Imaging of Tinnitus

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.

Imaging in Pulsatile Tinnitus: Case Based Review

Tinnitus refers to auditory perception of internal origin. It is a relatively common problem and affects men and women equally. Clinically, it may be divided as pulsatile or non-pulsatile and subjective and objective. Although pulsatile tinnitus (PT) is less common, it is more likely to be associated with underlying vascular tumors, lesions or anomalies. Imaging forms the baseline for evaluation of objective tinnitus, primarily in the form of computed tomography or magnetic resonance imaging. We present a review of common causes of PT, along with emphasis on key imaging findings.

Tinnitus and sound intolerance: evidence and experience of a Brazilian group

Introduction

Tinnitus and sound intolerance are frequent and subjective complaints that may have an impact on a patient's quality of life.

Objective

To present a review of the salient points including concepts, pathophysiology, diagnosis and approach of the patient with tinnitus and sensitivity to sounds.

Methods

Literature review with bibliographic survey in LILACS, SciELO, Pubmed and MEDLINE database. Articles and book chapters on tinnitus and sound sensitivity were selected. The several topics were discussed by a group of Brazilian professionals and the conclusions were described.

Results

The prevalence of tinnitus has increased over the years, often associated with hearing loss, metabolic factors and inadequate diet. Medical evaluation should be performed carefully to guide the request of subsidiary exams. Currently available treatments range from medications to the use of sounds with specific characteristics and meditation techniques, with variable results.

Conclusion

A review on tinnitus and auditory sensitivity was presented, allowing the reader a broad view of the approach to these patients, based on scientific evidence and national experience.

Aberrant sylvian vein: A newly described cause of pulsatile tinnitus

We herein report a newly described cause of venous pulsatile tinnitus: protrusion of an aberrant sylvian vein into the tympanum. A 60-year-old woman presented with a 4-month history of objective persistent pulsatile tinnitus in the right ear with no other complaints. The pulsatile tinnitus diminished with rotation of the head to the right side or by compression of the right cervical vascular structures. The frequency and intensity of the tinnitus were 125 Hz and 20 dB HL, respectively. Audiometry and otoscopic examination findings were normal. Radiologic examination showed that the right sylvian vein protruded into the tympanum through the dehiscent anterior cortical plate of the tympanum.

Imaging Interpretation of Temporal Bone Studies in a Patient with Tinnitus: A Systematic Approach

Tinnitus is an auditory perception of internal origin. Tinnitus is not a diagnosis but a symptom with many possible causes and correspondingly divergent pathophysiologic, anatomic, diagnostic, and therapeutic considerations. This article provides a summary of the imaging findings of structural causes of tinnitus.

Magnetic Resonance Imaging Findings in Children With Tinnitus

Objective:

Tinnitus in adults is generally investigated by contrast-enhanced magnetic resonance imaging (MRI) to rule out the diagnosis of acoustic neuroma. Acoustic neuroma is rare in children and, therefore, the role of MRI in children with tinnitus is unclear. This study was undertaken to determine the value of MRI in the investigation of tinnitus in children.

Methods:

Retrospective study of children younger than 18 years who underwent MRI for the investigation of tinnitus over a 10-year period.

Results:

Sixty-five patients were identified, but there were only 34 who had also undergone audiologic assessment. Among the 25 patients with normal audiology, MRI abnormalities were present in 9, but these were all thought to be nonspecific. Nine patients had abnormal audiograms and the MRI was abnormal in 4 of these cases, which included 3 children who were found to have multiple sclerosis.

Conclusion:

Magnetic resonance imaging would appear to be mandatory in the investigation of tinnitus in children who are found to have sensorineural hearing loss, particularly to rule out the diagnosis of multiple sclerosis. Although our study does not support the routine use of MRI in children with normal audiology, the numbers in our series are too small for a conclusive recommendation.

