Magnetic resonance imaging screening in acoustic neuroma

Clinical Practice Guideline: Age-Related Hearing Loss

OBJECTIVE

Age-related hearing loss (ARHL) is a prevalent but often underdiagnosed and undertreated condition among individuals aged 50 and above. It is associated with various sociodemographic factors and health risks including dementia, depression, cardiovascular disease, and falls. While the causes of ARHL and its downstream effects are well defined, there is a lack of priority placed by clinicians as well as guidance regarding the identification, education, and management of this condition.

PURPOSE

The purpose of this clinical practice guideline is to identify quality improvement opportunities and provide clinicians trustworthy, evidence-based recommendations regarding the identification and management of ARHL. These opportunities are communicated through clear actionable statements with explanation of the support in the literature, evaluation of the quality of the evidence, and recommendations on implementation. The target patients for the guideline are any individuals aged 50 years and older. The target audience is all clinicians in all care settings. This guideline is intended to focus on evidence-based quality improvement opportunities judged most important by the guideline development group (GDG). It is not intended to be a comprehensive, general guide regarding the management of ARHL. The statements in this guideline are not intended to limit or restrict care provided by clinicians based on their experience and assessment of individual patients.

ACTION STATEMENTS

The GDG made strong recommendations for the following key action statements (KASs): (KAS 4) If screening suggests hearing loss, clinicians should obtain or refer to a clinician who can obtain an audiogram. (KAS 8) Clinicians should offer, or refer to a clinician who can offer, appropriately fit amplification to patients with ARHL. (KAS 9) Clinicians should refer patients for an evaluation of cochlear implantation candidacy when patients have appropriately fit amplification and persistent hearing difficulty with poor speech understanding. The GDG made recommendations for the following KASs: (KAS 1) Clinicians should screen patients aged 50 years and older for hearing loss at the time of a health care encounter. (KAS 2) If screening suggests hearing loss, clinicians should examine the ear canal and tympanic membrane with otoscopy or refer to a clinician who can examine the ears for cerumen impaction, infection, or other abnormalities. (KAS 3) If screening suggests hearing loss, clinicians should identify sociodemographic factors and patient preferences that influence access to and utilization of hearing health care. (KAS 5) Clinicians should evaluate and treat or refer to a clinician who can evaluate and treat patients with significant asymmetric hearing loss, conductive or mixed hearing loss, or poor word recognition on diagnostic testing. (KAS 6) Clinicians should educate and counsel patients with hearing loss and their family/care partner(s) about the impact of hearing loss on their communication, safety, function, cognition, and quality of life (QOL). (KAS 7) Clinicians should counsel patients with hearing loss on communication strategies and assistive listening devices. (KAS 10) For patients with hearing loss, clinicians should assess if communication goals have been met and if there has been improvement in hearing-related QOL at a subsequent health care encounter or within 1 year. The GDG offered the following KAS as an option: (KAS 11) Clinicians should assess hearing at least every 3 years in patients with known hearing loss or with reported concern for changes in hearing.

Inner ear MRI: is it always useful to manage intravenous contrast?

OBJECTIVE

To evaluate the added value of administering intravenous contrast (IVC) routinely to the MRI of patients with audiovestibular symptoms in the assessment of a neuroradiologist and a resident.

MATERIALS AND METHODS

Retrospective study including patients who had an inner ear MRI for two months. Two radiologists reviewed independently and blinded the images. A first assessment was made analyzing just the sequences acquired without contrast and then a second evaluation of all the sequences, including post-contrast T1 sequences. The interobserver correlation and the correlation between MRI findings and the reason for requesting the study were calculated.

RESULTS

40 patients were included. The range age was 36-80 years. The most frequent reason for request the MRI was hearing loss (52.5%). Neuroradiologist without IVC found 82.5% of extraotic pathology and 17.5% of otic pathology, highlighting the neurinoma of the VIII pair (7.5%); ossifying labyrinthitis, retrofenestrated otosclerosis and cholesteatoma. After IVC administration, findings were similar. The resident identified otic pathology in 5% in baseline sequences and 20% using CIV. The interobserver correlation using IVC was excellent (0.97), but weak without IVC (0.52). There was a correlation between the reasons for request the MRI and the findings in the ears, both in protocols without IVC (p = 0.004) and in protocols with IVC (p = 0.002).

CONCLUSION

Inner ear MRI without contrast gives relevant information to assess audiovestibular symptoms. The use of IVC increases the degree of confidence in a novel radiologist, while in the expert its use is less relevant. A protocol should be proposed in which gadolinium is used in selected patients.

