Retrolabyrinthine Bone Thickness as a Radiologic Marker for the Hypoplastic Endotype in Menière Disease.

BACKGROUND AND PURPOSE: Menière disease (MD) manifests in 2 major endotypes: one with a hypoplastic, underdeveloped endolymphatic sac (MD-hp) and the other with a normally developed sac that degenerates over time (MD-dg). Determining the specific endotype in patients is important for predicting disease progression, tailoring patient counseling, and optimizing treatment strategies. Endotype diagnosis involves measuring an angular trajectory of the vestibular aqueduct (ATVA), with an ATVA ≥140° indicative of MD-hp and an ATVA ≤120° of MD-dg. However, assessing the ATVA can be challenging. This study aimed to explore the link between ATVA and the thickness of the retrolabyrinthine bone as an alternative diagnostic measure that could provide differentiation between MD endotypes using CT and MR imaging. MATERIALS AND METHODS: Retrospective review of CT temporal bone imaging from 32 adult patients with definite MD (60 ears) and 33 age-matched controls without MD or other inner ear symptoms (61 ears) was performed. The ATVA and retrolabyrinthine bone thickness were measured using uniform methodology on standardized axial CT images. Comparative analyses were performed to determine the correlation between ATVA and retrolabyrinthine bone thickness. Additionally, from a separate cohort of 11 patients (22 ears), CT and MR examinations of the temporal bone were retrospectively reviewed for retrolabyrinthine bone thickness measurements, to verify the correlation across the 2 modalities. RESULTS: The average retrolabyrinthine bone thickness was statistically significantly different between MD endotypes, being a mean of 0.8 (SD, 0.3) mm in patients with MD-hp (ATVA ≥140°) and 2.0 (SD, 0.9) mm in patients with MD-dg (ATVA ≤120°), with a consistent pattern of thin retrolabyrinthine bone in MD-hp and variable thickness in MD-dg. Receiver operating characteristic curve analysis within the MD cohort revealed that a retrolabyrinthine bone thickness ≥1.2 mm effectively rules out MD-hp. Excellent interrater reliability was noted for the retrolabyrinthine measurement, and there was near-perfect correlation between CT and MR measurements. CONCLUSIONS: Retrolabyrinthine bone thickness proved to be a useful and straightforward alternative marker for distinguishing MD endotypes, being particularly useful for excluding MD-hp. Including information on retrolabyrinthine bone thickness should be considered a routine part of reporting in the context of MD imaging.

A New Methodology for Evaluation of Large Vestibular Aqueduct in CT and MRI Images.

HYPOTHESIS: Development of a new method for large vestibular aqueduct (LVA)/large endolymphatic sac anomaly (LESA) assessment using magnetic resonance imaging (MRI) and computed tomography (CT)/cone beam CT (CBCT) images. The secondary objective was to compare both modalities. BACKGROUND: The gold standard for LVA diagnosis is the analysis of CT images using Valvassori and Clemis or Cincinnati criteria. The previous studies showed inconclusive results regarding the correlation between audiological and radiological data. METHODS: Retrospective analysis of radiological images from 173 patients (315 ears), who were diagnosed with LVA/LESA based on CT/CBCT and/or MRI images of the temporal bone. The images obtained using both techniques were used to measure the following dimensions of vestibular aqueduct (VA)/endolymphatic duct (ED)/intraosseous endolymphatic sac (ES): width of the opening, length, and width at external aperture. In MRI images, the maximal contact diameters of the extraosseous or intraosseous ES and dura mater were measured as well. RESULTS: LVA has been reported to be bilateral in 82% (142 patients) and unilateral in 18% (31 patients) of cases. Comparison of MRI and CT/CBCT measurements showed a moderate correlation (0.64) in external aperture, a moderate correlation (0.57) in the width of the VA opening, and a weak correlation (0.34) in length measurements (p < 0.05). CONCLUSION: We developed a new method to identify the heterogeneous pathology of LVA/LESA using reconstruction along the VA/ED/intraosseous ES axis, three measurements on two planes, and focus on the maximal contact diameter between the extraosseous or intraosseous ES and dura mater.

Endolymphatic Duct Blockage as a Surgical Treatment Option for Ménière's Disease.

