From the Guidelines
Pulsatile tinnitus does not always require an MRI brain, but rather a diagnostic algorithm based on a detailed history and clinical evaluation should guide the choice of imaging modality. According to the most recent guidelines, an MRI may be considered as a noninvasive alternative to screen for a suspected intracranial vascular malformation in patients with pulsatile tinnitus 1. The evaluation should be guided by a thorough clinical examination, as certain physical findings like a bruit heard on auscultation strongly suggest a vascular cause requiring imaging.
Key Considerations
- Pulsatile tinnitus can have various causes, including vascular, structural, and anatomic abnormalities, as well as systemic and mechanical causes 1.
- A diagnostic algorithm based on a detailed history and clinical evaluation should progress from less invasive to more invasive imaging studies 1.
- Temporal bone CT and CTA are appropriate to evaluate for a middle ear mass or vascular etiology in patients with pulsatile tinnitus 1.
- MRI of the internal auditory canals is the most appropriate imaging test for subjective nonpulsatile unilateral tinnitus without a clinically evident cause or other associated symptoms 1.
Imaging Recommendations
- An MRI with contrast may be considered as a noninvasive alternative to screen for a suspected intracranial vascular malformation in patients with pulsatile tinnitus 1.
- Additional imaging such as CT angiography or conventional angiography might also be necessary depending on the suspected cause.
- The choice of imaging modality should be guided by a thorough clinical examination and a detailed history 1.
From the Research
Diagnostic Approach to Pulsatile Tinnitus
Pulsatile tinnitus is a symptom that can have various causes, including vascular, structural, and metabolic factors. The diagnosis of pulsatile tinnitus often requires imaging studies to identify the underlying cause.
- The use of MRI and MR angiography has been shown to be effective in evaluating pulsatile tinnitus, as it can help identify vascular lesions, paraganglioma, and other abnormalities 2, 3.
- A comprehensive and targeted radiographic imaging protocol is recommended, including specific MR sequences to highlight different elements of cerebrovascular anatomy and physiology 3.
- The clinical findings and imaging studies must always be evaluated together, with thorough history-taking and clinical examination as the basis for the efficient use of imaging studies 4.
Role of MRI in Diagnosing Pulsatile Tinnitus
MRI can play a crucial role in diagnosing pulsatile tinnitus, particularly in cases where vascular or structural abnormalities are suspected.
- MRI can help identify dilated venous channels, arteriovenous malformations, and other vascular lesions that may be causing pulsatile tinnitus 5, 2.
- The use of MRI and MR angiography can also help rule out life-threatening conditions, such as dural arteriovenous fistulas or intracranial hypertension 6, 4.
Imaging Protocols for Pulsatile Tinnitus
The imaging protocol for pulsatile tinnitus should be comprehensive and targeted, including:
- Time-of-flight magnetic resonance angiography
- Arterial spin labeling
- Spoiled gradient recalled acquisition in the steady state
- Time-resolved imaging of contrast kinetics
- Diffusion weighted imaging
- 3-dimensional fluid-attenuated inversion recovery 3.