Diagnostic Imaging: Urogenital Tract

Question 1

What are the common clinical presentations that indicate urogenital imaging?

What are the commonly available methods?

Answer 1

Multiple:
* Pllakisuria, stranguria, discoloured urine, polyura, anuria, incontinence, vulval discharge

Commonly availabel: radiography, contrast radiography and ultrasound

Question 2

What are the positive and negatives of radiography, contrast radiography and ultrasound?

Answer 2

Plain radiography
* Adv- shape, size, location, readily accessible, low risk, easy
* Dis- Limited information, ionising radiation

Contrast radiography
* Adv- adds internal architexture, luminal space and ureters
* Dis- Ionising radiation, slight increased risk, operator dependent

Ultrasound
* Adv- high quality, fast, readily accessible, no radiation, low risk
* Dis- highly operator dependent

Question 3

When are the uterus and ovaries visible on radiographs?

How are they found on ultrasound?

Answer 3

Not visible on radiographs unless greatly enlarged

Ultrasound: difficult
Located between the urinary bladder ventrally and descending colon dorsally

Question 4

Describe a radiograph/ultrasound of a pyometra

Answer 4

Radiograph
* Dilated, soft tissue opacity loops originating between bladder and colon
* Mass effect displacing the intestines cranially and dorsally

Ultrasound:
* Fluid dilation of the uterine horns and dody
* Thin or thick, cystic wall

Question 5

Describe the normal prostate radiography:
1. Location
2. Size
3. Shape
4. Opacity

Answer 5

1. Caudal to the bladder- partly within the pelvic canal
2. Dependent on neutering status- entire < 70% height of the pelvic inlet
3. Symmetrical, ovoid to round, urethra centrally
4. Homogenous soft tissue opacity

Question 6

What can cause protatomegaly?

Answer 6

Benign prostatic hyperplasia
* Entire dogs
* Symmetrical enlargment
* Soft tisse opacity

Prostatitis
* Entier dogs
* Marked enlargment- irregular shape- mineralisation

Neoplasia
* More in castrated dogs
* Mineralisation
* Irragular shape ± serosal detail

Question 7

How does a prostatic neoplasia radiograph appear?

Answer 7

• In neutered dog mineralisation very specific for neoplasia
• Often asymmetrical and irregular shape
• Metastasis to the medial iliac lymph nodes and lumbar vertebrae and lung

Question 8

What positive and negative contrast media can be used?

Answer 8

Positive
* Iodine containing- ionic/no-ionic or high or low osmolarity

Negative
* Air
* CO2 or N2O

Question 9

What is the best study to assess mucosal detail of cystography?

What can be identified?

Answer 9

Double contrast cystography

• Calculi- dentral defects in contrast pool
• Blood clost- may adhere to bladder wall, often irregular
• Air bubbles- iatrogenic at the pool margins

Question 10

How is cystography performed?

Answer 10

• Catheterise and empty bladder
• Instill/insufflate with contrast medium until reasonably distended

Question 11

What is intravenous urography?

What is needed for a diagnostic study?

Answer 11

IV injection of iodine-based contrast mediun and documentation of its transition through the kidneys, ureters and into the bladder with multiple radiographs

Diagnostic study requires:
* Adequate renal function and hydration
* Good patient preparation
* GA/heavy sedation
* Multiple VD and lateral radiographs at short intervals

Question 12

How is retrograde urethrogram/vaginourethrogram performed?

Answer 12

• Catherterise, empty bladder
• Plave catheter tip in
• Inject iodine-baded medium

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Question 13

What type of study is best for bladder, urethra, ureters and kidneys?

Therefore what are the indications for Retrograde urethrogram, IVU, cystrography?

Answer 13

Cystography- bladder
* Radiolucent calculi, bladder masses, rupture, chronic cystitis

Retrograde urethrogram- urethra
* Stranguria- stenosis, inflammation, urethrolith
* Integrity
* Ectopic ureter

IVU- ureter, kidneys
* Suspected ectopic ureter
* Ureteroliths
* Ureteral stenosis
* renomegaly
* integrity

Question 14

How does a normal bladder appear on radiography and ultrasound?

