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Sriperumbudur KK, Appali R, Gummer AW, van Rienen U. Understanding the impact of modiolus porosity on stimulation of spiral ganglion neurons by cochlear implants. Sci Rep 2024; 14:9593. [PMID: 38671022 PMCID: PMC11053021 DOI: 10.1038/s41598-024-59347-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Accepted: 04/09/2024] [Indexed: 04/28/2024] Open
Abstract
Moderate-to-profound sensorineural hearing loss in humans is treatable by electrically stimulating the auditory nerve (AN) with a cochlear implant (CI). In the cochlea, the modiolus presents a porous bony interface between the CI electrode and the AN. New bone growth caused by the presence of the CI electrode or neural degeneration inflicted by ageing or otological diseases might change the effective porosity of the modiolus and, thereby, alter its electrical material properties. Using a volume conductor description of the cochlea, with the aid of a 'mapped conductivity' method and an ad-hoc 'regionally kinetic' equation system, we show that even a slight variation in modiolus porosity or pore distribution can disproportionately affect AN stimulation. Hence, because of porosity changes, an inconsistent CI performance might occur if neural degeneration or new bone growth progress after implantation. Appropriate electrical material properties in accordance with modiolar morphology and pathology should be considered in patient-specific studies. The present first-of-its-kind in-silico study advocates for contextual experimental studies to further explore the utility of modiolus porous morphology in optimising the CI outcome.
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Affiliation(s)
- Kiran K Sriperumbudur
- Institute of General Electrical Engineering, University of Rostock, Rostock, Germany.
- Research and Development, MED-EL Medical Electronics GmbH, Innsbruck, Austria.
| | - Revathi Appali
- Institute of General Electrical Engineering, University of Rostock, Rostock, Germany
- Ageing of Individuals and Society, Interdisciplinary Faculty, University of Rostock, Rostock, Germany
| | - Anthony W Gummer
- Department of Otolaryngology, University of Tübingen, Tübingen, Germany.
- Department of Otolaryngology, University of Melbourne, Melbourne, Australia.
| | - Ursula van Rienen
- Institute of General Electrical Engineering, University of Rostock, Rostock, Germany
- Ageing of Individuals and Society, Interdisciplinary Faculty, University of Rostock, Rostock, Germany
- Life, Light and Matter, Interdisciplinary Faculty, University of Rostock, Rostock, Germany
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Parlak S, Akgoz Karaosmanoglu A, Ozbal Batuk M, Sennaroglu L, Ozgen B. 3 Tesla MR imaging of the large endolymphatic duct and sac anomaly with audiological correlation. Eur J Radiol 2021; 145:110064. [PMID: 34839211 DOI: 10.1016/j.ejrad.2021.110064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 11/06/2021] [Accepted: 11/18/2021] [Indexed: 10/19/2022]
Abstract
PURPOSE Large endolymphatic duct and sac (LEDS) is one of the most common imaging abnormalities in congenital sensorineural hearing loss and is frequently seen with coexistent cochlear anomalies, especially incomplete partition type II. However, MRI findings of accompanying cochlear and especially modiolar dysplasias may be subtle. The purpose of this study is to evaluate the imaging findings of LEDS with high-resolution imaging at 3 T and correlate with the audiological data. METHODS 3 T temporal bone MRIs of 54 ears in 30 LEDS patients were retrospectively evaluated. The cochlear dysmorphism and modiolar deficiency were assessed qualitatively and quantitatively. The severity of LEDS anomaly, the signal changes within the LEDS and cochlea were also noted. The imaging findings were correlated to the audiological data. RESULTS The cochlea was abnormal in 77.8% of the ears with an isolated modiolar deficiency in 11.1%. Cochlea and modiolus were completely normal in 11.1% of the ears. In 63% of the ears X-distance was increased. T2 hypointensity within LEDS and cochlea were detected in 42.6%, and 7.4% of the ears, respectively. The median diameters of LEDS were higher in ears with severe to profound HL than ears with normal to moderate HL (p < 0.05). The X-distance, presence of T2 hypointensity within LEDS, and diameters of modiolus did not show statistical correlation with the audiographic data. CONCLUSION High-resolution 3 T imaging of patients with LEDS anomaly revealed a spectrum of cochlear anomalies, but up to 11.1% of the ears had no underlying anomaly despite severe (endolymphatic duct/sac) dilatation and/or profound HL.
