[Imaging of the prostate: three-dimensional ultrasonography].
Owing to its particular anatomic position, the prostate gland is an ideal organ for 3D ultrasound (US) study. However, although current US devices provide a large amount of information on the organ, they suffer from the limits of 2D imaging devices, as they cannot demonstrate the coronal plane. The latter plane shows details that could not otherwise be assessed; in fact, the central zone can only be viewed from the front, where it is also possible to visualize the course of the ejaculatory ducts and their outlet in the veru-montanum region. The high definition imaging power is also the reason why 3D US scanning provides a particularly reliable estimate of the prostate volume. The practical advantage of correct measurement of the organ volume, in toto or of particular suspicious areas, is that it enables better planning of both medical and surgical treatment. 3D US can also overcome the difficulties encountered with traditional transrectal US in performing local tumour staging. The presence of an extra plane can clarify the relationships between the tumour and healthy prostate tissue, in the capsula as well. Precise visualization of the whole course of the ejaculatory ducts enables individuation of any tumour invasion, the first step towards identifying invasion of the seminal vesicles, that has a distinctly unfavourable prognosis. The vesiculo-prostatic angle is also easier to see and investigate. 3D US seems also to have a role in procedures for the diagnosis of prostatic carcinoma. Some important studies have shown a greater incidence of tumours identified in the transition zone if biopsy is conducted by guided 3D US rather than the usual 2D US. This method is also indicated in cases requiring dynamic assessment of prostate lesions, preparatory to excision or brachytherapy (precise positioning of the radioactive seeds) as alternatives to traditional surgery.
Martino
Pasquale
P
Sezione di Nefrologia Chirurgica e Trapianto, Dipartimento dell'Emergenza e dei Trapianti d'Organo, Università degli Studi di Bari. martino@urologia.uniba.it
D006801:Humans; D021621:Imaging, Three-Dimensional; D008297:Male; D011471:Prostatic Neoplasms / Q000000981:diagnostic imaging*; D014463:Ultrasonography