Diagnostic ultrasound ( PDFDrive )

CHAPTER 6 The Biliary Tree and Gallbladder 175
A
B
C
D
E
F
G
H
I
FIG. 6.12 Hemobilia: Spectrum on Sonography. (A) Echogenic blood clot (arrowhead) within a dilated duct, after insertion of biliary drainage
catheter. Biliary obstruction was caused by pancreatic tumor. (B) and (C) Echogenic clot in the common hepatic duct in two patients after liver
biopsy. (D) and (E) Spontaneous hemobilia in patient receiving anticoagulation therapy. Note the tubular appearance of the clot (arrow) with central
hypoechoic lumen. (F) Corresponding MRCP image depicts the same. (G)-(I) Blood in gallbladder in three different patients. All patients developed
pain after liver biopsy. (H) Note the angled edge typical of blood clot.
Pneumobilia
Air within the biliary tree usually results from previous biliary
intervention, biliary-enteric anastomoses, or CBD stents. In the
acute abdomen, pneumobilia may be caused primarily by three
entities. Emphysematous cholecystitis may lead to pneumobilia;
its risk factors and indings are discussed under “Acute Cholecystitis.”
Inlammation caused by an impacted stone in the CBD
may cause erosion of the duct wall, leading to choledochoduodenal
istula. he third entity, prolonged acute cholecystitis,
may lead to erosion into an adjacent loop of bowel, most frequently
the duodenum or transverse colon, called cholecystenteric istula.
Stones may then pass from the gallbladder into the bowel and
can cause a gastric outlet or small bowel obstruction called
gallstone ileus.
Air in the bile ducts has a characteristic appearance. Bright,
echogenic linear structures following the portal triads are seen,
more oten in a nondependent position (Fig. 6.13). Posterior
“dirty” shadowing, reverberation, and ring-down artifacts
are seen with large quantities of air. Movement of the air bubbles,
best seen just ater changing the patient’s position, is diagnostic.