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Affiliation(s)
- Safak Parlak
- Hacettepe University, Faculty of Medicine, Department of Radiology, Turkey.
| | | | - Merve Ozbal Batuk
- Hacettepe University, Faculty of Health Sciences, Department of Audiology, Turkey
| | - Levent Sennaroglu
- Hacettepe University, Faculty of Medicine, Department of Otorhinolaryngology, Turkey
| | - Burce Ozgen
- University of Illinois at Chicago, Department of Radiology, United States
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Sousa R, Guerreiro C, Eça T, Campos J, Luis L. MR Imaging of Cochlear Modiolus and Endolymphatic Hydrops in Patients With Menière's Disease. Front Surg 2021; 8:667248. [PMID: 34355012 PMCID: PMC8329086 DOI: 10.3389/fsurg.2021.667248] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Accepted: 05/17/2021] [Indexed: 11/25/2022] Open
Abstract
Background: Menière's disease (MD) is an inner ear disorder characterized by recurrent episodes of spontaneous vertigo, unilateral low-frequency sensorineural hearing loss, tinnitus, and aural fullness. Current diagnosis still often has to rely on subjective and audiometric criteria only, although endolymphatic hydrops is recognized as the pathophysiological substrate of the disease, having been demonstrated in anatomical pathological studies and by magnetic resonance (MRI). The modiolus has a close functional and anatomical relationship with the cochlear nerve and membranous labyrinth and can be evaluated with MRI but no data exist on the modiolar size in MD. Purpose: Our purpose is to examine the following hypothesis. Is cochlear modiolus smaller in symptomatic ears in MD? Methods: We used a retrospective 3 Tesla MR study (heavily T2-weighted 3D fast asymmetric spin-echo images and 0.5 mm slice thickness) comparing the mean modiolar area (MMA) in the index and best ears of eight patients with definite MD based on audiometric data. The obtained MMA values were compared against the audiometric data and the presence of vestibular endolymphatic hydrops. Results: No differences were seen in MMA between best and worst ears. Ears with a pure tone average (PTA) ≥25 dB and more pronounced endolymphatic hydrops showed lower MMA (not statistically significant). Two patients with extreme endolymphatic hydrops showed a noteworthy ipsilateral decrease in the cochlear modiolus area. Conclusion: No differences were seen in MMA between best and worst ears in definite MD. Worse hearing function (PTA ≥ 25dB) and more pronounced endolymphatic hydrops seem to be associated with lower MMA. This might be related to bone remodeling as a consequence of endolymphatic hydrops. Further research is needed to corroborate and explore these findings.
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Affiliation(s)
- Rita Sousa
- Neuroradiology Department, Centro Hospitalar Universitário Lisboa Norte, Lisbon, Portugal
| | - Carla Guerreiro
- Neuroradiology Department, Centro Hospitalar Universitário Lisboa Norte, Lisbon, Portugal
| | - Tiago Eça
- Otorhinolaryngology Department, Centro Hospitalar Universitário Lisboa Norte, Lisbon, Portugal
| | - Jorge Campos
- Imaging Department, Red Cross Hospital, Lisbon, Portugal
| | - Leonel Luis
- Otorhinolaryngology Department, Centro Hospitalar Universitário Lisboa Norte, Lisbon, Portugal.,Clinical Physiology Translational Unit, Institute of Molecular Medicine, University of Lisbon, Lisbon, Portugal
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Connor SEJ, Dudau C, Pai I, Gaganasiou M. Is CT or MRI the optimal imaging investigation for the diagnosis of large vestibular aqueduct syndrome and large endolymphatic sac anomaly? Eur Arch Otorhinolaryngol 2019; 276:693-702. [PMID: 30635710 PMCID: PMC6411674 DOI: 10.1007/s00405-019-05279-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Accepted: 01/02/2019] [Indexed: 12/27/2022]
Abstract
BACKGROUND AND PURPOSE We explored whether there was a difference between measurements obtained with CT and MRI for the diagnosis of large vestibular aqueduct syndrome or large endolymphatic sac anomaly, and whether this influenced diagnosis on the basis of previously published threshold values (Valvassori and Cincinnati). We also investigated whether isolated dilated extra-osseous endolymphatic sac occurred on MRI. Secondary objectives were to compare inter-observer reproducibility for the measurements, and to investigate any mismatch between the diagnoses using the different criteria. MATERIALS/METHODS Subjects diagnosed with large vestibular aqueduct syndrome or large endolymphatic sac anomalies were retrospectively analysed. For subjects with both CT and MRI available (n = 58), two independent observers measured the midpoint and operculum widths. For subjects with MRI (± CT) available (n = 84), extra-osseous sac widths were also measured. Results There was no significant difference between the width measurements obtained with CT versus MRI. CT alone diagnosed large vestibular aqueduct syndrome or large endolymphatic sac anomalies in 2/58 (Valvassori) and 4/58 (Cincinnati), whilst MRI alone diagnosed them in 2/58 (Valvassori). There was 93% CT/MRI diagnostic agreement using both criteria. Only 1/84 demonstrated isolated extra-osseous endolymphatic sac dilatation. The MRI-based LVAS/LESA diagnosis was less dependent on which criteria were used. Midpoint measurements are more reproducible between observers and between CT/MR imaging modalities. CONCLUSION Supplementing MRI with CT results in additional diagnoses using either criterion, however, there is no net increased diagnostic sensitivity for CT versus MRI when applying the Valvassori criteria. Isolated enlargement of the extra-osseous endolymphatic sac is rare.
