Methodischer Ansatz zur Standardisierung der Introitussonographie

Purpose: Sonographical methods were often used as an alternative to radiologic cystourethrography when diagnosing female urinary stress incontinence. The anatomical changes of the bladder neck and the urethra are readily visualised by both methods, but there is no standardisation of ultrasound measurement procedures. The aim of the study was to investigate two different ultrasound methods of measurement, to find out a reproducible and standardised evaluation of introital sonography. Study design: Ultrasonic examination was performed by two independent and well-trained investigators on 46 patients at rest and during Valsalva's manoeuvre, using a 5-MHz transducer. The scanner was placed in the vaginal introitus in a sagittal orientation and positioned so as to obtain a view of the bladder, bladder base, urethrovesical junction, and the pubis. The first method needs a midline through the chondral part of the pubis for a rectangular coordinate system. The bladder neck was located by means of distance measurements. In addition, funnelling of the proximal urethra and the urethrovesical angle β were noted. For the second method we assume that the transducer is exactly inserted along the body axis. In this case a horizontal reference line through the upper point of the pubis (bone or chondral part) can be defined, as well as a rectangular coordinate system for the determination of the bladder neck. Using the second method it is not necessary to visualise the chondral part of the pubis. Results: In the first method the whole chondral part of the pubis could be seen in 61% (28 patients). Furthermore, we needed more time for this procedure than for the second method (13.1 to 20.7s versus 10.9 to 13.7s), so that the first method cannot be recommended as a reproducible procedure. There was a high significant inter-examiner correlation in the second method at rest and during strain (Pearson correlation coefficient r values from 0.5730 to 0.9093). Conclusion: Introital sonography provides reproducible information. For a standardised evaluation it is necessary that the transducer is inserted exactly along the body axis so that a horizontal reference line can be defined.