3D-FLAIR MRI findings in patients with low-tone sudden deafness

Prognosis of Acute Low-Tone Hearing Loss Without Vertigo: A Scoping Review

OBJECTIVE

Despite its relatively high prevalence, our understanding of the natural clinical course of acute low-tone hearing loss (ALHL) without vertigo remains incomplete. The purpose of this study is to summarize the findings of studies that evaluated recovery from hearing loss (HL), recurrence and/or fluctuation of HL, and progression to Meniere's Disease (MD) of patients presenting with ALHL without vertigo.

METHODS

A scoping review of the English literature was performed. On May 14, 2020 and July 6, 2022, MEDLINE, Embase, and Scopus were searched to identify articles related to the prognosis of ALHL. To be included, articles had to present outcomes that were clearly distinguishable for patients with ALHL without vertigo. Two reviewers evaluated articles for inclusion and extracted data. Disagreements were adjudicated by a third reviewer.

RESULTS

Forty-one studies were included. There was extensive heterogeneity between studies in regard to defining ALHL, treatment methods, and time of follow-up. Most of the cohorts (39 out of 40) reported partial or complete recovery of hearing in the majority (>50%) of patients, although reports of recurrence were relatively common. Progression to MD was infrequently reported. Shorter time from onset of symptoms to treatment predicted better hearing outcomes in 6 of 8 studies.

CONCLUSION

The literature suggests that although the majority of patients with ALHL experience hearing improvement, recurrence and/or fluctuation are common, and progression to MD occurs in a minority of patients. Additional trials utilizing standardized inclusion and outcome criteria are needed to determine the ideal treatment for ALHL.

LEVEL OF EVIDENCE

NA Laryngoscope, 133:2457-2469, 2023.

Automated Whole Cochlear T2 Signal Demonstrates Weak Correlation with Hearing Loss in Observed Vestibular Schwannoma

INTRODUCTION

We sought to evaluate the correlation between whole cochlear T2 signal changes obtained with a novel automated segmentation method and hearing levels, both at diagnosis and over time, in patients with observed vestibular schwannoma.

METHODS

This retrospective correlation study within an academic medical center neurotology practice evaluated 127 patients with vestibular schwannoma observed over time, each with ≥2 MRI scans (367 total) and ≥2 audiograms (472 total). 86 patients had T2-weighted sequences with sufficient resolution for cochlear signal analysis, yielding 348 unique timepoint intervals. The main outcome measure was correlation of the ipsilateral-to-contralateral ratio of whole cochlear T2 signal with hearing outcomes as measured by pure tone average (PTA) and word recognition score (WRS).

RESULTS

Whole cochlear T2 signal ratios did not show a correlation with hearing levels at diagnosis. Change in signal ratio over time showed weak correlation with changes in PTA, but not WRS, over time. Cochlear signal ratio did not precede changes in hearing but did follow changes in both PTA and WRS.

CONCLUSION

Whole cochlear T2 signal ratios were weakly correlated with changes in hearing in patients with observed vestibular schwannoma. The technology of automated segmentation and signal processing holds promise for future evaluation of clinical entities causing cochlear signal changes.

Injected 3T-3D-FLAIR-MRI labyrinthine patterns match with the severity and tonotopic alteration in sudden sensorineural hearing loss

PURPOSE

The aim of the study was to assess a correlation between MRI labyrinthine changes detected with IV-gadolinium optimized high-resolution 3D-FLAIR sequences 4 h after injection (OPT4-3DFLAIR) and the type of SSNHL, in terms of frequency alteration and severity.

METHODS

This was a prospective monocentric study achieved from July 2019 to December 2020. The inclusion criterion was acute hearing loss of at least 30 dB over three contiguous frequencies occurring within a 72-h period, documented by a pure-tone audiometry (PTA). The primary endpoint was the visual assessment of hyperintensity in labyrinthine structures on OPT4-3DFLAIR performed on 3T MRI.

