Editing Prostate: Transrectal Ultrasound (section)

==Estimating Prostate Volume==
*'''Most formulas assume that the gland conforms to an ideal geometric shape, either an''' 
**'''<span style="color:#ff0000">Ellipse (π/6 × transverse diameter × AP diameter × longitudinal diameter)</span>''' 
**Sphere (π/6 × transverse diameter3)
**Prolate (eggshaped) spheroid (π/6 × transverse diameter2 × AP diameter).
***'''All formulas reliably estimate gland volume and weight, with correlation coefficients > 0.90 with radical prostatectomy specimen weights,''' because 1 cm3 = approximately 1 g of prostate tissue.
*'''<span style="color:#ff0000">Planimetry is the most accurate means of volume measurement by US</span>'''
**Planimetry allows for variation in shape as the area is calculated in consecutive ultrasonographic cross-sections. The area is multiplied with the distance between the cross-sections and the total volume is determined by summation of all contributions.[https://pubmed.ncbi.nlm.nih.gov/7488974/]