Combined Central and Peripheral Stimulation for Treatment of Chronic Tinnitus

Background. Tinnitus is a common untreatable condition that originates from central maladaptive plasticity initiated by peripheral injury. Repetitive transcranial magnetic stimulation (rTMS), direct cochlear low-level laser therapy (LLLT), and acupuncture were tried for tinnitus treatment, but the results of these methods were clinically unsatisfactory. Objective. This study aimed to test the combined effect of the 3 methods targeting both peripheral and central auditory areas as a new therapeutic strategy for tinnitus. Methods. For this, 30 patients were randomized to 3 equal groups receiving 3 different interventions: inhibitory rTMS to the left auditory cortex, LLLT (which includes a combination of direct cochlear LLLT and laser acupuncture) to the affected ear(s), and finally, a combination of rTMS and LLLT. The Tinnitus Handicap Inventory (THI) and Visual Analogue Scale (VAS) were assessed before, immediately after, and at 2 weeks and 4 weeks after 10 consecutive every-other-day sessions for each intervention type. Results. We found that combined stimulation was effective in tinnitus treatment. This effect remained for 4 weeks after the end of the treatment. However, each of rTMS and LLLT alone had no significant effect. Repeated-measures ANOVA showed a significant effect of Time and Time × Intervention interaction for THI and VAS scores. The post hoc t test for different time points per intervention revealed a significant difference between baseline and all postintervention measurements of both THI and VAS for the combination intervention. Conclusion. Combined central rTMS and peripheral LLLT is more beneficial as a new method for management of tinnitus rather than these two used separately.

Persistent primitive trigeminal artery: an unusual cause of vascular tinnitus

Pulsatile tinnitus is generally of vascular origin and can be due to arterial, venous, or systemic causes. While certain congenital anatomical variants and arterial vascular loops have been commonly found in symptomatic patients undergoing imaging, persistent primitive trigeminal artery in association with isolated tinnitus is unusual. Thus we report a patient with unilateral isolated pulsatile tinnitus who was evaluated with magnetic resonance angiography and was found to have a persistent primitive trigeminal artery. We also briefly discuss vascular tinnitus as well as the embryology, imaging, and classification of persistent primitive trigeminal artery with the clinical implications.

Is it necessary to do temporal bone computed tomography of the internal auditory canal in tinnitus with normal hearing?

Objective. To investigate the compression of the vestibulocochlear nerve in the etiology of the tinnitus in the normal hearing ears with temporal bone computed tomography scans. Methods. A prospective nonrandomized study of 30 bilateral tinnitus and 30 normal hearing patients enrolled in this study. Results. A total of 60 patients (ages ranged from 16 to 87) were included. The tinnitus group comprised 11 males and 19 females (mean age 49,50 ± 12,008) and the control group comprised 6 males and 24 females (mean age 39,47 ± 12,544). Regarding the right and left internal acoustic canals measurements (inlet, midcanal, and outlet canal lengths), there were no significant differences between the measurements of the control and tinnitus groups (P > 0.005). There was no narrowness in the internal acoustic canal of the tinnitus group compared with the control group. High-frequency audiometric measurements of the right and left ears tinnitus group at 8000, 9000, 10000, 11200, 12500, 14000, 16000, and 18000 Hz frequencies were significantly lower than the control group thresholds (P < 0.05). There was high-frequency hearing loss in the tinnitus group. Conclusion. There were no anatomical differences in the etiology of tinnitus rather than physiological degeneration in the nerves.

Diagnostic utility of magnetic resonance imaging and magnetic resonance angiography in the radiological evaluation of pulsatile tinnitus

AIM

Our aim was to assess the diagnostic utility of magnetic resonance imaging with complimentary magnetic resonance angiography (MRI/MRA) in the radiological evaluation of patients with pulsatile tinnitus (PT).

MATERIALS AND METHODS

The present study was retrospectively conducted on 27 patients with pulsatile tinnitus. All patients showed normal otoscopic findings and were evaluated with magnetic resonance imaging (MRI) with complimentary magnetic resonance angiography (MRA), 9/27 (33.3%) patients were investigated by CT, and 12/27 (44.4%) were evaluated by angiography. All patients' clinical investigation was reviewed to discard systemic causes of PT.

RESULTS

All hard copies of MRI/MRA studies were evaluated. MRI/MRA detected the underlying etiology of subjective pulsatile tinnitus (PT) in 11/27 patients (40.7%), and 16/27 patients (59.5%) showed normal MRI/MRA examination. The most common cause was dural arteriovenous malformation (AFM) in 4/27 (14.8%) patients, high jugular bulbus in 2/27 (7.4%), aneurysm of internal carotid artery in 1/27 (3.7%), aberrant internal carotid artery in 1/27 (3.7%), vertebral artery hypoplasia in 2/27 (7.4%), and glomus tumor in 1/27 (3.7%). The statistical results of the present study showed that MRI/MRA had the following: 80% sensitivity, 88% specificity, 86% accuracy, 85% PPV, 83% NPV, and 15% error percentage for diagnosis of PT.

