Adrenals, Lymphnodes, Gall Bladder, and Pancreas

Jane MacLellan

Adrenal Glands

In the dog - peanut shapedIn the cat - more ovalLocated cranial and medial to kidneys

Left - caudal to the branches of the aortaRight - adjacent to caudal vena cava

Locate kidney, then fan medially with probeHypoechoic - similar to blood vessels

Can be hard to distinguish - use doppler

Overlying bowel can obscure

Adrenal Gland Disease

Measure length and widthLength with vary between animals

Proportional to body weight

Width does notWidth may increase with disease

Normal width = < 0.74 cmNote: New paper suggests dogs < 10Kg normal

width < 0.6 cm

Adrenal Gland Disease

Pituitary dependent hyperadrenocorticismBilaterally enlargedNormal shape - but ‘plump’Thickened polesUniformly hypoechoicNodular hyperplasiaNormal size does not r/o PDH

Adrenal Gland Disease

Adrenal tumorGland enlargementAbnormal shapeChange in echotextureUnilateral masses more commonCan’t distinguish benign from malignant tumors

May be able to tell if invading surrounding tissue

Lymph nodes

More sensitive then radiographsMedial iliac and jejunal lymph nodes

LargeMore often seen when normal

Normal - same echogenicity as surrounding mesentery

Easier to see in young, thin animalsWhen enlarged, more hypoechoicCan do ultrasound guided FNA

Lymph nodes

Medial iliacNear terminal portion of aorta and caudal vena

cavaNot normally seen unless enlargedBladder, prostatic neoplasia

VisceralSeen when doing routine scan

Gall BladderVisualized just right of midline in liverSize is variable - depending on last meal

Fasting or anorexia In cats, can be bi-lobedThings you might see

Thickened wall Stones Mucoceles Cholestasis Cholecystitis “Sludge” Icterus

Thickened WallWall normally thin, echogenic, poorly visualized

<1mm in cats, slightly thicker in dogDouble layered - inside and outside surfaces – Halo sign

Thickening is a non-specific signChronic hepatitisCholecystitisCholangiohepatitisRight CHFHypoalbuminemiaSepsisNeoplasia

SludgeCommonly seen

Especially if haven’t eaten recentlyDependent

Mucocele

Cystic mucinous hyperplasia

Proliferation of GB epithelium

Increased mucin production

Marked distension of the GB

Kiwi appearance

CholelithsUncommonIncidental findingShould be noted - cholecystitis or biliary obstructionHyperechoicAcoustic shadowingMobile

Bile DuctSeen as a continuation of

the GBDogs - not consistently

seenShould be < 3mm

Cats - more often seenShould be < 4mm

Ventral to portal veinExtrahepatic obstruction

Dilation of GB and bile duct

GB Artifacts

Mirror image duplicateSound wave bounces off the diaphragm, echos

off the gall bladder back towards diaphragm, reflected towards the transducer

RefractionWhen sound waves go through tissues of

different acoustic impedance

Acoustic enhancementLess attenuation compared to liver

Pancreas

Normal is routinely difficult to visualizeEchogenicity similar to surrounding fatNo defined capsule

Less echogenic then spleen, more echogenic then liver

Right limb just dorsal to duodenumMore likely to see in puppies, thin dogs, or

with free abdominal fluid

Pancreatitis

Acute - surrounded by a hyperechoic areaDue to peri-pancreatic fat necrosis

Severe - mixed echogenicityChronic - hyperechoic pancreas

Due to pancreatic fat necrosis

Pancreatic pseudocystsMass effect

Pancreas

NeoplasiaDifficult to identifyLooks similar to pancreatitis (mass effect)Fluid accumulationInvasion of surrounding tissuesEvidence of metastasis in other organs