Screening for vestibular schwannoma in the context of an ageing population

Objective

To review the literature regarding screening for vestibular schwannoma in the context of demographic changes leading to increasing numbers of elderly patients presenting with asymmetric auditory symptoms.

Methods

A systematic review of the literature was performed, with narrative synthesis and statistical analysis of data where appropriate.

Results

Vestibular schwannomas diagnosed in patients aged over 70 years exhibit slower growth patterns and tend to be of smaller size compared to those tumours in younger age groups. This fact, combined with reduced life expectancy, renders the probability of these tumours in the elderly requiring active treatment with surgery or stereotactic radiotherapy to be extremely low. Vestibular schwannomas in the elderly are much more likely to be managed by serial monitoring with magnetic resonance imaging. The weighted yield of magnetic resonance imaging in the diagnosis of vestibular schwannoma in all age groups is 1.18 per cent, with almost 85 scans required to diagnose 1 tumour.

Conclusion

An evidence-based approach to the investigation of asymmetric hearing loss and tinnitus in the elderly patient can be used to formulate guidelines for the rational use of magnetic resonance imaging in this population.

Radiographic findings in young adults with asymmetric sensorineural hearing loss

PURPOSE

To evaluate radiographic findings in US Navy recruits found to have asymmetric sensorineural hearing loss (ASNHL) during routine medical screening.

MATERIALS AND METHODS

Retrospective analysis of US Navy recruits receiving screening audiometry and medical suitability evaluation from January 2011 to October 2016. Single-institution, institutional review board-approved study of US Navy recruits screened for hearing loss over a six-year period. All recruits with ASNHL were evaluated by an otolaryngologist and received diagnostic radiographic evaluation. Audiometric and imaging results were retrospectively reviewed for this population and compared to common screening criteria.

RESULTS

ASNHL was identified in 674 of 228,504 total recruits screened. This population was 91% male and between 17 and 29 years old (mean age 21.1). Six-hundred fifty-three (97%) met criteria for further ASNHL evaluation. Subjective hearing loss was reported in only 6% of patients. Six-hundred sixty-one (99%) received magnetic resonance imaging of the internal auditory canals. Intracranial pathology was identified in 43 (6.3%) patients and 2 (0.3%) had a causative intracranial lesion corresponding to ASNHL. No patients were found to have a vestibular schwannoma.

CONCLUSIONS

In a population of healthy young adults with audiometric proven ASNHL, 0.3% had radiographic proven intracranial pathology explaining the hearing loss. Intracranial masses may be less likely to cause ASNHL in this population; further research is needed to determine appropriate MRI screening methods for young adults with ASNHL.

Diagnostics and therapy of sudden hearing loss

This article reviews recent aspects of diagnostics, differential diagnostics, and evidence in systemic and local therapy of idiopathic sudden sensorineural hearing loss (ISSHL). Since a number of disorders can be accompanied by sudden hearing loss, a meaningful and targeted diagnostic strategy is of utmost importance. An important differential diagnosis of sudden hearing loss are intralabyrinthine schwannomas (ILS). The incidence of ILS is probably significantly underestimated. This may be due to the lack of awareness or lack of explicit search for an intralabyrinthine tumor on MRI or an inappropriate MRI technique for the evaluation of sudden hearing loss ("head MRI" instead of "temporal bone MRI" with too high slice thicknesses). Therefore, the request to the radiologist should specifically include the question for (or exclusion of) an ILS. With special MRI techniques, it is possibly today to visualize an endolymphatic hydrops. The evidence in the therapy of ISSHL is - with respect to the quality and not quantity of studies - unsatisfying. The value of systemically (low dose) or intratympanically applied corticosteroids in the primary treatment of ISSHL is still unclear. In order to investigate the efficacy and safety of high dose corticosteroids as primary therapy for ISSHL, a national, multicenter, three-armed, randomized, triple-blind controlled clinical trial is currently performed in Germany (http://hodokort-studie.hno.org/). After insufficient recovery of the threshold with systemic therapy of ISSHL, intratympanic corticosteroid therapy appears to be associated with a significantly higher chance of an improved hearing threshold than no therapy or placebo. Both, hearing gain and final hearing threshold, however, appear to be independent from the onset of secondary therapy. Based on currently available data from clinical studies, no recommendation can be made with respect to the type of corticosteroid and specifics of the intratympanic application protocol.

Incidental findings on magnetic resonance imaging of the internal auditory meatus performed to investigate audiovestibular symptoms

OBJECTIVE

To determine the frequency of incidental findings found on magnetic resonance imaging scans of the internal auditory meatus performed to investigate audiovestibular symptoms, and to determine how to best manage these when found.

