile duct stones but CT
is used to confirm and stage malignant bile duct obstruction
from cholangiocarcinoma, pancreatic carcinoma, gallbladder
carcinoma, or extrinsic compression by lymphadenopathy. Bile
duct caliber should be correlated with symptoms and
biochemical tests, especially after cholecystectomy as dilated
bile ducts are not necessarily obstructed.
Fever, Sepsis: Rule Out Biliary/Gallbladder Source
This is a common indication in septic, postoperative, intubated
patients with multisystem failure. Ultrasound is less sensitive
and specific for acute cholecystitis given the difficulty in
detecting gallbladder tenderness and the fact that fasting,
total parenteral nutrition, hypoalbuminemia, sepsis, and heart
failure may contribute to gallbladder distension and wall
thickening. Cholescintigraphy is often required to confirm
acalculous cholecystitis.
The intrahepatic and extrahepatic bile ducts should be
evaluated for dilatation or thickening secondary to cholangitis.
Ascending cholangitis may be associated with biliary sludge or
pus and obstructing stones. Rarely, there is pneumobilia.
Cholangitis may be complicated by hepatic abscesses, typically
clustered around the abnormal bile ducts.
The liver, pancreas, and other organs should also be screened
for causes of sepsis during ultrasound.
Palpable Gallbladder
A palpable gallbladder could be secondary to gallbladder
carcinoma or other tumors, mucocele, or benign obstruction.
Gallbladder carcinoma has a poor prognosis and early
diagnosis is difficult. Early carcinoma may present as a
polypoid mass or wall thickening. More advanced tumors may
obliterate the gallbladder lumen and extend into the nearby
liver, making it difficult to determine the origin of the tumor.
Gallstones are typically present, suggesting the origin of the
tumor. Bile-filled obstructed noninflamed gallbladders
typically result from non-stone disease such as pancreatic or
distal bile duct carcinomas. Gallbladder mucoceles secondary
to chronic stone obstruction are typically minimally tender
with no wall thickening.
Selected References
1. Fagenholz PJ et al: Acute inflammatory surgical disease. Surg Clin North Am.
94(1):1-30, 2014
2. Yarmish GM et al: ACR appropriateness criteria right upper quadrant pain. J
Am Coll Radiol. 11(3):316-22, 2014
3. McArthur TA et al: The common duct dilates after cholecystectomy and with
advancing age: reality or myth? J Ultrasound Med. 32(8):1385-91, 2013
4. Kiewiet JJ et al: A systematic review and meta-analysis of diagnostic
performance of imaging in acute cholecystitis. Radiology. 264(3):708-20,
2012
5. Brook OR et al: Lessons learned from quality assurance: errors in the
diagnosis of acute cholecystitis on ultrasound and CT. AJR Am J Roentgenol.
196(3):597-604, 2011
6. Charalel RA et al: Complicated cholecystitis: the complementary roles of
sonography and computed tomography. Ultrasound Q. 27(3):161-70, 2011
7. Gore RM et al: Gallbladder imaging. Gastroenterol Clin North Am. 39(2):265-
87, ix, 2010
8. Horrow MM: Ultrasound of the extrahepatic bile duct: issues of size.
Ultrasound Q. 26(2):67-74, 2010
9. Oktar SO et al: Comparison of conventional sonography, real-time
compound sonography, tissue harmonic sonography, and tissue harmonic
compound sonography of abdominal and pelvic lesions. AJR Am J
Roentgenol. 181(5):1341-7, 2003
Diagnoses: Biliary System
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