genitourinary disorders
Erectile Dysfunction
Testing
 level; if the level is low or low-normal, Diagnosis of primary and secondary hypogonadism (LH) should be measured. Evaluation for occult diabetes, dyslipidemias, hyperprolactinemia, thyroid disease, and Cushing syndrome should be done based on clinical suspicion. Currently, duplex ultrasonography after intracavernous injection of a vasodilatory drug such as a mixture of prostaglandin E1,papaverine, andphentolamine(available commercially as a combination product) is most often used to evaluate penile vasculature. Normal values include a peak systolic flow velocity>25 cm/sec and a resistive index>0.8. Resistive index is the difference between peak systolic velocity and end-diastolic velocity divided by peak systolic velocity. Rarely, in selected patients for whom penile revascularization surgery is being considered after pelvic trauma, pelvic arteriography, dynamic infusion cavernosography, and cavernosometry may be done. Several sleep-entrained erectile episodes occur in healthy men. These erectile events, measured by nocturnal penile tumescence monitors, may help differentiate between organic and psychogenic etiology of erectile dysfunction. Its current use, however, is primarily in medico-legal settings. 