Inflammation and edema surround the bile duct, causing obstruction at the level of the pancreas. Extrahepatic Biliary ObstructionĮxtrahepatic biliary obstruction in dogs usually results from pancreatitis. Additionally, a focal effusion is noted in A (arrow).
The mesentery (MES) surrounds part of the gallbladder, and increased echogenicity is associated with the inflamed mesentery. Transverse (A) and long-axis (B) images in a dog with a mucocele in which the gallbladder wall has undergone necrosis and biliary leakage is present. Mucoceles have been reported in dogs with no clinical signs however, mucoceles progress, with the possibility of future wall necrosis and perforation, which should be considered a reason to monitor the lesion or pre-emptively surgically remove the mucocele.įIGURE 14. The abnormal mucus collection can extend into the cystic and bile ducts, resulting in extrahepatic biliary obstruction. Gallbladder wall necrosis leads to leakage of bile contents into the peritoneal cavity, with an increase in echogenicity to the mesentery, which is in contact with the gallbladder wall ( Figure 14). The gallbladder wall is typically thick and the gallbladder abnormally distended. These striations are secondary to fracture lines between the mucus collections. The ultrasound features of a mucocele include variations of mucus collections and ultimate linear striations (stellate or kiwi-like appearance), with the gallbladder completely filled with echogenic material. Dogs with hyperadrenocorticism have a 29-fold higher risk for developing a mucocele than those without hyperadrenocorticism. The pathogenesis of mucoceles is unknown, although multiple factors have been suggested to result in abnormal bile salt retention, decreased biliary motility (gallbladder contractility), and excessive mucus secretion by the biliary epithelium. Transverse image of the same dog as in D demonstrating curvilinear echogenic lines (E) there is a focal effusion noted (just below “Effusion” label). Long-axis image showing a central hyperechoic line and radiating stellate echogenic lines extending toward the gallbladder wall (D). Transverse image from the same dog as in B (C) note the hypoechoic, thickened edematous wall of the gallbladder. Long-axis image showing echogenic material within the cranial aspect of the gallbladder with stellate radiating lines of increased echogenicity (B) the gallbladder wall is thickened, hypoechoic, and edematous. Long-axis image of the gallbladder with a stellate-appearing mucocele (kiwi fruit sign A). Multiple examples of mucoceles in dogs with hepatobiliary disease. This appearance can be seen in dogs with mucoceles and is consistent with “leakage” of bile through a necrotic wall, resulting in a biliary peritonitis.įIGURE 13. There is a focal anechoic effusion lateral to the gallbladder (arrow) consistent with inflammation adjacent to the gallbladder wall. Transverse section of the right side of the liver in a dog with cholecystitis (C) the gallbladder wall is thickened and hyperechoic and has irregular margins. Dilated bile and cystic ducts in a cat with cholecystitis and cholangiohepatitis (B) the ductal walls are thickened, dilated, and tortuous (arrow). Hyperechoic material is noted in the middle of the gallbladder, and there is a slight effusion cranial to the gallbladder (small anechoic crescent). Hypoechoic areas are noted along the wall of the gallbladder consistent with abnormal mucus collections. Long-axis image of the right side of the liver in a dog with clinical signs of vomiting, weight loss, and icterus (A) the gallbladder wall is markedly thickened with irregular margins. Too much gain results in increased echogenicity and misinterpretation that the liver is abnormal, whereas too little gain results in decreased echogenicity and misinterpretation that the liver is abnormally hypoechoic ( Figure 1).įIGURE 11.
#Complete anatomy of the irritated liver how to
The clinician or technician must know how to improve and manipulate the image in order to present a “normal” liver with the appropriate echogenicity. The normal echotexture of the liver is a subjective evaluation. This article reviews abnormalities of the hepatobiliary system found via ultrasonography. Part 1 of this series-published in the May/June 2016 issue of Today’s Veterinary Practice-reviewed the normal ultrasound appearance of the liver and gallbladder as well as the sonographic appearance of nodules. Distribution of any abnormalities (focal, multifocal, or generalized).Appearance of the portal and hepatic veins.Overall echogenicity of the hepatic parenchyma.Margins/borders (smooth versus irregular).
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