Imaging Renal and Urinological Conditions# Flashcards
what usually causes renal colic and how does it present?
ureteric calculus
colicky pain localised to left or right side
what may present similar to renal colic?
pyelonephritis
gynaecological disease
AAA
types of renal calculi?
most are rich in calcium and are dense
some are calcium poor and of lower density (contain urate)
investigation of renal calculi
KUB plain X ray
CT
MRI
what is KUB X ray
first line imaging in suspected renal colic
typically comprise an image of the upper/mid abdomen and secondary image of pelvis
path of ureters?
pass inferiorly over psoas
descend anterior to tips of lumbar transverse processes
cross iliac bifurcation and enter pelvis
posteriormedially and enter posterior bladder
where do calculi commonly get stuck?
pelviureteric junction
pelvic brim
vesicoureteric junction
drawback of KUB X ray?
lacks specificity as many other causes of calcification can mimic renal calculi
lacks sensitivity as small or radiolucent calculi are not shown
what can mimic calculi?
phleboliths
lymph nodes
uterine fibroids
arterial calcification
what is the definitive test for ureteric calculus?
non-contrast CT (CT stone search)
benefits of stone search CT?
shows all calculi irrespective of size or calcium content
shows signs of obstruction raising diagnostic confidence
may show alternative diagnosis
drawbacks of CT stone search?
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)
renal colic follow up?
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)
what can cause macroscopic haematuria?
calculi infection tumour urethritis/prostatitis trauma clotting disorders can be multifocal
how are over 50s investigated?
CT urography
cystoscopy (examines bladder and urethra)
- gives option for ureteroscopy if needed (to confirm tumour, ablate tumours unfit for nephroureterectomy etc)
what do over 50s need different investigation?
higher cancer risk
how is CT urography performed?
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
CT urography is good at detecting what?
renal parenchymal tumours
urothelial tumours of collecting system/ureters
what type of tumour commonly occurs in the renal tract?
transitional cell carcinoma
investigation of under 50s with macroscopic haematuria?
kidney US
cystoscopy
CTU only when US and cystoscopy are normal and macroscopic haematuria persists
MR urography is useful in which patients?
contrast allergy
renal impairment
pregnancy
(as doesn’t require contrast or radiation)
how does CT characterise renal masses?
size
density
uniformity
internal morphology
what renal masses are generally safe?
those under 3cm rarely meatstasize so usually just monitored rather then excised
what characteristics indicate a benign renal mass?
containing fat
uniform cysts
what type of renal masses are often malignant?
complex cysts containing solid areas or thick septa
solid (non-cystic) masses larger than 3cm
how is malignant renal tumour staged?
CT
- shows spread, other organ involvement, vascular involvement
- shows nodal disease
- shows meatstases (cannon ball lung mets)
what do kidneys look like on CT?
sliced bananas
renal artery stenosis is what type of renal impairment?
pre renal
how is pre-renal renal impairment imaged?
MR angiography to detect renal artery stenosis
how is renal renal impairment imaged?
US used to guide biopsy
how is post renal renal impairment imaged?
US shows hydronephrosis (dilated renal pelvis), effectiveness of bladder emptying
- associated with obstruction
CT needed for other causes of obstruction
how can US be used to distinguish acute from chronic renal impairment?
assessment of renal size
3 causes of painful scrotum?
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
common causes of painless scrotal swelling?
hernia
variocele
hydrocele
epididymal cyst
good imaging for painless scrotal swelling?
US
how does variocele present on US?
dilated scrotal venous plexus
typically on left side
tortuous veins usually >2mm in diameter
how does hydrocele present on US?
black anechoic fluid surrounding the testicle
how does epididymal cyst present on US?
anechoic uni or multiocular cyst typically arise within epididymal head
how does testicular seminoma present on US?
intra-testicular soft tissue mass
often have demonstrable vascularity
renal trauma/injury is best assessed via what imaging?
CT
bladder injury/trauma is best assessed via what imaging?
cystography
CT cystography
e.g in bladder rupture,
- after filling the bladder, contrast leaks through the bladder tear into the intra or extraperitoneal space
how is imaging used I urethral trauma?
limited in an acute setting
urethrography used to define long term stricture
how can uroradiology be used interventionally?
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
