Color doppler ultrasound compared to a radionuclide scanning of spermatic cord torsion in a canine model

High resolution color doppler ultrasound can simultaneously display blood flow superimposed on detailed gray scale anatomic images. Using a single-blind study design, nine adult male dogs underwent intravaginal spermatic cord torsion and subsequent evaluation with technetium 99M-pertechnetate radionuclide, and color doppler ultrasound imaging techniques. Torsions of 90 to 720 degrees were created surgically, followed by examination with each modality at one hour (four animals), and four hours (five animals) following the procedure. Testicular torsion was diagnosed if perfusion was absent or markedly diminished on color doppler imaging or radionuclide scan. In all cases of 360 degrees or greater, torsion was diagnosed by either modality at both one and four hour time delays. If observers did not diagnose torsion, they were asked to assess the relative testicular perfusion. Color doppler ultrasound and radionuclide scanning were without error in correctly detecting a relative decrease in perfusion in each of these instances. Furthermore, color doppler imaging with spectral analysis was able to detect an enhancement of the diastolic component of the arterial signal at 180 degrees of torsion. This spectral pattern coupled with a relative decrease in blood flow allowed presumptive diagnosis at one hour of partial torsion that was subsequently apparent as absent perfusion only after 4 hours on radionuclide and repeat color doppler ultrasound. Color doppler ultrasound proved to be superior to radionuclide scanning in detecting diminished perfusion in this experiment. The detailed information provided by spectral and anatomic display with color doppler ultrasound recommends it for the evaluation of acute scrotal pathology of uncertain etiology.