Interventional Radiology Flashcards
What is IR?
- FLuoroscopy
- cystoscope
- Bronchoscopy
- Endoscopy
What advantages of IR?
- Decreased mortality in many cases
- Minimise an aesthetic times
- Reduced hospitalization
- Often reduced costs to clients
What conditions can Ir be useful in?
- Urinary (stones, incontinence, tumors, strictures, haematuria, infections)
- Respiratory (tracheal collapse, NP stenosis)
- Vascular -> intrahepatic shunts
- Oncology -> intra-arterial chemotherapy
Describe urinary stones
- Cause ureteral obstructions
- Most commonly due to stones (Strictures/neoplasia)
- More common in cats
- Underdiagnosed
- US appearance not predictive of return to function
What sizing of renal pelvis may mean obstruction on US?
Renal pelvis >1cm is obstructed
Renal pelvis >0.7cm is highly likely obstructed
What is most common stone obstruction?
Calcium oxalate - cannot be dissolved
What should you do in all azotaemic patients?
Ultrasound and radiograph
What medical management of stones?
- IVFT (2-4ml/kg/hr)
- Many older cats have cardiac dx - easy to volume overload
- Monitor weight and resp rate
- Prazosin (0.5 mg/cat)
- Buprenorphine
- Mannitol
What traditional surgery for stones?
Ureterotomy
- 20% mortality rate
- Post op strictures in 40%
- feline ureteral diameter <0.4mm
What other procedure can be done for stones?
Subcutaneous Ureteral Bypass (SUB)
What complications of SUB procedure?
- Associated mortality 5%
Kinks in 3% SUBs
Re-occlusion in <15% (7% require exchange)
What about stents?
- Can be placed via cystoscope
- Tolerated better in dogs than cats
- cats can develop pollakiuria
- Associated with irritation in people
- Stents are safe and effective at relieving obstruction
- Very few complications
Describe Ectopic Ureters
- Most common cause of incontinence in young females
- Inappropriate positioning of ureteral orifice
- 95% intra-mural : suitable for laser correction
What concurrent abnormalities are common with ectopic ureter cases?
- USMI (85%)
- Persistent paramesonephric remnant (90%)
- Hydroureter in males (80%)
- Recurrent Urinary Tract Obstruction
Intra vs Extra mural Ectopic Ureter?
In terms of detection/ diagnostic of ectopic uireter what is best?
Cystoscope replaces need for Ct studies
- Cheaper
- No nephrotoxic contrast given
- can laser correct at same time
BUT need to be trained in cystoscopy
Detail Traditional surgery option for tax of ectopic ureter
- 50% regain continence
- Up to 50% develop hydroureter
- 14% urea do en
Detail Laser correction option as to of ectopic ureter
- 50% completely continent post procedure
- Discharge same night with no recovery period
- Correction of PPMR may reduce infections
Describe tracheal Collapse
- Progressive degeneration of tracheal cartilage resulting in DV flattening of membrane
- Small breeds - Yorkshire terrier and Pomeranians
- Focal or generalised disease
- Viscious cycle of cough and inflammation
Diagnosis of tracheal collapse?
-> Radiographs
- dynamic process
- Obtain expiratory films
- assess for pneumonia
-> Bronchoscopy
- Requires anesthesia
- May not be the easiest patient to recover
- Allows BAL
-> Fluroscopy
Accessibility
Medical Management of tracheal collapse?
- Antitussives - codeine
- Steroids
- Trazadone
- Bronchodilators
- ABs
-> 75% respond to medication and environmental mods
What options when medication is no longer effective?
Tracheal stenting - considered salvage procedure => generally reserved for grade 3 or above
Describe Stenting?
- Minimally invasive
- Important to measure properly
Too small - stent migration
Too big - pressure necrosis of wall
=> stent entire trachea (1cm to larynx to 1cm cranial to carina)
Is long term meds still required after stent?
YES
Complications of stents?
- Stent fracture in 5%
- Granulation tissue in 30%
-> Steroids, colchicine, Laser therapy, 2nd stent placement
Describe IA chemo
- Targeted chemotherapy
- Significantly greater C° to the tumor
- Proven efficacy in certain canine tumors
- Most work carried out in liver, urinary and osteosarcoma
How do we admin IA chemo?
Access via carotid or femoral artery
When might we want to use urethral stents?
- Transitional Cell Carcinoma
- Strictures
- Stones
- Proliferative urethritis
What aftermaths of urethral stents?
- 15-20% will have some degree of incontinence
- Length and position of stent doesn’t influence continence
- Follow up NSAID and chemo
