CTと尿道鏡の併用による前立腺重量の推定

Abstract

前立腺CT scanと尿道鏡を併用し, おのおのの計測値をもとに, 仮想楕円球体積V1=π abc/6またはV2=2/3 Scで得られた前立腺仮想体積と手術(TURP, open surgery)で得られた前立腺重量とを比較した.34症例について, 術前の前立腺CT計測で, 計測値a, b, cを用いた場合, 回帰方程式y=1.21x+9.68 (r=0.9376), S, cを用いた場合, y=1.31x+10.58 (r=0.9471)と両者はいずれもよく相関した.この回帰方程式をもとに前立腺重量を推定するとW1=4.3 abc×10-4-8.0あるいはW2=5.1 Sc×10-4-8.1(単位, g, mm, mm2)となった

Preoperative determination of prostatic weight in patients with prostatic hyperplasia is important in determining the choice of the surgical technique used. Prostatic volume determination with CT scans, using the ellipsoid formula, appears to be quite accurate. CT scanning of the prostate gland was performed in 34 patients with prostatic hyperplasia (2 cases with cancer). All scans were performed with a Toshiba TCT-60A-30 scanner, and were made for 10 mm slices as follows. From the CT image the maximum transverse diameter (a) sagittal diameter (b), and the maximum transverse area (S) were easily determined. The long axis was calculated from the bladder neck to the distal edge of the vermontanum by urethroscopy (Fig.1). A rough calculation was given by formula V1 or V2. V1 = pi abc/6 or V2 = 2/3 Sc. Calculated volumes of the prostate were compared with the weight of surgical specimens (TUR-P 27 cases, open surgery 7 cases). A good correlation was obtained by this method, i.e., regression equation V1: y = 1.21x + 9.68 (gamma = 0.9376); V2: y = 1.31x + 10.58 (gamma = 0.9471). This method is considered valuable for preoperative measurement of prostatic size, and is useful when evaluating changes in prostatic volume during non-surgical treatment.