Equine imaging

Ultrasound

Can be used to image the kidneys, ureters (limited), bladder, urethra

Transabdominal or transrectal

Echogenic

Urine will appear ___ because it normally contains mucus and crystals.

Echogenic, acoustic shadow

Calculi are highly ___ and produce an ____.

L 15-17th ICS and paralumbar fossa

Left kidney

R 15-17th ICS

Right kidney

Hydronephrosis

No corticomedullary junction

No evidence of internal architecture

Ureters

Can be imaged via ultrasound at trigone region of bladder

Pulsatile bursts of urine can be visualized

Bladder

Can be visualized via transrectal ultrasound

Round to oval structure containing heterogenous swirling urine

Wall thickness varies

Ruptured bladder in foals

Free fluid in abdomen

Small bladder

Urethra

Can be ultrasounded transrectally

• Seminal vesicles visible in males

No difference in diameter or wall thickness between males and females

Cytoscopy

Direct imaging of urethra and bladder

Evaluate health of mucosa

Visualization of bladder/urethral stones

Evaluation of urine output from each ureter in trigone region

Normal urine is cloudy in appearance

Stones can vary in size, shape, and appearance

Stones in cytoscopy

Most commonly spiculated and yellowish-brown

Calcium carbonate

Urethroscopy

Urethral defects communicating with corpus spongeosum can lead to clinical signs of hematuria and/or hemospermia

Urethral obstructions can be directly visualized

Ureteropyeloscopy

Reported technique but not commonly used clinically

Requires a surgical procedure in males (perineal urethrotomy)

Radiography

Not feasible in adult horses

Contrast ___ used in foals in a limited number of cases

• Diagnosis of ruptured bladder

• Diagnosis of congenital abnormalities, e.g. hydronephrosis, ectopic ureter

CT

Using contrast enhancement to diagnose a ureteral tear in a foal

Chromocystoscopy

Methylene blue dye sprayed via catheter on the bladder walls

• Inflamed areas show as stained (diffusely or focally)

Ultrasound in bovids

Similar to horses— can examine transabdominally or transrectally

Cannot visualize the entire left kidney in a single view, so estimates of size are difficult to obtain

No renal pelvis

Normal urine is anechoic

Urethral lumen only visible when urine present

Neoplasia

Bladder tumors commonly associated with bracken poisoning

Ultrasound, contrast-enhanced CT

In small ruminants, ___ and ___ are used to visual proximal abnormalities.

Horse

Are the kidneys of small ruminants more similar to the horse or to the cow in appearance?

Radiography, ultrasound

In small ruminants, ___ is feasible to diagnose urinary calculi (calcium carbonate) due to their smaller size.

___ is used for non-radiopaque stones.

Horse

Are the kidneys of camelids more similar to the horse or to the cow in appearance?

Ultrasound, endoscopy

What are the most commonly used diagnostic imaging techniques for the urinary tract of large animals?

Ultrasound

Kidney anatomy/architecture is species-specific and can best be evaluated via ___.

Infection/infarction, dilation, neproliths

What are examples of kidney pathology that can be found via ultrasound?

Endoscopy

Useful for direct visualization of the urethra and bladder

Inflammation/irritation (e.g. cystitis), urolithiasis, neoplasia, urethral tears

What are some examples of urethra and bladder pathology that can be found via endoscopy?

Radiography, CT

___ and/or ___ may be of use in smaller animals.