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There can be many causes of unilateral tinnitus
. Though pulsatile quality is not very common. It is good and important that causes vascular causes for tinnitus have been ruled out in your case. Anybody will categorise causes of tinnitus as those originating in external, middle or internal ear. It can be s simple as wax to something as complicated as brain aneurysms. There are uncommon causes like Meniere's disease, which will usually have prominent vertigo
in most cases. It is best to go in for a detailed otoscopic examination and audiometric tests, which will help accurate diagnosis and thus treatment in your case.
Hope this helps.