Imaging of renal tract Flashcards
As a GP (in the community). When do you consider renal imaging?
- abdominal mass
- drop in renal function
- infection -> but not everyone (if recurrent UTI and in men)
- haematuria
In hospital (acute setting), when would you consider renal imaging?
- abdominal mass
- decreased renal function
- infection
- renal trauma - haematuria (?)
When to consider renal imaging in a hospital (outpatient) setting?
- follow up of malignancy
- congenital abnormalities
What pathologies of kidney is a renal imaging good to look at? What are not?
- Good: masses, stones
- Not suitable: glomerulus, tubular conditions *
* these are diagnosed by renal biopsy
Advantages of X-ray
cheap, quick and lower dose compared to CT
*but limited information provided (as compared with CT)
What can we use x-ray for (in terms of the renal system)?
- useful for radiopaque stones
*not used for gallstones as they contain fat/cholesterol
What landmarks on X-ray would allow us to identify kidney?
- psoas muscle
- L2 vertebra
What is this?
Opacity in renal region -> renal calculi
What’s that?
Could be renal but also ureteric calculi
What’s the abnormality?
Some sort of calculi (we cannot really determine if it is within the ureters or in the bladder)
What’s that?
Staghorn calculi
*opacity in the vertebra -> belly bottom piercing
How do we achieve intravenous urograms?
What are they used for?
- contrast is injected IV -> it goes through the kidney
- delayed radiograph would show opacification of the collecting system
What conditions do we assess for by the use of intravenous urogram?
- hydronephrosis (dilatation of renal pelvis/urethra)
- ureteric reflux (incompetent valve in the bladder -> urine backup) *
*now CT used more for that
What’s that?
Hydronephrosis (on the R) - dilated ureter
How does ultrasound work? How is the image formed?
USS
- high-frequency sound waves transmitted through the tissues
- forms an image by measuring the time taken by the echoes to return
Advantages of USS
- do not use radiation
- portable
look at the image of the kidney on USS
What’s that?
Hydronephrosis - renal pelvis is seen and grossly dilated
What’s that?
Image of the bladder - used also to assess the volume
*scan before the pt goes to wee -> then scan after -> to assess the amount of residual volume
What’s that?
Calculi in the bladder -> stone
What the difference between these two images?
on the first one: we cannot see past the mass’ -> possibly stone
on the right one: we can see it has a similar structure to the tissue around it -> bladder polyp
Pros and cons of ultrasound
- Pros: cheap, quick, portable, no ionising radiation, good detail in children, can assess vascularity (doppler function), real-time imaging
- Cons: difficult in obese (as the waves go through lots of fat), operator dependent, technical limitations
What’s the principle of CT scan?
multiple x - rays from different angles
Just look at the picture of that CT scan