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Affiliation(s)
- S E J Connor
- School of Biomedical Engineering and Imaging Sciences Clinical Academic Group, King's College, London, UK.
- Department of Radiology, Guy's and St. Thomas' Hospital, London, UK.
- Department of Neuroradiology, Ruskin Wing, Kings College Hospital, Denmark Hill, London, SE5 9RS, UK.
| | - C Dudau
- Department of Radiology, Guy's and St. Thomas' Hospital, London, UK
- Department of Neuroradiology, Ruskin Wing, Kings College Hospital, Denmark Hill, London, SE5 9RS, UK
| | - I Pai
- Department of Ear, Nose and Throat Surgery, Guy's and St Thomas' Hospital, London, UK
| | - M Gaganasiou
- 251 General and VA Air Force Hospital, Athens, Greece
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Abstract
CT and MR imaging are essential cross-sectional imaging modalities for assessment of temporal bone anatomy and pathology. The choice of CT versus MR depends on the structures and the disease processes that require assessment, delineation, and characterization. A thorough knowledge of the two imaging modalities' capabilities and of temporal bone anatomy greatly facilitates imaging interpretation of pathologic conditions.
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Affiliation(s)
- Amy F. Juliano
- Massachusetts Eye and Ear Infirmary, Boston, MA USA ,Harvard Medical School, Boston, MA USA
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Abstract
AbstractObjective:To describe our finding of increased ossification of the modiolus in paediatric patients with auditory neuropathy who met criteria for cochlear implantation.Methods:A retrospective case series with a comparison group at a tertiary referral centre is described. Seven paediatric patients with auditory neuropathy who met criteria for and underwent cochlear implantation were identified. Fifteen paediatric implantees with bilateral profound sensorineural hearing loss were included as the comparison group. All patients underwent pre-operative computed tomography. Attenuation at the modiolus was measured in all subjects by a neuroradiologist blinded to clinical information.Results:Attenuation values in the modiolus in the auditory neuropathy patients (mean ± standard deviation = 796.2 ± 53.0 HU) was statistically significantly higher than in the comparison sensorineural hearing loss patients (267.1 ± 45.6 HU; p < 0.05, t-test).Conclusion:Patients with auditory neuropathy who meet criteria for cochlear implantation demonstrate significantly higher modiolar attenuation on computed tomography imaging, consistent with increased ossification at the modiolus.
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Hanekom T, Hanekom JJ. Three-dimensional models of cochlear implants: A review of their development and how they could support management and maintenance of cochlear implant performance. Network 2016; 27:67-106. [PMID: 27136100 DOI: 10.3109/0954898x.2016.1171411] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Three-dimensional (3D) computational modeling of the auditory periphery forms an integral part of modern-day research in cochlear implants (CIs). These models consist of a volume conduction description of implanted stimulation electrodes and the current distribution around these, coupled with auditory nerve fiber models. Cochlear neural activation patterns can then be predicted for a given input stimulus. The objective of this article is to present the context of 3D modeling within the field of CIs, the different models, and approaches to models that have been developed over the years, as well as the applications and potential applications of these models. The process of development of 3D models is discussed, and the article places specific emphasis on the complementary roles of generic models and user-specific models, as the latter is important for translation of these models into clinical application.
