Clinical techniques Flashcards
What are the 2 broad types of radiography used in urology?
Plain (survey)
Contrast
What are the benefits of a contrast radiograph over a plain?
Gives more detail
What are the key points in radiography in urology?
- Need to radiograph whole abdomen
- Usually in VD (everything spreads)
- Starve 24 hous (faeces/urine obsscure view)
- GA or sedation
- Positioning, centring and collimation important
What is the correct positioning, centring and collimation to take a radiograph of the abdomen?
- VD, avoiding axial rotation using cradle for example
- centre on caudal border of last rib
- collimate to greater trochanter, spine and skin edges
What is meant by positive contrast agents? Give examples
- Appear more radiopaque than surrounding body tissues
- High atomic number e.g. barium or iodine
What is meant by negative contrast agents? Give examples
- Appear more radiolucent than surrounding body tissues
- Gases e.g. air or CO2
What types of radiography can be used to visualise the urethra?
- Plain
- Retrograde ureothrography - contrast (males)
- Retrograde vaginourethrography - contrast (females)
- Plain will only show if abnormal
List the types of contrast radiography that are used in urology
- Intravenous urography (IVU)
- Retrograde vaginourethrogram
- Retrograde cystogram
- Retrograde urethrogram
What are the benefits of an intravenous urography?
- Provides anatomical and functional info about kidneys
- Specific information obtained at each stage of IVU
What are some of the contraindications for an IVU?
- Dehydration/hypovolaemia
- Severe renal failure/anuria
What are the 2 techniques used for IVU?
- High concentration/low volume (inject bolus into peripheral vein)
- Low concentration/high volume (contrast given in IV drip)
Describe the technique for a retrograde vaginourethrogram
- Foley catheter or urinary catheter plus clamp
- Inject diluted iodine contrast media (careful to avoid vaginal rupture)
- Lateral views most helpful, VD maybe for some abnormalities
- Contrast into vagina via catheter, flows inot urethra
Describe the techniue for a retrograde cystogram
- Survey films lateral and VD
- Catheterise, empty, flush bladder
- Inject contrast medium until bladder just turgid (2 day old party balloon)
- Negative, positive or double contrast
What are the benefits and indications for use of negative contrast radiography?
- Cheap, readily available
- Useful to identify bladder, show position and wall thickness
- Poor mucosal detail, may miss small tears
What is the indication for use of positive contrast radiography?
- Suspected bladder rupture
- Expensive, need a lot
What is a double contrast cystogram and what are the benefits?
- Uses negative and positive contrast agents
- Excellent detail
- Useful contrast to see radiolucent calculi for example
Describe the technique for a retrograde urethrogram
- Catheterise urethra (widest possible)
- Position tip distal to area under investigation
- Clamp sheath tightly around catheter
- Inject diluted water soluble contrast medium
- Mix with gel, keeps distension of urethra long enough to take radiograph
- Exposure immediately after end of injection
- Lateral most helpful
What imaging modalities can be used in urology?
- Radiography
- Ultrasonography
- CT
- Endoscopy
What views of the kidney can be achieved with ultrasonography?
- Sagittal
- Transverse
- Frontal (dorsal)
Describe the ultrasonographic appearance of the renal cortex
- evenly granular
- Hypoechoic (occasionally isoechoic) to the liver in dogs
- Often more echogenic in cats
Describe the ultrasonographic appearance of the renal medulla
- Hypoechoic to cortex
- Look for good “cortico-medullary” definition
- Should be able to distinguish the cortex and medulla
Describe the ultrasonographic appearance of the renal pelvis
- Echogenic peripelvic fat (hyperechoic)
What are the 3 layers of the bladder visible on ultrasonography?
- Inner mucosal interface
- Muscle layer
- Outer serosal layer
What is the echogenicity of the inner mucosal interface of the bladder?
Hyperechoic