Radiology of the Renal Tract Flashcards
Describe an anatomical overview of the kidneys
Each kidney is about 10-12cm long
Kidneys slightly larger in men
Increase kin size up to 20 years and become smaller in later years
Weighs 120-170 grams each
Renal blood flow 1200cc/min
Describe the ureters
25-30cm long
3-8mm in diameter
3 points of narrowing
Passes at medial edge of psoas muscles which separate it from the tips of transverse processes
What are the points of narrowing of the ureters?
PUJ
Pelvic brim
VU junction
Describe the bladder
Pyramidal structure with its base posteriorly and apex behind the symphysis
Extraperitoneal
Trigone is a triangular area between ureteric and urethral orifices
What are the indications for renal imaging?
Renal colic and renal stone disease
Haematuria
Suspected renal mass
UTIs
Hypertension
What are the imaging techniques used for renal tract?
Plain film
Contrast studies - IVU, Pyelography, and cystography
US and maybe contrast
CT and CTU
MR and MRU
Isotope scans
PET-CT
What are the advantages of plain films?
Cheap and readily available
Functional and anatomical information (IVU)
What are the disadvantages of plain film?
Low sensitivity and specificity for urological diseases
Radiation
What does pyelography include?
Injection of contrast into ureters
What does micturating cystourethrography look at?
Vesico-ureteric reflex and its grade
What are the advantages of US?
Cheap and readily available
No radiation
Contrast is not nephrotoxic
real time imaging
What are the disadvantages of US?
Limited by body hiatus and gas
Poor visualisation of ureters
Operator dependant
No functional information
What is a ureterocele?
Dilation of the lower ureter which protrudes into urinary bladder
What are the advantages of CT?
Imaging modality of choice for detection of renal stones, staging renal tumours and investigation of haematuria
Good spatial resolution with capability of multi planar reformat
What are the disadvantages of CT?
Radiation dose
Cost
Contrast resolution less than MR
Contrast reaction and nephrotoxicity
What are the advantages of MR?
Multiplanar imaging
Excellent contrast resolution
Imaging of urothelium without contrast injection (MRU)
What are the disadvantages of MR?
Poor spatial resolution
Poor detection of calcification and stones
Cost and longer acquisition time
Contraindications - pacemaker and claustrophobia
Contrast reaction and other side effects
What are the types of isotope scans and their functions?
DMSA - look for renal scarring
MAG3 - assess renal function and drainage
Bone scan - metastatic disease (prostate cancer)
When is a PET scan used for renal tract?
Limited use in staging urological malignancies due to high uptake in urine and variable uptake by tumours
Maybe extra-urological metastatic disease
PMSA PET CT in assess metastases in prostate cancer
What is the best modality to diagnose renal tract stones?
CT scan
What is the best modality for staging renal tumours?
CT scan
What is the most helpful modality for assessment of patient with suspected renal artery stenosis?
US
