04-10-2007, 05:34 PM
Explanation:
The correct answer is E. This patient
has evidence of a prolonged episode
of biliary colic, which may progress
to acute cholecystitis. An abdominal
ultrasound has revealed a markedly
dilated common bile duct, as well as
gallstones within the gallbladder.
Acute cholecystitis is the result of
cystic duct obstruction, and this
would be best demonstrated by a HIDA
scan. A HIDA scan measures flow of
iminodiacetic acid, which follows the
flow of bile, i.e., from the blood
stream into the liver, into the
gallbladder, and then through the
cystic duct into the common bile
duct. If there is cystic duct
obstruction, the common bile duct is
not visualized on the HIDA scan.
An abdominal CT scan (choice A) may
reveal gallstones and pericholecystic
changes but does not demonstrate good
visualization of the cystic duct.
Abdominal MRI (choice B) is not
effective in the demonstration of
cystic duct obstructions.
An abdominal ultrasound (choice C) is
not as effective in revealing cystic
duct obstructions, and Doppler flow
studies are useful for blood flow
patterns but would not assist in the
diagnosis of acute cholecystitis.
An endoscopic retrograde
cholangiopancreatograph (ERCP)
(choice D) is more effective in
demonstrating the intra- and
extrahepatic biliary trees but is not
as effective in demonstrating the
cystic duct.
The correct answer is E. This patient
has evidence of a prolonged episode
of biliary colic, which may progress
to acute cholecystitis. An abdominal
ultrasound has revealed a markedly
dilated common bile duct, as well as
gallstones within the gallbladder.
Acute cholecystitis is the result of
cystic duct obstruction, and this
would be best demonstrated by a HIDA
scan. A HIDA scan measures flow of
iminodiacetic acid, which follows the
flow of bile, i.e., from the blood
stream into the liver, into the
gallbladder, and then through the
cystic duct into the common bile
duct. If there is cystic duct
obstruction, the common bile duct is
not visualized on the HIDA scan.
An abdominal CT scan (choice A) may
reveal gallstones and pericholecystic
changes but does not demonstrate good
visualization of the cystic duct.
Abdominal MRI (choice B) is not
effective in the demonstration of
cystic duct obstructions.
An abdominal ultrasound (choice C) is
not as effective in revealing cystic
duct obstructions, and Doppler flow
studies are useful for blood flow
patterns but would not assist in the
diagnosis of acute cholecystitis.
An endoscopic retrograde
cholangiopancreatograph (ERCP)
(choice D) is more effective in
demonstrating the intra- and
extrahepatic biliary trees but is not
as effective in demonstrating the
cystic duct.