Imaging of sensorineural hearing loss: a pattern-based approach to diseases of the inner ear and cerebellopontine angle

Cochlear Implantation: Systematic Approach to Preoperative Radiologic Evaluation

Sensorineural hearing loss results from abnormalities that affect the hair cells of the membranous labyrinth, inner ear malformations, and conditions affecting the auditory pathway from the cochlear nerve to the processing centers of the brain. Cochlear implantation is increasingly being performed for hearing rehabilitation owing to expanding indications and a growing number of children and adults with sensorineural hearing loss. An adequate understanding of the temporal bone anatomy and diseases that affect the inner ear is paramount for alerting the operating surgeon about variants and imaging findings that can influence the surgical technique, affect the choice of cochlear implant and electrode type, and help avoid inadvertent complications. In this article, imaging protocols for sensorineural hearing loss and the normal inner ear anatomy are reviewed, with a brief description of cochlear implant devices and surgical techniques. In addition, congenital inner ear malformations and acquired causes of sensorineural hearing loss are discussed, with a focus on imaging findings that may affect surgical planning and outcomes. The anatomic factors and variations that are associated with surgical challenges and may predispose patients to periprocedural complications also are highlighted. ^© RSNA, 2023 Quiz questions for this article are available through the Online Learning Center. Online supplemental material and the slide presentation from the RSNA Annual Meeting are available for this article.

Headache Attributed to Disorder of the Cranium and Base of the Skull

The article describes the approach to imaging that clinicians should adopt in cases of headaches suspected to be secondary to cranial vault or skull-base disorder. As a rule, computed tomography (CT) is superior to MRI for most of the osseous lesions, and lesions of the middle and external ear. MRI provides a complimentary role to CT and is the modality of choice in a few conditions such as extraosseous neoplasms of the skull base.

Guidelines for magnetic resonance imaging in pediatric head and neck pathologies: a multicentre international consensus paper

The use of standardized imaging protocols is paramount in order to facilitate comparable, reproducible images and, consequently, to optimize patient care. Standardized MR protocols are lacking when studying head and neck pathologies in the pediatric population. We propose an international, multicenter consensus paper focused on providing the best combination of acquisition time/technical requirements and image quality. Distinct protocols for different regions of the head and neck and, in some cases, for specific pathologies or clinical indications are recommended. This white paper is endorsed by several international scientific societies and it is the result of discussion, in consensus, among experts in pediatric head and neck imaging.

Unilateral sudden sensorineural hearing loss with vertigo as a first symptom of bilateral internal auditory canal metastases: a case report

There have been relatively few reports of bilateral internal auditory canal metastases of asymptomatic primary pulmonary adenocarcinoma presenting as unilateral sudden sensorineural hearing loss and vertigo. We report a case of a 60-year-old male patient who complained of sudden hearing loss in the right ear and vertigo. Upon a physical examination, no definite neurological signs or nystagmus were observed. Pure-tone audiometry showed deafness in the right ear at all frequencies and high-frequency sensorineural hearing loss in the left ear. The video head impulse test suggested bilateral vestibulopathy. Magnetic resonance imaging of the brain (with gadolinium contrast) revealed bilateral internal auditory canal enhancement and a variable-sized nodular and peripheral-enhancing lesion in the cerebrum and the right cerebellum. A computed tomographic and bronchoscopic biopsy identified asymptomatic primary pulmonary adenocarcinoma in the left upper lobe of the lungs. This is a rare report of bilateral internal auditory canal metastases in an asymptomatic patient with primary pulmonary adenocarcinoma who initially presented with symptoms of unilateral sudden sensorineural hearing loss with vertigo.

The role of diffusion tensor imaging in idiopathic sensorineural hearing loss: is it significant?

Purpose

To assess the role of diffusion tensor imaging metrics in the evaluation of the microstructural integrity of the central auditory tract in patients with idiopathic sensorineural hearing loss (SNHL), and to compare these patients with healthy controls.

