Is a temporal bone CT scan necessary for tinnitus?

Jul 05, 2022 Source: Cainiu Health
Dr. Jiang Weimin
Introduction
Tinnitus requires a temporal bone CT scan. A temporal bone CT can help identify the underlying cause of tinnitus, commonly including pulsatile tinnitus and internal auditory canal tumors. Pulsatile tinnitus refers to a rhythmic noise perceived in the ear that coincides with the heartbeat—specifically, when the rhythm of the tinnitus matches the patient’s pulse or heart rate. In such cases, a temporal bone CT may be performed to assess whether there is a bony defect between the sigmoid sinus and the mastoid process.

When people routinely visit hospitals for medical examinations, many undergo CT scans. So, does tinnitus require a temporal bone CT?

Is a Temporal Bone CT Necessary for Tinnitus?

A temporal bone CT is often indicated for tinnitus, as it helps identify underlying causes—such as pulsatile tinnitus or internal auditory canal tumors. Pulsatile tinnitus refers to a rhythmic noise perceived in the ear that synchronizes with the patient’s heartbeat or pulse. In such cases, a temporal bone CT can assess whether there is bony dehiscence (a defect) between the sigmoid sinus and the mastoid air cells. If part of the mastoid bone is deficient and lies close to nearby blood vessels, arterial pulsations may transmit sound vibrations into the middle ear, resulting in tinnitus. A temporal bone CT can also detect internal auditory canal tumors; however, certain types of tinnitus necessitate magnetic resonance imaging (MRI) of the internal auditory canal instead.

Initial evaluation for tinnitus should include audiological testing—specifically pure-tone audiometry and tympanometry. Subsequently, a temporal bone CT is performed to rule out structural abnormalities of the ear. Additionally, lesions adjacent to the ear (e.g., in the skull base or surrounding vasculature) may also cause tinnitus; therefore, cranial MRI—or MR venography/angiography—may be required. As noted, hearing assessment—including pure-tone audiometry and tympanometry—is the first step in evaluating tinnitus.

Next, a temporal bone CT is conducted to exclude structural ear abnormalities. Moreover, tinnitus may originate from periauricular pathology, warranting cranial MRI or MR venography/angiography. Tinnitus is defined as the perception of abnormal sound in the absence of external acoustic stimulation. Approximately 80% of tinnitus cases stem from pathology or dysfunction along the auditory neural pathway. We hope this article has been helpful. Wishing you a joyful life and good health!