Diagnostic Imaging: Urogenital Tract Flashcards
What are the common clinical presentations that indicate urogenital imaging?
What are the commonly available methods?
Multiple:
* Pllakisuria, stranguria, discoloured urine, polyura, anuria, incontinence, vulval discharge
Commonly availabel: radiography, contrast radiography and ultrasound
What are the positive and negatives of radiography, contrast radiography and ultrasound?
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
When are the uterus and ovaries visible on radiographs?
How are they found on ultrasound?
Not visible on radiographs unless greatly enlarged
Ultrasound: difficult
Located between the urinary bladder ventrally and descending colon dorsally
Describe a radiograph/ultrasound of a pyometra
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
Describe the normal prostate radiography:
1. Location
2. Size
3. Shape
4. Opacity
- Caudal to the bladder- partly within the pelvic canal
- Dependent on neutering status- entire < 70% height of the pelvic inlet
- Symmetrical, ovoid to round, urethra centrally
- Homogenous soft tissue opacity
What can cause protatomegaly?
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
How does a prostatic neoplasia radiograph appear?
- 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
What positive and negative contrast media can be used?
Positive
* Iodine containing- ionic/no-ionic or high or low osmolarity
Negative
* Air
* CO2 or N2O
What is the best study to assess mucosal detail of cystography?
What can be identified?
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
How is cystography performed?
- Catheterise and empty bladder
- Instill/insufflate with contrast medium until reasonably distended
What is intravenous urography?
What is needed for a diagnostic study?
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
How is retrograde urethrogram/vaginourethrogram performed?
- Catherterise, empty bladder
- Plave catheter tip in
- Inject iodine-baded medium
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What type of study is best for bladder, urethra, ureters and kidneys?
Therefore what are the indications for Retrograde urethrogram, IVU, cystrography?
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
How does a normal bladder appear on radiography and ultrasound?
Radiography
* Pear shaped, smoothly marginated, soft tissue opacity in caudoventral abdomen
Ultrasound
* Pear-shaped organ in the caudal abdomen with anechoid contents
How doe chronic cystitis appear on radiographs and ultrasound
Radiograph- has to be double contrast
* Thickened wall
* Irregular mucosa
* Blood clots
Ultrasound
* Irregularly thickened wall
* Blood clots
How do bladder calculi appear on radiographs and ultrasound?
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
How can bladder masses be imaged?
- Not visible on plain radiographs
- Defect in the contrast pool or soft tissue opacity on pneumocytogram
Ultrasound- sessile, polpoid echoic mass
Where are the predeliction sites for bladder masses?
Trigonum
Dorsal bladder wall
How can bladder rupture be imaged?
- 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
What can be indentified on urethra radiography?
Calculi- defect in contrast colum
Mural lesions- narrowing of contrast column
Describe normal kidneys on a radiograph
1. Location
2. Opacity
3. Shape
4. Margination
5. Size
- Retroperitoneal space- left kidney more caudal
- Homogenous soft tissue opacity ± fat at the hilus
- Bean-shaped in dog- more rounded in cats
- Sharp and smooth
- 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
How does a normal kidney appear on ultrasound?
Cortex
* Echoic, similar to hypoechoic liver
Medulla
* Near anechoic, least echogenicity of all organs
Renal pelvis and diverticula
* Hyperechoic
* Should not contain any urine
What can cause irregular or smooth renomegaly?
Irregular- focal
Unilateral
* Neoplasia, cyststs, abscess, haematoma
Bilateral
* Neoplasia/metastasis
* PKD
* FIP
Smooth- generalised
Unilateral
* Neoplasia
* Hyronephrosis
* Perinephric pseudocyst
Bilateral
* AKI
* Pyelonephritis
* Lymphoma
* FIP
What can be seen on ultrasound with pyelectasia and hydronephrosis?
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
What can caude small kidneys?
CKD
Dysplasia
Atrophy
How does CKD appear on enstage radiographs and ultrasound?
‘Classic enstage’: small and irregular but maybe smooth
Ultrasound: poor corticomedullary definition, small, irregular
How do renal cysts appear?
- Thin walled
- Most unicameral
- DIstal acoustic enhancement
- May discort surface
How do ureters appear on IVU radiography?
Location: retroperitoneum, lateral to spine on VD
Size- 1-2mm peristalsis
Ureteroveriscular junction: J-shaped, in the trigonal region, ureteral jets
