1.5 Diagnostic Imaging of the Urinary Tract, Prostate Gland, & Uterus

What are the indications for imaging the urinary tract?

Abdominal mass

Altered urination (dysuria, pollakiuria, hematuria)

Abdominal/pelvic trauma

Abnormal renal or urinary profile

Sampiling (cystocentesis, biopsy, etc)

What are the minimum radiographic projections needed when imaging the urinary tract?

Lateral of the abdomen

Ventrodorsal of the abdomen

Free lateral projection of the urethra (caudal abdomen & perineal)

Roentgen signs

Number

Location

Size

Shape

Margination

radiopacity

Describe the normal radiographic anatomy of canine kidneys

Number: 2

Location: retroperitoneal space

- Right: cranial, renal fossa, T13

- Left: More mobile, L1-L3, more caudal

Shape: oval (bean)

Margination: smooth

Opacity: soft tissue

Size: 2.5-3.5x L2 vertebra

Describe the normal radiographic appearance of feline kidneys

Number: 2

Location: Retroperitoneal space (L1-L4, right may be more cranial)

Shape: round or oval

Margination: smooth

Opacity: soft tissue

Size: 1.9-2.6x L2 vertebra (intact cats can be up to 3x)

Describe the normal radiographic appearance of the ureters in dogs & cats

Dogs: usually not visible

Cats: potentially visible, difficult to see

Describe the normal radiographic location of the urinary bladder

Caudoventral abdomen

Peritoneal cavity

Cranial to the pubis

Ventral to descending colon & uterine body/stump

Cranial to the prostate gland

Describe the normal radiographic appearance of the urinary bladder

Size: variable (filled or empty, species differences)

Shape: oval to ellipsoid (dogs) - ellipsoid in cats

Margination: smooth

Opacity: soft tissue

Describe the normal radiographic anatomy of the canine urethra

Normally not seen

Shorter & wider in females (more obstructions in males)

Describe the normal radiographic anatomy of the feline urethra

Normally not seen

Describe the normal radiographic location of the canine prostate

Surrounds prostatic urethra

Within the pelvic canal

Ventral to the colon

Caudal to the urinary bladder

Describe the normal radiographic appearance of the canine prostate

Size: <70% distance of pubis to sacrum

Shape: oval to round

Margination: smooth

Opacity: soft tissue

Mineralization indicative of neoplasia

Describe the normal radiographic appearance of the feline prostate

Typically not seen

Describe the normal radiographic location of the uterus

Ventral to colon

Dorsal to urinary bladder

Describe the normal radiographic appearance of the uterus

Shape: tubular

Margination: smooth

Opacity: soft tissue

not always visible unless distended

What are the general signs/characteristics being observed on ultrasonography?

Size

Shape

Margination

Echogenicity

Describe the normal appearance of a kidney on ultrasound (sagittal)

Shape: oval in dogs, more rounded in cats

Cortex: more hyperechoic

Medulla: more hypoechoic

Renal pelvis: v-shape, hypoechoic, up to 2 mm

Size: variable in dogs, 3.0-4.5 cm length in cats

Describe the normal appearance of ureters on ultrasound

Not always visible

Ureteral jets at uterovesical junction (Doppler) shows urine movement

Need to assess if renal pelvis is distended

Describe the normal appearance of the urinary bladder on ultrasound

Anechoic

Wall thickness <2 mm

urethra at the edge of the bladder trigone

Describe the normal appearance of the prostate gland in an intact male dog on ultrasound

Bilobed with smooth contour

Homogenous echogenicity

Central urethra visible

Describe the normal appearance of the prostate gland in a neutered male dog on ultrasound

Small

Round

Describe the normal appearance of the uterus on ultrasound

Tubular structure dorsal to the urinary bladder

Echogenic line in the middle (collapsed lumen, mucus)

Distended if in heat or with pathology (pyometra)

Describe the main radiographic findings in cases of nephromegaly/renomegaly

Enlarged kidney(s)

Ventral displacement of the gastrointestinal tract (mass effect)

What are some diseases that may show bilateral nephromegaly?

Lymphoma

Acute nephropathy

Hydronephrosis

What are some diseases that may show unilateral nephromegaly?

Hydronephrosis

Peri-renal pseudocyst

What are some diseases that may show bilateral nephromegaly with irregular margins?

Polycystic kidney disease

Neoplasia

What are some diseases that may show unilateral nephromegaly with irregular margins?

Mass lesion (cyst, neoplasia, abscess)

Nephrolithiasis

Presence of renal calculi (stones)

Main radiographic finding is increased opacity

What is a common radiographic abnormality of the urinary bladder diagnosed on radiography?

Calulus/calculi/urolithiasis

Radiopaque: Struvite or calcium oxalate

Non-radiopaque: Urate or cysteine

What are some causes/predispositions for development of urate calculi?

Portosystemic shunt

French Bulldog

Dalmatian

What are some abnormal findings on ultrasonography that would indicate urinary bladder calculi?

Abnormal echogenicity (normal urine is anechoic)

hyperechoic shadow interface

Thickened bladder wall

What are some characteristics of blood clots in the urinary bladder on ultrasound?

Heterogenous echogenicity (changes with probe movement)

Mobile

No shadowing

No blood flow on doppler

What are some characteristics of bladder neoplasia on ultrasound?

Heterogenous mass

Often located at trigone/prostate/urethra in dogs

May be at trigone or other bladder regions in cats

Important to check medial iliac lymph nodes

Check ventral aspect of lumbar vertebra on radiograph for metastasis to bone

transitional cell carcinoma is most common