A PILOT-STUDY OF FLACCID PENILE BLOOD-FLOW PATTERNS IN NORMAL SUBJECTS AND PATIENTS WITH ERECTILE DYSFUNCTION

Dynamic penile scintigraphy was performed using Tc-99m-labelled autolo gous erythrocytes in five normally potent volunteers and 22 patients w ith erectile dysfunction including 11 patients with psychogenic and 11 patients with vasculogenic impotence (four arteriogenic, three venoge nic, three arteriogenic and venogenic, one arteriogenic and neurogenic ). Penile radioactivity changes in the flaccid state were monitored by a gamma camera for 60 min after injection of the radionuclide. The pe nile time-activity curves of the normal controls characteristically sh owed secondary pulses of increased activity of variable amplitude, dur ation and frequency, consistent with phasic increase in penile blood p ool. This normal rhythmic pattern was impaired in patients with penile arterial insufficiency whereas a blunted pattern was seen in most pat ients with functional impotence as well as in patients with nonarterio genic organic impotence with a psychological overlay. This study provi des new insights into the flaccid penile circulatory physiology, which may contribute to our understanding of the pathophysiology of erectil e dysfunction. In arteriogenic subjects, the impaired response may be attributable to an inadequacy of penile arterial inflow as well as sec ondarily due to the resultant sinusoidal dysfunction subsequent to pen ile ultrastructural damage due to an altered nutritive environment. In creased adrenergic activity in patients with psychogenic impotence may be responsible for the observed deviation from the normal pattern.