Title: Early Physiologic Nephro-urography as a Test of Kidney Function
Abstract: Squire and Schlegel concluded from a recent study that the intravenous pyelogram is not a reliable test of renal function. The failure of these investigators to demonstrate the disparity between the function of one kidney and the other was felt by the present writer to be attributable to the circumstance that films had not been obtained at an early enough time. A program was therefore set up to remedy this shortcoming. Prior to intravenous pyelography a preliminary film is obtained. This is of importance) since the presence of a rotated kidney may result in what may appear to be a unilateral nephrogram, or) if the kidney is rotated about its long axis, it may seem shorter than its fellow and, in the absence of a function test, may be mistakenly regarded as diseased. Thirty cubic centimeters of 50 per cent Hypaque Sodium, by weight, is injected through a 20- to 22-gauge needle in two to fifty seconds. The first film is obtained one minute after the beginning of the injection, e.g., ten seconds after its termination if it takes fifty seconds, twenty seconds after its termination if it takes forty seconds, etc. A second film follows one minute after the first, and a third one minute after the second. Occasionally, it will be necessary to run the films sequentially into the four- and five-minute period. For brevity at our institution, this examination has been called “one-two-three intravenous pyelography.” The findings can be summarized as follows: (a) When the one-minute film is exposed, a nephrogram, including a glomerulonephrogram as well as a tubular nephrogram, is obtained. This is denser than on the plain film. At two minutes (in a normal patient) the nephrographic effect is fully apparent, and in three minutes (in normal patients, without elevated blood pressure) bilateral calyceal delineation has begun. As the calyces appear, there is a gradual decrease in the “nephrographic” effect, due to successive dilution of the contrast material by urine within the parenchymal substance of the kidney. In (essential) hypertensive patients, the calyces are often seen on the two-minute film. It would seem, therefore, that the rapidity with which the medium traverses the kidney is due to the renal arterial blood pressure. (b) After obtaining the one-, two-, and three-minute physiologic or functional films, the routine five-, ten-, fifteen-, and twenty-minute morphologic films are exposed. Sometimes it is necessary to carry the sequential physiologic exposures to four minutes. The important question is whether or not there is differential function between right and left kidneys in the early one-, two-, and three-minute films. The easiest end-point to delineate is the calyceal stage, i.e., in which kidney the calyces are first shown. Clinical Reports Case I: A 41-year old white male bartender was admitted to the VA Hospital, Long Beach, Calif., April 5, 1960, in heart failure with cardiomegaly. He gave a four-year history of hypertension, 200/135 mm.Hg.