Lecture 10: Radiology of the Renal Tract Flashcards
list the indications for renal imaging
- renal colic and renal stone disease: diagnosis and follow up
- haematuria
- suspected renal mass
- UTIs
- hypertension
what are the advantages and disadvantages of plain film x rays?
advantages:
- cheap
- readily available
- functional and anatomical information (IVU)
disadvantages:
- low sensitivity and specificity for urological diseases
- radiation
what is pyelography?
Intravenous pyelography (IVP), or intravenous urography, is a diagnostic test that involves the administration of intravenous contrast and X-ray imaging of the urinary tract e.g. into ureters.
what does micturating cystourethrography involve?
- injecting contrats into bladder and urethra to observe as x-ray > vesico-ureteric reflux and its grade.
US advantages
- cheap and readily available
- no radiation
- contrast is not nephrotoxic
- real-time imaging
US disadvantages
- limited by body habitus and gas
- poor visualisation of ureters
- operator dependant
- no functional info
CT advantages
- currently the imaging modality of choice for detection of renal stones, staging renal tumours, investigation of haematuria.
- good spatial resolution with capability of multi planar reformat
CT disadvantages
- radiation dose
- cost
- contrast resolution less than MRI
- contrast reaction and nephrotoxicity
MRI advantages
- multiplanar imaging
- excellent contrast resolution
- imaging of urOthelium without contrast injection (MRU)
MRI disadvantages
- poor spatial resolution
- poor detection of calcification and stones
- cost and longer acquisition time
- contraindications: pace maker, claustrophobia, etc.
- contrast reaction and other side effects
what condition does this MRU show?
duplex collecting system
what does this MRU show?
horseshoe kidney
list the types of isotope scans and what urological thing they are useful for detecting
DMSA (dimercaptosuccinic acid):
- to look for renal scarring
MAG3 (mercaptoacetyltriglycine):
- assess renal function and drainge
Bone scan (Tc 99 MDP methylene disphosphonate):
- metastatic disease e.g. prostate cancer
what does this US show?
hydronephrosis
The US shows hydronephrosis with an undilated ureter, indicating PUJ obstruction. What other imaging test(s) would you like to request?
- CT: assess anatomy and cause of obstruction e.g. stone, tumour
- MAG3: assess function
- or MRI
what is the management for a PUJ obstruction causing hydronephrosis?
- confirm diagnosis of PUJ
- exclude an aberrant renal artery
- treatment: interventional radiology, surgery
what imaging would you request for a patient with medically resistant hypertension and suspected renal artery stenosis?
- MRI angiography
- CT angiogram
how would you manage renal artery stenosis?
conventional angiography
dilation and stent
