Third window lesions of the inner ear: A pictorial review.

PURPOSE: Radiographic review of pathologies that associate with third window syndrome. METHODS: Case series and literature review. RESULTS: Eight unique third window conditions are described and illustrated, including superior, lateral, and posterior semicircular canal dehiscence; carotid-cochlear, facial-cochlear, and internal auditory canal-cochlear dehiscence, labyrinthine erosion from endolymphatic sac tumor, and enlarged vestibular aqueduct. CONCLUSION: The present study highlights the characteristic imaging features and symptoms to differentiate third window pathologies for expedient diagnosis and management planning.

Labyrinthine fistulas: Surgical outcomes and an additional diagnostic strategy.

PURPOSE: To evaluate perioperative findings and audiological and vestibular outcomes in patients operated for cholesteatoma with labyrinthine fistulas. Also to assess radiological fistula size. MATERIALS AND METHODS: Patients who underwent surgery for a labyrinthine fistula caused by a cholesteatoma between 2015 and 2020 in a tertiary referral center were retrospectively investigated. Fistula size was determined on preoperative CT scan. Bone and air conduction pure tone average thresholds were obtained pre- and postoperatively. Clinical outcomes, such as vertigo and otorrea were also evaluated. Main purpose was to determine whether there is a correlation between fistula size and postoperative hearing. Furthermore, perioperative findings and vestibular outcomes are evaluated. RESULTS: 21 patients (22 cases) with a labyrinthine fistula were included. There was no significant change after surgery in bone conduction pure tone average (preoperatively 27.6 dB ± 26.7; postoperatively 30.3 dB ± 34.3; p = 0.628) or air conduction pure tone average (preoperatively 58.7 dB ± 24.3; postoperatively 60.2 dB ± 28.3; p = 0.816). Fistula size was not correlated to postoperative hearing outcome. There were two patients with membranous labyrinth invasion: one patient was deaf preoperatively, the other acquired total sensorineural hearing loss after surgery. CONCLUSIONS: Sensorineural hearing loss after cholesteatoma surgery with labyrinthine fistula is rare. Fistula size and postoperative hearing loss are not correlated, however, membranous labyrinthine invasion seems to be related to poor postoperative hearing outcomes. Therefore, additional preoperative radiological work up, by MRI scan, in selected cases is advocated to guide the surgeon to optimize preoperative counselling.

Pneumolabyrinth as an Early Computed Tomographic Finding After Cochlear Implantation and its Clinical Significance.

OBJECTIVE: To determine the incidence and volume of pneumolabyrinth using early temporal bone computed tomography (TBCT) findings and evaluate the correlation between pneumolabyrinth and various clinical variables. STUDY DESIGN: Retrospective case review. SETTING: Tertiary academic center. PATIENTS: Fifty-three consecutive adult cochlear implantation (CI) recipients (53 ears) with normal inner ears who underwent high-resolution TBCT within 3 days after CI were included. INTERVENTION: Axial TBCT images were used for detection and measurement of pneumolabyrinth. MAIN OUTCOME MEASURES: Incidence and volume of pneumolabyrinth were evaluated. In addition, the following clinical variables were analyzed to evaluate the correlation with pneumolabyrinth volume: demographics, implant type, surgical approach, postoperative dizziness, and preservation of functional residual hearing. RESULTS: Pneumolabyrinth was present in all patients, and the average volume was 8.496 mm3. Pneumolabyrinth was confined to the cochlea (pneumocochlea) in all patients except for one who also had pneumovestibule. The pneumolabyrinth volume in patients with postoperative dizziness was significantly larger than that in patients without postoperative dizziness (10.435 mm3 vs. 8.016 mm3; p = 0.029). Multivariate analysis showed that a larger volume of pneumolabyrinth was significantly associated with postoperative dizziness (odds ratio, 1.420; 95% confidence interval, 1.114-1.808; p = 0.005). CONCLUSION: A certain volume of pneumolabyrinth was always present in the early stage after CI, and the volume of pneumolabyrinth measured using early TBCT findings was significantly associated with the occurrence of postoperative dizziness.

Construction of an MRI-based decision tree to differentiate autoimmune and autoinflammatory inner ear disease from chronic otitis media with sensorineural hearing loss.