Endolymphatic duct blockage is a relatively new treatment option for Ménière's disease, aiming to reduce vertigo attacks while sparing hearing and equilibrium. After a regular mastoidectomy, the posterior semicircular canal is identified, and Donaldson's line is determined. This is a line through the horizontal semicircular canal, crossing the posterior semicircular canal. The endolymphatic sac is usually found at this site under the posterior semicircular canal. The bone of the endolymphatic sac and the dura are thinned until the sac is skeletonized, after which the endolymphatic duct is identified. The duct is then blocked with a titanium clip. Using a computerized tomography (CT) scan, the position is confirmed. Follow-up visits take place 1 week, 6 weeks and 1 year after surgery. To this day, only one prospective trial assessing this method has been conducted, comparing this new method to endolymphatic sac decompression. Results of the duct blockage are promising, with 96.5% of the patients free of vertigo after 2 years. However, further research is required.

Endolymphatic sac tumour: exploring the role of CT and MRI features in the diagnosis of 22 cases.

AIM: To explore the role of imaging features in the diagnosis of endolymphatic sac tumour (ELST). MATERIALS AND METHODS: Twenty-two patients with ELST confirmed at histopathology were included in this retrospective study. All patients underwent computed tomography (CT) and magnetic resonance imaging (MRI) examinations, including diffusion-weighted imaging (DWI; n=18) and dynamic contrast-enhanced (DCE) MRI (n=3). The imaging features of this series were analysed. RESULTS: All lesions appeared as irregular soft-tissue mass lesions located in the middle and posterior margin of the petrous bone. At CT, the normal vestibular aqueduct structure disappeared. Multiple osteoid tissues were present inside the tumour, and destructive bone changes had a "honeycomb" pattern. Twenty cases were accompanied by the incomplete thin bony peripheral rim along the medial margin. On both T1-weighted imaging (WI) and T2WI, all lesions showed hyperintense, hypointense, and isointense mixed signal intensity. Scattered peripheral hyperintensities were found in all cases on T1WI. The mean apparent diffusion coefficient (ADC) value of 18 lesions was (1.35 ± 0.13) × 10-3 mm2/s, which was similar to that of masseter muscles. On enhanced T1WI, all lesions had significant heterogeneous enhancement, and the vascular flowing-void effect was seen in larger lesions (≥1.5 cm). The time-signal intensity curve (TIC) showed a plateau type in all three cases. CONCLUSIONS: The imaging features of ELST, including its location, bone destruction form, MRI signal intensity, and enhancement pattern, are helpful to improve the diagnostic accuracy of this rare tumour.

Endolymphatic Sac Tumour: A Case Report and Review of the Literature

Introduction Endolymphatic sac tumor (ELST) is a slow-growing, low-grade, locallyinfiltrative tumor arising from the endolymphatic sac/duct, which is located in the posterior part of the petrous temporal bone. It may be sporadic in origin, or may be associated with Von-Hippel Lindau (VHL) syndrome. Case description A 40-year-old female patient with an ELST without VHL syndrome who was treated successfully by microsurgical extirpation of the tumor. Discussion We discuss the radiological features and the histopathology of this rare tumor and review the relevant literature. Conclusion The case herein reported adds to the previously-reported cases of this rare tumor.

A comparison of endolymphatic duct blockage, endolymphatic sac drainage and endolymphatic sac decompression surgery in reversing endolymphatic hydrops in Meniere's disease.

BACKGROUND: To explore the differences between endolymphatic duct blockage, endolymphatic sac drainage and endolymphatic sac decompression surgery in the reversal of endolymphatic hydrops (EH) in patients with intractable Meniere's disease (MD). METHODS: A total of 27 MD patients receiving endolymphatic duct blockage surgery (n = 10), endolymphatic sac drainage surgery (n = 9) and endolymphatic sac decompression surgery (n = 8) underwent gadolinium-enhanced inner ear magnetic resonance imaging (MRI) scans prior to, 2 weeks after and at > 12 months following surgery. RESULTS: In the group with endolymphatic duct blockage, the second MRI revealed no changes in EH, whereas the third MRI revealed a reversal of vestibular EH in 3 patients and a downgrading of cochlear hydrops in 2 of these 3 patients, who presented with an improvement in their hearing and complete control of vertigo. In the group with endolymphatic sac drainage, the second MRI showed a reversal of EH in 4 patients, and no changes in EH in the remaining 5 patients, whereas the third MRI showed that those 4 patients who presented with a reversal of EH at the second MRI stage remained unchanged except a recurrence of vestibular hydrops in 1 patient. All 4 patients exhibited a complete control of vertigo, but hearing improved in 1, worsened in 1 and remained unchanged in 2. In the group with endolymphatic sac decompression, both the second and third MRI examination revealed no reversal of EH. CONCLUSIONS: The present study has shown that both endolymphatic duct blockage surgery and endolymphatic sac drainage surgery have the potential to reduce EH in certain MD patients, but none of the patients receiving endolymphatic sac decompression surgery showed reversal of their EH.

