Testicular ultrasound is a non-invasive and non-painful test. It is a useful tool to assess male reproductive structures including the testis, epididymis, seminal vesicle and prostate gland. However, Doppler Ultrasound is another variant required to evaluate the blood vessels of the testis, including the arteries which are the main source of blood supply, and the veins which are the sources of varicocele. Your physician will request an ultrasound when in doubt of structural abnormalities of the testis, like feeling a lump in your testis, swelling of your scrotum, discrepancy of testicular sizes and signs suggestive of infection. Whenever there is a suspicion of varicocele or defective blood supply a Doppler ultrasound will be requested (also referred to as ‘Duplex scan’) to properly evaluate the blood flow to and from the testis.