Autoimmune and autoinflammatory inner ear diseases (AIED/AID) are characterized by the symptom of sensorineural hearing loss (SNHL). To date, standardized diagnostic tools for AIED/AID are lacking, and clinically differentiating AIED/AID from chronic otitis media (COM) with SNHL is challenging. This retrospective study aimed to construct a magnetic resonance imaging (MRI)-based decision tree using classification and regression tree (CART) analysis to distinguish AIED/AID from COM. In total, 67 patients were enrolled between January 2004 and October 2019, comprising AIED/AID (n = 18), COM (n = 24), and control groups (n = 25). All patients underwent 3 T temporal bone MRI, including post-contrast T1-weighted images (postT1WI) and post-contrast FLAIR images (postFLAIR). Two radiologists evaluated the presence of otomastoid effusion and inner ear contrast-enhancement on MRI. A CART decision tree model was constructed using MRI features to differentiate AIED/AID from COM and control groups, and diagnostic performance was analyzed. High-intensity bilateral effusion (61.1%) and inner ear enhancement (postFLAIR, 93.8%; postT1WI, 61.1%) were the most common findings in the AIED/AID group. We constructed two CART decision tree models; the first used effusion amount as the first partitioning node and postT1WI-inner ear enhancement as the second node, whereas the second comprised two partitioning nodes with the degree of postFLAIR-enhancement of the inner ear. The first and second models enabled distinction of AIED/AID from COM with high specificity (100% and 94.3%, respectively). The amount of effusion and the degree of inner ear enhancement on MRI may facilitate the distinction between AIED/AID and COM with SNHL using decision tree models, thereby contributing to early diagnosis and intervention.

Magnetic resonance imaging of endolymphatic hydrops in patients with unilateral Meniere's disease: a comparison between with and without herniation into the posterior and lateral semi-circular canals.

BACKGROUND: The presence of endolymphatic hydrops (ELH) in patients with Meniere's disease (MD) is considered a pathological hallmark. AIMS/OBJECTIVES: We aimed to conduct a quantitative volumetric measurement of inner ear ELH in patients with unilateral MD (uMD). The values of uMD with and without herniation into the posterior semi-circular canal (h-PSC) and the lateral semi-circular canal (h-LSC) were compared using 3 D magnetic resonance imaging. MATERIAL AND METHODS: This study included 130 individuals (47 controls and 83 patients with uMD). We measured the total fluid space (TFS) and endolymphatic space (ELS) volumes. We also evaluated the ELS/TFS volume ratios (%). RESULTS: The ELS/TFS volume ratios in the inner ear, cochlea, and vestibule were significantly different between the affected and contralateral sides in patients with h-PSC. Moreover, the ELS/TFS volume ratios of the inner ear, vestibule, and semi-circular canals in the affected ear were significantly higher in patients with h-PSC than in those without h-PSC. The vestibular ELS/TFS volume ratio in the affected ear was significantly higher in patients with h-LSC than in those without h-LSC. CONCLUSIONS AND SIGNIFICANCE: H-LSC is present in extended vestibular ELH. However, this is a result of ELH progression in the inner ear.

Inner ear salivary gland choristoma extending to the middle ear with congenital profound hearing loss and facial palsy: a case report.

BACKGROUND: Salivary gland choristoma (SGCh) is a rare benign tumor reported in several unusual sites, such as the gastrointestinal tract, the optic nerve, and the internal auditory canal, but never reported in the inner ear. CASE PRESENTATION: An 8-year-old girl with a history of left profound congenital hearing loss presented to us with ipsilateral progressive severe facial nerve palsy (House-Brackmann Grade VI). The left tympanic membrane was swollen with a pulsatile tumor. Radiological investigations revealed a multilocular tumor in the inner ear extending into the middle ear and internal auditory canal (IAC). We performed a partial resection of the tumor by transmastoid approach to preserve the anatomical structure of the facial nerve. The tumor was pathologically diagnosed as SGCh. Two years after surgery, her facial function recovered to House-Brackmann Grade II and the residual tumor did not show regrowth on MRI. CONCLUSIONS: Although the natural course of this rare tumor is unknown, a partial resection is an acceptable treatment procedure when functional recovery of the facial nerve is anticipated.

Imaging Analysis for Cholesteatoma Extension to the Perilymphatic Space in Labyrinth Fistulae.

