MRI in otology: applications in cholesteatoma and Ménière's disease

Magnetic Targeting of Gadolinium Contrast to Enhance MRI of the Inner Ear in Endolymphatic Hydrops

OBJECTIVES

1. Determine the feasibility and efficiency of local magnetic targeting delivery of gadolinium (Gad) contrast to the inner ear in rodents. 2. Assess any potential ototoxicity of magnetic targeting delivery of Gad in the inner ear. 3. Study the utility of magnetic targeting delivery of Gad to visualize and quantify endolymphatic hydrops (EH) in a transgenic mouse model.

STUDY DESIGN

Controlled in vivo animal model study.

METHODS

Paramagnetic Gad was locally delivered to the inner ear using the magnetic targeting technique in both rat and mouse models. Efficiency of contrast delivery was assessed using magnetic resonance imaging (MRI). Ototoxicity of Gad was examined with histology of the cochlea and functional audiological tests. The Phex mouse model was used to study EH, hearing loss, and balance dysfunction. Magnetic targeting delivery of Gad contrast was used in the Phex mouse model to visualize the effects of EH using MRI.

RESULTS

Magnetic targeting improved the delivery of Gad to the inner ear and the technique was reproducible in both rat and mouse models. The delivery method did not result in microstructural damage or any significant hearing loss in a normal animal. Magnetic targeting of Gad in the Phex mouse model allowed detailed visualization and quantification of EH.

CONCLUSION

This study provided the first evidence of the effectiveness and efficiency of the local magnetic targeting delivery of gadolinium contrast to the inner ear and its application to the visualization and quantification of EH. Laryngoscope, 133:914-923, 2023.

A systematic review on delayed acquisition of post-gadolinium magnetic resonance imaging in Ménière's disease: imaging of the endolymphatic spaces

OBJECTIVE

This study aimed to assess the clinical implications of delayed-acquisition post-gadolinium magnetic resonance imaging in identifying endolymphatic hydrops in Ménière's disease.

METHOD

This study was a systematic review using Medline and Embase and following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines with predetermined criteria, namely Ménière's disease, post-gadolinium magnetic resonance imaging and endolymphatic hydrops. The Quality Assessment of Diagnostic Accuracy Studies-2 tool was used to assess bias.

RESULTS

Eleven studies were included; they all used 3T magnetic resonance imaging, with three-dimensional fluid-attenuated inversion recovery being the most common sequence. Intravenous gadolinium administration was more widely used compared with the intratympanic route. As for the timing of acquisition, 4 hours post-administration was universally used for the IV gadolinium and 24 hours was used for the intratympanic gadolinium. Despite patient-selection associated bias, all studies reported adequate visualisation of the endolymphatic spaces.

CONCLUSION

The use of delayed-acquisition magnetic resonance imaging is increasingly supported in visualising the endolymphatic spaces in Ménière's disease. Although the accessibility of 3T magnetic resonance imaging questions its wider applicability, it is a promising tool for the near future.

The Clinical Role of Diffusion-Weighted MRI for Detecting Residual Cholesteatoma in Canal Wall up Mastoidectomy

OBJECTIVES

The purpose of this study was to assess the value of the diffusion MRI with the non-echoplanar imaging (Non-EPI) technique for follow-up the post-operative patients to detect residual cholesteatomas.

STUDY DESIGN

This prospective study was performed on 40 patients. All patients were at least one year after Canal Wall Up mastoidectomy surgery for cholesteatoma and scheduled for a second-look surgery.

PATIENTS AND METHODS

This prospective study was performed on 40 patients. All patients were subjected to Canal Wall Up surgery and planned for the second-look operation. After one year as removal of choleasteatoma is uncertain in first surgery. The study done at Tertiary referral centers (Ain shams, Mansoura, and Minia university hospitals), non-echoplanar diffusion MRI (NEP-DWI) technique for follow-up the post-operative patients to detect residual cholesteatomas, then second look surgery done 2 weeks after MRI.

RESULTS

Forty patients underwent MRI with Non-echoplanar diffusion-weighted imaging (NEP-DWI). Twenty-six patients had positive MRI results with the remaining 14 patients had negative results. These results were compared to operative findings. All positive MRI cases showed positive intra-operative findings. Ten of negative MRI cases showed negative intra-operative findings. Four of DWI-negative cases showed small cholesteatomas.

CONCLUSION

The use of NEP-DWI is a valuable tool in detecting residual cholesteatoma that could replace the second look surgery in many cases.

