Diagnostic ultrasound ( PDFDrive )

CHAPTER 6 The Biliary Tree and Gallbladder 171
Caroli Disease
Caroli disease is a rare congenital disease of the intrahepatic
biliary tree that results from malformation of the ductal plates,
the primordial cells that give rise to the intrahepatic bile ducts.
here are two types of Caroli disease: the simple, classic form
and the second, more common form, which occurs with congenital
hepatic ibrosis. 14 he second form has also been called
Caroli syndrome. Caroli disease has been associated with cystic
renal disease, most oten renal tubular ectasia (medullary sponge
kidneys). However, both forms may also be seen in patients
with autosomal recessive polycystic kidney disease. Caroli disease
afects men and women equally, and more than 80% of patients
present before the age of 30 years. 15
Caroli disease leads to saccular dilation or, less oten, fusiform
dilation of the intrahepatic biliary tree, resulting in biliary stasis,
stone formation, and bouts of cholangitis and sepsis (Fig. 6.8).
he disease most oten afects the intrahepatic biliary tree difusely,
but it may be focal. he dilated ducts contain stones and sludge.
Unlike recurrent pyogenic cholangitis, the ductal contents do not
form a cast of the dilated system and thus are more easily identiied
as ductal contents. 16 Also, small portal vein branches surrounded
by dilated bile ducts and bridging echogenic septa traversing the
dilated ducts have been described on ultrasound. hese correspond
to persistent embryonic ductal structures. 17 If associated with
congenital hepatic ibrosis, indings of altered hepatic architecture
and portal hypertension are also present. Cholangiocarcinoma
develops in 7% of patients with Caroli disease. 15
Overview of Biliary Tree Obstruction
Elevation of cholestatic liver parameters, which may appear
clinically as jaundice, is a frequent indication for sonographic
examination of the abdomen. he major objective in performing
these scans is to determine if the patient has obstruction of the
bile ducts, as opposed to a hepatocellular or biliary ductular
disease. Sonography is highly sensitive in the detection of dilation
of the biliary tree and is therefore an excellent modality for
A
B
C
FIG. 6.8 Caroli Disease. (A) Oblique image through
the right lobe of the liver demonstrates dilated ducts with
sacculations typical of Caroli disease. Note the incomplete
bridging echogenic septa (short arrows). (B) Transverse
imaging through the left lobe shows a nonshadowing stone
(arrow) in the dilated duct. (C) Corresponding MRCP shows
the extent of the disease.