OBJECTIVES/HYPOTHESIS: Disturbed perilymph behind a labyrinth fistula can lead to hearing deterioration; thus, delicate manipulation is required during surgery for cholesteatomatous fistulae with matrix extension to the perilymphatic space (EPS). However, it remains challenging to identify the EPS preoperatively. This study aimed to evaluate the diagnostic value of computed tomography (CT) for preoperative prediction of the EPS of cholesteatomatous fistulae. STUDY DESIGN: Retrospective study. METHODS: We included serial high-resolution CT images showing a cholesteatomatous bone defect in the lateral semicircular canal (LSC) requiring mastoidectomy. CT and intraoperative findings were analyzed retrospectively. Using axial CT planes, we evaluated the length and angle between the margins of bone defects. Receiver operating characteristic (ROC) curves were constructed to determine the cutoff points. RESULTS: We extracted data from 30 bone defects, of which six (20.0%) showed EPS intraoperatively. Bone defects with EPS (n = 6) had significantly greater length and angle values than those without EPS (n = 24) (P < .001 for both, Wilcoxon rank sum test). For length and angle, the area under the curve was 0.944 (95% confidence interval [CI]: 0.858-1.000) and 0.951 (95% CI: 0.875-1.000), respectively, according to the ROC analysis, and the optimal cutoff values were 3.65 mm and 71.6°, respectively, with 100% sensitivity and 91.67% specificity for both. CONCLUSIONS: Results demonstrated that a length >3.65 mm and an angle >71.6° for LSC bone defects on axial CT images are reliable diagnostic markers of EPS. Preoperative high-resolution CT analysis can provide surgeons with a more conscientious preparation for handling deeper labyrinth fistulae. LEVEL OF EVIDENCE: 4 Laryngoscope, 131:E1301-E1307, 2021.

Meningiomas of the Internal Auditory Canal.

OBJECTIVE: Identify and define specific preoperative and postoperative characteristics of intracanalicular meningiomas (ICMs) in order to improve their diagnosis and management, and to differentiate them from intrameatal vestibular schwannomas (IMVSs). METHODS: Preoperative symptomatology, magnetic resonance imaging (MRI), and postoperative outcomes of 28 ICMs were analyzed. The results were compared to the literature and IMVSs treated by our group. RESULTS: Anacusis and progressive hearing loss were more frequent in the present population than the cases reviewed (P = .0064 and P = .0001, respectively). Hearing loss affected more than 90% of the patients, with anacusis in 32.1% of the cases. Facial palsy affected 17.9% of the patients. In comparison to IMVSs, preoperative anacusis was more associated to meningiomas (P = .0037), and the facial nerve was more compromised in ICMs than IMVSs, both preoperatively (P = .0011) and at follow-up (P < .0001). According to a re-evaluation of preoperative MRIs and comparison with IMVSs, linear tumor borders, and linear morphology along the internal auditory canal wall, but not the presence of a dural tail, were significantly more present in ICMs (P = .0035, P = .0004, P = .1963, respectively). These characteristics could have led to a correct preoperative diagnosis in 61% of our cases. CONCLUSION: Contrariwise to IMVSs, the frequent preoperative anacusis and facial palsy demonstrate the more aggressive nature of ICMs, which also carry a higher risk of postoperative facial palsy and difficulty to preserve hearing. An attentive evaluation of imaging should ease diagnosis, and asymptomatic or stable ICMs should be enrolled in a wait-and-scan protocol. LEVEL OF EVIDENCE: 4 Laryngoscope, 131:E413-E419, 2021.

Surgical treatment of cholesteatomatous labyrinthine fistula by hydrodissection.

Middle ear cholesteatoma is a destructive lesion that can potentially erode the bone. Cholesteatoma is a clinical diagnosis in the vast majority of cases. Patients must be systematically investigated for the presence of signs suggestive of complications, the most common of which is labyrinthine fistula. However, the clinical features of labyrinthine fistula are inconstant and the fistula sign may sometimes be negative. CT scan of the petrous temporal bone is performed systematically to specify the site and extension of the cholesteatoma, and to assess the extent of osteolysis that can result in exposure of the membranous labyrinth. Surgical treatment has three main objectives: complete resection of the cholesteatoma, which is the only way to avoid residual cholesteatoma, prevention of recurrence by an adapted, preferably one-step, technique, and restoration of good quality hearing. Hydrodissection of the cholesteatoma matrix in the presence of labyrinthine fistula is a simple technique that can achieve the three main general objectives of cholesteatoma surgery.

