Department of Urology, Juntendo University, School of Medicine
Ultrasonography, Prostate, 3-D image
Since 1983, the system of the transrectal ultrasonogram to display longitudinal and reconstructed transverse images (TRUS-L/RT) have been developed for the purpose of improving the diagnostic accuracy and imagining the three dimentional shape of the prostate. The outline of this system had been reported, therefore, the results of the additional basic study and the clinical study were reported in this issue. In the basic study, the reconstructed transverse image had a good resolution and little distortion. Thirty eight cases who underwent a needle biopsy, transurethral resection or prostatectomy were examined on the prostate by the TRUS-L/RT. In term of cancer diagnosis, this study resulted in a sensitivity of 90.9%, a specificity of 85.2%, a positive predictive value of 71.4% and a negative predictive value of 95.8%. The volume of prostate was calculated in 6 cases with normal prostate, 8 with prostatitis, 10 with begign prostatic hypertrophy and 14 with prostatic cancer. In the normal prostate, the average volume of peripheral zone (18.7 cm3) accounted for 85.8% of the whole prostate volume (21.8 cm3). In the prostatitis, the average volume of peripheral zone (24.7 cm3) accounted for 86.7% of the whole prostate volume (28.5 cm3). In the BPH, the average volume of peripheral zone (20.8 cm3) accounted for 46.0% of the whole prostate volume (57.4 cm3). The shape of the prostate was imagined with longitudinal images and reconstracted transverese images of the TRUS-L/RT (the imagined 3-D shape). The normal prostate looked like a spaceship (spaceship type) and the BPH looked like balls (hyperplastic nodules) and a deflated ball (peripheral zone) (balls on a deflated ball type). In 10 of cases with proatatic cancer, the imagined 3-D shape looked like a loquat (loquat type).