['Stuttering priapism (SP) is seen in sickle cell disease (SCD) and characterized by short-lived painful erections. Imbalanced vascular tone is the postulated cause and this may be reflected in changes in baseline penile blood flow as measured using penile Doppler ultrasound (PDU).', 'The aim of this study was to investigate the baseline penile blood flow characteristics in men with SCD and SP, by comparing with men without SP.', "PDU findings were retrospectively analyzed in 100 men during flaccid state. Nine men had SP (age range 20-40 years), 4 had Peyronie's disease (PD) (35-48 years), 67 men had erectile dysfunction (16-67 years), and 20 men had normal erectile function (18-42 years).", 'The variables measured were peak systolic and end-diastolic velocities, and the Doppler velocity waveform. Values in men with SP were compared with those in the other groups.', 'Median systolic and diastolic velocity was significantly higher in men with SP (systolic/diastolic velocity was 26/4\u2009cm/second in men with SP vs. 13/0\u2009cm/second, 14/0\u2009cm/second, and 16/0\u2009cm/second in men with PD, ED, and normal erectile function, respectively; P=0.0001). Men with SP had a characteristic low peripheral resistance (PR) waveform with fluctuating velocities; the diastolic velocity was consistently positive (2-7\u2009cm/second) and fluctuated between +2 and +8\u2009cm/second. In comparison, the other 91 men had high PR waveform and consistently negative diastolic velocity (range 0 to -2\u2009cm/second).'] Is penile Doppler ultrasound in men with stuttering priapism and sickle cell disease -- a labile baseline diastolic velocity a characteristic finding?