Material and methods

This prospective study, which was conducted upon 30 subjects (21 males, 9 females; age range from 16 to 65 years, mean age 45years) with SNHL proven by audiometric tests. Ten age- and sex-matched healthy volunteers were included as a control group. Patients (n = 30) and volunteers (n = 10) underwent conventional magnetic resonance imaging and diffusion tensor imaging of the brain. Both fractional anisotropy and mean diffusivity (MD) of 3 points along the acoustic tract (inferior colliculus, lateral lemniscus and superior olivary nucleus) were measured bilaterally in all patients and correlated with controls.

Results

Mean fractional anisotropy (FA) values were reduced bilaterally at the superior olivary nucleus and/or lateral lemniscus and more significantly at the inferior colliculus of subjects with SNHL in comparison to the volunteers. In patients of unilateral SNHL, similar results were obtained in the contralateral side when compared to controls with statistically significant difference at the 3 regions (p = 0.001). No significant changes were noticed in the MD parameters either in patient or control groups.

Conclusions

The FA value was a valuable non-invasive biomarker in evaluating the subtle microstructural abnormalities of the central auditory tract in idiopathic SNHL and correlated well with hearing impairment.

Radiologic Findings in Pediatric Sudden Sensorineural Hearing Loss

OBJECTIVE

Pediatric sudden sensorineural hearing loss (pSSNHL) is a rare phenomenon. There is currently no consensus on the role of imaging in the work-up for this patient population. We aim to evaluate the efficacy of magnetic resonance imaging (MRI) and high-resolution computed tomography (CT) studies in determining the etiology of pSSNHL.

STUDY DESIGN

Retrospective case review.

SETTING

Tertiary Hospital and Ambulatory Otolaryngology Clinic.

PATIENTS

Patients ≤18 years of age with sudden sensorineural hearing loss (SSNHL) and who had either MRI or CT imaging between January 2010 and May 2019 were included.

INTERVENTION

Diagnostic imaging.

MAIN OUTCOME MEASURES

Clinical characteristics and radiology impressions.

RESULTS

A total of 11 patients were identified, and 10 had unilateral SSNHL. MRI was performed on all patients, five patients had additional CT imaging. Abnormal imaging findings relevant to SSNHL were observed in five patients (45.5%), which included enlarged endolymphatic duct and sac, labyrinthine ossification, apical petrositis, hypoplastic cochlear nerve, and arachnoid cyst in the internal auditory canal; one patient had unrelated findings (enlarged pituitary gland), all remaining imaging studies were normal.

CONCLUSION

In our cohort, we found a higher imaging yield on pSSNHL than what has been reported for adult populations, indicating that the use of imaging in the diagnostic work-up is especially important in children.

Cross-Sectional Imaging Evaluation of Congenital Temporal Bone Anomalies: What Each Radiologist Should Know

Hearing loss in pediatric age group is associated with many congenital temporal bone disorders. Aberrant development of various ear structures leads into either conductive or sensorineural hearing loss. Knowledge of the embryology and anatomical details of various compartments of the ear help better understanding of such disorders. In general, abnormalities of external and middle ears result in conductive hearing loss. Whereas abnormalities of inner ear structures lead into sensorineural hearing loss. These abnormalities could occur as isolated or part of syndromes. Temporal bone disorders are a significant cause of morbidity and developmental delays in children. Imaging evaluation of children presented with hearing loss is paramount in early diagnosis and proper management planning. Our aim is to briefly discuss embryology and anatomy of the pediatric petrous temporal bones. The characteristic imaging features of commonly encountered congenital temporal bone disorders and their associated syndromes will be discussed.

MRI of the Internal Auditory Canal, Labyrinth, and Middle Ear: How We Do It

MRI is firmly established as an essential modality in the imaging of the temporal bone and lateral skull base. It is used to evaluate normal anatomic structures, evaluate for vestibular schwannomas, assess for inflammatory and/or infectious processes, and detect residual and/or recurrent cholesteatoma. It is also extensively used in pre- and postoperative evaluations, particularly in patients with vestibular schwannomas and candidates for cochlear implantation. Nevertheless, despite the widespread use of MRI for these purposes, many radiologists remain unfamiliar with the complex anatomy and expected imaging findings with such examinations. The purpose of this review is to provide an overview of the most useful MRI sequences for internal auditory canal and labyrinthine imaging, review the relevant anatomy, and discuss the expected appearances of the most commonly encountered pathologic entities. In addition, the features at pre- and postprocedural MRI will be discussed to help ensure that diagnostic radiologists may be of greatest use to the ordering physicians. © RSNA, 2020.

