Biplane planimetry as a new method for prostatic volume calculation in transrectal ultrasonography.
BACKGROUND
We developed a new prostatic volume calculation method using the full information obtained from biplane transrectal ultrasonogram.


METHODS
Based on the cross and sagittal contours, a model composed of sequentially arranged copies of the cross sections, which are reduced so that the anteroposterior diameters of the copies fit the contour of the sagittal section, was created. The volume of this model was the sum of the square of the reduced rates of the height multiplied by the area of the maximum cross section and by slice thickness. Sonograms of 150 patients who underwent ultrasonography with a transrectal chair-type probe were used for the comparison of this method with the ellipsoid volume calculation and the prolate ellipse volume calculation methods. The step-section planimetric volume calculation method was used as the gold standard.


RESULTS
This new method showed the least difference from the step-section planimetry among the 3 calculation methods evaluated.


CONCLUSIONS
The formula of the new method is very simple, so it is easy for it to be incorporated in ultrasonic consoles that are capable of measuring distance and area.
Kimura
A
A
Department of Urology, Faculty of Medicine, University of Tokyo, Japan.
Kurooka
Y
Y
Kitamura
T
T
Kawabe
K
K
D005069:Evaluation Studies as Topic; D006801:Humans; D008297:Male; D008953:Models, Anatomic; D011467:Prostate / Q000000981:diagnostic imaging*; D014463:Ultrasonography / Q000379:methods