Ultrasound assessment of the female perineum: technique, methods, indications and ultrasound anatomy.

PURPOSE: To present and promote the use of ultrasound in the evaluation of perineal disorders.
MATERIALS AND METHODS: The technique and methodology for a correct ultrasound examination of the perineum, starting from the preparation of patient and equipment, are reported in detail. Ultrasound accesses to the perineum are the following: perineal or vulvar; introital; vaginal; transrectal. The transducers used also vary in technical features and morphology. There is no general agreement as to which access and transducer should be used in the ultrasound assessment of the perineum. We believe that each type of access and transducer has advantages and disadvantages over the others and that the opposition among supporters of different accesses and transducers should be overcome. The various systems should be considered complementary with one another and can all be used to reach a better ultrasound diagnosis. ULTRASOUND ANATOMY OF THE PERINEUM: A detailed description of the possible indications and of the ultrasound anatomy of the pelvic floor in relation to the type of transducer and access that can be used is reported. It is suggested that each ultrasound examination of the perineum should be performed following fast abdominal ultrasound evaluation. Perineal scans should be obtained during all functional phases: at rest, during abdominal straining and contraction. When a perineal access is used, it is always advisable to visualize the pubis as it is an important anatomical landmark for dynamic biometric evaluations. We believe that urethral ultrasound, performed during the dynamic phases, is the most accurate method for evaluating cervico-urethral mobility and is thus extremely useful for a correct pre-operative analysis. An increase in normal urethral mobility is correlated with female urinary incontinence, particularly with stress incontinence. Further-more, ultrasound proves to be valuable in the evaluation of other disorders, such as urogenital prolapses, especially enterocele, and anal sphincter defects. In the latter case, when a specific rotating endoanal probe for anal sphincter dysfunctions is not available, perineal ultrasound may be a useful adjunct for correct evaluation if complemented by a sensible use of clinical data.
CONCLUSIONS: As in other anatomical fields, ultrasound proves to be inexpensive, harmless and well tolerated by patients. The wealth of information provided by this method in the assessment of the main anatomic and functional alterations of the perineum makes the use of more invasive and expensive radiographic techniques unnecessary. Its correct use, following an adequate training period, significantly reduces the need for conventional radiography and MR contrast-enhanced examinations which should be regarded as second-line examination tools.