RESULTS

Thirty-six affected ears were included (20 men, 15 women; mean age: 54.5 ± 16.3 years) with 69.4% full-spectrum hearing loss. The median hearing loss, expressed as median and interquartile range [IQR] was 91 dB [74-120], with 47.2% of concomitant acute vestibular syndrome. Pathological signal was found in 26 out of 36 ears (72.2%). Basal turn enhancement was found in all abnormal MRIs, with 73.1% of apical turn enhancement and 50% of vestibular enhancement. Seventeen on 19 cases (89.5%) with apical involvement on MRI had low-frequency hearing loss. Vestibular involvement on MRI was significantly associated with a wider frequency range of hearing loss (p = 0.0002) and the severity of SSNHL (84.5 [71.7-92.5] dB versus 120 [85.8-120] dB, p = 0.0158).

CONCLUSION

This report shows that in pathological MRI in SSNHL, a pathologic cochlear base signal is always detected, a cochlear apical turn enhancement matches with low-tone impairment, and a pathological signal within the posterior labyrinth is associated with an impairment of all frequencies and the severity of SSNHL.

Visualization of Endolymphatic Hydrops in Patients With Unilateral Idiopathic Sudden Sensorineural Hearing Loss With Four Types According to Chinese Criterion

Objective: The aim of this study is to evaluate the possible value of endolymphatic hydrops (EH) in patients with unilateral idiopathic sudden sensorineural hearing loss (UISSNHL) with four types according to audiometry.

Methods: Seventy-two patients (40 men and 32 women; age range, 28–78 years; mean age: 50.0 ± 12.9 years) with UISSNHL were admitted retrospectively into this study. Based on the pure tone audiometry before treatment, the hearing loss of all these patients were categorized into four types: low-frequency group (LF-G), high-frequency group (HF-G), flat group (F-G), and total deafness group (TD-G). The average time from symptom onset to the first examination was 6.9 ± 4.4 days (1–20 days). 3D-FLAIR MRI was performed 24 h after intratympanic injection of gadolinium (Gd) within 1 week after the UISSNHL onset. The incidence of EH in the affected ears based on four types of hearing loss were analyzed using the Chi-square test, and the possible relationship with vertigo and prognosis were also assessed.

Results: Eleven of 21 patients (52.4%) in LF-G had the highest EH-positive rate, followed by 18.2% in HF-G, 11.8% in F-G, and 17.4% in TD-G. The significant difference was found in the four groups (P = 0.018). The EH rate of LF-G was statistically significantly higher than that of F-G and TD-G (P = 0.009, P =0.014), respectively. After being valued by the volume-referencing grading system (VR scores), the EH level was represented by the sum scores of EH. In LF-G, no statistically significant difference was found in the prognosis of ISSNHL patients between with the EH group and the no EH group (P = 0.586). The symptom “vertigo” did not correlate with EH and prognosis.

Conclusions: EH was observed in UISSNHL patients by 3D-FLAIR MRI. EH may be responsible for the pathology of LF-G but not related to prognosis. It might be meaningless to assess EH in other hearing loss types, which might be more related to the blood-labyrinth dysfunction.

MRI With Gadolinium as a Measure of Blood-Labyrinth Barrier Integrity in Patients With Inner Ear Symptoms: A Scoping Review

Objective: Capillaries within the inner ear form a semi-permeable barrier called the blood-labyrinth barrier that is less permeable than capillary barriers elsewhere within the human body. Dysfunction of the blood-labyrinth barrier has been proposed as a mechanism for several audio-vestibular disorders. There has been interest in using magnetic resonance imaging (MRI) with intravenous gadolinium-based contrast agents (GBCA) as a marker for the integrity of the blood labyrinth barrier in research and clinical settings. This scoping review evaluates the evidence for using intravenous gadolinium-enhanced MRI to assess the permeability of the blood-labyrinth barrier in healthy and diseased ears.

Methods: A systematic search was conducted of three databases: PubMed, EMBASE, CINAHL PLUS. Studies were included that used GBCA to study the inner ear and permeability of the blood-labyrinth barrier. Data was collected on MRI protocols used and inner ear enhancement patterns of healthy and diseased ears in both human and animal studies.

