Imaging of The Urinary System Flashcards
What are the indications of renal imaging?
Renal colic and renal stone disease
Haematuria
Suspected renal mass
UTIs
Hypertension
What are the different imaging techniques for the kidney?
Plain film
Contrast studies
–IVU
–Pyelography: antegrade, retrograde, ileal conduit
–Cystography
Ultrasound +/- contrast
CT and CTU
MR and MRU
Isotope scans
PET-CT
Define IVU
Intravenous urogram
- IV injection of contrast allowes visulisation of the renal parenchyma, renal pelvis and calyces
Advantages and disadvantages of plain films
Advantages
–Cheap and readily available
–Functional and anatomical information (IVU)
Disadvantages
–Low sensitivity and specificity for urological diseases
–Radiation
What is pyelography?
Injection of contrast into the ureters
What does micturating cystourethrography assess?
Vesico - ureteric refulx and its grade
What are the advantages and disadvantages of US?
Advantages
–Cheap and readily available
–No radiation
–Contrast is not nephrotoxic
–Real time imaging
Disadvantages
–Limited by body habitus and gas
–Poor visualisation of ureters
–Operator dependant
–No functional information
What is ureterocele?
Ureterocele
(cystic outpouching of ureter into bladder)
What are the advantages and disadvantages of a CT?
lAdvantages
–Currently the imaging modality of choice for detection of renal stones, staging renal tumours, investigation of hematuria
–Good spatial resolution with capability of multi planar reformat
lDisadvantages
–Radiation dose
–Cost
–Contrast resolution less than MR
–Contrast reaction and nephrotoxicity
What are the advantages and disadvantages of MR
lAdvantages
–Multiplanar imaging
–Excellent contrast resolution
–Imaging of urothelium without contrast injection (MRU)
lDisadvantages
–Poor spatial resolution
–Poor detection of calcification and stones
–Cost
–Contraindications: pace maker, claustrophobia,etc
–Contrast reaction and other side effects
What are the different isotope scans and what are the used for?
DMSA - renal scarring
MAG3 - Assess renal function and drainage
Bone scan - metastatic disease e.g prostate cancer
Why does PET CT have limited use in urinary system?
Limited use in staging of urological malignancies due to high uptake in urine and variable uptake by tumours.
When might PET-CT be useful?
May be useful for extra-urological metastatic disease if other imaging modalities are equivocal or in poor surgical candidates
What is the best imaging modailty to diagnose renal tract stones?
CT
What is the best imaging modality for the staging of renal tumours?
CT
