[Importance of the tridimensional ultrasound in the anorectal evaluation]

Anorectal endosonography is actually the main image exam to evaluate some anorectal diseases.

To show the three-dimensional endosonography importance in the anal canal anatomic evaluation and the anorectal diseases diagnosis.

Seventy four anorectal ultrasound were performed, 23 normal individuals (13 women) and 51 patients (33 women) with benign and malignant diseases. All the patients were examined with a 3-D equipment with 360 degrees transducer. Normal individuals were evaluated in midline sagittal plane concerning to the length of the anal canal, the internal anal sphincter, the external anal sphincter and the anatomic defect in the anterior quadrant.

There were no differences in the anal canal and the internal anal sphincter length between men and women. Otherwise, the external anal sphincter length is longer in men and the anatomic defect is longer in women. In those with anorectal diseases, 11 sphincter injuries, 8 anal fistulas, 7 abscess, 1 perirectal endometriosis, 1 pre-sacral cyst, 3 anal canal and 10 rectal malignant neoplasias were diagnosed. The surgical findings confirmed the ultrasound diagnosis in all the patients.

Three-dimensional endosonography demonstrated the anatomic differences between male and female anal canal, justifying the larger incidence of pelvic floor disorders in female patients. It was possible to diagnose the anorectal diseases, in multi-plane, with high spatial resolution, adding also important informations about the therapeutic decision. Such characteristics become it similar to nuclear magnetic resonance with intra-rectal coil, with the advantages to be easier, quicker, low cost and better tolerated.