Results: The search yielded 14 studies in animals and 53 studies in humans. In healthy animal and human inner ears, contrast-enhanced MRI demonstrated gradual increase in inner ear signal intensity over time that was limited to the perilymph. Signal intensity peaked at 100 min in rodents and 4 h in humans. Compared to controls, patients with idiopathic sudden sensorineural hearing loss and otosclerosis had increased signal intensity both before and shortly after GBCA injection. In patients with Ménière's disease and vestibular schwannoma, studies reported increased signal at 4 h, compared to controls. Quality assessment of included studies determined that all the studies lacked sample size justification and many lacked adequate control groups or blinded assessors of MRI.

Conclusions: The included studies provided convincing evidence that gadolinium crosses the blood-labyrinth barrier in healthy ears and more rapidly in some diseased ears. The timing of increased signal differs by disease. There was a lack of evidence that these findings indicate general permeability of the blood-labyrinth barrier. Future studies with consistent and rigorous methods are needed to investigate the relationship between gadolinium uptake and assessments of inner ear function and to better determine whether signal enhancement indicates permeability for molecules other than gadolinium.

Prognostic Value of Early Magnetic Resonance Imaging Patterns in Sudden Hearing Loss

INTRODUCTION

Sudden sensorineural hearing loss (SSHL) is a relatively frequent disease, but a sensitive marker or a reliable test to identify the underlying cause is still unavailable. Neuroradiology appears to offer the most promising tools, especially magnetic resonance imaging (MRI). In a recent study from our group, we explored the ability of MRI to detect subtle changes in the inner ear compartments by means of a 3D-fluid-attenuated inversion recovery sequence, aiming at identifying 3 distinct MRI patterns (haemorrhagic, inflammatory, brain-labyrinth barrier breakdown). In the present study, we contrasted the MRI patterns at onset with relevant prognostic factors, with the audiological features of each patient's SSHL and with treatment outcomes.

METHODS

In this retrospective study, we enrolled 50 adult subjects (54.61 ± 18.26 years) with SSHL. They underwent an MRI within 72 h from admission, and 5 audiological evaluations: at admission, on the 5th day after the start of medical therapy, at the end of the first cycle of hyperbaric oxygen therapy, then 1 and 6 months later.

RESULTS

Abnormalities of the MRI signal and/or post-contrast enhancement asymmetry of the cochlea ("pattern+ MRI") correlated with worse audiological outcomes at 1 month, but the different MRI patterns were not correlated with any specific prognostic model, despite rigid protocol settings. However, a significant difference was found for low-tone SSHL, which were always "pattern" negative at MRI (p = 0.01), and for profound SSHL which demonstrated a pattern+ MRI in 80% (p = 0.04). At the onset of SSHL, a pattern+ MRI was found in 29/50 cases (58.0%) and was related with lesser degree of recovery of pure-tone average at 1 month and lesser chance to retain the hearing threshold benefit in the long term. Given the limited numbers of patients enrolled so far, the relative impact of comorbidities on each MRI pattern remains uncertain. At 6 months, we observed a trend of greater and more stable recovery (p = 0.023) and less frequent recurrence of SSHL in patients with a normal MRI.

CONCLUSIONS

The 3 observed MRI patterns did not correlate consistently with specific audio-vestibular features or any peculiar aspect of the patient's clinical history. Larger series of patients with SSHL are needed, possibly from multicentric studies.

The Role of Anti-Endothelial Cell Autoantibodies and Immune Response in Acute Low-Tone Hearing Loss

OBJECTIVE

Immunity is associated with acute low tone hearing loss. However, the exact pathophysiology of immunity-mediated acute low tone hearing loss remains unknown. In this study, we evaluated the presence, therapeutic effectiveness, and immunopathological mechanisms of anti-endothelial cell autoantibodies (AECEs) in patients with acute low-frequency hearing loss.

MATERIAL AND METHODS

Forty-nine patients who were treated as inpatients having acute low-frequency hearing loss and additional symptoms, such as ear fullness, tinnitus, dizziness, or hyperacusis, were enrolled in this study. Serum samples from these patients were collected for laboratory serum autoimmunity detection, including AECAs, antinuclear antibodies, immunoglobulin, and circular immune complex. Therapeutic responses to combination therapy in short-term outcome and serum cytokine levels were compared between AECA-positive and AECA-negative patients.