CONCLUSION

MRI/MRA was an effective radiological imaging method in detecting the underlying pathology of pulsatile tinnitus. Magnetic resonance may be considered a first line diagnostic imaging modality in the assessment of subjective pulsatile tinnitus.

Pulsatile tinnitus: imaging and differential diagnosis

BACKGROUND

Pulsatile tinnitus, unlike idiopathic tinnitus, usually has a specific, identifiable cause. Nonetheless, uncertainty often arises in clinical practice about the findings to be sought and the strategy for work-up.

METHODS

Selective literature review and evaluation of our own series of patients.

RESULTS

Pulsatile tinnitus can have many causes. No prospective studies on this subject are available to date. Pulsatile tinnitus requires both a functional organ of hearing and a genuine, physical source of sound, which can, under certain conditions, even be objectified by an examiner. Pulsatile tinnitus can be classified by its site of generation as arterial, arteriovenous, or venous. Typical arterial causes are arteriosclerosis, dissection, and fibromuscular dysplasia. Common causes at the arteriovenous junction include arteriovenous fistulae and highly vascularized skull base tumors. Common venous causes are intracranial hypertension and, as predisposing factors, anomalies and normal variants of the basal veins and sinuses. In our own series of patients, pulsatile tinnitus was most often due to highly vascularized tumors of the temporal bone (16%), followed by venous normal variants and anomalies (14%) and vascular stenoses (9%). Dural arteriovenous fistulae, inflammatory hyperemia, and intracranial hypertension were tied for fourth place (8% each).

CONCLUSION

The clinical findings and imaging studies must always be evaluated together. Thorough history-taking and clinical examination are the basis for the efficient use of imaging studies to reveal the cause of pulsatile tinnitus.

3-Dimensional reconstruction of the venous system in patients suffering from pulsatile tinnitus

CONCLUSIONS

An abrupt change in the venous caliber, producing turbulent flow, may be a cause of pulsatile tinnitus (PT). The largest area/smallest area (L/S) ratio >4.75 may be a criterion indicating abrupt caliber change and causing PT.

OBJECTIVES

Contrast-enhanced CT is recommended as an initial work-up modality in PT. But, in the majority of cases, no definite pathology can be found, even after extensive work-up. In these cases, the unilateral dominant venous system may be the cause of PT. The aim of this study was to compare, through 3D-reformatted images of the intracranial venous system, the volume, cross-sectional area, and caliber changes in patients with PT and normal controls.

METHODS

This was a cross-sectional study set in a tertiary referral center. Eleven patients (11 unilateral PT ears) and 12 normal control ears were enrolled. All the subjects were confirmed with normal CT angiography findings. The intracranial venous structure was three-dimensionally reconstructed. Three areas with the largest and the smallest dimension were selected for further analysis: the transverse sinus (T), isthmus (I), and the jugular bulb (B). The total volume, cross-sectional area, and cross-sectional area ratios of the three areas were compared in the PT group and the normal control group.

RESULTS

The L/S ratio was significantly increased in the PT group (5.01), compared with the control group (3.42). When the threshold value of the L/S ratio was assessed by the ROC method, 4.75 seemed to be the significant dissecting point. The sensitivity of this method was 0.64 and the specificity was 0.83.

Arteriovenous malformation in the parotid region presenting as pulsatile tinnitus: a case report

BACKGROUND

Pulsatile tinnitus is a unique symptom in the general population and often leads patients to medical attention.

METHODS AND RESULTS

We report a patient who had an arteriovenous malformation of superficial temporal artery in the parotid region causing pulsatile tinnitus and insomnia. Magnetic resonance angiography and carotid angiography were useful tools for the detection of this vascular malformation. Successful treatment of this lesion was achieved by endovascular embolization.

CONCLUSION

This case illustrates a thorough diagnostic work-up with a high index of suspicion and a proper treatment option is rewarding when dealing with such a rare disease.