METHOD

A retrospective review was conducted of internal auditory meatus magnetic resonance imaging scans during a three-month period in the radiology department at a UK district general hospital.

RESULTS

A total of 109 scans were reviewed. Of these, 92.7 per cent showed no retrocochlear pathology, 0.9 per cent showed vestibular schwannoma, 6.4 per cent revealed vascular loops, and 2.8 per cent showed incidental findings that warranted further action and investigation. Of the scans, 40.4 per cent showed other incidental pathologies such as age-related ischaemic changes, and sinus disease that required no further intervention. Of the magnetic resonance imaging scans reviewed, 49.5 per cent were entirely normal.

CONCLUSION

Almost half of the scans investigating audiovestibular symptoms showed incidental findings. Otolaryngologists should have an understanding of the significance of the most commonly encountered incidental findings, and should counsel patients appropriately and refer them onward when necessary.

Developing a one-stop tinnitus service: outcomes of a joined up management strategy: a retrospective observational cohort study

RATIONALE, AIMS AND OBJECTIVES

The pressure to deliver quality care with finite resources means that dealing with single-symptom conditions like tinnitus in an efficient and individualized manner has never been more important. Both primary and secondary care practitioners have an obligation to explore efficient delivery of simple management pathways. Commissioners of health care are in a unique position to affect evidence-based strategic change in the management of uncomplicated tinnitus. This study is an attempt to explore one such option. We present the outcomes of a tinnitus patient pathway designed for one-stop management, thereby minimizing unnecessary additional appointments.

METHOD

A retrospective observational cohort study of 452 patients referred to a NHS one-stop tinnitus clinic from 2008 to 2012. Clinical care guided was through the use of a structured approach to history taking, neurotological examination and management.

RESULTS

294 out of 452 (65%) of patients referred had unilateral tinnitus. The most common associated complaints were hearing loss (387/452, 86%) and hyperacusis (329/452, 73%). 210 (46%) of patients had their presenting complaint dealt with in a single clinic visit.

CONCLUSION

A structured system for referral and management of tinnitus within the health system ensures patients have timely access to evidence-based investigation and treatment. A consistent approach to imaging aimed at identifying retrocochlear pathology can benefit patients through early diagnosis of central pathology and the reassurance provided by a negative scan.

Hearing disorders in brainstem lesions

Auditory processing can be disrupted by brainstem lesions. It is estimated that approximately 57% of brainstem lesions are associated with auditory disorders. However diseases of the brainstem usually involve many structures, producing a plethora of other neurologic deficits, often relegating "auditory symptoms in the background." Lesions below or within the cochlear nuclei result in ipsilateral auditory-processing abnormalities detected in routine testing; disorders rostral to the cochlear nuclei may result in bilateral abnormalities or may be silent. Lesions in the superior olivary complex and trapezoid body show a mixture of ipsilateral, contralateral, and bilateral abnormalities, whereas lesions of the lateral lemniscus, inferior colliculus, and medial geniculate body do not affect peripheral auditory processing and result in predominantly subtle contralateral abnormalities that may be missed by routine auditory testing. In these cases psychophysical methods developed for the evaluation of central auditory function should be employed (e.g., dichotic listening, interaural time perception, sound localization). The extensive connections of the auditory brainstem nuclei not only are responsible for binaural interaction but also assure redundancy in the system. This redundancy may explain why small brainstem lesions are sometimes clinically silent. Any disorder of the brainstem (e.g., neoplasms, vascular disorders, infections, trauma, demyelinating disorders, neurodegenerative diseases, malformations) that involves the auditory pathways and/or centers may produce hearing abnormalities.

Is a redefinition of the growth criteria of vestibular schwannomas needed?

PURPOSE

The natural history of vestibular schwannomas is poorly understood. Knowledge of growth rate and growth pattern is essential because the treatment strategy is based upon these. The purpose of this study was to determine the inter- and intraobserver variability in measuring VS size.

MATERIALS AND METHODS

Two consultant neuroradiologists independently made three linear measurements (d1, d2, d3) using digital MRI scans. MRI scans from 72 patients diagnosed between 2002 and 2010 with VS were obtained. These patients had a total of 223 MRI scans. d1 (medio-lateral diameter) was made perpendicular to d2. d2 was made parallel to the posterior border of the petrous ridge, and d3 was a measure of the cranio-caudal height of the tumor.

RESULTS

Limits of Agreement ranges are larger for interobserver reliability compared to intraobserver reliability. Measurement error for all diameters (except d1, intraobserver) is greater than 2mm. d1 measurements had the least variability and d3 measurements the highest variability, both for intra and interobserver measurements.

