Contrast imaging of the lower urinary tract Flashcards
Which views to take on xray of urethra and urinary bladder?
- orthogonal view of abdomen
- lateral view of caudal/perineal region (male dog)
Radiographic appearance - urinary bladder
- variable size
- pear shaped
- soft tissue opacity
- smooth margin- cuadoventral abdomen: ventral to colon, ventral to uterus/uterine stump, cranial to prostate, normally cranial to pubis
What are the different contrast studies of urinary bladder?
- retrograde (vagino-) urethrography
- positive contrast cystography
- double contrast cystography
- negative contrast cystography (pneumocytography)
Outline patient prepartion of contrast studies
- survey radiographs (colon empty? –> enema)
- GA
- urine sampling prior to contrast administration
+/- 2-5ml 2% lidocaine - contrast media (CO2, nitrous oxide vs. water soluble I2 based contrast media)
Outline a pneumocytsogram
- foley catheter inserted retrograde into the urinary bladder
- 4-11ml/kg gas (CO2, NO, room air)
- lateral (L and R) and VD
Why be careful doing a pneumocytsogram of animal with inflamed bladder
inflamed bladders don’t distend as much as normal bladders so care not to rupture!
Risks of overdistending bladder on pneumocytsogram
- rupture
- gas retrograde into ureters and renal pelvis (can bring infection up)
What contrast media should you use if you suspect a ruptured blader?
positive contrast
Describe contrast medium for cystogram
- 4-11ml/kg water soluble I2 based
- undiluted contrast if suspected rupture
- dilute to 25% concentration with saline for other indications
- prefill catheter with contrast medium
- VIEWS: lateral (L and R) and VD views
Procedure - double contrast cystogram
- empty urinary bladder
- small volume non-diluted I2 based contrast medium
- add gas (CO2, NO) at 4-11ml/kg
- reposition patient (‘roll’)
- VIEWS: L and R lateral, VD, +/- oblique views
Ddx - double contrast studies
- urolith (in middle of contrast puddle)
- blood clot (at rim of contrast puddle, give odd shape to edge)
- air bubble/ mural lesions (rim of contrast, bubbles - smal, regular outline; mural lesion - small to large, irregular outline)
Uses - positive contrast retrograde (vagino-) urethro-cystogram
- urethra
- vagina
+/- urinary bladder
Method - positive contrast study, retrograde (vagino-) urethro-cystogram
- catheter (foley for females with balloon tip)
- clamps
- 10-15ml water soluble contrast medium (dogs), 5-10ml in cats
- VIEWS: lateral views when injecting the last 2-3ml
Radiographic findings - positive contrast retrograde (vagino-) urethro-cystogram
- FILLING DEFECTS: lesion - intraluminal, mural, extramural
- EXTRAVASATION OF CONTRAST: rupture, fistula, diverticula
- ABNORMAL SHAPE, POSITION, NUMBER: strictures, displacement, duplications
How do you keep bladder full with positive contrast retrograde (vagino_) urethro-cystogram
- ideally prefill with contrast or saline
- 25% diluted water soluble I2 based contrast (dilute with saline)
- dynamic study )ideally fluoroscopy guided)
- Lateral views (+/- oblique)