Resonancia magnética de conducto auditivo interno: ¿es siempre útil administrar contraste intravenoso? / Inner ear MRI: is it always useful to manage intravenous contrast?

OBJETIVO: Evaluar el valor añadido que aporta administrar contraste intravenoso (CIV) rutinariamente en las resonancias magnéticas (RM) de pacientes con síntomas audiovestibulares en la lectura de un neurorradiólogo y un residente. MATERIAL Y MÉTODOS: Estudio retrospectivo que incluía pacientes que durante 2 meses se realizaron una RM de oídos. Dos radiólogos revisaron las imágenes de forma independiente y cegada. Se realizó una lectura analizando las secuencias adquiridas sin contraste, y posteriormente una segunda lectura analizando todas las secuencias, incluidas las secuencias T1-poscontraste. Se calculó la correlación interobservador y la correlación entre los hallazgos en RM y el motivo de solicitud. RESULTADOS: Se incluyeron 40 pacientes. El rango de edad fue de 36-80 años. El motivo de solicitud más frecuente fue hipoacusia (52,5%). El neurorradiólogo sin CIV encontró un 82,5% de patología extraótica y un 17,5% de patología ótica, entre las que destacaba un neurinoma del VIII par (7,5%); también laberintitis osificante, otosclerosis retrofenestrada y colesteatoma. Tras la administración de CIV, los hallazgos fueron similares. El residente identificó patología ótica en el 5% en las secuencias basales y un 20% usando CIV. La correlación interobservador usando CIV fue excelente (0,97), pero débil sin CIV (0,52). Existió correlación entre los motivos de solicitud y los hallazgos en los oídos, tanto en los protocolos sin CIV (p = 0,004) como en los protocolos con CIV (p = 0,002). CONCLUSIONES: La RM de oídos sin contraste da información relevante para valorar síntomas audiovestibulares. El uso de CIV aumenta el grado de confianza en un radiólogo novel, mientras que en el experto su uso es menos relevante. Se debería plantear un protocolo en el que se use gadolinio en pacientes seleccionados

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

Prevalence of occult cochlear basal turn patency.

BACKGROUND: Perilymph gusher (PLG) is a rare complication of otologic surgery attributed to a communication between the cochlea and the internal auditory canal (IAC). Subtle patency between the cochlear basal turn and IAC has recently been identified on computed tomography (CT) as a risk factor, specifically when the defect is > 0.75 mm. OBJECTIVES: Investigate the prevalence of radiographic cochlear basal turn patency. MATERIALS AND METHODS: Patients with CT of the temporal bones and inner ears interpreted as "normal" were included. An otologist and a radiologist independently reviewed CTs to measure radiographic dehiscence in an oblique plane along the interface of the cochlea and IAC. Known PLGs were excluded. RESULTS: Two hundred and ten ears were included (88 conductive or mixed hearing loss, 62 sensorineural hearing loss, 41 audiometrically normal ears). 71 ears (33.8%) were radiographically patent. Mean defect width was 0.41 mm (0.15-0.7 mm). Defect width was not associated with type of hearing loss, age, or gender. No defects were wider than 0.75 mm. CONCLUSIONS: Radiographic patency of the cochlear basal turn may be present in patients with hearing loss and normal hearing, but patency > 0.75 mm (i.e. risk for PLG) is rare.

Significance of high signal intensity in the endolymphatic duct on magnetic resonance imaging in ears with otological disorders.

BACKGROUND: High signal intensity in the endolymphatic duct (ED) is occasionally observed on magnetic resonance imaging (MRI) in ears that have otological disorders. OBJECTIVE: The signal intensity (SI) in the ED on post-contrast MRI was investigated in subjects with various otological disorders, and the meaning of high SI in the ED was evaluated. MATERIAL AND METHODS: 392 patients with otological disorders and 21 controls without otological symptoms underwent 3 T MRI. The SIs of the ED and the cerebellum were measured, the SI ratio (SIR) was calculated, and ears with SIR ≥4 were identified. RESULTS: A high SIR was identified in the ED of 3.7% of ears affected by definite Meniere's disease (dMD), 100% of ears affected by large vestibular aqueduct syndrome (LVAS), and 7.1% of ears with no otological symptoms. On the whole, a significant relationship was found between the existence of vestibular or cochlear EH and the SIR in the ED. CONCLUSION: The MRI finding of high SI in the ED may indicate the mechanism of inner ear disturbances in ears with otological disorders, especially in those with LVAS, and it may suggest an underlying disorder in some ears in which otological symptoms are not apparent.

