06: Abdominal Ultrasound

Opacity scale for ultrasound

• Anechoic: fluid

• Hypoechoic: soft tissues

• Hyperechoic: bone/air

How would you orient the probe to get a sagittal view

Parallel to the spine; may also be parallel to the long axis of the organ you are scanning

How would you orient the probe to get a trasverse view

Perpendicular to the spine; may also be parallel to the short axis of the organ you are scanning

Best way to prep a patient for abdominal ultrasound

• Fast the animal

• Let them out to empty their bladder

• Shave the animal

• Lots of alcohol and gel

Reason we shave a patient for ultrasound

Hair traps and disrupts sound waves, making for poor quality images

Proper way to position a patient for an abdominal ultrasound

Dorsal recumbency with their head towards the viewing screen

Organs that can/should be scanned when you do an abdominal ultrasound

• Liver and gallbladder

• Stomach

• Right kidney and adrenal

• Duodenum and pancreas

• Left kidney and adrenal

• Spleen

• Colon: ascending, transverse, descending

• Small intestines

• Urinary bladder and prostate

• Gonads

• LNs

Proper way to conduct a thorough ultrasound

Have a system so that you scan every organ in sagittal and transverse views

How do you decide if an organ has a normal echogenicity

Compare to other organs that you know should be more/less echogenic

Scale of echogenicity in abdominal organs

For most cats love sunny places

• Fluid: anechoic

• Medulla (renal)

• Cortex (renal)

• Liver

• Spleen

• Prostate

• Peritonitis: hyperechoic

Which kidney is harder to find and why

Right kidney → higher up, may be under the ribs

Normal US features to find on the kidney

Distinct differentiation between cortex and medulla

Normal US features to find on the urinary bladder

• Anechoic urine

• Normal wall for the volume contained (contracted or stretched out?)

What should you do if you see an abnormality in the bladder

Shake the bladder to see if it is attached or gravity dependent

Part of the bladder that cancer loves to set up shop in

Trigone region

US artifact seen when there are stones

Distal shadowing

Spleen difference between cats and dogs

• Dog spleens are large and can even cross midline

• Cat spleens are small!

Normal US features to find in the spleen

• Texture should be homogenous

• Hyperechoic capsule

• Anechoic vessels

• May be folded on itself

• Benign nodules are common

How to tell if splenic nodules are benign

Cytology :(

Likely diagnosis if you see a hyperechoic nodule on a spleen

Benign myelolipomas

US finding on the spleen that should make you very suspicious of cancer

“target lesions” → hypoechoic nodule with a hyperechoic center

Normal US findings on the proximal urethra

May not be visible if normal, lumen should be anechoic

US finding that indicates a urethral stone

Hyperechoic nodule, dilated urethra, distal shadowing

Normal US finding in the prostate

Homogenous and bilaterally symmetrical

Patients where it is normal to not see the prostate

• Males neutered early

• Male cats

• Females :)