Imaging Renal and Urinological Conditions#

Question 1

what usually causes renal colic and how does it present?

Answer 1

ureteric calculus

colicky pain localised to left or right side

Question 2

what may present similar to renal colic?

Answer 2

pyelonephritis
gynaecological disease
AAA

Question 3

types of renal calculi?

Answer 3

most are rich in calcium and are dense

some are calcium poor and of lower density (contain urate)

Question 4

investigation of renal calculi

Answer 4

KUB plain X ray
CT
MRI

Question 5

what is KUB X ray

Answer 5

first line imaging in suspected renal colic

typically comprise an image of the upper/mid abdomen and secondary image of pelvis

Question 6

path of ureters?

Answer 6

pass inferiorly over psoas
descend anterior to tips of lumbar transverse processes
cross iliac bifurcation and enter pelvis
posteriormedially and enter posterior bladder

Question 7

where do calculi commonly get stuck?

Answer 7

pelviureteric junction
pelvic brim
vesicoureteric junction

Question 8

drawback of KUB X ray?

Answer 8

lacks specificity as many other causes of calcification can mimic renal calculi
lacks sensitivity as small or radiolucent calculi are not shown

Question 9

what can mimic calculi?

Answer 9

phleboliths
lymph nodes
uterine fibroids
arterial calcification

Question 10

what is the definitive test for ureteric calculus?

Answer 10

non-contrast CT (CT stone search)

Question 11

benefits of stone search CT?

Answer 11

shows all calculi irrespective of size or calcium content
shows signs of obstruction raising diagnostic confidence
may show alternative diagnosis

Question 12

drawbacks of CT stone search?

Answer 12

struggles to distinguish small pelvic calculi and phleboliths when there are no secondary signs
high radiation dose (should be avoided in pregnancy, all young females where MRI/US could give similar info)

Question 13

renal colic follow up?

Answer 13

most calculi pass spontaneously
use simplest test which showed calculus initially to check its progress (don’t use a CT to check a stone which was shown on X ray, don’t expect an X ray to show a stone which was only seen on CT initially)

Question 14

what can cause macroscopic haematuria?

Answer 14

calculi
infection
tumour
urethritis/prostatitis
trauma
clotting disorders
can be multifocal

Question 15

how are over 50s investigated?

Answer 15

CT urography
cystoscopy (examines bladder and urethra)
- gives option for ureteroscopy if needed (to confirm tumour, ablate tumours unfit for nephroureterectomy etc)

Question 16

what do over 50s need different investigation?

Answer 16

higher cancer risk

Question 17

how is CT urography performed?

Answer 17

CT scan before contrast
administer IV contrast which is concentrated and excreted by kidneys over 15 mins
top up does of IV contrast to enhance renal parenchyma
second CT scan following contrast

Question 18

CT urography is good at detecting what?

Answer 18

renal parenchymal tumours

urothelial tumours of collecting system/ureters

Question 19

what type of tumour commonly occurs in the renal tract?

Answer 19

transitional cell carcinoma

Question 20

investigation of under 50s with macroscopic haematuria?

Answer 20

kidney US
cystoscopy
CTU only when US and cystoscopy are normal and macroscopic haematuria persists

Question 21

MR urography is useful in which patients?

Answer 21

contrast allergy
renal impairment
pregnancy
(as doesn’t require contrast or radiation)

Question 22

how does CT characterise renal masses?

Answer 22

size
density
uniformity
internal morphology

Question 23

what renal masses are generally safe?

Answer 23

those under 3cm rarely meatstasize so usually just monitored rather then excised

Question 24

what characteristics indicate a benign renal mass?

Answer 24

containing fat

uniform cysts

Question 25

what type of renal masses are often malignant?

Answer 25

complex cysts containing solid areas or thick septa | solid (non-cystic) masses larger than 3cm

Question 26

how is malignant renal tumour staged?

Answer 26

CT - shows spread, other organ involvement, vascular involvement - shows nodal disease - shows meatstases (cannon ball lung mets)

Question 27

what do kidneys look like on CT?

Answer 27

sliced bananas

Question 28

renal artery stenosis is what type of renal impairment?

Answer 28

pre renal

Question 29

how is pre-renal renal impairment imaged?

Answer 29

MR angiography to detect renal artery stenosis

Question 30

how is renal renal impairment imaged?

Answer 30

US used to guide biopsy

Question 31

how is post renal renal impairment imaged?

Answer 31

US shows hydronephrosis (dilated renal pelvis), effectiveness of bladder emptying - associated with obstruction CT needed for other causes of obstruction

Question 32

how can US be used to distinguish acute from chronic renal impairment?

Answer 32

assessment of renal size

Question 33

3 causes of painful scrotum?

Answer 33

``` epididymo-ochitis - viral/bacterial infection which may be complicated by an abscess or ischaemia - testes and/or epididymis are hypervascular on US testicular torsion - young males - testicle is avascular on US - surgical emergency trauma ```

Question 34

common causes of painless scrotal swelling?

Answer 34

hernia variocele hydrocele epididymal cyst

Question 35

good imaging for painless scrotal swelling?

Answer 35

US

Question 36

how does variocele present on US?

Answer 36

dilated scrotal venous plexus typically on left side tortuous veins usually >2mm in diameter

Question 37

how does hydrocele present on US?

Answer 37

black anechoic fluid surrounding the testicle

Question 38

how does epididymal cyst present on US?

Answer 38

anechoic uni or multiocular cyst typically arise within epididymal head

Question 39

how does testicular seminoma present on US?

Answer 39

intra-testicular soft tissue mass | often have demonstrable vascularity

Question 40

renal trauma/injury is best assessed via what imaging?

Answer 40

CT

Question 41

bladder injury/trauma is best assessed via what imaging?

Answer 41

cystography CT cystography e.g in bladder rupture, - after filling the bladder, contrast leaks through the bladder tear into the intra or extraperitoneal space

Question 42

how is imaging used I urethral trauma?

Answer 42

limited in an acute setting | urethrography used to define long term stricture

Question 43

how can uroradiology be used interventionally?

Answer 43

relief of ureteric obstruction (nephrostomy) drainage of abscess/cyst biopsy of renal mass guided ablation of renal tumours correction of renal artery stenosis control of arterial bleeding sites (embolization) varicocoele embolisation