Answer 14

Radiography
* Pear shaped, smoothly marginated, soft tissue opacity in caudoventral abdomen

Ultrasound
* Pear-shaped organ in the caudal abdomen with anechoid contents

Question 15

How doe chronic cystitis appear on radiographs and ultrasound

Answer 15

Radiograph- has to be double contrast
* Thickened wall
* Irregular mucosa
* Blood clots

Ultrasound
* Irregularly thickened wall
* Blood clots

Question 16

How do bladder calculi appear on radiographs and ultrasound?

Answer 16

Radiographs
* Accumulate in the most dependent part of the bladder
* Visibility depends on radiopacity and size-
struvite, oxalate, calcium phosphate: moderate to marked
Silicate: moderate
Cystine and urate: non-opaque

Ultrasound
* Strong distal shadowing

Question 17

How can bladder masses be imaged?

Answer 17

• Not visible on plain radiographs
• Defect in the contrast pool or soft tissue opacity on pneumocytogram

Ultrasound- sessile, polpoid echoic mass

Question 18

Where are the predeliction sites for bladder masses?

Answer 18

Trigonum
Dorsal bladder wall

Question 19

How can bladder rupture be imaged?

Answer 19

• Plain radiographs: may see loss of serosal detail and small bladder
• If suspected do positive contrast cystography- leakage of contrast
• US rarely able to show defect but will see free fluid

Question 20

What can be indentified on urethra radiography?

Answer 20

Calculi- defect in contrast colum
Mural lesions- narrowing of contrast column

Question 21

Describe normal kidneys on a radiograph
1. Location
2. Opacity
3. Shape
4. Margination
5. Size

Answer 21

1. Retroperitoneal space- left kidney more caudal
2. Homogenous soft tissue opacity ± fat at the hilus
3. Bean-shaped in dog- more rounded in cats
4. Sharp and smooth
5. Best assessed on VD radiographs
   Dog: length 2.5-3.5x L2 body
   Cat- length 2-2.6x length of L2 body

Marked enlarmgent of kidnets causes mass effect- ventrally displaced colon

Question 22

How does a normal kidney appear on ultrasound?

Answer 22

Cortex
* Echoic, similar to hypoechoic liver

Medulla
* Near anechoic, least echogenicity of all organs

Renal pelvis and diverticula
* Hyperechoic
* Should not contain any urine

Question 23

What can cause irregular or smooth renomegaly?

Answer 23

Irregular- focal
Unilateral
* Neoplasia, cyststs, abscess, haematoma

Bilateral
* Neoplasia/metastasis
* PKD
* FIP

Smooth- generalised
Unilateral
* Neoplasia
* Hyronephrosis
* Perinephric pseudocyst

Bilateral
* AKI
* Pyelonephritis
* Lymphoma
* FIP

Question 24

What can be seen on ultrasound with pyelectasia and hydronephrosis?

Answer 24

Both show dilation of the renal pelvis

Pyelectasia
* mild to moderate dilation secondary to diuresis or inflammation

Hydronephrosis
* Moderate to severe often secondary to obstruction
* Overall enlargment of the kidney

Question 25

What can caude small kidneys?

Answer 25

CKD
Dysplasia
Atrophy

Question 26

How does CKD appear on enstage radiographs and ultrasound?

Answer 26

‘Classic enstage’: small and irregular but maybe smooth

Ultrasound: poor corticomedullary definition, small, irregular

Question 27

How do renal cysts appear?

Answer 27

• Thin walled
• Most unicameral
• DIstal acoustic enhancement
• May discort surface

Question 28

How do ureters appear on IVU radiography?

Answer 28

Location: retroperitoneum, lateral to spine on VD
Size- 1-2mm peristalsis
Ureteroveriscular junction: J-shaped, in the trigonal region, ureteral jets