CONCLUSIONS

The optimal method of estimating VS size needs further investigation, and measurements need to be standardized and clearly defined. d3 seems to be the most difficult diameter to measure reliably. Interobserver measurement error for all diameters is greater than 2mm. The current VS growth criterion of more than 1-2mm, used to triage patients to surgery, lies within this error range, and thus is problematic as a guide for clinical practice. We therefore suggest that the growth criterion for VS be redefined.

Yield of CT angiography and contrast-enhanced MR imaging in patients with dizziness

BACKGROUND AND PURPOSE

Dizziness is a common symptom in emergency and outpatient settings. The purpose of our study was to compare the diagnostic and therapeutic efficacy of CTA of the head and neck, contrast-enhanced MR imaging of the brain (CE-MR), and contrast-enhanced MR imaging of the internal auditory canals and temporal bones in patients with isolated dizziness, to determine which of these modalities should be preferred in the evaluation of dizziness.

MATERIALS AND METHODS

We retrospectively identified patients presenting with dizziness from January 2011 to June 2012 who underwent a CTA, CE-MR, or MRIAC. We excluded patients with signs or symptoms suggestive of other neurologic pathology or a history of an abnormality known to cause dizziness. We calculated the proportion of patients with abnormal findings on a study, tabulated the nature of the abnormality, and reviewed the medical records to determine whether imaging changed management.

RESULTS

Two hundred twenty-eight CTAs, 304 CE-MRs, and 266 MRIACs were included. Five patients (2.2%) with CTAs, 4 (1.3%) with CE-MRs, and 4 (1.5%) with MRIACs demonstrated significant findings that related to the history of dizziness or were incidental but judged to be clinically significant. Of these, 3 CTA (1.3%), 2 CE-MR (0.7%), and 3 MRIAC (1.1%) examinations resulted in a change in clinical management.

CONCLUSIONS

Imaging evaluation of the patient with uncomplicated dizziness is unlikely to identify clinically significant imaging findings and is very unlikely to result in a change in clinical management, with an overall TE of 1.0%. Thus, the routine use of imaging in the evaluation of the patient with dizziness cannot be recommended.

Three-Year Ear, Nose, and Throat Cross-sectional Analysis of Audiometric Protocols for Magnetic Resonance Imaging Screening of Acoustic Tumors

Objectives. (1) Evaluate audiometric protocols and recommend protocols with best sensitivity and specificity for magnetic resonance imaging (MRI) screening of acoustic tumors; (2) determine clinical risks (false negative) of missing acoustic tumors and potential wastes in screening (false positive) nonacoustic tumors or radiologically “normal” cases; and (3) identify the decibel difference and range of frequencies compared by the best-performing protocols.

Study Design. Cross-sectional study with chart review.

Setting. Ear, nose, and throat (ENT); audiology; and radiology departments in a tertiary-care hospital.

Subjects and Methods. Three-year cohort (2006-2009) of 1751 ENT patients underwent MRI screening and pure-tone audiometry indicating sensorineural hearing loss. Audiometric protocols were ranked by highest sensitivity to acoustic tumors, specificity A to nonacoustic tumors, and specificity B to “radiologically normal” cases.

Results. No audiometric protocols achieved 100% sensitivity or specificity rates. Only 2 protocols achieved ≥90% sensitivity: the AMCLASS-A-Urben protocol (93.16%) and the Mangham protocol (91.58%). Eleven of 15 protocols for specificity A and 12 of 15 protocols for specificity B achieved ≥50%. Clinical risks ranged from 6.84% to 18.95%, whereas potential wastes ranged from 33.56% to 68.37% for specificity A and 31.76% to 66.86% for specificity B. Interaural difference parameters indicating highest mean sensitivity were on the order of ≥10 dB, ≥15 dB, and ≥20 dB. For frequency comparison parameters, “2 or more adjacent frequency” and “single-frequency” comparison indicated higher mean sensitivity than the “averaged multifrequency” comparison. Mean specificity showed an opposite pattern.

Conclusions. For optimum sensitivity, the Mangham protocol is preferred (sensitivity, 91.58%; specificity A, 44.23%; specificity B, 44.91%), which proposes a ≥10-dB interaural difference, averaging 1 to 8 kHz. For optimum specificity, the American Academy of Otolaryngology–Head and Neck Surgery protocol is preferred (sensitivity, 87.37%; specificity A, 65.38%; specificity B, 66.04%), which proposes ≥15 dB between ears, averaging 0.5 to 3 kHz.