Potential nanotechnology-based diagnostic and therapeutic approaches for Meniere's disease

Meniere's disease (MD) is a progressive inner ear disorder involving recurrent and prolonged episodes or attacks of vertigo with associated symptoms, resulting in a significantly reduced quality of life for sufferers. In most cases, MD starts in one ear; however, in one-third of patients, the disorder progresses to the other ear. Unfortunately, the etiology of the disease is unknown, making the development of effective treatments difficult. Nanomaterials, including nanoparticles (NPs) and nanocarriers, offer an array of novel diagnostic and therapeutic applications related to MD. NPs have specific features such as biocompatibility, biochemical stability, targetability, and enhanced visualization using imaging tools. This paper provides a comprehensive and critical review of recent advancements in nanotechnology-based diagnostic and therapeutic approaches for MD. Furthermore, the crucial challenges adversely affecting the use of nanoparticles to treat middle ear disorders are investigated. Finally, this paper provides recommendations and future directions for improving the performances of nanomaterials on theragnostic applications of MD.

Correlation of semi-quantitative findings of endolymphatic hydrops in MRI with the audiometric findings in patients with Meniere’s disease

Purpose: To investigate the correlation between vestibular hydrops (VH), cochlearhydrops (CH), vestibular aqueduct non-visibility (VANV), and visually increased perilymphatic enhancement (VIPE) with the findings of pure-tone audiometry (PTA) in Meniere’s disease (MD) patients.

Methods: In this cross-sectional study, 53 ears belonging to 48 patients were divided into two groups and evaluated. In group “MD patients,” there were 24 ears of 19 patients diagnosed with the definite MD (14 patients with unilateral and 5 patients withbilateral involvements). The “control group” consisted of 29 non-symptomatic ears belonging to patients diagnosed with unilateral sudden sensory-neural hearing loss or unilateral schwannoma. All the patients underwent 2 sessions of temporal bone MRI using the same 3T system: an unenhanced axial T1, T2, and 3D-FLAIR MRI, an intravenous gadolinium-enhanced axial T1 fat-sat, and 4 h after the injection, an axial 3D-T2 cube and 3D-FLAIR session. VH, CH, VANV, and VIPE were assessed. Subsequently, the correlation between EH indices and PTA findings (in three frequency domains of low, middle, and high) were evaluated, and the predictive value of MRI was calculated.

Results: VH was significantly correlated with the hearing threshold in the low, middle, and high-frequency domains. CH was also correlated with the hearing threshold in the low and middle domains. Contrarily, VIPE was not associated with hearing thresholds, and VANV was only correlated with the hearing threshold in low frequencies.

Conclusion: The grade of VH, CH, and VANV were significantly correlated with the hearing thresholds in PTA.

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Endolymphatic hydrops (EH) is commonly found in Meniere's disease (MD).

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MRI-detected EH is associated with the diagnosis of definite MD.

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EH in MD includes vestibular and cochlear hydrops and invisible vestibular aqueduct.

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The EH grade is correlated with the degree of hearing loss in pure-tone audiometry.

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Low grades of EH were seen in normal ears of unilateral MD and non-MD patients.

Dimensions and forms of artefacts in 1.5 T and 3 T MRI caused by cochlear implants

Cochlear implantation is a standard treatment option due to expanding indications. Cranial magnetic resonance imaging (cMRI) has become a widespread diagnostic tool. Therefore, an increased number of cochlear implant (CI) users are undergoing cMRI scans. This study aimed to investigate the issue of the CI magnet impacting MRI quality and artifacts. 1.5 T and 3 T MRI scans with 4 defined sequences (T2-TSE, T2-TIRM, T1-3D-MPRAGE, and TDI) were performed on a phantom with a CI (SYNCHRONY System by MED-EL Austria) in place. The resulting MRI artifacts were retrospectively compared to MRI artifacts observed in patients with a CI. All images were transferred to AMIRA and visualized by manual segmentation. Usable image quality was achieved in three sequences (T2-TSE, T2-TIRM and T1-mprage). Observed artifacts differed in shape and size depending on the sequence. Maximum diameters of signal void areas ranged from 58 × 108 × 98 mm to 127 × 123 × 153 mm. Image distortions were larger. MRI artifacts caused by the SYNCHRONY system are asymmetric with varying shape, depending on the sequence. The phantom artefacts are similar to those in CI users. Considering the observed asymmetry, the hypothesis of varying implantation locations resulting in varying positions of the signal void area needs to be further investigated.

