Imaging of the Urinary System Flashcards
Anatomical overview
Each kidney is about ______ cm long
The kidneys are slightly ______ in men than in women
They increase in size up to the age of 20 years and become _______ again in later life
Each kidney weighs 120-170 grams
Renal blood flow ____ cc/min
10- 12
larger
smaller
1200
Ureters:
______ cm long
3-8 mm in diameter
_ points of narrowing
___
______ ____
__ _______
Passes on the medial edge of ____ muscles which separate it from the tip of the transverse processes
25-30
3
PUJ
Pelvic brim
VU junction
psoas
Bladder:
Pyramidal structure with its base _________ and apex behind the ________
Extra-_______
_______ is a triangular area between the ureteric and urethral orifices
posteriorly
symphysis
peritoneal
Trigone
what are indications of renal imaging?
Renal colic and renal stone disease - Diagnosis and follow up
Hematuria
Suspected renal mass
UTIs
Hypertension
What are different imaging techniques?
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 the advantages of plain films?
Cheap and readily available
Functional and anatomical information (IVU)
what are the disadvantages of plain films?
Low sensitivity and specificity for urological diseases
Radiation
what is shown here?
KUB
Urethral stone
What is shown here?
IVU
Stone left ureter
What is shown here?
IVU showing bladder tumour
what are some other contrast studies?
Pyelography - Injection of contrast into the ureters
Micturating cystourethrography - Vesico-ureteric reflux 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 habitus and gas
Poor visualisation of ureters
Operator dependant
No functional information
what is shown here?
Ultrasound
normal right kidney
what is shown here?
Horseshoe kidney
US and CT
what is shown here?
Ureterocele
a congenital abnormality found in the ureter. In this condition the distal ureter balloons at its opening into the bladder, forming a sac-like pouch
what is shown here?
Megaureter
medical anomaly whereby the ureter is abnormally dilated
what is shown here?
Renal tumour
What is shown here?
Urothelial tumours
What is shown here?
Doppler US
Normal
what is shown here?
Renal artery stenosis
what are the 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 the disadvantages of CT?
Radiation dose
Cost
Contrast resolution less than MR
Contrast reaction and nephrotoxicity
What is shown here?
CT
right sided renal stone
what is shown here?
CT showing renal tumour with IVC thrombus
what is shown here?
CT
Bladder tumour
what is shown here?
CTU
left ureteric tumour
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
Contraindications: pace maker, claustrophobia,etc
Contrast reaction and other side effects
what is shown here?
Angiomyolipoma Right kidney
MR
what is shown here?
Tumour right kidney
MR
what is shown here?
MRU
Duplex collecting system
What is shown here?
MRU
Horseshoe kidney
What is shown here?
MRU
transitional cell tumour
What is shown here?
Bilateral renal tumours and cysts
Isotope scan - what are each of the following used for:
DMSA
MAG3
Bone scan
DMSA - To look for renal scarring
MAG3 - Assess renal function and drainage
Bone scan - Metastatic disease e.g. prostate cancer
is a PET-CT useful?
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
case 1:
45 year old man with right sided renal colic
No hematuria
No other medical problems of note
What does US show?
What other imaging test that you would like to request?
What is your plan of management?
What does US show?
- Hydoronephrosis
- Ureter not dilated. .?PUJ obstruction
What other imaging test(s) that you would like to request?
- CT: Assess anatomy and cause of obstruction: eg stone, tumour
- MAG3: Assess function
- Or MR
What is your plan of management?
- Confirm diagnosis of PUJ
- Exclude an aberrant renal artery
- Treatment - Interventional radiology, Surgery
What is shown here?
CT angiography
crossing accessory renal artery
Case 2:
65 year old male with medically resistant hypertension and suspected renal artery stenosis. eGFR 55 ml/min
What is the initial test that you would like to request?
How would you plan further management?
What is the initial test that you would like to request?
- MRA
- CTA
- Historically US and Renal isotope
How would you plan further management?
- Conventional angiography
- Dilation and stent
What is the best imaging modality to diagnose renal tract stones?
a) Plain films
b) US
c) CT
d) MR
e) Pyelography
C
What imaging modality of choice in staging of renal tumours
a) US
b) CT
c) MR
d) PET-CT
B
What is the least helpful imaging modality in assessment of patient with suspected renal artery stenosis
a) CTA
b) MRA
c) US
d) Conventional angiography
C
