As per the American Urological Association, you can use CPT 76856 Ultrasound, pelvic (nonobstetric), real time with image documentation; complete, to evaluate the elements of a complete male pelvic examination include the evaluation and measurement (when applicable) of the urinary bladder, prostate, and seminal vesicles to the extent they are visualized transabdominally, and any pelvic pathology (eg, bladder tumor, enlarged prostate, free pelvic fluid, pelvic abscess)
OR
you can use CPT 76857 Ultrasound, pelvic (nonobstetric), real time with image documentation; limited or follow-up (ie,for follicles), this "limited" CPT code covers a focused examination in the assessment of 1 or more elements listed in the "complete" pelvic ultrasound CPT code 76856.
In our facility, we most commonly use CPT 76857 for ultrasound of penis.