Diagnosing Urolithiasis of the Urinary Bladder, Kidneys, and Ureters in Dogs Using Radiology and Ultrasonography
Dr. Geoff Carullo, DVM, FPCCP, DPCVSCA
- Articles
- 5 min read
A dog with urinary stones can present with anything from mild hematuria to life-threatening acute kidney injury. The challenge for veterinarians is not simply identifying the presence of stones, but determining their exact location, size, number, and whether they are causing obstruction.
The combination of radiography and ultrasonography remains one of the most powerful diagnostic approaches for canine urolithiasis.
The images shown in this case demonstrate why both modalities are often necessary.
Survey radiographs remain the first-line imaging tool for many urinary stone cases.
In this patient, the abdominal radiographs reveal multiple mineral-dense structures within the urinary tract. Radiopaque calculi are visible in the region of both kidneys and along the urinary tract.
Radiography is particularly useful for:
Radiographs are highly sensitive for mineralized calculi but may miss radiolucent stones such as urate and cystine uroliths.
While radiographs identify mineral opacities, ultrasonography provides information about soft tissues and urinary tract function.
In this patient, ultrasound images demonstrate:
The ultrasonographic appearance of ureteral obstruction typically includes:
Color Doppler can further assist in identifying vascular structures and differentiating vessels from dilated ureters.
Many bladder stones cause discomfort.
Ureteral stones can destroy kidneys.
A ureterolith may obstruct urine flow from the kidney to the bladder. Even partial obstruction can lead to progressive renal damage.
Common findings include:
Dogs with bilateral ureteral obstruction may rapidly become critical patients.
Neither radiography nor ultrasonography should be considered sufficient in every case.
Radiography answers:
“Where are the stones?”
Ultrasound answers:
“What are those stones doing to the urinary tract?”
Together they allow clinicians to:
This multimodal approach often determines whether a patient requires medical management, cystotomy, ureterotomy, ureteral stenting, SUB placement, or referral for advanced intervention.
When evaluating dogs with hematuria, dysuria, pollakiuria, recurrent urinary tract infections, or unexplained azotemia, always remember that stones may exist in multiple locations simultaneously.
A bladder stone may be the most obvious finding.
The kidney stone may be the most important finding.
But the ureteral stone may be the one that ultimately threatens the patient’s life.
Radiographs help us see the stones.
Ultrasound helps us understand their consequences.
Using both imaging modalities together gives veterinarians the best opportunity to accurately diagnose and successfully manage canine urolithiasis.
BSAVA Manual of Canine and Feline Nephrology and Urology
American College of Veterinary Internal Medicine Consensus Recommendations for Management of Urolithiasis in Dogs and Cats.
International Renal Interest Society Guidelines on Obstructive Uropathy and Acute Kidney Injury.
Berent AC. Ureteral Obstruction in Dogs and Cats: Diagnosis and Interventional Management. Veterinary Clinics of North America: Small Animal Practice.
Nyland TG, Mattoon JS. Small Animal Diagnostic Ultrasound.
Thrall DE. Textbook of Veterinary Diagnostic Radiology.
Dr. Geoff Carullo is a Fellow and the current President of the Philippine College of Canine Practitioners.
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