SONOGRAPHY WITH SONICATED ALBUMIN IN THE DETECTION OF VESICOURETERAL REFLUX

The primary radiological procedures for diagnosing vesicoureteral refl ux are fluoroscopic and radionuclide cystography. Ultrasonography, wit h no ionizing radiation, would be useful as a screening tool for the d iagnosis of reflux due to its absence of radiation exposure. We evalua ted the usefulness of ultrasonography with sonicated albumin in the di agnosis of vesicoureteral reflux. Sonicated albumin contains approxima tely 3 to 5 X 10(8) microspheres per ml., which are echogenic. Sonicat ed albumin was tested in vitro, alone, and in human and porcine urine to assess microsphere stability. Urine dilutions, specific gravity, te mperature and pH were used as variables. The mode of delivery was also tested in vitro and in vivo. These studies showed that sonicated albu min microspheres were stable over a wide range of chemical variables a nd urine composition. Sonicated albumin produced an image of uniform e chogenicity when it was pre-loaded into a Foley catheter and followed by saline infusion in vitro. Fluoroscopic cystograms, using standard r adiopaque contrast media, in 5 Hanford mini-swine in which unilateral reflux had been created previously confirmed the presence of reflux un ilaterally. Sonographic cystograms with various dilutions of sonicated albumin in 0.9% sodium chloride (1:100, 1:250, 1:500, 1:750 and 1:1,0 00) were performed. At a dilution of 1:100 sonicated albumin produced dramatic echogenicity in the bladder and refluxing ureters during sono graphic imaging. The microspheres appeared to be stable for prolonged periods (more than 40 minutes), thus allowing for a careful sonographi c assessment of the entire genitourinary tract. Sonicated albumin may be valuable for the sonographic detection of vesicoureteral reflux.