Imaging Features Differentiating Vestibular Ganglion from Intracanalicular Schwannoma on Single-Sequence Non-Contrast Magnetic Resonance Imaging Study

Introduction: This study aimed to identify imaging features on single-sequence noncontrast magnetic resonance imaging (MRI) that differentiate the vestibular ganglion from small intracanalicular schwannomas. Materials and Methods: Ninety patients (42 men and 48 women; age: 24‒87 years old) with 102 internal auditory canal (IAC) nodules (59 vestibular ganglia and 43 intracanalicular schwannoma) who underwent both singlesequence T2-weighted (T2W) non-contrast enhanced MRI studies and contrast-enhanced T1-weighted (T1W) MRI studies between May 2012 and April 2017 were evaluated. The length, width, distance to the IAC fundus and length/width ratios for all lesions were obtained and compared among groups. Diagnostic performance and cutoff values of the parameters were evaluated with receiver operating characteristics curve analysis. Area under the curve (AUC) value was calculated. Results: Vestibular ganglia have significantly smaller lengths and widths compared to intracanalicular vestibular schwannomas (1.7 ± 0.4 mm and 1.0 ± 0.2 mm versus 5.6 ± 3.0 mm and 3.7 ± 1.5 mm). They are more fusiform in shape compared to vestibular schwannomas (length/width ratio: 1.8 ± 0.4 versus 1.5 ± 0.4). The lesion width demonstrated the highest diagnostic performance (AUC: 0.998). Using a cutoff width of <1.3 mm, the sensitivity, specificity and overall accuracy for diagnosing vestibular ganglia were 97% (57/59), 100% (43/43) and 98% (100/102), respectively. Conclusion: Vestibular ganglia may mimic intracanalicular vestibular schwannomas on a single-sequence T2W MRI. However, a fusiform shape and width <1.3 mm increases confidence in the diagnosis of ganglia. Identifying the vestibular ganglion on single-sequence T2W MRI studies may obviate the need for a contrast-enhanced MRI, reducing the risks of contrast administration, additional scanning time and cost. Key words: Acoustic neuroma, Internal auditory canal, Vestibulocochlear nerve

A pediatric medulloblastoma presenting as isolated sensorineural hearing loss: Case report and review of the literature

Medulloblastoma is the most common pediatric malignant brain tumor and carries a relatively grim prognosis despite recent advances in multimodality therapy. Delays in diagnosis and treatment initiation may contribute to worst outcomes. Signs of increased intracranial pressure and ataxia are known presentations of posterior fossa tumors, but sensorineural hearing loss (SNHL) is a seldom reported symptom. We report the case of a 2-year-old girl who had progressive unilateral SNHL since birth, which was later found to have a posterior fossa medulloblastoma when a head magnetic resonance imaging was ordered following subsequent progression to bilateral hearing impair. We further report our review of 17 additional cases of medulloblastoma presenting with SNHL and their associated head and neck findings. The present study provides insight into the current state of the literature on this rare symptom of a commonly encountered diagnosis, while highlighting the need to consider dedicated brain imaging in pediatric unilateral SNHL when a syndromic etiology or inner ear anomaly is not readily identified on initial investigations.

Imaging of Nontraumatic Temporal Bone Emergencies

This section aims to cover the non-traumatic pathologies affecting the temporal bone including external auditory canal, middle ear and inner ear which usually need emergent clinical attention. Many of the conditions in this section are secondary to infections in different clinical settings with resultant complications which may leave temporary or permanent sequelae if not suspected, timely diagnosed or treated.