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Affiliation(s)
- Tania Hanekom
- a Bioengineering, Department of Electrical, Electronic and Computer Engineering , University of Pretoria , Pretoria , South Africa
| | - Johan J Hanekom
- a Bioengineering, Department of Electrical, Electronic and Computer Engineering , University of Pretoria , Pretoria , South Africa
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Juliano AF, Ginat DT, Moonis G. Imaging Review of the Temporal Bone: Part II. Traumatic, Postoperative, and Noninflammatory Nonneoplastic Conditions. Radiology 2015; 276:655-72. [PMID: 26302389 DOI: 10.1148/radiol.2015140800] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The first part of this review of the temporal bone discussed anatomy of the temporal bone as well as inflammatory and neoplastic processes in the temporal bone region (1). This second part will first discuss trauma to the temporal bone and posttraumatic complications. The indications for common surgical procedures performed in the temporal bone and their postoperative imaging appearance are then presented. Finally, a few noninflammatory nonneoplastic entities involving the temporal bone are reviewed. They are relatively uncommon diagnoses compared with infectious or inflammatory diseases. However, because patients present with symptoms that are either common (hearing loss) or distinctive (sensorineural hearing loss in a child), they are important for the radiologist to be aware of and recognize.
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Affiliation(s)
- Amy F Juliano
- From the Department of Radiology, Massachusetts Eye and Ear Infirmary, 243 Charles St, Boston, MA 02114 (A.F.J.); Department of Radiology, The University of Chicago Medicine, Chicago, Ill (D.T.G.); and Department of Radiology, Beth Israel Deaconess Medical Center, Boston, Mass (G.M.)
| | - Daniel T Ginat
- From the Department of Radiology, Massachusetts Eye and Ear Infirmary, 243 Charles St, Boston, MA 02114 (A.F.J.); Department of Radiology, The University of Chicago Medicine, Chicago, Ill (D.T.G.); and Department of Radiology, Beth Israel Deaconess Medical Center, Boston, Mass (G.M.)
| | - Gul Moonis
- From the Department of Radiology, Massachusetts Eye and Ear Infirmary, 243 Charles St, Boston, MA 02114 (A.F.J.); Department of Radiology, The University of Chicago Medicine, Chicago, Ill (D.T.G.); and Department of Radiology, Beth Israel Deaconess Medical Center, Boston, Mass (G.M.)
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Connor SE, Siddiqui A, O'Gorman R, Tysome JR, Lee A, Jiang D, Fitzgerald-O'Connor A. Magnetic resonance imaging features of large endolymphatic sac compartments: audiological and clinical correlates. J Laryngol Otol 2012; 126:586-93. [PMID: 22643203 DOI: 10.1017/S0022215112000606] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECTIVES (1) To study the prevalence and characteristics of large endolymphatic sac internal compartments on thin-section T2- and T2*-weighted magnetic resonance imaging, and to relate these to other large endolymphatic sac magnetic resonance imaging features, and (2) to correlate the compartment imaging features, endolymphatic sac size and labyrinthine anomalies with the patients' clinical and audiological data. METHOD Magnetic resonance imaging studies for 38 patients with large endolymphatic sac anomalies were retrospectively reviewed in a tertiary referral centre. Endolymphatic sac compartment presence, morphology and imaging signal were assessed. Endolymphatic sac size and labyrinthine anomalies were also recorded. Endolymphatic sac compartments and other imaging features were correlated with clinical and audiological data. RESULTS Compartments were present in 57 per cent of the imaged endolymphatic sacs, but their presence alone did not correlate with other imaging features or clinical data. The endolymphatic sac : internal auditory meatus signal ratio was associated with a history of sudden or fluctuating hearing loss. Hearing loss correlated with opercular and extraosseous endolymphatic sac size measurements. A larger midpoint intraosseous endolymphatic sac size was associated with clear fluid loss at cochlear implantation. CONCLUSION The magnetic resonance imaging characteristics of large endolymphatic sac compartments have been defined. The endolymphatic sac size and distal compartment signal should be recorded, as these provide prognostic information and assist the planning of appropriate interventions.
