[Using contrast inversion to extend the diagnostic value of perineal ultrasound for urethral and paraurethral pathologies]. / Die Kontrastumkehr als Methode zur Optimierung der perinealen Ultraschalldiagnostik bei urethralen und paraurethralen Pathologien.

ABSTRACT

PURPOSE: The aim of our study was to show how using contrast inversion extends the diagnostic value of perineal ultrasound, in particular with regard to paraurethral pathologies. MATERIALS AND METHODS: To assess the practical value of contrast inversion in the daily routine, 42 women with urinary incontinence underwent perineal ultrasound examination. Pictures were converted to contrast inversion and then checked for the visibility of sonographic reference points for urogynecological measurements (urethra, meatus urethrae internus, vesical base) by two independent evaluators both in B-mode and contrast inversion. Visibility was compared using a coefficient of agreement. The results were then tested for significance. In addition, in our clinical routine we detected several paraurethral pathologies (e. g. paraurethral abscess, glandula paraurethralis, urethral diverticulum), each being presented in B-mode and contrast inversion. RESULTS: There was no significant difference between contrast inversion and B-mode with regard to the reproducibility of visibility of the three sonographic reference points. Contrast inversion was superior for depicting paraurethral pathologies and postoperative anatomical findings. CONCLUSION: With respect to routine evaluation, the two modes do not reveal any significant difference. For the sonographic evaluation of paraurethral pathologies, contrast inversion provides better contour sharpness than B-mode, suggesting a higher diagnostic value for ambiguous anatomical settings. The nature of contrast inversion nevertheless facilitates misinterpretations and requires frequent comparison with B-mode pictures. In conclusion, we propose contrast inversion as an initial screen and a refinement to established diagnostic methods, such as MRI and voiding cysturethrography, not as their substitute.