Page 360 - WSAVA2018
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 25-28 September, 2018 | Singapore
Cholecystocentesis is helpful in these instances for performing bacteriology and cytology. Extrahepatic bile duct obstruction often results in dilation of the common bile duct, between the porta hepatis and the major duodenal papilla. The papilla is fairly easy to identify in cats as it is round and echogenic, located at the wall of the cranial duodenum, a short distance from the pylorus. The common bile duct is easily visible in most cats as
a thin anechoic tube ventral to the portal vein, another large and easy to identify structure in the cat. Only about half of cats with obstructive biliary disease have a dilated gallbladder. The bile duct should be traced and observed for wall thickening, intraluminal echogenic
or hyperechoic shadowing material and for papillary masses. Inflammatory disease of the papilla can be as obstructive as a cholelith. Spleen
identify the stomach and trace it rightward and the pylorus and duodenum will be easily visible. Continuing, trace the duodenum along its short length and notice the small papilla at its cranial end for entrance of the common bile duct and pancreatic duct.
The jejunum
Randomly distribute, 2-3mm in thickness with distinct five wall layers. The most common abnormality of the small intestine is muscularis thickening seen in both inflammatory bowel disease and lymphoma. Linear foreign bodies have a specific appearance where the bowel is plicated together and often a thin hyperechoic band is evident pulling them together.
The ICCJ (Ileocecocolic junction)
The feline cecum is a small bulbous organ having
a subtle curvature (concave side toward the ileum), located in the right abdomen ventral to the descending duodenum. A small constriction demarcates the transition with the colon and the ileum enters the ascending
colon obliquely from the left, just distal to the cecocolic transition. The position of the ileum relative to the cecum is fixed by the presence of the ligamentum ileocecalis,
in which the ileocecal lymph nodes are located. These lymph nodes are usually paired and can be found along the concavity of the cecum. The ascending mesocolon contains one to five colonic lymph nodes. Urinary Tract
Normal kidneys are 30-45mm in length. Fat deposited
in the renal tubules in cats leads to a more hyperechoic cortex in some animals. Bilateral pelvic dilation is often due to obstruction in male cats. Uni- or bilateral pelvic or ureteral dilation in cats often occurs due to inflammation secondary to ureterolithiasis. If ureterolithiasis is suspected and ureteral dilation is noted in ultrasound, abdominal radiographs following an enema should be performed
to screen for uroliths which may be challenging to find sonographically but easy to see radiographically. Any toxin that cat ingests can also affect the kidneys. Ethylene glycol and Easter Lily are two and the retroperitoneal space may develop fluid secondary to acute renal injury. Ethylene glycol affected kidneys may become so hyperechoic that shadowing will result. Polycystic kidney disease in cats and results in several cysts in both kidneys to complete absence of recognizable renal tissue. The cysts are thin walled, with a near and far wall hyperechoic border and anechoic content.
Congenital defects of the kidneys include hypo- and dysplasia as well as aplasia. When young cats have small and irregularly shaped kidneys, dysplasia is more likely than chronic renal disease. Chronic renal injury in cats is due to chronic nephritis, glomerulonephritis, amyloidosis and nephrocalcinosis. In all cases the kidneys are smaller in length, hyperechoic and often irregularly shaped.
Loss of corticomedullary distinction is also apparent. Occasional small round anechoic cortical cysts are
The spleen is small in healthy cats and is very laterally located in the left cranial abdomen. Sometimes it is necessary to scan intercostally to find the spleen. Usually if one cannot find the spleen, it is small and dorsal and the sonographer needs to strive to find it intercostally.
Splenomegaly in the cat can be caused by extramedullary hematopoiesis, hyperplasia, chronic inflammation, immune mediated disease, neoplasia,
and infectious organisms. Lymphoma is by far the most common neoplasm affecting the spleen. Mast cell tumor and histiocytic sarcoma are also possible and often cause splenomegaly. Histoplasmosis is a systemic fungal infection that affects many organs in the cat, including the spleen. Sonographically it appears enlarged and diffusely hypoechoic and in some instances can be mottled.Gastrointestinal Tract
The stomach
Gastritis is very difficult to diagnose sonographically and there are few specific signs. Cats rarely get ulcers unless induced by an overdose or chronic use of anti- inflammatory agents. Ulcers can lead to a focal wall thickening that, if not masked by gas and ingesta, can be identified sonographically. Linear foreign bodies anchored at the tongue may also cause bunching up of the stomach in addition to the jejunum. Hair balls are identified as a heterogenous structure with gas reverberations and shadowing.
The gastric wall in the cat is usually about 3mm thick. Thickening with loss of layering is mainly due to neoplasia. Gastric neoplasia can only be identified with sonography approximately 50% of the time compared with endoscopy. Gastric lymphoma often leads to a transmural, hypoechoic wall thickening, often diffuse or within a large section of the stomach.
The duodenum
The duodenum is very midline and to find it sonographically, one must focus on the porta hepatis,

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