Endolymphatic Sac Surgery And Posterior Semicircular Canal Fenestration For Meniere's Disease.

Objective: To evaluate the efficiency and safety of the simultaneous endolymphatic sac drainage (ELSD) and posterior semicircular canal fenestration (PSCF) primary on the vestibular function as an new therapeutic strategy in the patients with medically refractory Meniere's disease (MD).Study Design: retrospective follow-up study.Setting: University Clinic of Otolaryngology.Methods: Twenty-six patients with MD with severe vertigo and disability who underwent ELSD and PSCF in the same time in the period of 1988 and 2007 were reviewed. The main outcome measures were frequency of vertigo, functional disability according the guidelines for diagnosis and evaluation of therapy in MD. The canal paresis was evaluated by caloric test. The degree of reduced vestibular response rates as an indicators of the vestibular function were compared before and after surgery.Results: The preoperative audition was already altered in all cases except in 8 patients who had no significant changes in hearing threshold. The mean value of vertigo attacks before operation was 8.6. After 3 years of surgery only one patient (3.8%) had one vertigo attack. Functional level was highly ameliorated except in two patients who presented functional level 2 or B in the late postoperative period. The mean caloric testing duration after 3 years postoperatively showed that the 50% of the patients approaching the normal results.Conclusion: Based on the results of simultaneous endolymphatic sac surgery and posterior canal fenestration, they are effective methods for treatment of the refractory Meniere's disease. Endolymphatic sac surgery enables drainage of endolymphatic fluid and the fenestration of the posterior semicircular canal enables the distension or dilatation of the membranous canal in the decompressed perilymphatic space across the perilymphatic leak at the level of the new fenestra, and, so, appearing of certain decrease of the endolymphatic pressure. Both techniques at the same time decrease the pressure in the case of the endolymphatic hydrops.

The endolymphatic sac tumor: challenges in the eradication of a localized disease.

OBJECTIVE: Identify the critical points that lead to recurrences and lack of radicality in endolymphatic sac tumors (ELSTs). STUDY DESIGN: Retrospective case study and review of the literature. SETTING: Tertiary referral center. PATIENTS: Thirteen cases of ELST were included in the study and their preoperative, intraoperative and postoperative data were analyzed and compared to a review of the literature. INTERVENTION(S): Therapeutical. MAIN OUTCOME MEASURE(S): Prevalence of recurrent and residual tumors, comparison to the literature and analysis of ELST characteristics. RESULTS: Diagnosis was made 26 ± 17 months after the onset of symptomatology, and an ELST was preoperatively suspected in only six cases. At the time of surgery, 10 patients suffered from hearing loss. Preoperative symptoms or audiometry could not predict labyrinth infiltration, although speech discrimination scores were significantly associated with labyrinth infiltration (p = 0.0413). The labyrinth was infiltrated in 8 cases (57.1%), and in 7 cases (46.7%) the tumor eroded the carotid canal, whereas 6 cases (40%) presented an intradural extension. A gross total resection was achieved in 11 cases. There were two residual tumors, one of which because of profuse bleeding, and one recurrence (23.1%). A mean of 22.8% of recurrent or residual tumors are described in the literature based on 242 published cases, in more than half of the cases as a consequence of subtotal tumor resection (STR). CONCLUSIONS: Recurrence derives mostly from the difficulty to identify the extension of the tumor due to the extensive bone infiltration. Accurate diagnosis and correct preoperative planning, with embolization when possible, will facilitate surgery and avoid STR due to intraoperative bleeding. Long follow-ups are important in order to avoid insidious recurrences.

Vestibular impairment in cochlear implanted children presenting enlarged vestibular aqueduct and enlarged endolymphatic sac.

Enlarged vestibular aqueduct (EVA) is a common finding in tomodensitometry. When cranial MRI is performed, enlarged endolymphatic sac (EES) can also be found. Profound hearing loss is a common finding in these patients but a few studies have investigated vestibular function after cochlear implantation (CI) in EVA and EES patients. Our main objective was to find out whether in EVA children candidates to CI, a higher endolymphatic sac (ES) volume was predictive for higher rates of postsurgical vestibular complications. METHODS: We retrospectively included EVA children who benefited from CI, during the last 2 years. Two groups were constituted according to the presence or not of a vestibular impairment (decrease in the VOR gain on the VHIT test on one of the semicircular canals and/or a loss of cVEMPs) 6 months after CI. Endolymphatic volume of both VA and ES was measured for each patient. RESULTS: Fifteen patients were included. The mean endolymph volume was significantly higher in the impaired group (0.40 cm3 ± 0.23, range 0.08-0.70) than in the non-impaired group (0.11 cm3 ± 0.07, range 0.04-0.29; p = 0.029). Four children of the impaired group were followed during one year. At the end of vestibular rehabilitation, all children recovered a lateral canal function and a saccular function. CONCLUSION: In EVA children, a combined EES appears to increase the risk of severe post CI vestibular impairment. To minimize this risk prior CI surgery, besides tomodensitometry, MRI measurement of the ES volume should be systematically performed.

