前立腺癌の診断におけるEndorectal coil MRIとプロトンMR spectroscopyの役割

Abstract

前立腺の正常所見, 良悪性の鑑別及び病期診断について, 直腸内コイル(ERC)を用いたMRI及びMRスペクトロスコピー(MRS)の有用性と限界について解説した.ERCを用いることによって, 前立腺の明瞭なMRIが得られるが, 現時点ではフェーズドアレイコイルで撮像されたMRIで異常を認めた場合の補助にとどまっている.MRSにはERCが必須であり, 良好なMRIを得る目的も合わせて, ERCのより一層の進歩が望まれる

The role of magnetic resonance (MR) imaging and MR spectroscopy with an endorectal coil in tissue characterization and local staging was reviewed. Endorectal coil (ERC) MR imaging demonstrated the detailed zonal anatomy of the normal prostate. The sensitivity and specificity of staging prostate cancer for ERC MR imaging was superior to both conventional MR imaging and transrectal ultrasound. ERC MR imaging is the most accurate noninvasive method of staging prostate cancer. However, the accuracy of the diagnosis made by inexperienced radiologists was significantly inferior to that made by experienced radiologists. Endorectal MRI failed to differentiate benign from malignant lesions in some patients demonstrating low signal intensity on T2-weighted imaging in the peripheral zone. MR spectroscopy may provide additional information on tissue characterization, monitoring after treatment and staging.