Citations

Standard clinical protocols require hearing protection during magnetic resonance imaging (MRI) for patient safety. This investigation prospectively evaluated the auditory function impact of acoustic noise exposure during a 3.0T MRI in healthy adults. Twenty-nine participants with normal hearing underwent a comprehensive audiologic assessment before and immediately following a clinically indicated head MRI. Appropriate hearing protection with earplugs (and pads) was used per standard of practice. To characterize noise hazards, current sound monitoring tools were used to measure levels of pulse sequences measured. A third audiologic test was performed if a significant threshold shift (STS) was identified at the second test, within 30 days post MRI. Some sequences produced high levels (up to 114.5 dBA; 129 dB peak SPL) that required hearing protection but did not exceed 100% daily noise dose. One participant exhibited an STS in the frequency region most highly associated with noise-induced hearing loss. No participants experienced OSHA-defined STS in either ear. Overall, OAE measures did not show evidence of changes in cochlear function after MRI. In conclusion, hearing threshold shifts associated with hearing loss or OAE level shifts reflecting underlying cochlear damage were not detected in any of the 3.0T MRI study participants who used the current recommended hearing protection.

AbstractObjectiveDescribe the presentation and management strategy for patients with symptomatic foramen of Huschke (FH).PatientsAdults with persistent FH confirmed on imaging.InterventionsDiagnosis and management of symptomatic persistent FH.Main outcome measureResolution of otologic symptoms.ResultsA total of four patients with symptomatic, radiographically‐confirmed persistent FH were included. The majority of patients endorsed otalgia (n = 4) and otorrhea (n = 3), and only one patient was noted to have a conductive hearing loss. All patients were noted to have dynamic movement of an external auditory canal mass with mandible manipulation on examination, and all patients had an identifiable fistula on imaging. Patients underwent surgical intervention, including both preauricular (n = 2) and transcanal (n = 2) approaches, and all endorsed symptomatic resolution after convalescence.ConclusionsPersistent FH remains an uncommon and potentially underrecognized cause of otologic symptoms. Diagnosis requires a high index of suspicion, and one must rely on both key examination findings and imaging to confirm this diagnosis. In appropriately selected patients, surgical intervention can provide durable symptomatic resolution.Level of evidenceIV

Objective: The differential of an external auditory canal mass is broad. One rare potential cause is a pneumatocele of the tympanic membrane, which has only been described 1 other time in the literature. This report serves to describe the second case of this pathology, including its unique presentation, and benign clinical course. Methods: Case report. Results: A case is discussed in which a pneumatocele of the tympanic membrane was incidentally identified during evaluation of contralateral otologic pathology. The etiology was suspected to be habitual auto-insufflation. After cessation of this practice, the pneumatocele was noted to resolve without further intervention. Conclusion: A tympanic membrane pneumatocele represents a rare cause of an external auditory canal mass. The diagnosis can be made clinically via history, palpation, and otoscopy during auto-insufflation, potentially avoiding further diagnostic testing. Depending on the etiology, resolution can occur after lifestyle modification; however, further interventions may definitively treat the condition if so required.

BackgroundFusion of diffusion‐weighted imaging (DWI) to computed tomography (CT) has been touted as a possible technique to improve cholesteatomas localization. This study set out to assess the ability of DWI images fused with thin‐slice heavily T2‐weighted images to similarly localize surgically‐confirmed cholesteatomas.Materials and MethodsA retrospective review was completed of consecutive patients that underwent MR temporal bone imaging (9/2011–3/2020) with both DWI and thin‐slice T2‐weighted imaging. Included patients underwent surgical resection of primary or recidivistic cholesteatoma after preoperative MR imaging. A neuroradiologist, who was blinded to operative and clinical notes, localized each lesion on both DWI and fused DWI‐T2 images in 11 anatomic subdivisions of the temporal bone. Surgical confirmation of cholesteatoma location was used as the gold standard for comparison.ResultsOf 24 included examinations, the average age at time of MR was 48.2 ± 24.7 years; 12/24 (50.0%) were female. Five of 24 had primary cholesteatoma, while the remainder had recidivistic disease. Sensitivity, specificity, and accuracy of unfused DWI images were 52.1%, 88.9%, and 75.8%, respectively. Sensitivity, specificity, and accuracy of fused DWI‐T2 images were 57.1%, 94.8%, and 81.8%, respectively.ConclusionFused DWI‐T2 images outperformed unfused DWI images in the anatomic localization of temporal bone cholesteatomas. This method represents a potential alternative to MR‐CT fusion for pre‐operative cholesteatoma evaluation, and warrants future investigations. Opposed to MR‐CT fusion, this method only necessitates MR sequences and removes the need for additional CT acquisition.Level of Evidence3 Laryngoscope, 131:E1662–E1667, 2021

