An intravenous pyelogram or IVP for short is a radiological procedure used
to visualize abnormalities of the urinary system, including the kidneys,
ureters, and bladder. Procedure
An injection of X-ray contrast medium is given to a patient via a needle or
cannula into the vein, typically in the arm. The contrast is excreted or removed
from the bloodstream via the kidneys, and the contrast media becomes visible
on X-rays almost immediately after injection. X-rays are taken at specific
time intervals to capture the contrast as it travels through the different
parts of the urinary system. This gives a comprehensive view of the patient's
anatomy and some information on the functioning of the renal system.
= Normal Appearances = Immediately after the contrast is
administered, it appears on an X-ray as a 'renal blush'. This is the contrast
being filtered through the cortex. At an interval of 3 minutes, the renal blush
is still evident but the calyces and renal pelvis are now visible. At 9 to 13
minutes the contrast begins to empty into the ureters and travel to the
bladder which has now begun to fill. To visualize the bladder correctly, a post
micturition X-ray is taken, so that the bulk of the contrast is emptied.
An IVP can be performed in either emergency or routine circumstances.
= Emergency IVP = This procedure is carried out on
patients who present to an Emergency department, usually with severe renal
colic and a positive hematuria test. In this circumstance the attending
physician requires to know whether a patient has a kidney stone and if it is
causing any obstruction in the urinary system.
Patients with a positive find for kidney stones but with no obstruction are
usually discharged with a follow-up appointment with a urologist.
Patients with a kidney stone and obstruction are usually required to stay
in hospital for monitoring or further treatment.
An Emergency IVP is carried out roughly as follows:
plain KUB or abdominal X-ray; an injection of contrast media,
typically 50 ml; delayed abdominal X-ray, taken at
roughly 15 minutes post injection. If no obstruction is evident on this
film a post-micturition film is taken and the patient is sent back to the
Emergency department. If an obstruction is visible, a post-micturition film is
still taken, but is followed up with a series of radiographs taken at a "double
time" interval. For example, at 30 minutes post-injection, 1 hour, 2 hours,
4 hours, and so forth, until the obstruction is seen to resolve. This
time delay can give important information to the urologist on where
and how severe the obstruction is. = Routine IVP =
This procedure is most common for patients who have unexplained
microscopic or macroscopic hematuria. It is used to ascertain the presence of a
tumour or similar anatomy-altering disorders. The sequence of images is
roughly as follows: plain or Control KUB image;
immediate X-ray of just the renal area; 5 minute X-ray of just the renal area.
15 minute X-ray of just the renal area. At this point, compression may or may
not be applied. In pyelography, compression involves
pressing on the lower abdominal area, which results in distension of the upper
urinary tract. If compression is applied: a 10 minutes
post-injection X-ray of the renal area is taken, followed by a KUB on release
of the compression. If compression is not given: a standard
KUB is taken to show the ureters emptying. This may sometimes be done
with the patient lying in a prone position.
A post-micturition X-ray is taken afterwards. This is usually a coned
bladder view. = Image Assessment =
The kidneys are assessed and compared for:
Regular appearance, smooth outlines, size, position, equal filtration and
flow. The ureters are assessed and compared
for: Size, a smooth regular and symmetrical
appearance. A 'standing column' is suggestive of a partial obstruction.
The bladder is assessed for: Regular smooth appearance and complete
voiding. Contraindications
Historically, the drug metformin has been required to stop 48 hours pre and
post procedure, as it known to cause a reaction with the contrast agent.
However the newest guidelines published by the Royal College of Radiologists
suggests this is not as important for patients having