Ménière's disease: new guidelines, subtypes, imaging, and more

PURPOSE OF REVIEW

This article reviews recent developments in Ménière's disease including etiologic, diagnostic, and therapeutic investigations that have changed the landscape for medical providers. These updates shed light onto the complex nature of Ménière's disease and generate additional means to provide optimal care to patients.

RECENT FINDINGS

Given the multifactorial cause of Ménière's disease, five subtypes of Ménière's disease have recently been proposed. A knowledge of these subtypes will aid in the development of an appropriate treatment algorithm. Although newer treatments have not been developed, stepwise treatment algorithms have been proposed and can improve patient care. New MRI modalities and serum testing hold promise as clinical clues and biomarkers.

SUMMARY

As these updated diagnostic criteria are used, Ménière's disease can be identified and treated more precisely. This will in turn allow for future randomized controlled studies to improve the quality of treatment options available. Future imaging, vestibular testing, and the potential for serum biomarkers may illuminate additional diagnostic criteria, only furthering the improvement in clinical care.

Imaging of Petrous Apex Lesions

The petrous apex may be affected by a range of lesions, commonly encountered as incidental and asymptomatic findings on imaging performed for other clinical reasons. Symptoms associated with petrous apex lesions commonly relate to mass effect and/or direct involvement of closely adjacent structures. Petrous apex lesions are optimally assessed using a combination of high-resolution CT and MRI of the skull base. Management of petrous apex lesions varies widely, reflecting the range of possible pathologies, with imaging playing a key role, including lesion characterization, surveillance, surgical planning, and oncological contouring.

MRI of middle ear cholesteatoma: The importance of observer reliance from diffusion sequences

BACKGROUND AND PURPOSE

Diffusion-weighted imaging(DWI) in MRI has been developed as an important tool for the detection of cholesteatoma. Various DWI sequences are available. This study aims to evaluate the importance of the observer's reliance level for the detection of cholesteatoma.

METHODS

Forty patients meeting the following criteria were included in the study: (1) chronic otitis media, (2) preoperative MRI including various DWI sequences, and (3) middle-ear surgery. The MRI protocol contained the following sequences: (1) axial and (2) coronal echoplanar imaging (EPI) readout-segmented (RESOLVE) DWI with Trace acquisition and (3) coronal non-EPI half-Fourier acquired single-shot turbo spin-echo (HASTE) DWI. Cholesteatoma diagnosis was based on standard diagnostic criteria for cholesteatoma with DWI. Additionally, the radiologists were asked to grade personal reliance on their diagnosis using a Likert-type scale from 1 = very insecure to 5 = very secure.

RESULTS

Axial and coronal RESOLVE DWI showed a sensitivity of 77.3% and a specificity of 72.2%, respectively. The mean reliance was 3.9 for axial and 3.8 for coronal images. HASTE DWI had a sensitivity/specificity of 81.8%/66.7% with the highest reliance of all evaluated sequences (4.4). Cases with a reliance level of 5 showed a sensitivity/specificity of 100% in all sequences. A reliance level of 5 was given in the axial and coronal RESOLVE DWI in 32.5% of cases and in the HASTE DWI in 57.5%.

CONCLUSION

The evaluated DWI sequences showed comparable results. The reliance level significantly improved the predictor of cholesteatoma disease with MRI techniques.

Progressive and Degenerative Peripheral Vestibular Disorders

Initial diagnosis of peripheral vestibulopathy requires a detailed history, physical examination, and, in some cases, audiovestibular testing, radiographic imaging, or serology. Differentiation of a peripheral vestibulopathy as progressive or degenerative is often nuanced and influenced by a characterization of a patient's symptoms or natural history over time. A diverse group of vestibular pathology may fit into this category, including Ménière's disease, autoimmune conditions, congenital pathologies, ototoxic medications, radiation therapy, and perilymphatic fistula. Differentiation among these entities may be guided by initial or subsequent symptomatology, with various combinations of audiovestibular testing, serology, and imaging. Treatment options are disparate and disease-specific, ranging from observation to medical management or surgical intervention, underscoring the need for astute investigation and diagnosis.

Usage Patterns of CT and MRI in the Evaluation of Otologic Disease

OBJECTIVE

To evaluate the current trends and usage patterns of radiographic imaging for otologic disease by specialty, length of practice, practice setting, geographic region, and pediatric volume.

STUDY DESIGN

Cross-sectional study.

SETTING

Survey of physicians.

SUBJECTS

General Otolaryngologists and Otologists/Neurotologists (O/N) of the American Academy of Otolaryngology - Head and Neck Surgery (AAO-HNS).

