泌尿器科悪性腫瘍におけるMRIの臨床的位置づけ 第1報. 前立腺癌のlocalstagingにおける各種画像診断の位置づけ: MRI,CT,経直腸的超音波検査の比較

Abstract

前立腺癌23例に対し, MRIを施行した.内6例に全摘術を施行したが, stagingはMRIがperiprostatic plexusの描出や精嚢浸潤の判断の容易さなどにより最も正確であった.また限局した癌は, MRIではT2-WI上high intensityを示すべき外腺内のlow intensity areaとして描出され, USでは, hypoechoic areaとして描出された.広範な癌ではMRIでは内外腺の境界線の一部または全部の消失として判断できたが, USでは全体にheterogenousなエコーを示した.CTは限局性の癌に対してほとんど不用であった

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.