Radiology Flashcards
What causes renal colic?
ureteric calculus
Why must you ensure the history and exam are consistent with renal colic, before requesting imaging?
Tests used to detect calculi give a high radiation dose
What diseases mimic renal colic?
pyelonephritis or gynaecological disease
What imaging modality should be used to visualise pyelonephritis or gynaecological disease?
Ultrasound
What imaging modalities should be used to minimise radiation exposure to a foetus during pregnancy?
US and/or MRI
What substance is found in high density vs low density calculi?
Dense calculi = calcium
lower density = urate
What forms of imaging can be used to visualise renal calculi?
KUB X-ray
CT
MRI
What is involved in a KUB X-Ray?
Kidney, Ureter, Bladder
Photo taken of Upper Urinary tract and separate photo of Lower Urinary tract
Describe the course of the ureters?
- Pass inferiorly over the psoas muscles
- Descend anterior to the lumbar transverse processes
- Cross the iliac bifurcation and enter the pelvis
- Pass posteromedially and enter the posterior aspect of the bladder
What are the predictable sites where ureteric calculi will get stuck?
pelviureteric junction
pelvic brim
vesicoureteric junction
Why is contrast not usually used to visualise renal calculi?
The contrast is dense, as are most calculi
=> the contrast would obscure visualisation of calculi
What other causes of calcification may simulate renal calculi?
Phleboliths
Lymph nodes
Uterine fibroids
Arterial calcification
Aside from the calculus itself, what other signs of obstruction can be seen on CT?
perinephric stranding (oedema in perinephric fat)
hydroureteronephrosis (widening of ureter above blockage)
Most calculi pass spontaneously. TRUE/FALSE?
TRUE
What are the potential causes of macroscopic haematuria?
Calculi Infection Tumour Urethritis/prostatitis Trauma Clotting disorders
At what age does Renal cell carcinoma present vs transitional cell carcinoma?
RCC - any age
TCC - over 50
What is the difference between Cystoscopy and ureteroscopy?
Cystoscopy = camera inserted to visualise the bladder and urethra Ureteroscopy = passed further up to visualise ureters also
Describe how CT urography is carried out?
- First CT scan before contrast
- Administration of IV contrast
- This is excreted by kidneys over 15 minutes
- Top up dose given 60 seconds before 2nd CT (to enhance renal parenchyma)
- Second CT scan following contrast
What is CT urography particularly sensitive in detecting?
- renal parenchymal tumours
- urothelial tumours of the collecting systems or ureters
What is meant by a multifocal TCC?
Present in multiple parts of urinary tract
e.g. in kidney and in bladder
Why is CT urography less commonly carried out in patients under 50 who develop macroscopic haematuria?
urothelial tumours of kidney or ureter = very low at this age
CTU imparts a double radiation dose which is unjustified
How are patients <50 investigated for macroscopic haematuria?
US of kidneys
Cystoscopy
CTU only when US and cystoscopy are normal and macroscopic haematuria persists
Over what size are kidney tumours more likely to be malignant?
3cm
How are renal masses characterised?
size
density (fat, fluid, soft tissue, calcified)
uniformity (varying density?)
internal morphology (nodules, septa)