METHODS AND OUTCOME MEASURES

An electronic questionnaire was distributed to AAO-HNS members. Respondents were separated into groups by specialty, length of practice, practice setting, region, and pediatric exposure. Chi-square tests were performed for the determination of significance.

RESULTS

The survey was sent to 5,168 members of AAO-HNS. The response rate was 10.6% (n = 546) and 18.1% for only O/N (n = 143). Most respondents were generalists (74%), in practice >20 years (51%), with a primarily adult practice (95%). O/N were more often academics (44 versus 17% combined, 40% private; p < 0.001) and saw fewer children (80 fewer than 25%; p < 0.001). Compared with generalists, O/N were more likely to respond with more frequent and earlier magnetic resonance imaging (MRI) utilization in the workup of the majority of otologic diseases. Significant differences in usage patterns for various conditions were demonstrated across all categories, but specialty training was the most common. Generalists (34 versus 12% of O/N; p < 0.001), physicians practicing >20 years (32 versus 18% of < 5 yrs; p = 0.006), and private practice physicians (34 versus 14-20% of others; p < 0.001) relied more heavily on the radiology report to interpret MRI scans.

CONCLUSION

Subspecialty training seems to be the main variable correlating with significant differences in the use of MRI and computed tomography imaging in patients with otologic disease.

Postoperative Imaging of the Temporal Bone

The anatomy of the temporal bone is complex, and postoperative imaging evaluation of this bone can be challenging. Surgical approaches to the temporal bone can be categorized didactically into tympanoplasty and ossicular reconstruction, mastoidectomy, and approaches to the cerebellopontine angle and internal auditory canal (IAC). In clinical practice, different approaches can be combined for greater surgical exposure. Postoperative imaging may be required for follow-up of neoplastic lesions and to evaluate unexpected outcomes or complications of surgery. CT is the preferred modality for assessing the continuity of the reconstructed conductive mechanism, from the tympanic membrane to the oval window, with use of grafts or prostheses. It is also used to evaluate aeration of the tympanic and mastoid surgical cavities, as well as the integrity of the labyrinth, ossicular chain, and tegmen. MRI is excellent for evaluation of soft tissue. Use of a contrast-enhanced fat-suppressed MRI sequence is optimal for follow-up after IAC procedures. Non-echo-planar diffusion-weighted imaging is optimal for detection of residual or recurrent cholesteatoma. The expected imaging findings and complications of the most commonly performed surgeries involving the temporal bone are summarized in this review. Online supplemental material is available for this article. ^©RSNA, 2021.

Non-EPI versus Multishot EPI DWI in Cholesteatoma Detection: Correlation with Operative Findings

BACKGROUND AND PURPOSE

Although multishot EPI (readout-segmented EPI) has been touted as a robust DWI sequence for cholesteatoma evaluation, its efficacy in disease detection compared with a non-EPI (eg, HASTE) technique is unknown. This study sought to compare the accuracy of readout-segmented EPI with that of HASTE DWI in cholesteatoma detection.

MATERIALS AND METHODS

A retrospective review was completed of consecutive patients who underwent MR imaging for the evaluation of suspected primary or recurrent/residual cholesteatomas. Included patients had MR imaging examinations that included both HASTE and readout-segmented EPI sequences and confirmed cholesteatomas on a subsequent operation. Two neuroradiologist reviewers assessed all images, with discrepancies resolved by consensus. The ratio of signal intensity between the cerebellum and any observed lesion was noted.

RESULTS

Of 23 included patients, 12 (52.2%) were women (average age, 47.8 [SD, 25.2] years). All patients had surgically confirmed cholesteatomas: Six (26.1%) were primary and 17 (73.9%) were recidivistic. HASTE images correctly identified cholesteatomas in 100.0% of patients. On readout-segmented EPI sequences, 16 (69.6%) were positive, 5 (21.7%) were equivocal, and 2 (8.7%) were falsely negative. Excellent interobserver agreement was noted between reviews on both HASTE (κ = 1.0) and readout-segmented EPI (κ = 0.9) sequences. The average signal intensity ratio was significantly higher on HASTE than in readout-segmented EPI, facilitating enhanced detection (mean difference 0.5; 95% CI, 0.3-0.8; P = .003).

CONCLUSIONS

HASTE outperforms readout-segmented EPI in the detection of primary cholesteatoma and disease recidivism.