Objective: To evaluate adverse events and feasibility of performing 1.5-T MRI in patients with cochlear implants (CI) and auditory brainstem implants (ABI). Setting: Single tertiary academic referral center. Patients: CI and ABI recipients undergoing 1.5-T MRI without internal magnet removal. Intervention(s): MRI after tight headwrap application. Main Outcome Measures: Adverse events, patient tolerance. Results: A total of 131 MR studies in 79 patients were performed, with a total of 157 study ears. Sixty-one patients (77%) had unilateral devices. Four patients (5%) underwent MRI with ABI magnets in place. Sixteen patients (20%) had MRI-compatible devices that did not require a head wrap. There were no instances of device stimulation, device malfunction, or excessive heating of the receiver-stimulator package. Magnet tilt requiring manual repositioning occurred during seven studies (4.5%) and magnet displacement requiring operative intervention occurred during seven studies (4.5%). Significant pain where imaging had to be discontinued occurred during three episodes (2%). No adverse events were noted among patients who underwent MRI with an MRI-compatible magnet. Conclusions: MRI with CI or ABI magnets in place is associated with a low prevalence of adverse events when performed in a controlled setting. Many partial magnet displacements can be corrected with firm manual pressure. Devices with magnets that align with the field within their housing were not associated with any adverse events and do not require immobilization of the magnet during the scan. These may be valuable in patients with known or anticipated need for MRI.

Objectives: To evaluate blood–labyrinth barrier permeability using delayed gadolinium enhanced three-dimensional fluid-attenuated inversion recovery (3D-FLAIR) in patients with untreated sporadic vestibular schwannoma (VS) to interrogate the etiopathogenesis of progressive sensorineural hearing loss. Design: Prospective case series. Setting: Single institution tertiary care center. Participants: Patients with previously untreated small to medium-sized unilateral VS undergoing 3D-FLAIR imaging 10 minutes (immediate) and 5 to 8 hours (delayed) after administration of intravenous gadolinium. Main Outcome Measures: Comparison of cochlear and vestibular signal intensity ratios (SIRs) across immediate and delayed images and across the tumor and nontumor ear. Results: Six of eight (75%) patients demonstrated asymmetric enhancement of inner ear structures on delayed contrast-enhanced imaging. Delayed mean cochlea and vestibule SIRs were significantly greater than immediate SIRs (cochlea: 1.91 versus 1.21 [p = 0.02]; vestibule 1.74 versus 1.15 [p = 0.02]). A higher vestibule SIR was statistically significantly associated with poorer pure-tone average and word recognition scores (p = 0.001). Conclusion: Ears with VS exhibited increased enhancement on delayed 3D FLAIR imaging. These findings suggest that alterations in blood–labyrinth barrier permeability may explain progressive sensorineural hearing loss in a subset of patients with untreated VS.

ObjectiveAlthough granulomatosis with polyangiitis (GPA; Wegener’s granulomatosis) is classically characterized by systemic disease involving the kidneys and airway, approximately 10% of patients who have it present with isolated central nervous system disease. When involving the skull base, GPA frequently mimics more common pathology, resulting in diagnostic challenges and delay. The primary objective of this study is to characterize the cranial base manifestations of GPA, highlighting aspects most relevant to the skull base surgeon.Study DesignRetrospective review.SettingTertiary academic referral center.Subjects and MethodsRetrospective analysis of all patients with skull base GPA treated at a tertiary referral center from January 1, 1996, to May 1, 2018.ResultsTwenty‐nine patients met inclusion criteria. Twenty‐one (72%) initially presented with skull base symptomatology as their cardinal manifestation of GPA. Twenty‐four (82%) presented with cranial neuropathy at some point in their disease course. The trigeminal nerve was most commonly involved (12 of 24, 50%), followed by the facial (11 of 24, 46%) and optic (8 of 24, 33%) nerves. Eighteen patients reported hearing loss attributed to the GPA disease process, presenting as conductive, sensorineural, or mixed. The most common locations for GPA‐derived inflammatory skull base disease on imaging included the cavernous sinus (12 of 29, 41%) and the orbit (7 of 29, 24%).ConclusionEstablishing the diagnosis of skull base GPA remains challenging. Cranial neuropathy is diverse in presentation and often mimics more common conditions. Imaging findings are also unpredictable and frequently nonspecific. Careful review of patient history, clinical presentation, serology and biopsy results, and imaging can reveal important clues toward the diagnosis.