IMAGING - Interventional Radiology Flashcards
What is interventional radiology?
Interventional radiology is the use of fluroscopic imaging to guide minimally invasive procedures that tradiotionally would require major surgery
What are guide wires?
Guide wires are atraumatic, flexible wires that are introduced into body cavities, vessels or lumens over which catheters and over devices can be fed to gain access to those cavities, vessels or lumens
What is one of the most common uses of guide wires?
Guide wire assisted chest drain placement
Watch the clip that demonstrates this (M17.W1 lecture)
Which species are most prone to ureteral obstruction?
Cats
Which three techniques can be used to relieve a ureteral obstruction?
Ureterotomy
Ureteral stent
Subcutaneous ureteral bypass (SUB)
Why are ureterotomies not typically done any more?
High complication rate including leakage, stricture and reobstruction
High mortality rate
What is a ureteral stent?
A ureteral stent is a thin, flexible, fenestrated tube which is placed inside the ureter to hold it open
What are the benefits of a ureteral stent?
Ureteral stents require no maintenance once placed
What are the limitations of a ureteral stent?
Ureteral stents are very challenging to place, especially in cats
What is a subcutaneous ureteral bypass (SUB)?
A subcutaneous ureteral bypass (SUB) is a procedure done under fluroscopic and guide wire guidance, involving the placement of a nephrostomy tube which sits in the renal pelvis and exits at the caudal pole of the kidney and connects to a subcutaneous access port which connects to a cystostomy tube which inserts into the urinary bladder. This system bypasses the ureters and drains the urine into the bladder
What are the benefits of a subcutaneous ureteral bypass (SUB)?
Easy to place
Can take urine samples and flush the system via the access port
What are the limitations of a subcutaneous ureteral bypass (SUB)?
The system has to be flushed and maintained regularly
How do you manage a subcutaneous ureteral bypass (SUB)?
The subcutaenous access port should be flushed under sedation every three weeks for the first year, and then every three to four months
What are the potential complications of ureteral stents and subcutaneous ureteral bypass (SUB)?
Blockage with uroliths, sediment of kinking of the tubing
Leakage
Urinary tract infection (UTI)
Which interventional radiology procedure can be done to correct an intrahepatic portosystemic shunt?
Percutaneous transvenous coil embolisation (PTCE)
Describe briefly the process of a percutaneous transvenous coil embolisation (PTCE) procedure
A percuteneous transvenous coil embolisation (PTCE) procedure involves stents and coils to occlude the intrahepatic shunt. Fluoroscopy and contrast is used to guide this procedure. A stent is passed along guide wires and deployed within the vena cava across the mouth of the shunt, with its role to stop the coils from migrating from the shunt into the vena cava. Then a series of coils are passed and these coils are thrombogenic and gradually the clot will occlude the vessel