IE-Map: a novel in-vivo atlas and template of the human inner ear

Brain atlases and templates are core tools in scientific research with increasing importance also in clinical applications. Advances in neuroimaging now allowed us to expand the atlas domain to the vestibular and auditory organ, the inner ear. In this study, we present IE-Map, an in-vivo template and atlas of the human labyrinth derived from multi-modal high-resolution magnetic resonance imaging (MRI) data, in a fully non-invasive manner without any contrast agent or radiation. We reconstructed a common template from 126 inner ears (63 normal subjects) and annotated it with 94 established landmarks and semi-automatic segmentations of all relevant macroscopic vestibular and auditory substructures. We validated the atlas by comparing MRI templates to a novel CT/micro-CT atlas, which we reconstructed from 21 publicly available post-mortem images of the bony labyrinth. Templates in MRI and micro-CT have a high overlap, and several key anatomical measures of the bony labyrinth in IE-Map are in line with micro-CT literature of the inner ear. A quantitative substructural analysis based on the new template, revealed a correlation of labyrinth parameters with total intracranial volume. No effects of gender or laterality were found. We provide the validated templates, atlas segmentations, surface meshes and landmark annotations as open-access material, to provide neuroscience researchers and clinicians in neurology, neurosurgery, and otorhinolaryngology with a widely applicable tool for computational neuro-otology.

Deep learning for the fully automated segmentation of the inner ear on MRI

Segmentation of anatomical structures is valuable in a variety of tasks, including 3D visualization, surgical planning, and quantitative image analysis. Manual segmentation is time-consuming and deals with intra and inter-observer variability. To develop a deep-learning approach for the fully automated segmentation of the inner ear in MRI, a 3D U-net was trained on 944 MRI scans with manually segmented inner ears as reference standard. The model was validated on an independent, multicentric dataset consisting of 177 MRI scans from three different centers. The model was also evaluated on a clinical validation set containing eight MRI scans with severe changes in the morphology of the labyrinth. The 3D U-net model showed precise Dice Similarity Coefficient scores (mean DSC-0.8790) with a high True Positive Rate (91.5%) and low False Discovery Rate and False Negative Rates (14.8% and 8.49% respectively) across images from three different centers. The model proved to perform well with a DSC of 0.8768 on the clinical validation dataset. The proposed auto-segmentation model is equivalent to human readers and is a reliable, consistent, and efficient method for inner ear segmentation, which can be used in a variety of clinical applications such as surgical planning and quantitative image analysis.

Modulation of hearing function following the downgrading or upgrading of endolymphatic hydrops in Meniere's disease patients with endolymphatic duct blockage

The present study was to investigate the dynamics of endolymphatic hydrops (EH) and hearing function, and explore whether the hearing loss is caused by EH alone and whether the hearing function can be modulated by changes in the EH. The extent of EH visualized by gadolinium (Gd)-enhanced inner ear magnetic resonance imaging, hearing thresholds and the summating potential/action potential ratio (-SP/AP ratio) of electrocochleography (ECochG) were recorded prior to and following surgery in 22 patients with intractable Meniere's disease (MD) who underwent endolymphatic duct blockage (EDB). The difference value of the hearing threshold and -SP/AP ratio was significantly positively correlated with the difference value of the endolymph to vestibule-volume ratio (EVVR) and grading of cochlear hydrops between prior to and following surgery. Among patients with a decreased EVVR, the average hearing threshold and -SP/AP ratio was significantly decreased following surgery, as compared to that prior to surgery. Six out of seven patients with a hearing improvement (≥10-dB decline) and 4/5 patients with a negative conversion of EcochG showed downgrading of their hydrops in the cochlea and/or vestibule. By contrast, among patients with an increased EVVR, the average hearing threshold and -SP/AP ratio tended to increase following EDB, as compared with that prior to surgery. One out of two patients with a hearing deterioration (≥10-dB elevation) showed upgrading of her hydrops in both cochlea and vestibule. The present results showed the downgrading of cochlear and/or vestibular hydrops accompanied by the downregulation of the hearing threshold and -SP/AP ratio of EcochG, as well as the upgrading of cochlear and/or vestibular hydrops that tended to upregulate the hearing threshold and -SP/AP ratio of EcochG; this suggested that hearing loss is likely to be caused by hydrops and that the impaired hearing function be modulated by changes in the hydrops.

