The retrograde pyelogram uses a dye to
find out whether a
kidney stone or something else is blocking your
urinary tract. During the test, your doctor will insert a thin, lighted tube
(cystoscope) into the
urethra, which carries urine out of the body from the
bladder. He or she will then put a
catheter through the cystoscope and into a
ureter, which carries urine from the kidney to the
bladder. Dye is injected through the catheter, and X-rays are taken.
Kidney stones are created when certain substances in urine -- including calcium, oxalate, and sometimes uric acid -- crystallize. These minerals and salts form crystals, which can then join together and form a kidney stone.
Kidney stones usually form within the kidney, where urine collects before flowing into the ureter, the tube that leads to the bladder. Small kidney stones are able to pass out of the body in the urine -- and may go completely unnoticed by you. But larger stones can irritate...
Pregnant women normally do not have this test, because the
X-rays may harm the unborn baby.
Findings of the retrograde pyelogram may
include the following.
The kidneys, ureters, and bladder appear normal.
The flow of the dye (contrast material) is blocked,
either by a stone or another urinary problem.
What To Think About
The retrograde pyelogram provides
the same information as an intravenous pyelogram (IVP). But the retrograde
pyelogram can be used even if you are allergic to the dye. This test does not
risk making existing kidney damage worse.
Unlike the IVP, the
retrograde pyelogram requires an anesthetic and uses a catheter inserted
into the urinary tract.