Intravenous urogram

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Also known as an intravenous pyelogram (IVP, IVU).

A radiographic technique to demonstrate the urinary tract. It involves a series of X-rays taken following injection of intravenous contrast.

A full series can be very involved. They are done on a prepared patient to minimise overlying shadows from bowel gas and contents. They includes control films, films with and without straps (which compress the ureters and slow the passage of urine to increase the detail seen) and tomograms as well as pre- and post-micturition films to demonstrate any bladder abnormalities. They are not always available around the clock.

In practise much useful information can be seen on a "one-shot" or "emergency protocol" IVU which should be able to be done "out-of-hours". (Although the requesting doctor should be prepared to inject the contrast neccessary.)

Interpreting

  1. Always ask to see the control film. This should be a formal KUB type abdominal x-ray but often a standard abdominal plain film is all that is present which will usually suffice.
    • Check for obvious abnormalities along the line of the ureters (roughly along the line of the tips of the transverse processes of the lumbar vertebra and then over the sacroiliac joints) as renal stones are often calcified and may be seen.
  2. Films at 0 mins from injection should show the development of a renogram as the contrast initially filters into nephrons.
    • Delay in the development of a renogram unilaterally suggests hold up of urine in the ureter but may also indicate:
      • Damage to the blood supply of the kidney
      • Absent kidney
    • If the expected renogram does not appear on either side loook closely for other anatomical abnormalities such as horsehoe kidney.
  3. Film at 5 mins should show the pelvicalyceal system or even parts of the ureter itself (if you can see all of the ureter then it is almost certainly dilated as the normal ureter exhibits waves of peristalsis)
    • Any unilateral delay suggests obstruction
    • Dilation of the pelvicalyceal region can be seen (again suggesting obstruction)
    • Filling defects of the pelvis or ureter might be noted which may be stone, clot or tumour.
    • Abnormalities of the ureters such as a bifid ureter may be seen
  4. Later films
    • Delay in filling suggestive of obstruction will prompt the radiographer to perform films at later times to try and visualise the obstructed tract. They should then show the level of obstruction or any filling defects causing partial obstruction.
  5. Pre-micturition films
    • Once urine has travelled to the bladder any filling defects or diverticulae may be noted.
    • If no urine gets to the bladder your patient is in trouble
  6. Post-micturition films
    • Ensure the bladder empties fully.

Risks

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