Endolymphatic hydrops magnetic resonance imaging in Ménière's disease

This review is designed to help radiologists interested in developing a magnetic resonance imaging service for patients with symptoms of Ménière's disease. Examples are selected from our experience with delayed post-gadolinium three-dimensional (3D) fluid attenuated inversion recovery (FLAIR) inner ear imaging of endolymphatic hydrops. The imaging features of the normal and hydropic endolymphatic structures, semiquantitative grading systems, normal variations, and differential diagnoses will be illustrated, whilst appropriate clinical referrals, approaches to reporting and diagnostic pitfalls will be discussed.

Endolymphatic hydrops evaluation on MRI: Practical considerations

Four-hour delayed three-dimensional fluid-attenuated inversion recovery (3D-FLAIR) sequence after intravenous gadolinium-based contrast agent administration is an optimal magnetic resonance imaging technique to evaluate endolymphatic hydrops in patients with known or suspected Ménière's disease. Nonenhanced endolymphatic space surrounded by enhanced perilymphatic space is evaluated in the cochlea and vestibule separately. In cochlear hydrops, the scala media is enlarged, potentially obliterating the scala vestibuli. In vestibular hydrops, the size of the saccule becomes equal to or larger than that of the utricle; as hydrops progresses, the saccule and utricle become larger and confluent until complete obliteration of the vestibule's perilymphatic space. In patients with a unilateral clinical presentation of Ménière's disease, it is possible to depict the asymmetries of perilymph enhancement, which may be increased on the affected side and reflect a permeability alteration of the blood-perilymph barrier. In addition, endolymphatic hydrops can be observed in the asymptomatic ear of these patients with a unilateral clinical presentation, showing that Ménière's disease tends to undergo bilateral evolution over time.

Imaging the facial nerve: A contemporary review of anatomy and pathology

PURPOSE

The facial nerve is the seventh paired cranial nerve which anatomically can be divided into six distinct segments. There are a wide range of pathologies that may occur along each segment of the nerve. The aim of this pictorial review is to untangle the complex appearances of the facial nerve, both in its normal anatomical course and when affected by pathology.

METHOD

This review takes an evidence-based segmental approach to the evaluation of the facial nerve in terms of its anatomy and clinical features of common pathologies affecting specific segments of the nerve. The typical multimodal radiological findings of common facial nerve pathologies are included in the review using imaging from select pathologically confirmed cases.

RESULTS

A wide range of pathologies ranging from congenital abnormalities to inflammatory, infective and neoplastic processes can affect the facial nerve. As select segments of the nerve are better evaluated on certain imaging modalities a clear understanding of the anatomy and clinical features associated with specific facial nerve pathologies enables the radiologist to tailor the imaging test to best answer the clinical question.

CONCLUSIONS

This review provides a segmental clinical-radiological approach to imaging the facial nerve. In addition, recent developments in facial nerve imaging that may come into mainstream use in the near future are touched upon.

Diagnostic Value of the Magnetic Resonance Imaging With Intratympanic Gadolinium Administration (IT-Gd MRI) Versus Audio-Vestibular Tests in Menière's Disease: IT-Gd MRI Makes the Difference

OBJECTIVE

Our aim was to evaluate the validity and reliability of clinically relevant tests in the diagnosis of Menière's disease (MD) according to the criteria formulated during 2015 as well as their efficacy in detecting endolymphatic hydrops (EH). The focus was on: three-dimensional fluid-attenuated inversion recovery-SPectral Attenuated Inversion Recovery (3D-FLAIR-SPAIR) sequences using 3 Tesla magnetic resonance imaging (3T MRI) performed 24 hours after intratympanic Gadolinium injection (IT-Gd) in comparison with the functional tests pure tone audiometry (PTA), caloric test, video head impulse test (vHIT), and cervical-vestibular-evoked-myogenic-potentials (cVEMP).

STUDY DESIGN

Retrospective study.

SETTING

Tertiary care center.

PATIENTS

Primary eligibility criteria were given clinical suspicion of MD and the performance of an IT-Gd MRI leading to a group of 31 patients and 52 ears to be analyzed separately.

MAIN OUTCOME MEASURE (S)

Reanalysis of the raw diagnostic data leading to comparability of IT-Gd MRI, PTA, caloric test, vHIT, and cVEMP concerning their valency for clinically diagnosed MD and quantifiability of EH.

RESULTS

Considering sensitivity, specificity, and the likelihood-ratio only the IT-Gd MRI displayed results qualifying it as a viable device for MD-diagnostics in regards to the criteria of 2015 (p = 0.01), it even provides direct imaging evidence for the underlying pathology of the disease. Furthermore, the comparison between MRI images and test results of caloric test, vHIT and cVEMP revealed that neither of these diagnostic functional tests serves as a reliable indicator for EH.

