泌尿器科腫瘍の鑑別診断およびstagingにおけるMRIの意義特にCTとの比較を中心として

Abstract

約1年間にわたって49例の泌尿器科腫瘍のMRIを施行し, その意義についてretrospectiveに検討した.胃疾患におけるMRIの特徴:腎の皮膚, 髄質が区別できる.腎癌は, T2画像でhigh intensityを示し, pseudocapsule, Gerota筋膜が抽出され, 更に腫瘍血栓の明瞭な描出や, chemical shiftが存在することにより, stagingは正確であった.副腎疾患におけるMRIの特徴:T2画像で, ある程度内容診断が可能であった.膀胱癌におけるMRIの特徴:high stageの腫瘍に有用であるが, low stageの腫瘍には不向きである.T2画像による壁内浸潤の検討が今後の課題である.前立腺癌におけるMRIの特徴:periprostatic plexusの描出は, 被膜外浸潤の診断に有用である.前立腺の内腺, 外腺の描出による前立腺癌の進展の仕方が分かる

Magnetic resonance imaging (MRI) was performed on 49 urological tumors (11 renal cell carcinomas, 3 renal pelvic cancers, 2 renal angiomyolipomas, 1 renal leiomyosarcoma, 1 large renal cyst, 4 adrenal tumors, 11 bladder cancers, 2 bone metastasis from bladder cancer, 10 prostatic cancers, 1 prostatic sarcoma, 1 urethral cancer, 1 penile cancer and 1 perivesical granuloma) since October 1985 to September 1986. MRI was performed using a Signa (G.E.) with a 1.5T superconductive magnet and 3 images, including T1 weighted image, T2 weighted image, and proton density image, were obtained. In conclusion MRI is a noninvasive examination and gives more information than computed tomography despite its high cost. In renal cell carcinoma, the chemical shift in MRI and clear visualization of tumor thrombus enable accurate staging. Differential diagnosis from other renal mass lesions may be possible by the T2 weighted image. In adrenal disease, most of the adrenal masses can be differentiated, but in some cases it is impossible. In bladder cancer, wall invasion of tumor may be evaluated in T2 weighted image, and MRI is suitable for staging of locally advanced tumor. In prostatic cancer, visualization of periprostatic plexus and differentiation between internal and external gland may enable local staging and identification of low stage tumors.