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What are anatomical characteristics of the liver? (4)
- largest solid organ in the abdomen
- located between the diaphragm and the stomach--> enlargement causes displacement of stomach
- should be nearly all within the costal arches
- caudal ventral border is the left lateral liver lobe, which has a sharp triangular-shaped margin
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What are radiographic characteristics of the gall bladder? (2)
- not identifiable when normal
- border effaces with surrounding liver; need a change in opacity to see on rads
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How can you assess the size of the liver?
- gastric axis is USUALLY parallel to the ribs; in deep chested dogs gastric acid is cranial; in shallow bodied dogs, gastric acid is caudal
- young animals will appear to have large livers
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Describe the orientation of the liver in cats.
- majority of liver is right-side on VD image
- abundant falciform fat may cause dorsal displacement of liver
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What are radiographic characteristics of a normal liver? (4)
- soft tissue opaque
- sharp margins
- within costal arches
- gastric axis parallel to ribs and perpendicular to spine
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What radiographic changes suggest generalized enlargement of the liver? (3)
- blunting of caudoventral liver margin
- extension beyond the costal arches
- caudal +/- medial displacement of the gastric axis
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Why might older dogs have normal livers that APPEAR larger on radiographs?
stretching/ elongation of triangular ligaments attached to the diaphragm
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What are causes of generalized hepatomegaly? (5)
- congestion (right heart failure)
- inflammation
- neoplasia
- vacuolar hepatopathy
- endocrine hepatopathy
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What are common radiographic findings with focal hepatomegaly (mass)? (1)
asymmetrical shift of gastric axis (pedunculated masses may not cause a gastric axis shift)
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What are differentials for focal hepatomegaly? (5)
- neoplasia
- abscess
- cyst
- hyperplastic nodule
- granuloma
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How does microhepatia appear radiographically?
cranial displacement of gastric axis
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What are causes of microhepatia? (2)
- congenital portosystemic shunt
- chronic liver disease and cirrhosis
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What might cause a decrease in hepatic opacity (becomes more radiolucent)? (3)
- abscess
- biliary gas
- portal vein gas
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What might cause an increase in liver opacity (becomes more radiopaque)? (4)
- post-contrast
- cholelithiasis
- mineral within the intrahepatic bile ducts
- mineralized mass (neoplasia, granuloma, hematoma)
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On ultrasound, the liver is _______ to spleen.
hypoechoic
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How thick should the gallbladder wall be on ultrasound of dogs and cats?
- dogs: 2-3mm thick
- cats: <1mm thick
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What are causes of hepatic hyperechogenicity on ultrasound? (4)
- vacuolar hepatopathy
- infiltrative neoplasia
- chronic active inflammation
- cirrhosis (often with irregular nodules)
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What are differentials for hepatic nodules? (7)
- nodular hyperplasia
- metastatic neoplasia
- granuloma
- vacuolar change
- hematoma
- abscess
- cysts
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How does a biliary mucocele appear on ultrasound?
like cross-section of a kiwi
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What are anatomic characteristics of the spleen? (3)
- only anchor is to the gastric fundusby the gastrosplenic ligament, otherwise location and size are variable
- tail may extend along left body wall or across the body
- splenic head is triangular (dorsally)
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How might generalized splenomegaly appear on radiographs? (2)
- rounded or blunted margins of the spleen
- dorsal +/- caudal displacement of jejunum
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What are causes for generalized splenomegaly? (5)
- congestion
- neoplastic infiltration
- splenitis
- extra-medullary hematopoiesis
- lymphoid hyperplasia
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On ultrasound, the spleen is _________ to the liver and has __________.
hyperechoic; fine echotexture
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How does splenic torsion appear on ultrasound?
hypoechoic and "lacy" with no doppler signal
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What are differentials for splenic nodules? (7)
- lymphoid hyperplasia
- extramedullary hematopoiesis
- hematoma
- neoplasia
- granuloma
- myelolipoma
- infarcts
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