CT Findings Of Pulsatile Tinnitus Caused By Transverse-sigmoid Sinus Diverticulum

BackgroundTinnitus is a frequent presenting symptom. The severity of tinnitus varies from scarcely noticeable (by the patient) to an unbearable roar that may disturb an affected patient’s life. Many classification schemes have been developed to facilitate the diagnosis and treatment of tinnitus. Tinnitus has been divided according to the characteristics of the sound and based on the location of the cause. The sound may be pulsatile (coinciding with the patient’s heartbeat) or continuous (nonpulsatile). The cause of pulsatile tinnitus (PT) may be divided into two broad groups:vascular and nonvascular. More people have vascular pulsatile tinnitus than nonvascular ones. Pulsatile tinnitus originating from vascular aetiologies may be due to the blood flow turbulence. Vascular PT can be either arterial or venous, according to the vessel of origin. Transverse-sigmoid sinus diverticulum is a cause of vascular aetiologies. At present, various imaging strategies have been proposed for the investigation of PT, including high resolution computerized tomography (HRCT), CT Arteriography and Venography (CTA/CTV), magnetic resonance imaging (MRI), magnetic resonance angiopraphy (MRA), magnetic resonance venography (MRV), digital subtraction angiography (DSA) and Doppler examination. CTA/V can be a valuable imaging tool in the assessment of PT. With this technique, arterial, venous, and nonvascular causes of PT can be excluded. Transverse-sigmoid sinus diverticulum is a cause of vascular aetiologies.ObjectiveTo evaluate the CT imaging of pulsatile tinnitus caused by transverse-sigmoid sinus diverticulum.Methods18Pulsatile tinnitus patients underwent CTA/V in dual energy mode with a dual source CT machine (SOMATOM Definition Flash, Siemens Healthcare, Forchheim, Germany). Temporal bone images were reconstructed in Source images of CTV using standard bone reconstruction algorithms. Source images were reviewed on a workstation Comprehensivly. Arterial causes of PT include carotid artery stenosis, carotid occlusion, dissection, fibromuscular dysplasia, a persistent stapedial artery, and an aberrant or lateralized ICA course. Venous etiologies include benign intracranial hypertension, a high-riding or dehiscent jugular vein, venous diverticulum, abnormal condylar and mastoid emissary veins. CT arteriography and venography imagings of18cases of pulsatile tinnitus caused by transverse-sigmoid sinus diverticulum were analyzed comprehensively.ResultsTransverse-sigmoid sinus diverticulum was found in18cases of pulsatile tinnitus, also in the dominant side of cerebral venous drainage system. Dual energy bone removal imaging of CTV can display the local expansion of the transverse-sigmoid sinus visually, like saccular, digitatio and processus spinosus. It was seen in CTV that the cerebral venous sinus focally protruded into the neighboring mastoid through the focal defect of bone shell overlying the transverse-sigmoid sinus and formed diverticulum in18patients.ConclusionCTA/V can be a valuable imaging tool in the diagnosis of pulsatile tinnitus caused by transverse-sigmoid sinus diverticulum.