Absence of Endolymphatic Sac Ion Transport Proteins in Large Vestibular Aqueduct Syndrome-A Human Temporal Bone Study.

HYPOTHESIS: Epithelial ion transport pathologies of the endolymphatic sac (ES) are associated with large vestibular aqueduct syndrome (LVAS). BACKGROUND: LVAS is defined by the pathognomonic features of a widened bony vestibular aqueduct (VA) and an enlarged ES. The underlying cause of its associated cochleovestibular symptoms remains elusive. Disturbances in epithelial ion transport in the enlarged ES, affecting inner ear fluid regulation, were proposed as a possible pathophysiology. However, although respective epithelial ion transport pathologies have been demonstrated in the enlarged ES from transgenic LVAS mouse models, these pathologies have not been investigated in human LVAS cases. METHODS: Histological and immunohistochemical analysis of the enlarged ES epithelium in postmortem temporal bones from two individuals with a clinical diagnosis of LVAS. RESULTS: The enlarged ES epithelium demonstrated an overall atypical epithelial differentiation and a lack of the immunolocalization of signature ion transport proteins. Notably, in both cases, a rudimentary branch of the ES with a typically differentiated ES epithelium was present. CONCLUSIONS: The described cellular and molecular pathologies of the enlarged ES in humans provide evidence of epithelial transport pathology as one potential cause of cochleovestibular symptoms in LVAS. The present findings also emphasize the clinical relevance of already established LVAS mouse models.

68Ga-DOTATATE Uptake in an Endolymphatic Sac Tumor: Radiologic-Pathologic Correlation.

After dedicated CT and MRI, Ga-DOTATATE PET/CT was performed in a patient with a temporal bone mass with primary diagnostic considerations of an endolymphatic sac tumor versus a glomus jugulotympanicum paraganglioma. The Ga-DOTATATE PET showed mild radiotracer uptake in the mass (SUVmax, 10.9). After surgical resection, pathology revealed an endolymphatic sac tumor. Immunohistochemical staining demonstrated somatostatin receptor type 2A expression in the vasculature of the mass, but not in the tumor cells.

"Endolymphatic sac tumour": A case report with review of literature.

Endolymphatic sac tumour (ELST) is a non-metastasizing low grade adenocarcinoma of endolymphatic sac origin. It is also known as Heffner tumour, low grade adenocarcinoma of endolymphatic sac origin and aggressive papillary middle ear tumour. These tumours are closely associated with Von Hippel Lindau (VHL) disease. Here we report a case of Endolymphatic sac tumour in a 63 yr old lady who presented with left sided facial palsy. Since the tumour was highly vascular and required preoperative embolization, initial clinicoradiological diagnosis was Jugulotymphanic paraganglioma. Histopathology showed features of Endolymphatic sac tumour, which was confirmed by immunohistochemistry. Since this tumour is locally aggressive low grade adenocarcinoma, the diagnosis is difficult in advanced cases where there is erosion of petrous temporal bone or the lesion shows extension into cerebellopontine angle as in our case. Since the association of this tumour with VHL disease is well established, it is important to screen all the patients of VHL disease for this lesion and also all the patients of ELST should be screened for other lesions of VHL disease to aid in early diagnosis and treatment. The case is presented here for its rarity and difficulty in initial diagnosis.

[Imaging characteristics of patients with large vestibular aqueduct syndrome and its relationship with the acoustically evoked short latency negative response].

