Adrenals, Lymphnodes, Gall Bladder, and Pancreas

1. Adrenals, Lymphnodes, Gall Bladder, and Pancreas Jane MacLellan

2. Adrenal Glands • In the dog - peanut shaped • In the cat - more oval • Located cranial and medial to kidneys • Left - caudal to the branches of the aorta • Right - adjacent to caudal vena cava • Locate kidney, then fan medially with probe • Hypoechoic - similar to blood vessels • Can be hard to distinguish - use doppler • Overlying bowel can obscure

4. Adrenal Gland Disease • Measure length and width • Length with vary between animals • Proportional to body weight • Width does not • Width may increase with disease • Normal width = < 0.74 cm • Note: New paper suggests dogs < 10Kg normal width < 0.6 cm

5. Adrenal Gland Disease • Pituitary dependent hyperadrenocorticism • Bilaterally enlarged • Normal shape - but ‘plump’ • Thickened poles • Uniformly hypoechoic • Nodular hyperplasia • Normal size does not r/o PDH

6. Adrenal Gland Disease • Adrenal tumor • Gland enlargement • Abnormal shape • Change in echotexture • Unilateral masses more common • Can’t distinguish benign from malignant tumors • May be able to tell if invading surrounding tissue

8. Lymph nodes • More sensitive then radiographs • Medial iliac and jejunal lymph nodes • Large • More often seen when normal • Normal - same echogenicity as surrounding mesentery • Easier to see in young, thin animals • When enlarged, more hypoechoic • Can do ultrasound guided FNA

9. Lymph nodes • Medial iliac • Near terminal portion of aorta and caudal vena cava • Not normally seen unless enlarged • Bladder, prostatic neoplasia • Visceral • Seen when doing routine scan

11. Gall Bladder • Visualized just right of midline in liver • Size is variable - depending on last meal • Fasting or anorexia • In cats, can be bi-lobed • Things you might see • Thickened wall • Stones • Mucoceles • Cholestasis • Cholecystitis • “Sludge” • Icterus

12. Thickened Wall • Wall normally thin, echogenic, poorly visualized • <1mm in cats, slightly thicker in dog • Double layered - inside and outside surfaces – Halo sign • Thickening is a non-specific sign • Chronic hepatitis • Cholecystitis • Cholangiohepatitis • Right CHF • Hypoalbuminemia • Sepsis • Neoplasia

13. Sludge • Commonly seen • Especially if haven’t eaten recently • Dependent

14. Mucocele • Cystic mucinous hyperplasia • Proliferation of GB epithelium • Increased mucin production • Marked distension of the GB • Kiwi appearance

15. Choleliths • Uncommon • Incidental finding • Should be noted - cholecystitis or biliary obstruction • Hyperechoic • Acoustic shadowing • Mobile

16. Bile Duct • Seen as a continuation of the GB • Dogs - not consistently seen • Should be < 3mm • Cats - more often seen • Should be < 4mm • Ventral to portal vein • Extrahepatic obstruction • Dilation of GB and bile duct

17. GB Artifacts • Mirror image duplicate • Sound wave bounces off the diaphragm, echos off the gall bladder back towards diaphragm, reflected towards the transducer • Refraction • When sound waves go through tissues of different acoustic impedance • Acoustic enhancement • Less attenuation compared to liver

18. Pancreas • Normal is routinely difficult to visualize • Echogenicity similar to surrounding fat • No defined capsule • Less echogenic then spleen, more echogenic then liver • Right limb just dorsal to duodenum • More likely to see in puppies, thin dogs, or with free abdominal fluid

19. Pancreatitis • Acute - surrounded by a hyperechoic area • Due to peri-pancreatic fat necrosis • Severe - mixed echogenicity • Chronic - hyperechoic pancreas • Due to pancreatic fat necrosis • Pancreatic pseudocysts • Mass effect

22. Pancreas • Neoplasia • Difficult to identify • Looks similar to pancreatitis (mass effect) • Fluid accumulation • Invasion of surrounding tissues • Evidence of metastasis in other organs