Radioisotope-assisted diagnosis of traumatic rupture of the diaphragm.

Traumatic rupture of the diaphragm is usually not diagnosed early after injury. We hypothesized that the diagnostic yield could be improved by injecting 50 uC of Tc99m macroaggregated albumin in 300 ml of normal saline solution and using simple scintillation counting. Thirty dogs were divided into four groups, anesthetized, and mechanically ventilated. In all groups, counting was done bilaterally 5 cm from the midline at the sternal notch and at 8, 16, 24, 32, 40, 48, and 56 cm below that level immediately and at 10, 20, and 30 min after instillation of the nuclide. In group I, the nuclide was instilled through a left thoracostomy tube, and counting was done with the dogs in reversed Trendelenberg position. In group II, blunt diaphragmatic rupture was simulated before instillation of the nuclide, and counting was done as in group I. In group III, the nuclide was instilled through a standard peritoneal lavage catheter, and counting was done with the dogs in Trendelenberg position. In group IV, blunt diaphragmatic rupture was simulated, nuclide was instilled, and counting was done as in group III. In each dog, there was no significant difference in the counts per minute (cpm) taken immediately and at 10, 20, and 30 min after instillation. In group I, radioactivity was concentrated in the areas adjacent to the diaphragm. In group II, radioactivity was concentrated at the sites lowest in the abdomen where the mean cpm differed significantly (p = .034) from group I.(ABSTRACT TRUNCATED AT 250 WORDS)