Imaging

Question 1

How long are the kidneys?

Answer 1

10-12 cm long

Question 2

How does the size of kidneys vary in individuals?

Answer 2

• The kidneys are slightly larger in men than in women

- They increase in size up to the age of 20 years and become smaller again in later life

Question 3

How much does each kidney weight?

Answer 3

120-170grams

Question 4

What is the renal blood flow to the kidneys?

Answer 4

1200cc/min

Question 5

How long are the ureters?

Answer 5

25-30cm

Question 6

What is the diameter of the ureters?

Answer 6

3-8mm

Question 7

What are the anatomical points of narrowing of the ureters?

Answer 7

• PUJ
• Pelvic brim
• VUJ

Question 8

What separates the ureters from the tip of the transvers processes of the vertebrae?

Answer 8

Passes on the medial edge of psoas muscles which separate it from the tip of the transverse processes.

Question 9

What is the structure of the bladder?

Answer 9

Pyramidal structure with its base posteriorly and apex behind the symphysis

Question 10

How is the bladder peritonised?

Answer 10

Extra-peritoneal structure

Question 11

What is the trigone of the bladder?

Answer 11

Trigone is a triangular area between the ureteric and urethral orifices

Question 12

What indication are there for renal imaging?

Answer 12

Renal colic and renal stone disease (diagnosis and follow up)

• Haematuria
• Suspected renal mass
• UTIs
• Hypertension

Question 13

What imaging techniques can be used in renal medicine?

Answer 13

• Plain film
• Contrast studies including IVU, pyelography: and cystography
• Ultrasound +/- contrast
• CT and CTU
• MR and MRU
• Isotope scans
• PET-CT

Question 14

What are the advantages of plain film x-rays?

Answer 14

• Cheap and readily available

- Functional and anatomical information (IVU)

Question 15

What are the disadvantages of plain film x-rays?

Answer 15

• Low sensitivity and specificity for urological diseases

- Radiation

Question 16

What does pyelography involve?

Answer 16

Injection of contrast into the ureters

Question 17

What does micturating cystourethrography assess?

Answer 17

Vesico-ureteric reflux and its grade

Question 18

What are the advantages of ultrasound?

Answer 18

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

Question 19

What are the disadvantages of ultrasound?

Answer 19

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

Question 20

What are the advantages of CT?

Answer 20

• 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

Question 21

What are the disadvantages of CT?

Answer 21

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

Question 22

What are the advantages of MR?

Answer 22

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

Question 23

What are the disadvantages of MR?

Answer 23

• Poor spatial resolution
• Poor detection of calcification and stones
• Cost
• Contraindications: pace maker, claustrophobia ,etc
• Contrast reaction and other side effects

Question 24

Give examples of isotope scans.

Answer 24

• DMSA
• MAG3
• Bone scan

Question 25

What is a DMSA used for?

Answer 25

To look for renal scarring

Question 26

What is a MAG3 used for?

Answer 26

Assess renal function and drainage

Question 27

What is a bone scan used for?

Answer 27

Metastatic disease e.g. prostate cancer

Question 28

Why is there a limited use for PET-CT in urological malignancies?

Answer 28

Limited use in staging of urological malignancies due to high uptake in urine and variable uptake by tumours

Question 29

What may PET-CT be useful for?

Answer 29

May be useful for extra-urological metastatic disease if other imaging modalities are equivocal or in poor surgical candidates

Question 30

What is the best imaging modality to diagnose renal tract stones?

Answer 30

CT

Question 31

What imaging modality of choice in staging of renal tumours?

Answer 31

CT

Question 32

What is the least helpful imaging modality in assessment of patient with suspected renal artery stenosis

Answer 32

US