Imaging Flashcards
What is contrast-induced nephropathy?
A condition in which impairment in renal function occurs within 3 days following intravascular administration of a contrast medium in the absence of an alternative aetiology.
Rise in serum creatinine and urea – usually peaks at 72 – 96 hours post contrast.
Name A, B and the arrows.
A - right lobe of the liver.
B - dilated calyx.
C - renal cortex.
Which CT phase best depicts the calculi in the kidney?
Pre-contrast.
Which CT phase best depicts the cortex of the kidney?
Corticomedullary phase.
Which CT phase best depicts the renal medulla and cortex in the kidney equally?
Nephrographic phase.
Which CT phase best depicts the renal collecting system and ureters?
Excretory phase.
What are the risk factors for contrast-induced nephropathy?
Renal impairment - +/- diabetes mellitus.
Dehydration.
Congestive heart failure.
LV ejection fraction < 40%.
Acute MI (within 24 hours).
Nephrotoxic drugs.
What measures are put in place to reduce the risk of contrast-induced nephropathy?
Hydration protocols:
- 1-1.5 ml/kg/h 0.9% normal saline 12 or 6 hrs before and after contrast administration.
- Sodium bicarbonate instead of sodium chloride – urine alkalinization – prevention of oxygen free radicals; bicarbonate administered from 1 hour pre-procedure to 6 hrs post.
What vessels are seen on a renal angiogram?
Abdominal aorta.
Right renal artery.
Left renal artery.
Aortic bifurcation into common iliacs (right and left).
Splenic artery.
Lumbar arteries.
What is nephrogenic systemic sclerosis?
Severe systemic fibrosing disorder associated with the exposure to gadolinium-containing contrast media.
Initial skin erythema, pruritis, pain.
Involvement of other organs:
- Neuropathic symptoms
- Joint contractures
- Respiratory insufficiency
- Muscular atrophy
With time, the skin thickens, hardens and appears wood-like.
What are the risk factors for nephrogenic systemic sclerosis?
Renal impairment.
Should the bladder be full or empty for USS?
Full - to adequately assess the outline.
What structures is USS the primary choice for?
Testes/scrotum.
Uterus and ovaries.
Prostate biopsies.
What structures is hysterosalpingogram the primary choice for?
Infertility - tubal patency.
Uterine abnormalities.
What structures is MRI the primary choice for?
Prostate cancer - local staging.
Troubleshooting for adnexal, uterine, ovarian abnormalities not characterisable by USS.
What is renal colic?
Usually due to ureteric calculus (stone in ureter).
What is the presentation of renal colic?
Unilateral, severe pain going from loin to groin area.
Colicky pain.
What conditions can cause renal colic?
Ureteric calculus.
Pyelonephritis - better doing USS.
Gynaecological disease - better doing USS.
Ithe n elderly patient, potentially leaking AAA.
What is the composition of most renal calculi?
Most are rich in calcium and are dense - show up on plain radiograph or CT scans.
Some are calcium poor and of lower density due to urate (5-10%).
What is a KUB x-ray?
An xray of the kidneys, ureters and bladder (KUB; bladder view is separate to that of kidneys and ureters).
Usually first imaging test in patients with renal colic.
Only a minority of renal tract calculi are visible on KUB x-ray.
At what vertebral level do ureters leave the kidney?
L1.
What is the course of a normal ureter?
Pass inferiorly over the psoas muscles.
Descend anterior to the tips of 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 that renal calculi get stuck at?
Pelviureteric junction (PUJ).
Pelvic brim.
Vesicoureteric junction (VUJ).
What conditions can mimic ureteric calculus on a plain film xray?
Calcified veins (phleboliths).
Calcified lymph nodes.
Uterine fibroids.
Arterial calcification.
