BERKELEY, CA (UroToday.com) - PSAVD was first proposed by Choi, et al.[1] in 2011; its most important theoretical foundation is that the estimated average annual change of prostate volume was 1.6% across all age groups.[2] Generally PSAVD combines the velocity of PSA and prostate volume, therefore it has the shortage of both velocities, which relates to serum PSA levels, age and examination intervals.