Imaging Renal and Urological Disease Flashcards
What is renal colic usually caused by?
A ureteric calculus
Why must you be careful about organising tests to detect calculi?
They give high doses of radiation so you must ensure that the presentation of the patient is consistent
What are some mimics of renal colic?
Pyelonephritis and gynaecological disease
What investigation should be done if pyelonephritis or gynaecological disease are suspected?
Ultrasound
What investigation should be done in a pregnant patient with suspected renal colic?
Ultrasound and/or MRI
What are some features of renal calculi?
Most are rich in calcium and dense, some are calcium poor and of lower density (urate)
How may renal calculi be detected?
KUB x-ray, CT and MRI
What is the first line investigation for suspected renal colic?
KUB x-ray = easy to obtain and may show dense ureteric calculi
What is a drawback of using a KUB x-ray to investigate renal colic?
Only a minority of renal calculi are visible on this type of imaging
Lacks specificity and sensitivity for calculi
What does a KUB x-ray view typically consist of?
Upper/mid abdomen = kidneys and proximal ureters
Pelvis = distal ureters and bladder
What is the normal course of the ureters?
Pass inferiorly over the psoas muscles and descend anterior to the tips of the lumbar transverse processes
What structure do the ureters cross before they enter the pelvis?
Iliac bifurcation
How do the ureters enter the bladder?
Pass posteromedially and enter the posterior aspect of the bladder
What can help make the renal collecting systems, ureters and bladder more visible?
IV urogram (IVU) = obtain x-ray following IV contrast injection/excretion
Where do ureteric calculi tend to get stuck?
Pelviureteric junction, pelvic brim, vesicoureteric junction
What are mimics of ureteric calculi?
Phleboliths, lymph nodes, uterine fibroids and arterial calcification
What is the definitive test to confirm a symptomatic ureteric calculus?
Non-contrast enhanced CT = shows virtually all calculi and signs of obstruction
What are some signs of obstruction that may be present due to a ureteric calculi?
Perinephric stranding and hydrourteronephrosis
What are the issues of using a non-contrast enhanced CT?
Struggles to distinguish between small pelvic calculi and phleboliths when there are no secondary signs
Gives high dose of radiation
In what groups should you avoid using a non-contrast enhanced CT?
Pregnant women and young female (where possible)
What is done to follow up on renal colic?
Most calculi pass spontaneously
Use simple imaging test to check progress
What are some areas that macroscopic haematuria may arise from?
Kidneys, ureters, bladder or urethra
May be multi-focal
What are some causes of macroscopic haematuria?
Calculi, infection, tumour, urethritis, prostatitis, trauma, clotting disorders
What investigations are done for patients over 50 who have macroscopic haematuria?
CT urography (CTU) and cytoscopy
How is CT urography carried out?
Scan before contrast = to detect calculi
Administer IV contrast = concentrated/excreted by kidneys over 15 mins then top up dose given
Scan again = detects tumours
What is the purpose of topping up the IV contrast during CT urography?
Enhances the renal parenchyma
How is cytoscopy carried out?
Examines bladder and urethra = gives option for ureteroscopy (to confirm tumour where equivocal to CT or ablate tumours if unfit for nephroureterectomy)
What are the benefits of MR urography?
Doesn’t require contrast or radiation = useful in patients with contrast allergy, renal impairment or pregnancy
When is MR urography done?
When CTU is contra-indicated as less sensitive
How do renal masses present?
May present with haematuria but most are incidental findings
What imaging technique is used to assess renal masses?
CT = assesses size, density, uniformity and internal morphology
How are renal masses that are <3cm managed?
Often followed up rather than operated on = rarely metastasise
What are some examples of renal masses?
Benign angiomyolipomas = contain fat
Cysts = fluid density
What are some features of malignant renal masses?
Complex cysts containing solid areas or thick septa
Solid masses > 3cm
What can be used to image a simple cyst?
Ultrasound
How are malignant tumours staged?
CT = assesses local extent, nodal disease and metastatic disease
What are the classes of renal impairment?
Pre-renal, renal and post-renal
How is pre-renal disease imaged?
MR angiography to detect RAS
How is renal disease imaged?
Ultrasound to guide biopsy
How is post-renal disease imaged?
US = shows hydronephrosis which accompanies obstruction
Other causes of obstruction require CT
How is renal size assessed?
Ultrasound = distinguishes between acute and chronic
How do the testes and epididymis appear on ultrasound in epididymo-orchitis?
Hypervascular
What are some causes of a painful scrotum?
Epididymo-orchitis = viral/bacterial, may cause ischaemia or abscess formation
Testicular torsion and trauma
What are some features of testicular torsion?
Young males, surgical emergency due risk of infarction, avascular testes on ultrasound
What is the best investigation for a painless scrotal swelling?
Ultrasound
What are some examples of painless scrotal swellings?
Variocoele, hydrocoele, epididymal cysts, testicular seminoma
What are some features of variocoele?
Dilated scrotal venous plexus, typically left side, tortuous veins usually >2mm in diameter
How do hydrocoeles appear?
Black anechoic fluid surrounds testicle
What are some features of epididymal cysts and testicular seminoma?
Epididymal cysts = anechoic cyst, arise within the epididymal head
Testicular seminoma = intra-testicular soft tissue mass, often show vascularity
How is renal trauma imaged?
Best assessed by CT = usually blunt trauma
What are the types of bladder rupture?
Extraperitoneal = common, treated conservatively Intraperitoneal = due to compression of full bladder, needs surgery
What is the mechanism for urethral injury in trauma?
Anterior pelvic fracture/dislocation or straddle injury
What are some features of urethral trauma injuries?
Don’t attempt catherisation if suspected, role of imaging limited, may be complicated by long term stricture formation (defined by urethrography)
What are some examples of non-vascular interventional uroradiology?
Relief of ureteric obstruction, drainage of abscess/cyst, biopsy of masses, guided ablation of tumours
What are some examples of vascular interventional uroradiology?
Correction of renal artery stenosis, correction of arterial bleeding, variocoele embolisation
