- Arm II: Patients receive oral placebo once daily on days 1-14. On day 14, patients in both arms undergo blood collection and contrast-enhanced (perflutren protein-type A microspheres) transrectal ultrasound. Conventional gray-scale imaging, color Doppler imaging, and power Doppler imaging are performed. Biopsies are then performed; first up to 6 targeted ultrasound-guided biopsies and then up to 12 systematic biopsies.