Diagnostic ultrasound ( PDFDrive )

CHAPTER 18 Organ Transplantation 627
A
B
C
D
E F G H
FIG. 18.4 Bile Duct: Strictures in Four Patients. Patient 1: (A) Gray-scale sonogram and (B) endoscopic retrograde cholangiopancreatography
(ERCP) of common bile duct (CBD) anastomotic stricture (arrows). Patient 2: (C) Gray-scale sonogram and (D) ERCP show grossly thickened CBD
walls (arrows), secondary to ascending cholangitis, a consequence of an anastomotic stricture. Patient 3: (E) Transverse sonogram shows central
biliary dilation (arrows). (F) Magnetic resonance cholangiopancreatography (MRCP) image shows anastomotic stricture (arrow). Patient 4: (G)
Transverse sonogram and (H) radial T2-weighted MRCP image show left intrahepatic bile duct stricture (between arrows), secondary to ischemia
from hepatic artery stenosis. (A and B with permission from Crossin JD, Muradali D, Wilson SR. US of liver transplants: normal and abnormal.
Radiographics. 2003;23[5]:1093-1114. 5 )
caused by prolonged cold preservation time of the donor
organ. 16,18 Other causes of intrahepatic strictures include immunogenic
injury produced by chronic rejection, recurrent sclerosing
cholangitis, ascending cholangitis, and cytomegalovirus (CMV)
infections.
Ultrasound indings include focal areas of narrowing in the
intrahepatic or proximal CBD and segmental dilation of the
intrahepatic bile ducts, without evidence of an obstructing mass.
he presence of echogenic intraluminal material within a dilated
biliary tree is an ominous sign, sometimes caused by severe
biliary ischemia, resulting in sloughing of the entire biliary
epithelium. In this scenario the intraluminal echogenic material
represents a combination of biliary sludge or stones, sloughed
biliary epithelium, and intraluminal hemorrhage 16 (Fig. 18.5).
Bile Leaks
he incidence of bile leaks in patients with cadaveric liver
transplants is 5% to 23%. he biliary complication rate is substantially
higher in living related transplant recipients, possibly
because of (1) leaks caused by division of the liver at retrieval,
(2) variant biliary anatomy resulting in more than one bile duct
oriice at the resection margin, and (3) ischemia of the right
biliary tree. 19 Overall, biliary leaks can be categorized as occurring
(1) at the anastomotic site, (2) at the T-tube exit site, (3) as a
result of bile duct necrosis, and (4) secondary to percutaneous
liver biopsies 20 (Fig. 18.6).
Most anastomotic leaks and T-tube exit site leaks occur within
the irst postsurgical month. Anastomotic leaks may be related
to surgical technique or may result from ischemia caused by
hepatic artery compromise. Clinically, anastomotic leaks are
associated with bile peritonitis or intraabdominal sepsis and
may manifest on ultrasound as a large periportal collection, a
subhepatic collection, or ascites. T-tube exit leaks are related to
technical errors when placing the T-tube and are usually detected
incidentally at cholangiography. he resulting biloma is usually
small, and patients with these types of bile leaks are usually
asymptomatic. 20
Leaks from bile duct necrosis usually occur ater the irst
postsurgical month and are a result of severe hepatic artery
stenosis or hepatic artery thrombosis. his condition is oten
associated with progressive hepatic dysfunction and a poor
clinical course, eventually necessitating retransplantation.
On ultrasound, the biliary tree may be dilated and thick
walled and may communicate with multiple surrounding
bilomas. 20
In rare cases, bile leaks can occur as a result of bile duct injury
from percutaneous liver biopsies. Bile may leak from the needle
track into the peritoneal cavity. hese leaks can resolve without