Diagnostic Imaging of the Lower Urinary Tract Flashcards
What is a Pneumocystogram? What type of contrast does it use? What is it used to image? How is the contrast put in?
A pneumocystogram is a cystogram using negative contrast (gas etc. which shows up black). It is used to image the bladder (CYSTogram). Contrast put in using a foley catheter.
In which situation would you use a positive contrast cystogram over a pneumocystogram? Why?
Use a positive over a negative if there is a suspected bladder rupture. Why? Allows you to see where the leak is.
What is a double contrast cystogram? What situations is a double contrast cystogram good for imaging?
A double contrast cystogram involves putting in a small amount of positive contrast, then adding gas (negative contrast). It is good for imaging uroliths, blood clots and bubbles.
How would you distinguish uroliths in the bladder from blood clots and air bubbles/mass using a double contrast cystogram?
Uroliths tend to sit in the middle of the “puddle” of positive contrast, and are also quite round shaped.
How would you distinguish blood clots in the bladder from uroliths and air bubbles/mass using a double contrast cystogram?
They tend to be odd shaped (not round), and tend to adhere to the bladder wall.
How would you distinguish air bubbles/masses in the bladder from blood clots and uroliths using a double contrast cystogram?
They tend to be at the rim, and more fixed to the wall. Air bubbles are small and round, masses may look odd shaped.
What is a retrograde urethro-cystogram? How is it done? What is it used to image? What type of contrast is used?
A retrograde urethro-cystogram is done using positive contrast to image the urethra and bladder in a male dog using a catheter inserted into the proximal urethra, and then occluding the end.
What is a retrograde vagino-urethro-cystogram? How is it done? What is it used to image? What type of contrast is used?
A retrograde vagino-urethro-cystogram is done using positive contrast to image the vagina, urethra and bladder in a female dog using a catheter inserted into the proximal urethra and vagina.
How thick should the wall of the urinary bladder be on a normal ultrasound?
<2mm (be careful of folding making it look thicker)
When doing a retrograde urethro-cystogram, what is it important to look for in the urethra? How would you differentiate stones from air bubbles?
Look for strictures, trauma, stones etc.
Stones are harder to move and tend to lodge around the os penis etc. Also air bubbles tend to be more elongated than stones.
Where is the most common place for urethral neoplasia to occur? What is the most common type of tumour here?
Most common place is around the neck of the bladder in the trigonal area, it is most commonly a transitional cell carcinoma.
On ultrasound, how would uroliths sitting in the bladder look?
You can see them sitting on the wall, and they have shadows underneath indicating they are heavy and cannot be penetrated.
On ultrasound, how would blood clots sitting in the bladder look?
They look a lot like tissue, but they are not attached to the bladder wall.
