Pathak RA, et al. - A retrospective review of 2,043 individuals who underwent Color Doppler Duplex Ultrasound (CDDU) from January 1, 2005, to December 31, 2014, was carried out in order to describe age-specific normal CDDU parameters on the basis of a large institutional database of men referred for vascular erectile testing, but discovered to have normal and maintained rigidity after penile injection of alprostadil. In men with normal vascular erections, as measured by the resistive index, there seemed to be an important, age-related reduction in postvisual sexual stimulation peak systolic velocity without compromise to cavernous venous occlusion. In individuals without vascular erectile dysfunction, Doppler parameters were used to determine age-specific normalcy.