Post-traumatic pneumolabyrinth: a rare cause of hearing loss.

Pneumolabyrinth (PL) is the presence of air within the vestibule, semicircular canals, or cochlea. It represents an abnormal connection between the inner ear and middle ear spaces. PL most commonly occurs after blunt head trauma, followed by penetrating injuries. Temporal fractures may or may not accompany. Prognosis of hearing loss is poor, while prognosis of vestibular symptoms is good. Herein we present a 45-year-old female with unilateral pneumolabyrinth, who presented with significant dizziness and unilateral total hearing loss after a car accident.

Use of topical fluorescein in the diagnosis and localization of perilymphatic fistula.

OBJECTIVE: The purpose of this video presentation is to demonstrate the effect of intraoperative dilute topical fluorescein in perilympatic fistula diagnosis and localization. MATERIALS AND METHODS: Explorative tympanotomy was performed for the diagnosis, localization and repair of the fistula in the patient who had a pre-diagnosis of perilymphatic fistula. Topical fluorescein was applied intraoperatively to localize the defect. RESULT: A clear change of color was distinguished from yellow to green leading to diagnosis of the perilymphatic fistula and also showed the origin of the fistula. CONCLUSION: Topical application of dilute fluorescein is a convenient and effective tool in the diagnosis and localization of perilymphatic fistula.

Application value of magnetic resonance hydrography of the inner ear in cochlear implantation.

OBJECTIVE: This study aims to investigate the application value of magnetic resonance (MR) hydrography of the inner ear in cochlear implantation. METHODS: 146 patients were enrolled. MR hydrography and spiral CT examinations for the intracranial auditory canal were performed before surgery, and all imaging results were statistically analyzed in order to explore the application value of MR hydrography of the inner ear in cochlear implantation. RESULTS: 146 patients (292 ears) were examined. Among these patients, 13 were diagnosed with abnormal vestibular aqueducts (20 ears) by MR hydrography, while five were diagnosed with this disease by CT; 15 patients were diagnosed with inner ear malformation (19 ears) by MR hydrography, while 11 were diagnosed by CT (four were misdiagnosed); five patients were diagnosed with internal acoustic canal stenosis (eight ears) by MR hydrography, while two were diagnosed by CT (three were misdiagnosed); and four patients were diagnosed with cochlear fibrosis (five ears) by MR hydrography, while four were diagnosed by CT (four ears). The correct rate of diagnosis was 77.40% (113/146) based on CT, while the rate was 93.84% (137/146) based on MR hydrography. CONCLUSIONS: MR hydrography imaging technique can be applied to the preoperative evaluation of cochlear implantation, providing accurate and reliable anatomic information on the inner membranous labyrinth and nerves in the internal acoustic canal and an accurate basis for the diagnosis of cochlear fibrosis and nerve development. This has a guiding significance for the selection of treatment schemes.

CT and MRI for the diagnosis of perilymphatic fistula: a study of 17 surgically confirmed patients.

BACKGROUND: We evaluated the usefulness of CT and MRI for the diagnosis of perilymphatic fistula (PLF) of the round (RW) and/or oval (OW) windows, with surgery as gold standard. METHODS: We retrospectively enrolled 17 patients who presented a surgically confirmed PLF of the round (RW) or oval (OW) windows. All patients were imaged by CT + MRI (T2W SSFP without contrast) prior to surgery (= gold standard). Two radiologists, analyzed the RW and OW on the side of the clinical symptoms and sensitivity (Se) + Specificity (Sp) were calculated. RESULTS: Round window fistula was the most frequent (71%). The best sign of PLF on imaging was a fluid filling of the window niches, which had good Se (83-100% for RW, 66-83% for OW) and Sp (60% for RW, 91-100% for OW). Disorientation of the footplate and pneumolabyrinth were also only observed in 50% of OW PLF. CONCLUSION: The combination of CT and MRI is a reliable tool for a fast and accurate diagnosis of round and oval window perilymphatic fistula, with good sensitivity (> 80%). The most common sign of PLF on imaging is the presence of a fluid-filling in the RW (especially if > 2/3 of the RW niche) or in the OW niches on both CT and MRI. A disorientation of the footplate or the presence of a pneumolabyrinth are clearly in favor of an oval window perilymphatic fistula.