[Clinical application of MRI for urological malignancy. 1: Usefulness of various imaging modalities for local staging of prostatic cancer; a comparison between MRI, CT and transrectal ultrasonography].

Twenty-three pathologically revealed prostatic cancer patients were examined by magnetic resonance imaging (MRI), computed tomography (CT) and transrectal ultrasonography, (US) and 6 of them underwent radical prostatectomy. A localized prostatic cancer was identified as a low intensity area in the outer zone with high intensity or showed a partial or total destruction of the border line between the internal and the outer zone when cancer invaded into the internal zone from the outer zone, on T2 weighted image of MRI, as we have already reported. On US, a localized prostatic cancer was identified as a hypoehoic area in the outer zone, and showed a heterogeneous image when cancer enlarged. On CT, a localized cancer could not be identified. A diagnostic criteria for local staging by MRI was made and preoperative staging were done in 6 total prostatectomy cases. The accuracy of preoperative staging of cancer seemed to be the highest by MRI, because it was more accurate in diagnosing the extracapsular invasion, seminal vesicle invasion and bladder neck invasion of the tumor than by CT and US.