Flocculus Herniation and Hearing Disturbance Induced by Remote Tentorial Meningioma: A Case Report

Tentorial meningiomas, not involving the cerebellopontine angle cistern or cranial nerves, rarely cause symptoms of cranial nerve disturbance. We report a case of a patient with a paramedian tentorial meningioma who presented with hearing loss as a result of indirect compression of the vestibulocochlear nerve by the herniated cerebellar flocculus into the internal acoustic meatus. A 50-year-old woman had presented with hearing loss in her right ear. Magnetic resonance imaging (MRI) revealed a large tentorial meningioma in the right posterior cranial fossa. Constructive interference in steady-state (CISS) imaging demonstrated a non-enhanced solid structure at the ipsilateral cerebellopontine angle cistern and internal acoustic meatus. During surgery, after resection of the tumor, the herniated cerebellar flocculus into the internal auditory canal was observed at the ipsilateral cerebellopontine angle. MRI obtained following meningioma resection demonstrated the herniated flocculus regressing from the fundus of the internal acoustic meatus to the cerebellopontine angle cistern, and her hearing was improved as a result of decompression. This is a rare case report of flocculus herniation caused by remote tentorial meningioma. Patients with paramedian tentorial meningiomas rarely present with hearing loss. In these cases, the causes of the hearing loss (microvascular compression, transformed brainstem, and venous circulation disorders) have been described in the literature. In this report, a new mechanism became evident: a herniated flocculus into the internal acoustic meatus by a tumor can cause hearing loss. MRI, particularly CISS imaging, can clearly show the flocculus during the entire clinical course.

Hearing loss in patients with scleroderma: associations with clinical manifestations and capillaroscopy

Systemic sclerosis is a multi-systemic disease with widespread small-vessel vasculopathy and fibrosis. Involvement of the middle and inner ear and hearing loss has been reported as an uncommon manifestation of scleroderma in some studies. In this study, we evaluated hearing problems in scleroderma patients and determined its association with clinical manifestations and capillaroscopy. We evaluated 54 patients with scleroderma referred to Hafez Hospital clinic of scleroderma related to Shiraz University of Medical Science; they fulfilled the LeRoy and ACR/EULAR criteria for scleroderma. Control group consisted of 60 normal individuals. All clinical manifestations, nail fold capillaroscopy, pure tone audiometry, speech reception threshold, and speech audiometry were recorded during evaluation. Subjective hearing loss and objective hearing loss were seen in 10 and 36 patients of the case group (18.5%, 66.7%) and 6 and 10 of the control group (10%, 28.3%) (P values 0.03, < 0.001). Sensorineural hearing loss, abnormal pure tone audiometry, and abnormal speech reception threshold were more common in scleroderma patients compared to the control group (P values of < 0.001, < 0.001, and < 0.001). There was no correlation between objective hearing loss and type of scleroderma, duration of disease, skin score, interstitial lung disease, digital ulcer, gastrointestinal involvement, or nail fold capillaroscopy patterns (all P values > 0.05). In our study, subjective and objective hearing loss were higher in patients with scleroderma compared to the control group and also sensorineural hearing loss, abnormal pure tone audiometry, and abnormal speech reception threshold. There was no correlation between objective hearing loss and clinical manifestations or capillaroscopy findings.

Bilateral Labyrinthine and Internal Auditory Canal Enhancement in an Infant With Severe Labyrinthine Dysplasia: A Previously Unreported Phenomenon

OBJECTIVE

To describe a novel case of congenital profound bilateral sensorineural hearing loss in a patient with bilateral nodular internal auditory canal and labyrinthine enhancement and temporal bone dysplasia.

PATIENTS

A 76-day-old female was referred to the authors' center for evaluation of congenital deafness. Behavioral observations and objective audiometric evaluation demonstrated bilateral profound sensorineural hearing loss and a comprehensive multidisciplinary evaluation identified compound heterozygous pathogenic variants in MYO7A, a gene associated with Usher Syndrome Type 1B or DFNB2. Computed tomography and contrast-enhanced magnetic resonance imaging studies demonstrated bilateral temporal bone anomalies with unique middle and inner ear malformations, as well as unique contrast enhancement in the membranous labyrinth, internal auditory canals, and cranial nerves, which have not been previously described with MYO7A variants.

INTERVENTIONS

Given the potential risk for progressive bilateral labyrinthitis ossificans, bilateral simultaneous cochlear implantation was performed at 4 months of age.

MAIN OUTCOME MEASURES

Subsequent audiologic follow up after implantation shows significantly improved access to auditory information and increased vocalizations. At last testing, speech and language skills for both receptive and expressive language abilities were found to be commensurate with her chronological age.