RESULTS

Anti-endothelial cell autoantibodies-positive patients tended to show significantly less response to standard therapy compared with AECAs controls (P < .05). Moreover, some serum cytokine levels elevated in both AECAs- and AECAs+ groups. Positive ratio of interleukin-8 and concentrations of macrophage inflammatory protein-1α were found higher in AECAs+ groups (P < .05).

CONCLUSION

The results supported that AECAs might wield influence on the short-term outcome of acute low-tone hearing loss (ALHL) treatment. Furthermore, AECA-mediated acute low-frequency hearing loss possibly involved dysregulation of inflammation process and release of cytokines.

Post-contrast 3D-FLAIR in idiopathic sudden sensorineural hearing loss

PURPOSE

Our study investigated correlations between clinical characteristics, particularly hearing recovery, interval time between onset and three-dimensional fluid attenuation inversion recovery magnetic resonance imaging (3D-FLAIR MRI), and the signal intensity of post-contrast 3D-FLAIR MRI in patients with idiopathic sudden sensorineural hearing loss (SSNHL).

METHODS

The study enrolled 100 SSNHL patients. The signal intensities and asymmetry ratios of the inner ear structures, including the cochleae, vestibules and vestibulocochlear nerve, were evaluated and calculated. The relationships between the clinical characteristics and MRI findings were assessed.

RESULTS

After intravenous gadolinium (Gd) injection, 3D-FLAIR revealed high signal intensities in 65 patients. The corrected asymmetry ratios of cochlea correlated closely with interval time between onset and MRI. The asymmetry ratios of the inner ear structures were significantly lower in patients with final complete to partial hearing recovery. The corrected asymmetry ratios of the inner ear structures correlated with initial/final pure tone audiometry (PTA) and hearing recovery in the affected ear. Notably, it was shown that the corrected asymmetry ratios identified a poor prognosis for hearing recovery, with a sensitivity and specificity of 67.9% and 75.0% in the cochlea, 83.3% and 75.0% in the vestibule, and 52.4% and 81.2% in the vestibulocochlear nerve, respectively.

CONCLUSIONS

Post-contrast 3D-FLAIR after intravenous Gd injection in SSNHL can be used to assess the permeability of the blood-labyrinth and blood-nerve barriers. The asymmetry ratios of the inner ear structures may identify patients with poor prognosis for hearing recovery. Signal characteristics are closely related to interval time between onset and MRI.

Update on consensus on diagnosis and treatment of idiopathic sudden sensorineural hearing loss

INTRODUCTION

Idiopathic sudden sensorineural hearing loss (ISSNHL) is a sudden, unexplained unilateral hearing loss.

OBJECTIVES

To update the Spanish Consensus on the diagnosis, treatment and follow-up of ISSNHL.

MATERIAL AND METHODS

After a systematic review of the literature from 1966 to March 2018, on MESH terms «(acute or sudden) hearing loss or deafness», a third update was performed, including 1508 relevant papers.

RESULTS

Regarding diagnosis, 11ISSNHL is clinically suspected, the following diagnostic tests are mandatory: otoscopy, acumetry, tonal audiometry, speech audiometry, and tympanometry, to discount conductive causes. After clinical diagnosis has been established, and before treatment is started, a full analysis should be performed. An MRI should then be requested, ideally performed during the first 15 days after diagnosis, to discount specific causes and to help to understand the physiopathological mechanisms in each case. Although treatment is very controversial, due to its effect on quality of life after ISSNHL and the few rare adverse effects associated with short-term steroid treatment, this consensus recommends that all patients should be treated with steroids, orally and/or intratympanically, depending on each patient. In the event of failure of systemic steroids, intratympanic rescue is also recommended. Follow-up should be at day 7, and after 12 months.

CONCLUSION

By consensus, results after treatment should be reported as absolute decibels recovered in pure tonal audiometry and as improvement in speech audiometry.

