a. General. Nephrography is a special procedure for the radiographic
demonstration of the parenchymal structures of the kidneys during their
radiopacification by means of a contrast medium.
b. Patient Preparation and Scheduling. Patient preparation and scheduling
are essentially the same as for intravenous pyelography. However, in some cases, a
test is administered for the calculation time (for example, arm-to-tongue decholin) to
determine the optimum intervals of time and the sequence to be used in exposing the
films following the injection of the contrast medium.
(1) The patient is placed in the supine position with the midline of the body
to the center of the x-ray table unit. A 10x12-inch or a 14x17-inch film is placed in the
Potter-Bucky diaphragm film tray and centered at the level of the 2d lumbar vertebra.
The CR is directed to the center of the film.
(2) The pertinent aspects of the procedure should be explained to the
patient, and he should be warned about the sensations he is likely to experience during
the procedure (such as hot flashes, gagging, and nausea). The necessity for controlling
respiratory or bodily movements during the exposure of the films should be stressed.
(3) A preliminary film is exposed, developed, and immediately presented to
the examiner for reading. This film will serve as a check for correctness of positioning,
technique factors, and adequacy of patient preparation.
(4) A 12-gauge injection needle (for example, Robb-Steinberg type) is
inserted into an antecubital vein of the arm. A wide-bore syringe that has been
previously filled with the contrasting medium (consisting of one of the sterile aqueous
solutions and containing 70 to 75 percent iodine compound such as Hypaque or
Renografin) is attached to the needle.
(5) With all participants alerted, technique factors selected, and x-ray
apparatus in readiness, the examiner gives the "ready" signal and starts injecting the
contrast medium (40 to 50 cc). As the last of the contrast solution leaves the syringe,
the examiner calls out, "Now," at which time the x-ray specialist (or an assistant) starts a
stopwatch or audibly counts the passage of seconds on any available timepiece which
has a second hand.