목적: The mechanism of pulsatile tinnitus (PT) is presumed to be secondary to turbulent blood flow. Recently, it was reported that turbulence is not the only cause of PT, but pulsation of the venous sinus wall itself by dehiscence might cause a vibration of tympanic membrane and PT. Thus, we evaluated the result of water occlusion test (WOT) in patients with PT on the various causes. 방법:We retrospectively reviewed the patients with PT who had abnormal radiologic findings between January 2010 and July 2021. Temporal bone CT/angiography and/or brain MR/MRA were performed to identify possible structural abnormalities. The patients were asked about the changes of PT during water occlusion test (WOT), IJV compression, head rotation, and after ventilation tube insertion. 결과:Total 22 patients (3 male, 19 female) were analyzed and the mean age was 45.7 ± 16.2 years. Venous sinus dehiscence was the most common cause of PT (15 of 22, 68.2%). In all venous sinus dehiscence only group (VSD only), PT disappeared during WOT (10 of 10). In venous sinus dehiscence plus group (VSD plus; co exists of turbulence and VSD), PT was increased during WOT (5 of 5). In turbulence (venous and/or arterial) group, PT was increased in 75% (3 of 4), and persistent in 25% (1 of 4) during WOT. Disappearance of PT in VSD only was a significant frequent finding compared to VSD or Turbulence group (each P<0.001, Fisher’s exact test.) Two patients with superior canal dehiscence (SCD) had increased PT during WOT. Objective PT was auscultated in two case of VSD plus and Turbulence (arterial) group, respectively. Ventilation tube was inserted in four patients in VSD only group and PT disappeared in all cases after the procedure. 결론:During WOT, PT disappeared in VSD only group and was increased in VSD plus and turbulence group. WOT was a useful test to define possible etiologies of PT.