Veterinary Ultrasound

B- mode scan zones

Transducer Marker

Sagittal view: marker faces cranially

Transverse view: marker faces right side of patient

Echogenicity of common organs

• spleen is hyperechoic to liver

• liver is hyperechoic (or isochoeic) to renal cortex

• renal cortex is hyperechoic to renal medulla

Liver

• coarsely grained 

• large vessels, gallbladder is visible

• diaphragm lies beneath the liver

• portal veins have clearly defined, bright, hyperechoic walls

• hepatic veins have poorly defined walls

• Function:

- digestion and absorption of nutrients

- synthesizing nutrients and regulating their release into the bloodstream 

- excreting toxic substances 

- producing most plasma proteins, cholesterol, and many of the blood coagulation factors

Spleen

• elliptical, flat, with smooth contours

• more echogenic than liver

• may see splenic sinusoids

• Function:

- stores RBC and produces RBC during fetal development

- filters the blood and lymph

GI tract

• stomach is caudal to liver on midline in canine and to the left in feline

Pancreas

• medial to the duodenum on right side

• echogenicity similar to liver

• Function:

- has exocrine and endocrine functions

- produces important digestive enzymes (exocrine)

- produces hormones and deposits them directly into the bloodstream

Kidneys

• pelvis, cortex, and capsule are visible

• adrenal glands are a dumbbell shape and are just cranial to the kidneys

• Function:

- production of urine to facilitate the elimination of metabolic waste materials from the body

- helps maintain homeostasis by manipulating the composition of blood plasma

Urinary bladder

• bladder wall should be smooth and uniform 

• routinely used to collect urine sample via cystocentesis

• Function:

- collect, store, and release urine

Acoustic Shadowing

• occurs at interfaces that reflect and/or absorb a significant portion of the U/S beam

• common with mineral interfaces (bones, calculi, foreign bodies)

Edge Shadowing

• most common with round fluid filled structures

• occurs at edge parallel to the sound beam

• causes a dark shadow from edge of structure

• gallbladder, urinary bladder, cysts, and sometimes kidneys

Reverberation (Ring Down)

• highly reflective surfaces

• sound waves bounce back and forth - produce echoic lines at regular intervals

• commonly caused by gas or free air

Comet Tails

• type of reverberation artifact seen with gas interfaces 

• smaller width strong lines produced 

• air pockets in GI tract or metallic objects, a foreign body, or tip of a biopsy needle

Mirror Image

• caused by highly reflective curved surfaces 

• produces duplicate of structure deep to reflective surface

• most common - liver will appear in thorax due to diaphragm

Acoustic Enhancement

• increased echogenicty of tissue deep to an area or structure

• often seen deep to fluid filled structures

AFAST

• Abdominal Focused Assessment with Sonography for Trauma

• rapidly identify free fluid in the peritoneal space

• blunt trauma cases

• performed ASAP and repeated PRN

• 4 specific areas in the abdomen examined

• scoring system for abdominal fluid 0-5

TFAST

• Thoracic Focused Assessment with Sonography for Trauma 

• used for detection of free air and free fluid 

• 5 specific areas in thorax are assessed 

• emergency medicine, monitoring post surgery complications 

• used with suspected pneumothorax, hemothorax, pyothorax