Pathophysiology of the cochlear intrastrial fluid-blood barrier (review)

The blood-labyrinth barrier (BLB) in the stria vascularis is a highly specialized capillary network that controls exchanges between blood and the intrastitial space in the cochlea. The barrier shields the inner ear from blood-born toxic substances and selectively passes ions, fluids, and nutrients to the cochlea, playing an essential role in the maintenance of cochlear homeostasis. Anatomically, the BLB is comprised of endothelial cells (ECs) in the strial microvasculature, elaborated tight and adherens junctions, pericytes (PCs), basement membrane (BM), and perivascular resident macrophage-like melanocytes (PVM/Ms), which together form a complex "cochlear-vascular unit" in the stria vascularis. Physical interactions between the ECs, PCs, and PVM/Ms, as well as signaling between the cells, is critical for controlling vascular permeability and providing a proper environment for hearing function. Breakdown of normal interactions between components of the BLB is seen in a wide range of pathological conditions, including genetic defects and conditions engendered by inflammation, loud sound trauma, and ageing. In this review, we will discuss prevailing views of the structure and function of the strial cochlear-vascular unit (also referred to as the "intrastrial fluid-blood barrier"). We will also discuss the disrupted homeostasis seen in a variety of hearing disorders. Therapeutic targeting of the strial barrier may offer opportunities for improvement of hearing health and amelioration of auditory disorders. This article is part of a Special Issue entitled <Annual Reviews 2016>.

Heavily T₂-Weighted 3D-FLAIR Improves the Detection of Cochlear Lymph Fluid Signal Abnormalities in Patients with Sudden Sensorineural Hearing Loss

Purpose:

To compare the signal increase in cochlear lymph fluid on three-dimensional fluid-attenuated inversion recovery (3D-FLAIR) in patients with sudden sensorineural hearing loss (SNHL) between regular contrast 3D-FLAIR (FL) and heavily T₂-weighted 3D-FLAIR (HF).

Methods:

Twenty-five patients with unilateral sudden SNHL and eight healthy volunteers were included. Patients were divided into two groups: the mild group consisted of 9 patients, with an average hearing level of 60 dB or less; the severe group consisted of 16 patients, with an average hearing level of more than 60 dB. All patients and healthy volunteers underwent magnetic resonance (MR) cisternography for anatomical reference of the fluid space with FL and HF at 3 T. The region of interest (ROI) was manually drawn on the mid-modiolar section of the MR cisternography around the cochlea. The ROI for noise was drawn within the air space. ROIs were copied onto the FL and HF images. The contrast-to-noise ratio (CNR) between the affected and non-affected ear was measured in the patient group and the CNR between the right and left ear was also measured in the control group. Differences in the CNR on FL and HF images among the three groups were tested by one-way analysis of variance (ANOVA).

Results:

There was a statistically significant difference in mean CNR on HF among the three groups (P < 0.001). Furthermore, based on pairwise comparisons, there was a statistically significant difference between them in mean CNR on HF (P < 0.05). There was no statistically significant difference in mean CNR on FL among the three groups (P = 0.074).

Conclusions:

HF is more sensitive to signal alterations in cochleae with sudden SNHL than FL.

Usefulness of three-dimensional fluid-attenuated inversion recovery magnetic resonance imaging to detect inner-ear abnormalities in patients with sudden sensorineural hearing loss

OBJECTIVE

Three-dimensional fluid-attenuated inversion recovery magnetic resonance imaging has been used to detect alterations in the composition of inner-ear fluid. This study investigated the association between hearing level and the signal intensity of pre- and post-contrast three-dimensional fluid-attenuated inversion recovery magnetic resonance imaging in patients with sudden-onset sensorineural hearing loss.

METHOD

Three-dimensional fluid-attenuated inversion recovery magnetic resonance imaging was performed in 18 patients with sudden-onset sensorineural hearing loss: 12 patients with mild-to-moderate sensorineural hearing loss (baseline hearing levels of 60 dB or less) and 6 patients with severe-to-profound sensorineural hearing loss (baseline hearing levels of more than 60 dB).

RESULTS

High-intensity signals in the inner ear were observed in two of the six patients (33 per cent) with severe-to-profound sensorineural hearing loss, but not in those with mild-to-moderate sensorineural hearing loss (mid-p test, p = 0.049). These signals were observed on magnetic resonance imaging scans 6 or 18 days after sensorineural hearing loss onset.

CONCLUSION

The results indicate that three-dimensional fluid-attenuated inversion recovery magnetic resonance imaging is not a useful tool for detecting inner-ear abnormalities in patients with mild sensorineural hearing loss.