Vesical Physiology Demonstrated by Cinéradiography and Serial Roentgenography

On applying new technics to the study of an old problem, we have been forced to question some of the current concepts of the mechanism of urination, concepts which are based on cystometrographic studies (1–4) or on direct film or fluoroscopic observation (5–8). We were not able to convince ourselves that what seemed apparent on the fluoroscopic screen was not the result of our inability to separate rapid sequential movements, although these technics might profitably be explored by others. With suggestions from Dr. Howard L. Steinbach, we made use of cinéradiography and serial roentgenography to produce sequences of cystograms during voiding. With the x-ray movies we were able to make exposures at the rate of 3.25 frames per second; with the Fairchild roll-film cassette, the time between films was 1.1 seconds. In this way we gained the dimension of motion without sacrificing the ability to study each film of the sequence individually and in relation to the rest of the exposures. In the preliminary study described here, we limited ourselves to analyzing micturition in the normal female subject. Materials and Methods Two hundred cubic centimeters of 7 per cent sodium iodide and 25 per cent Skiodan (or of 25 per cent Skiodan alone) was instilled by catheter into the bladder in normal nulliparous women. After the subject was placed before the radiographic apparatus, she was told to call out when she was about to void. At the call, the camera or the roll-film cassette was started. Some patients were studied during the entire time of emptying the bladder. Others were instructed to start and stop urination. Radiographic Technic for the Fairchild Roll- Film Cassette: The patient was placed in the erect position facing the Fairchild roll-film cassette. Films were exposed for 0.6 second with intervals of 0.5 second between exposures. The tube-film distance was 36 inches. Other exposure factors were: 66 kv., 100 ma., 2 mm. aluminum filter, and a 10 × 12-inch field. The skin dose was 1.5 r per exposure. The total amount received by the patient was 25 to 30 r depending upon the duration of the study. This is about the amount received during four to five minutes of fluoroscopy. Technic for Cinéradiography: The patient was placed in the erect position facing the 10 × 12-inch fluoroscopic screen. The exposure factors were: 110 kv., 100 ma., 0.25 mm. copper filter, 0.3 mm. copper h.v.l., 32 inches distance, 3.25 frames per second, total exposure 14 seconds. The camera was set at 4 feet from the screen, and the lens was set at f 0.85. The total skin dose was 50 r. Interpretation We will not at this writing postulate what sequence of activities constitutes “normal micturition.” Our study is still incomplete and, besides, normal voiding will vary from time to time depending on the subject's urge to void. If she has repressed the desire to void, she will then urinate in a different fashion than if she voids on command.