CONCLUSION

We report a novel presentation and imaging findings of congenital bilateral profound sensorineural hearing loss in a patient with nodular internal auditory canal and labyrinthine enhancement and coexisting inner ear dysplasia. Despite the multiple radiologic abnormalities, the patient has demonstrated good benefit from cochlear implantation. Future study of rare variants of congenital deafness, such as this, is critical toward defining new disease processes and determining optimal treatment.

Lyme disease: sudden hearing loss as the sole presentation

BACKGROUND

Lyme disease is an uncommon tick-borne multisystemic infection caused by Borrelia burgdorferi. The most common clinical manifestation is erythema migrans. In this report, a very unusual presentation of this condition is described, in which sudden onset sensorineural hearing loss was the sole presenting symptom.

METHODS

Case report and review of English-language literature.

RESULTS

A patient presented with sensorineural hearing loss, with no other symptoms or signs. Acute Lyme infection was detected by laboratory tests. Magnetic resonance imaging showed signs of labyrinthitis of the same inner ear. After hyperbaric oxygen and systemic antibiotic treatment, the patient showed total hearing recovery, and magnetic resonance imaging showed complete resolution of the labyrinthitis.

CONCLUSION

To our knowledge, this is the first reported case of Lyme disease presenting only with sensorineural hearing loss. Borreliosis should be considered as an aetiological factor in sensorineural hearing loss. Adequate treatment may provide total recovery and prevent more severe forms of Lyme disease.

Imaging diagnostics: congenital malformations and acquired lesions of the inner ear

INTRODUCTION

Congenital malformations and acquired lesions of the inner ear are characterised by small structural changes in this region. In recent decades, treatment options have improved considerably. At the same time, there has been a great advancement in diagnostic methods, obtaining high-resolution labyrinth images. Currently, we use a 64-multislice computed tomography scanner in spiral mode (Brilliance 64 Phillips, Eindhoven, the Netherlands), with an overlap of 0.66 mm and an interval of 0.33 mm, 120 KV and 300 mA. The magnetic resonance images were taken with Signa HDxt 1.5 and 3.0 T units (GE Healthcare, Waukesha, WI, USA). We reviewed the radiological features of the lesions affecting the inner ear. They are classified as congenital (labyrinth malformation and statoacoustic nerve deficiencies) or acquired (otospongiosis, labyrinthitis, Ménière's disease, inner ear haemorrhage, intralabyrinthine schwannoma and endolymphatic sac tumour).

CONCLUSION

Magnetic resonance imaging and computed tomography play an essential role in diagnosing patients with inner ear pathology. The technique selected should be chosen depending on the clinical setting. In a generic way, tomography is the method of choice for the study of traumatic pathology or otospongiosis. When tumour or inflammatory pathology is suspected, magnetic resonance is superior. In cases of congenital malformation, both techniques are complementary.

Visualization of human inner ear anatomy with high-resolution MR imaging at 7T: initial clinical assessment

BACKGROUND AND PURPOSE

In many centers, MR imaging of the inner ear and auditory pathway performed on 1.5T or 3T systems is part of the preoperative work-up of cochlear implants. We investigated the applicability of clinical inner ear MR imaging at 7T and compared the visibility of inner ear structures and nerves within the internal auditory canal with images acquired at 3T.

MATERIALS AND METHODS

Thirteen patients with sensorineural hearing loss eligible for cochlear implantation underwent examinations on 3T and 7T scanners. Two experienced head and neck radiologists evaluated the 52 inner ear datasets. Twenty-four anatomic structures of the inner ear and 1 overall score for image quality were assessed by using a 4-point grading scale for the degree of visibility.

RESULTS

The visibility of 11 of the 24 anatomic structures was rated higher on the 7T images. There was no significant difference in the visibility of 13 anatomic structures and the overall quality rating. A higher incidence of artifacts was observed in the 7T images.

CONCLUSIONS

The gain in SNR at 7T yielded a more detailed visualization of many anatomic structures, especially delicate ones, despite the challenges accompanying MR imaging at a high magnetic field.