Ultrasonography of the normal feline pancreas and associated anatomic landmarks: A prospective study of 20 cats

The sonographic appearance of the feline pancreas and associated anatomic l andmarks including the pancreatic duct, duodenum, duodenal papilla, portal vein, and gastric lymph node were evaluated in 20 healthy, awake cats. The pancreas appeared nearly isoechoic to surrounding mesenteric tissues, isoec hoic to slightly hyperechoic to adjacent liver lobes, and hypoechoic to the spleen. The mean thickness measurements for the right pancreatic lobe, bod y, and left pancreatic lobe were 4.5 mm (range 2.8-5.9), 6.6 mm (range 4.7- 9.5), and 5.4 mm (range 3.4-9.0), respectively. The pancreatic duct was con sistently visualized in the left pancreatic lobe and had a mean thickness o f 0.8 mm (range 0.5-1.3). It could be differentiated from the pancreatic ve ssel, by its central location, and the duct's lack of Doppler flow signal. The duodenum was used as a landmark to identify the right lobe of the pancr eas. The mean duodenal wall thickness measurement was 2.8 mm (range 2.1-3.8 ) in sagittal section, and 3.0 mm (range 2.2-4.4) in transverse section. Th e duodenal papilla was identified in 4 of 20 cats. It ranged in size from 2 .9 to 5.5 mm in width, and had a maximum height of 4.0 mm in transverse sec tion. The portal vein was used as a consistent anatomic landmark for identi fication of the left lobe and body of the pancreas. The mean diameter of th e portal vein at the level where the pancreatic body joins the left pancrea tic lobe was 4.3 mm (range 2.7-5.9) when viewed in sagittal section, and 4. 5 mm (range 3.6-6.1) in transverse section. The gastric lymph node was iden tified cranial and ventromedial to the pyloroduodenal angle in 6 of 20 cats . It had an asymmetrical shape with a larger caudal pole in five of the six cats. The largest dimensions of the gastric lymph node were 10 mm in lengt h, and 6 mm in width for the larger caudal pole, and 5.1 mm in width for th e smaller cranial pole.