Objective: To explore the imaging characteristics of large vestibular aqueduct syndrome (LVAS) patients and their relationship with the acoustically evoked short latency negative response (ANSR), so as to provide reference for the diagnosis of LVAS. Methods: Clinical data of 174 patients(334 ears) with LVAS diagnosed and treated by the Department of Otorhinolaryngology Head and Neck Surgery of the First Affiliated Hospital of Guangxi Medical University, from October 2009 to December 2017 were retrospectively analyzed, including 117 males and 57 females, aged from 5 months to 47 years old, with the median age of 4 years and 4 months. ABR and imaging data of patients were collected. Midpoint diameter and the outlet diameter of the vestibular aqueduct were measured on CT images, the midpoint diameter of the intraosseous parts and the extraosseous parts of enlarged endolymphatic sac(EES) were measured on MRI images. The correlation between the above measurements was analyzed by Pearson test using SPSS 17.0. According to whether ASNR was detected in ABR, the above data were divided into two groups, and the differences of the above imaging measurements were compared by the Independent-Sample Test. Results: The average midpoint diameter of the vestibular aqueduct was (1.87±0.58) mm (x±s, the following was the same), and the outlet diameter was (3.07±0.99) mm on CT; the average midpoint diameter of the intraosseous parts in enlarged endolymphatic sac(EES) was (2.39±1.37) mm, and the extraosseous parts was (2.50±2.18) mm on MRI. There was a correlation between the four measurements (P<0.05), among which the midpoint diameter of vestibular aqueduct was strongly positively correlated with the outlet diameter (r=0.760), and the remaining pairs were weakly correlated. ASNR was detected in 241 ears (72.16%,241/334) and undetected in 93 ears (27.84%, 93/334) of the 334 ears with LVAS. Midpoint diameter and the outlet diameter of the vestibular aqueduct in no ASNR group were smaller than the ASNR group, and the difference was statistically significant (t value was 2.814 and 2.754, P<0.05). There was no significant difference in the midpoint diameter of the intraosseous parts and the extraosseous parts of enlarged endolymphatic sac between the two groups, and the difference was no statistically significant(t value was 0.101 and 0.683, P>0.05). Conclusions: There is a strong positive correlation between the midpoint diameter of vestibular aqueduct and the outlet diameter in LVAS patients. There is a certain correlation between the size of vestibular aqueduct and the size of endolymphatic sac. The smaller the diameter of vestibular aqueduct, the lower the occurrence rate of ASNR.

Relationship between changes in hearing function and volumes of endolymphatic hydrops after endolymphatic sac drainage.

Background: Endolymphatic sac drainage (ELSD) may have a positive effect on endolymphatic hydrops (EH) and may help to preserve inner ear function. However, the relationship between changes in EH volumes and hearing function after ELSD has not been described. Objectives: We aimed to reveal the factors related to changes in hearing and EH following ELSD. Material and Methods: Twenty-one patients who received ELSD were enrolled. Pure tone audiometry and 3-T magnetic resonance imaging (MRI) 4 h after intravenous injection of gadolinium enhancement were performed just before surgery and 2 years later. To characterize the endolymphatic space (ELS), we measured the volume of the total fluid (TFS) and ELS and calculated the ratio of ELS to TFS (ELS ratio). Results: The ELS ratio of the patients who showed hearing improvement was 18.5 ± 11.4% before surgery and 23.9 ± 14.3% after. For those with no change, it was 29.7 ± 10.8% before and 29.4 ± 9.5% after, and in patients with worsened hearing function it was 22.7 ± 7.5% before and 27.2 ± 13.4% after. Conclusion: We found no correlation between the changes in hearing function and the volume of EH after ELSD.

Clinicoradiologic characteristics of endolymphatic sac tumors.

PURPOSE: Endolymphatic sac tumor (ELST) is a rare, slow-growing, and low-grade malignant tumor arising from the endolymphatic sac in the posterior petrous bone. The purpose of this study is to describe the clinical and radiologic features, and investigate the clinicoradiologic correlation of ELST. METHODS: We retrospectively reviewed the clinical, computed tomography (CT), magnetic resonance imaging (MRI), and pathologic findings of 14 patients with 15 ELSTs. RESULTS: Patients comprised of eight women and six men with a mean age of 42.3 years at the time of diagnosis and 35.2 years at the time of initial symptoms. The mean interval between initial symptoms and diagnosis was 84.7 months. The most frequent cochleovestibular symptom was hearing loss in 14 patients (100%); other cochleovestibular symptoms were tinnitus in eight patients (57.1%), vertigo in three patients (21.4%), and aural fullness in three patients (21.4%). Ten patients (71.4%) presented with facial paralyses and five patients (14.3%) presented lower cranial nerve deficits. CT findings revealed spiculated, stippled, or reticular high density within the tumors. The lesions involved mastoid cells, vertical facial nerve canal, semicircular canal, cochlea, tympanum, jugular foramen, internal auditory canal, or petrous apex. On the available MRI, all the eight lesions showed patchy and/or speckled hyperintensity on unenhanced T1WI. Five lesions showed flow voids on T2WI and T1WI. Three lesions had blood fluid levels within cysts. CONCLUSION: CT and MRI findings of ELSTs are associated with clinical features. Imaging tests should be performed to identify ELSTs early and ensure greater potential for hearing preservation in patients with cochleovestibular symptoms.