CONCLUSIONS

It appears that the diagnosing process of MD would benefit from turning IT-Gd MRI into a standard diagnostic procedure in cases of suspected MD, displaying better results than caloric test, vHIT, and cVEMP.

Surgical mapping of middle ear cholesteatoma with fusion of computed tomography and diffusion-weighted magnetic resonance images: Diagnostic performance and interobserver agreement

OBJECTIVE

To assess the diagnostic performance in detecting primary cholesteatoma at various anatomical subsites using Computed Tomography (CT), Diffusion-weighted Magnetic Resonance Imaging (DWMRI) and Fusion of CT and DWMRI (Fusion CT-MRI) images.

STUDY DESIGN

A retrospective study of 22 children identified from a prospective database of surgically treated cholesteatoma cases over a five year period. All cases underwent pre-operative CT, non-echo planar DWMRI and Fusion CT-DWMRI, and with clearly documented surgical findings. For each imaging modality, two radiologists scored for the presence or absence of cholesteatoma with confidence levels at different anatomical subsites. The radiologists were blinded to the surgical findings to which their findings were compared.

SETTING

Large Teaching Hospital in London.

PATIENTS

22 children with cholesteatoma confirmed surgically.

INTERVENTION

CT, DWMRI imaging and fusion CT-MRI.

MAIN OUTCOME MEASURE

Diagnostic performance of subsite localisation of cholesteatoma by CT, DWMRI and fusion CT-MRI imaging with intra-operative findings.

RESULTS

Twenty-two patients were included (12 women and 10 men). The median age of patients was 11 years. When considering all subsites combined, the result for all imaging methods suggested 'good' agreement between both observers. When all subsites were examined together, all methods had relatively high sensitivity values (87% for CT vs 84% for DWMRI vs 85% for fusion CT-DWMRI). Specificity was highest with fusion CT-DWMRI (46% for CT vs 76% for DWMRI vs 97% for fusion CT-DWMRI), as was accuracy (66% for CT vs 80% for DWMRI vs 91% for fusion).

CONCLUSIONS

Our study has demonstrated that fusion CT-DWMRI is superior to DWMRI or CT separately in localizing cholesteatoma at various middle ear cleft subsites and bony relations, making it a valuable tool for surgical planning.

Wideband Tympanometry in Meniere's Disease

The aim of our study was to obtain wideband tympanometry (WBT) findings in Meniere's disease (MD). It also aimed to evaluate whether the data obtained have diagnostic significance. 21 patients who were followed-up for unilateral Meniere's Disease were evaluated. The ears with Meniere disease were grouped as the MD group and the opposite ears were grouped as the control group. WBT results were recorded as resonance frequency (RF) and frequency-specific absorbance values at 10 different frequencies in the 0.25-8.0 kHz range. Statistical analysis was performed with t test and receiver-operating characteristic analysis. Considering the WBT results, RF was significantly lower in the MD group compared to the control group (p < 0.001). Frequency-specific absorbance values at 0.25, 0.5, 0.75 and 1 kHz were significantly lower in the MD group compared to the control group (p <  0.05). No significant difference was found at 1.5 kHz and above (p > 0.05). For the MD, the RF below 598 Hz was 85.7% sensitive and 76.2% specific, the absorbance at 0.25 kHz below 8% was 66.7% sensitive and 61.9% specific, the absorbance below 17% at 0.5 kHz was 71.4% sensitive and 62.1% specific, the absorbance below 36% at 0.75 kHz was 81% sensitive and 57.8% specific, and the absorbance below 46% at 1 kHz was 71.5% sensitive and 66.7% specific. When MD was compared with intact ears, it was observed that RF was lower, and absorbance decreased in low frequencies. These data is statistically significant, but the sensitivity level is not enough for diagnostic use. Therefore, it is considered as an complementary test for the diagnosis.

Readout-Segmented Echo-Planar DWI for the Detection of Cholesteatomas: Correlation with Surgical Validation

BACKGROUND AND PURPOSE

MR imaging has become an important tool for the detection of cholesteatomas of the middle ear. Various diffusion-weighted imaging sequences are available and have shown promising results. This study aimed to evaluate readout-segmented echo-planar DWI for the detection of cholesteatoma and compare the results with surgical validation.

