Radiology of the Renal Tract

Question 1

Describe an anatomical overview of the kidneys

Answer 1

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

Question 2

Describe the ureters

Answer 2

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

Question 3

What are the points of narrowing of the ureters?

Answer 3

PUJ
Pelvic brim
VU junction

Question 4

Describe the bladder

Answer 4

Pyramidal structure with its base posteriorly and apex behind the symphysis
Extraperitoneal
Trigone is a triangular area between ureteric and urethral orifices

Question 5

What are the indications for renal imaging?

Answer 5

Renal colic and renal stone disease
Haematuria
Suspected renal mass
UTIs
Hypertension

Question 6

What are the imaging techniques used for renal tract?

Answer 6

Plain film
Contrast studies - IVU, Pyelography, and cystography
US and maybe contrast
CT and CTU
MR and MRU
Isotope scans
PET-CT

Question 7

What are the advantages of plain films?

Answer 7

Cheap and readily available
Functional and anatomical information (IVU)

Question 8

What are the disadvantages of plain film?

Answer 8

Low sensitivity and specificity for urological diseases
Radiation

Question 9

What does pyelography include?

Answer 9

Injection of contrast into ureters

Question 10

What does micturating cystourethrography look at?

Answer 10

Vesico-ureteric reflex and its grade

Question 11

What are the advantages of US?

Answer 11

Cheap and readily available
No radiation
Contrast is not nephrotoxic
real time imaging

Question 12

What are the disadvantages of US?

Answer 12

Limited by body hiatus and gas
Poor visualisation of ureters
Operator dependant
No functional information

Question 13

What is a ureterocele?

Answer 13

Dilation of the lower ureter which protrudes into urinary bladder

Question 14

What are the advantages of CT?

Answer 14

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

Question 15

What are the disadvantages of CT?

Answer 15

Radiation dose
Cost
Contrast resolution less than MR
Contrast reaction and nephrotoxicity

Question 16

What are the advantages of MR?

Answer 16

Multiplanar imaging
Excellent contrast resolution
Imaging of urothelium without contrast injection (MRU)

Question 17

What are the disadvantages of MR?

Answer 17

Poor spatial resolution
Poor detection of calcification and stones
Cost and longer acquisition time
Contraindications - pacemaker and claustrophobia
Contrast reaction and other side effects

Question 18

What are the types of isotope scans and their functions?

Answer 18

DMSA - look for renal scarring
MAG3 - assess renal function and drainage
Bone scan - metastatic disease (prostate cancer)

Question 19

When is a PET scan used for renal tract?

Answer 19

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

Question 20

What is the best modality to diagnose renal tract stones?

Answer 20

CT scan

Question 21

What is the best modality for staging renal tumours?

Answer 21

CT scan

Question 22

What is the most helpful modality for assessment of patient with suspected renal artery stenosis?

Answer 22

US