Detecting causes of pulsatile tinnitus on CT arteriography-venography: A pictorial review

Non-invasive imaging modalities for diagnosing pulsatile tinnitus: a comprehensive review and recommended imaging algorithm

Pulsatile tinnitus (PT) is a challenging diagnostic condition arising from various vascular, neoplastic, and systemic disorders. Non-invasive imaging is essential for identifying underlying causes while minimizing risks of invasive diagnostic angiography. Although no consensus exists on the primary imaging modality for PT and currently CT, ultrasound, and MRI are used in the diagnostic pathway, MRI is increasingly preferred as the first-line screening test for its diagnostic efficacy and safety. MRI protocols such as time-of-flight, magnetic resonance angiography, diffusion-weighted imaging, and arterial spin labeling can identify serious causes, including vascular shunting lesions, venous sinus stenosis, and tumors. In this narrative review of the current literature we discuss the benefits and limitations of various non-invasive imaging modalities in identifying the characteristic imaging findings of the most common causes of PT and also provide an algorithm that clinicians can use to guide the imaging evaluation.

An in vitro experimental study on the synergistic pathogenicity analysis of pulsatile tinnitus involving venous flow velocity, sigmoid sinus wall dehiscence and sinus malformation

Pulsatile tinnitus (PT) is synchronous with patients' heartbeat, with various reported intracranial etiologies. Sigmoid sinus wall dehiscence (SSWD), sinus malformation and high venous flow velocity were common marks of PT and were generally treated as independent etiology in clinic, but their coupling effect remains unclear. This study aimed to investigate the synergistic pathogenicity of these etiologies. The generation and propagation of venous sound was simulated by in vitro experiment. The entity models of sinus vessel, sinus wall and temporal bone cavity were 3D-printed using resin based on CT imaging. Pulsatile venous flow was generated through sinus lumen, with five velocity levels. Venous sound was collected and analyzed. It was found that pressure and pulsation of venous sound were determined by the coupling of three etiology conditions. Low velocity would not induce pulsatile sound anyway. Sub-high or higher velocity induced mild pulsatile sound coupling with normal sinus and wall. Medium or higher velocity induced moderate pulsatile sound coupling with SSWD and normal sinus. Sub-low or higher velocity induced moderate or severe pulsatile sound coupling with SSWD and sinus malformation. In conclusion, PT diagnosis should include the three investigated etiologies due to their contribution to amplifying venous sound. Among the three etiologies, SSWD exhibits the highest pathogenicity, while high venous flow velocity may reduce the effectiveness of SS wall reconstruction, and sinus malformation may exacerbate the intensity of tinnitus induced by SSWD.

Pulsatile tinnitus due to stenosis of the supraclinoid segment of the internal carotid artery: Management with a low-profile self-expanding stent

Atherosclerotic stenosis of the internal carotid artery is a rare cause of pulsatile tinnitus. Stenosis responsible for tinnitus is usually located in the petrous segment of the vessel or, even more uncommonly, in the extracranial segment. However, to the best of our knowledge, a stenosis of the intradural supraclinoid segment of the internal carotid had never been reported as a source of pulsatile tinnitus. We describe the case of a man with a history of previous ischaemic stroke and invalidating pulsatile tinnitus, caused by a high grade, diaphragm-like shaped, stenosis of the supraclinoid internal carotid artery. The stenosis was treated with angioplasty and stenting with a low-profile self-expanding high radial force stent (Acclino flex HRF, Acandis). Tinnitus disappeared immediately after the procedure. At the two-year follow-up no recurrence of the tinnitus and the stenosis occurred. Intradural internal carotid artery stenosis should be considered as a very rare cause of pulsatile tinnitus.

ACR Appropriateness Criteria® Tinnitus: 2023 Update

Tinnitus is abnormal perception of sound and has many subtypes. Clinical evaluation, audiometry, and otoscopy should be performed before ordering any imaging, as the choice of imaging will depend on various factors. Type of tinnitus (pulsatile or nonpulsatile) and otoscopy findings of a vascular retrotympanic lesion are key determinants to guide the choice of imaging studies. High-resolution CT temporal bone is an excellent tool to detect glomus tumors, abnormal course of vessels, and some other abnormalities when a vascular retrotympanic lesion is seen on otoscopy. CTA or a combination of MR and MRA/MRV are used to evaluate arterial or venous abnormalities like dural arteriovenous fistula, arteriovenous malformation, carotid stenosis, dural sinus stenosis, and bony abnormalities like sigmoid sinus wall abnormalities in cases of pulsatile tinnitus without a vascular retrotympanic lesion. MR of the brain is excellent in detecting mass lesions such as vestibular schwannomas in cases of unilateral nonpulsatile tinnitus. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

Surgical treatment of pulsatile tinnitus related to the sigmoid sinus

Objective

Tinnitus-a common clinical symptom-can be categorized into pulsatile tinnitus (PT) and non-PT. Among these, PT is usually associated with sigmoid sinus symptoms, such as sigmoid sinus wall defect or diverticulum, for which various surgical treatments are available. We have discussed the clinical efficacy of surgery for sigmoid sinus-associated PT via the transmastoid approach in this study.

Methods

We conducted a retrospective review of 4 patients who underwent surgery for sigmoid sinus-associated PT via the transmastoid approach at Nanjing Drum Tower Hospital from January to December 2020. Of these, 2 patients had sigmoid sinus wall defect and 2 had sigmoid sinus diverticulum. Post-operative tinnitus grading and surgical efficacy were determined.

Results

After surgery, PT dissolved in 3 patients, while tinnitus significantly decreased in 1 patient. During the follow-up period of 12-18 months, none of the 4 patients showed complications related to increased intracranial pressure or venous sinus thrombosis, and tinnitus symptoms disappeared in 3 patients without recurrence, although 1 patient occasionally developed tinnitus. Postoperative thin-slice CTA of the temporal bone indicated that the sigmoid sinus bone wall defect or diverticulum was completely repaired with a thick soft tissue coverage.

Conclusion

Surgical repair of sigmoid sinus-associated PT via the transmastoid approach deserves clinical promotion as it exhibited better efficiency while being relatively less invasive.

Pediatric tinnitus: The role of neuroimaging

Tinnitus is defined as the perception of sound without an external source and can be categorized as either pulsatile or nonpulsatile (ie, continuous). A variety of etiologies have been reported to cause pediatric tinnitus, many with long-lasting implications due to hearing and concentration impairments. Therefore, imaging can be an essential part of the accurate and timely diagnosis of treatable etiologies. We describe neuroimaging findings in different etiologies of pediatric tinnitus. Etiologies of pulsatile tinnitus are frequently vascular in nature and include vascular loops, congenital vascular anomalies or variants, high riding jugular bulbs with or without a jugular bulb diverticulum, idiopathic intracranial hypertension, aneurysms, internal auditory canal hemangiomas, and petrous apex cephaloceles. Etiologies of continuous tinnitus frequently affect the middle/inner ear structures and include vestibular schwannomas, cholesteatomas, trauma, Chiari malformations, and labyrinthitis ossificans. CT and MR are often complementary modalities: CT is better suited to evaluate the integrity of the temporal osseous structures and MR is better suited to evaluate the vestibulocochlear nerve and to assess for the presence of any masses or malformations. Prompt diagnosis of the etiology of tinnitus in pediatric patients is important to avoid any potential long-term developmental impairments. In the approach to pediatric tinnitus, categorizing the symptoms as either pulsatile versus nonpulsatile and then being aware of the possible causes and imaging findings of either can assist both the clinician and the radiologist in making an expeditious diagnosis.