Diagnostic ultrasound ( PDFDrive )

626 PART II Abdominal and Pelvic Sonography
A B C
FIG. 18.2 Echogenic Foci in Liver Transplant. Transverse sonograms show similar bright echogenic foci with posterior acoustic shadowing
secondary to (A) intrahepatic calciication; (B) hepatic arterial calciications; and (C) pneumobilia. Note the ring-down artifact associated with the
pneumobilia.
A B C
FIG. 18.3 Normal Liver Transplant: Color and Spectral Doppler. Color and spectral Doppler images of normal (A) hepatic artery, (B) main
portal vein, and (C) right hepatic vein. (With permission from Crossin JD, Muradali D, Wilson SR. US of liver transplants: normal and abnormal.
Radiographics. 2003;23[5]:1093-1114. 5 )
Choledochocholedochostomy-related complications most frequently
manifest ater the irst posttransplantation month and
are oten managed by endoscopic retrograde cholangiopancreatography
(ERCP). 11 Regardless of the type of anastomoses used,
biliary tract complications can be broadly classiied as those
related to leaks, strictures, intraluminal sludge or stones, dysfunction
of the sphincter of Oddi, and recurrent disease.
Biliary Strictures
Early diagnosis of biliary tree complications may be diicult
because transplant recipients do not typically experience colic;
the transplanted liver has a poor supply of nerves. 13 herefore
patients with biliary strictures may be asymptomatic or may
have painless obstructive jaundice or abnormalities in liver
function test (LFT) results. 11 hese strictures can be categorized
based on location and pathophysiology as anastomotic (extrahepatic)
and intrahepatic strictures (Fig. 18.4).
Anastomotic strictures are the most common cause of biliary
obstruction ater transplantation 14,15 and arise from postsurgical
scarring, resulting in retraction of the duct wall and narrowing
of the luminal diameter. 16 hese strictures are more common in
patients with a Roux-en-Y choledochojejunostomy than in patients
with an end-to-end biliary anastomosis. On ultrasound, a focal
narrowing can sometimes be observed at the anastomoses,
associated with dilation of the intrahepatic bile ducts, with a
normal-sized or near-normal-sized distal CBD.
Intrahepatic strictures occur proximal to the anastomosis
and may be unifocal or multifocal. he arterial supply of the
distal CBD (recipient duct) is rich because of prominent collateral
low, whereas the reconstructed hepatic artery is the only blood
supply to the proximal CBD and intrahepatic bile ducts (donor
ducts). 11,17 herefore most intrahepatic duct strictures result from
ischemia caused by hepatic artery occlusion (thrombosis or
signiicant stenosis). In rare cases, biliary ischemia may also be