radiology of the renal tract Flashcards
what imaging techniques are available?
Plain film
Contrast studies
IVU
Pyelography: antegrade, retrograde, ileal conduit
Cystography
Ultrasound +/- contrast
CT and CTU
MR and MRU
Isotope scans
PET-CT
what are indications of renal imaging?
Renal colic and renal stone disease
Diagnosis and follow up
Hematuria
Suspected renal mass
UTIs
Hypertension
what are advantages of plain films?
Cheap and readily available
Functional and anatomical information (IVU)
what are disadvantages of plain films?
Low sensitivity and specificity for urological diseases
Radiation
what are alternate contrast studies?
pyelography
Injection of contrast into the ureters
Micturating cystourethrography
Vesico-ureteric reflux and its grade
what are advantages of ultrasound?
Cheap and readily available
No radiation
Contrast is not nephrotoxic
Real time imaging
what are disadvantages of us?
Limited by body habitus and gas
Poor visualisation of ureters
Operator dependant
No functional information
what are advantages of CT?
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
what are disadvantages of CT?
Radiation dose
Cost
Contrast resolution less than MR
Contrast reaction and nephrotoxicity
what are advantages of MRI?
Multiplanar imaging
Excellent contrast resolution
Imaging of urothelium without contrast injection (MRU)
what are disadvantages of MRI?
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 are different available isotope scans?
DMSA (dimercaptosuccinic acid)
To look for renal scarring
MAG3 (mercaptoacetyltriglycine)
Assess renal function and drainage
Bone scan (Tc 99 MDP methylene diphosphonate)
Metastatic disease e.g. prostate cancer
what is PET used for?
PET CT - Limited use in staging of urological malignancies due to high uptake in urine and variable uptake by tumours.
May be useful for extra-urological metastatic disease if other imaging modalities are equivocal or in poor surgical candidates.
PSMA PET CT in problem solving to assess metastases in prostate cancer
PET MRI