MATERIALS AND METHODS

Fifty patients with chronic otitis media (24 females and 26 males; range, 12-76 years of age; mean age, 41 years) who underwent MR imaging before an operation of the middle ear (1-169 days) were included. The MR imaging protocol consisted of axial and coronal readout-segmented echo-planar DWI with b-values of 0 and 1000 s/mm² and 3-mm slice thickness. The readout-segmented echo-planar diffusion-weighted images were fused with standard T2-weighted sequences for better anatomic assignment. The results of the MR imaging evaluation were correlated with the results from the operation.

RESULTS

Readout-segmented echo-planar DWI detected 22 of the 25 cases of surgically proved cholesteatoma. It has an accuracy of 92% (95% confidence interval, 80.8%-97.8%), a sensitivity of 88%, a specificity of 96%, a positive predictive value of 96%, and a negative predictive value of 89%. In 1 case, a positive finding for cholesteatoma with readout-segmented echo-planar DWI could not be proved by histology, and in 3 cases, histology yielded a cholesteatoma that was not detected with MR imaging.

CONCLUSIONS

Readout-segmented echo-planar DWI is a promising and reliable MR imaging sequence for the detection and exclusion of cholesteatoma.

The role of magnetic resonance imaging in Ménière disease: the current state of endolymphatic hydrops evaluation

Technical advances in magnetic resonance imaging have allowed to accurately detect and grade endolymphatic space distension in Ménière disease; this was only possible in post-mortem histological studies until a few years ago. Magnetic resonance imaging rules out other causes of vertigo and hearing loss, and is able to evaluate the cochlear and vestibular compartments of the endolymphatic space using a dedicated protocol.

Imaging of Ménière Disease

Visualization of the morphologic substrate of Ménière disease, the endolymphatic hydrops, can be performed using noncontrast or contrast-enhanced MR imaging techniques. Noncontrast MR imaging uses a heavily T2-weighted sequence; however, its reproducibility remains to be confirmed. Contrast-enhanced MR imaging techniques mainly use a 3-dimensional fluid-attenuated inversion recovery sequence after intratympanic gadolinium administration or after a 4-hour delayed intravenous gadolinium administration. The latter technique is most frequently used and is able to detect and grade Ménière disease. It is a reliable technique with a high diagnostic accuracy, enabling visualization of endolymphatic hydrops.

Incidental Findings in TMJ Imaging

For years, the conventional imaging modalities are generally used in dental practice routine. They provide precious information about dentomaxillofacial region; they also have some limitations such as superimpositions, magnifications, distortions, and low-image quality. Because of these limitations, some pathologies, calcifications, and anatomical variations may be missed. Any findings on a radiographic image which are not related to the research areas of interest could be a description of “incidental findings.” Calcifications are one of these incidental findings. They are asymptomatic and also common in TMJ images. Although most of the calcifications require no treatment, correct identification will reduce further diagnostic assessments. Incidental findings on TMJ images were rare, while examining images for temporomandibular disorders and associated issues, it is important not only to examine the TMJ structures but also to look at the nearby anatomical features to check for evidence of incidental findings pathologies that may have mimicked signs and symptoms of TMJ disorders.

ADC Benchmark Range for Correct Diagnosis of Primary and Recurrent Middle Ear Cholesteatoma

OBJECTIVES

Magnetic resonance imaging (MRI) and in particular diffusion-weighted imaging (DWI) have been broadly proven to be the reference imaging method to discriminate between cholesteatoma and noncholesteatomatous middle ear lesions, especially when high tissue specificity is required. The aim of this study is to define a range of apparent diffusion coefficient (ADC) values within which the diagnosis of cholesteatoma is almost certain.

METHODS

The study was retrospectively conducted on a cohort of 124 patients. All patients underwent first- or second-look surgery because primary or secondary acquired cholesteatoma was clinically suspected; they all had preoperative MRI examination 15 days before surgery, including DWI from which the ADC maps were calculated.

RESULTS

Average ADC value for cholesteatomas was 859,4 × 10-6 mm2/s (range 1545 × 10-6 mm2/s; IQR = 362 × 10-6 mm2/s; σ = 276,3 × 10-6 mm2/s), while for noncholesteatomatous inflammatory lesions, it was 2216,3 × 10-6 mm2/s (range 1015 × 10-6 mm2/s; IQR = 372,75 × 10-6 mm2/s; σ = 225,6 × 10-6 mm2/s). Interobserver agreement with Fleiss' Kappa statistics was 0,96. No overlap between two groups' range of values was found and the difference was statistically significant for p < 0.0001.

CONCLUSIONS

We propose an interval of ADC values that should represent an appropriate benchmark range for a correct differentiation between cholesteatoma and granulation tissue or fibrosis of noncholesteatomatous inflammatory lesions.