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Mohan S, Hoeffner E, Bigelow DC, Loevner LA. Applications of Magnetic Resonance Imaging in Adult Temporal Bone Disorders. Magn Reson Imaging Clin N Am 2012; 20:545-72. [DOI: 10.1016/j.mric.2012.06.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Gibson D, Gluth MB, Whyte A, Atlas MD. Rotation of the osseous spiral lamina from the hook region along the basal turn of the cochlea: results of a magnetic resonance image anatomical study using high-resolution DRIVE sequences. Surg Radiol Anat 2012; 34:781-5. [DOI: 10.1007/s00276-011-0896-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2011] [Accepted: 11/04/2011] [Indexed: 10/15/2022]
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Abstract
Recent magnetic resonance imaging (MRI) techniques have made it possible to examine the compartments of the cochlea using gadolidium-chelate (GdC) as a contrast agent. As GdC loads into the perilymph space without entering the endolymph in healthy inner ears, the technique provides possibilities to visualize the different cochlear compartments and evaluate the integrity of the inner ear barriers. This critical review presents the recent advancements in the inner ear MRI technology, contrast agent application and the correlated ototoxicity study, and the uptake dynamics of GdC in the inner ear. GdC causes inflammation of the mucosa of the middle ear, but there are no reports or evidence of toxicity-related changes in vivo either in animals or in humans. Intravenously administered GdC reached the guinea pig cochlea about 10 minutes after administration and loaded the scala tympani and scala vestibuli with the peak at 60 minutes. However, the perilymphatic loading peak was 80 to 100 minutes in mice after intravenous administration of GdC. In healthy animals the scala media did not load GdC. In mice in which GdC was administered topically onto the round window, loading of the cochlea peaked at 4 hours, at which time it reached the apex. The initial portions of the organ to be filled were the basal turn of the cochlea and vestibule. In animal models with endolymphatic hydrops (EH), bulging of the Reissner's membrane was observed as deficit of GdC in the scala vestibuli. Histologically the degree of bulging correlated with the MR images. In animals with immune reaction-induced EH, MRI showed that EH could be limited to restricted regions of the inner ear, and in the same inner ear both EH and leakage of GdC into the scala media were visualized. More than 100 inner ear MRI scans have been performed to date in humans. Loading of GdC followed the pattern seen in animals, but the time frame was different. In intravenous delivery of double-dose GdC, the inner ear compartments were visualized after 4 hours. The uptake pattern of GdC in the perilymph of humans between 2 hours and 7 hours after local delivery needs to be clarified. In almost all patients with probable or suspected Ménière's disease, EH was verified. Specific algorithms with a 12-pole coil using fluid attenuation inversion recovery sequences are recommended for initial imaging in humans.
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Affiliation(s)
- Ilmari Pyykkö
- Department of Otolaryngology, University of Tampere, Teiskontie 35, 33520, Tampere, Finland.
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Kawai H, Naganawa S, Ishihara S, Sone M, Nakashima T. MR imaging of the cochlear modiolus after intratympanic administration of Gd-DTPA. Magn Reson Med Sci 2010; 9:23-9. [PMID: 20339263 DOI: 10.2463/mrms.9.23] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
PURPOSE We evaluated whether enhancement of the cochlear modiolus could be visualized 24 hours after intratympanic injection of gadolinium diethylenetriamine penta-acetic acid (Gd-DTPA) using a 3-dimensional real inversion recovery sequence combined with a 32-channel head coil at 3 tesla. Intratympanic injection of Gd-DTPA has been reported for visualizing endolymphatic hydrops in Meniere's disease, and its use has shown communication between the cochlear perilymph and cerebrospinal fluid in the internal auditory canal. Although the cochlear modiolus has been considered the route for this communication, this has not been confirmed through direct visualization of its enhancement. MATERIALS AND METHODS We qualitatively and quantitatively evaluated the presence of contrast enhancement in the modiolus in 19 patients with clinically suspected endolymphatic hydrops or hearing loss who underwent imaging as described above. RESULTS The contrast ratio (CR) between the cochlear modiolus and cerebellar white matter on the injected side was 1.09+/-1.23, and that on the non-injected side was -0.48+/-0.38 (P<0.01). In all subjects, the CR value was larger on the injected than non-injected side, and enhancement of the cochlear modiolus was also recognized visually. CONCLUSIONS Intratympanic Gd-DTPA can be administered to visualize enhancement of the cochlear modiolus and may thereby reveal its functional anatomy.
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Affiliation(s)
- Hisashi Kawai
- Department of Radiology, Nagoya University Graduate School of Medicine, Nagoya, Japan
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Teissier N, Van Den Abbeele T, Sebag G, Elmaleh-Berges M. Computed Tomography measurements of the normal and the pathologic cochlea in children. Pediatr Radiol 2010; 40:275-83. [PMID: 20012953 DOI: 10.1007/s00247-009-1423-2] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/25/2008] [Revised: 06/10/2009] [Accepted: 08/31/2009] [Indexed: 11/26/2022]
Abstract
BACKGROUND Radiological investigation is frequently undertaken to assess the aetiology of sensorineural hearing loss (SNHL). OBJECTIVE To establish the CT measurements of the normal cochlea in children and to determine radiological criteria correlated with SNHL. MATERIALS AND METHODS A retrospective study of temporal bone CT performed in 159 children, age range from 3 days to 16 years between February 1999 and July 2004. A control group (n = 88) comprised children without SNHL; the SNHL group comprised 71 children. The width of the second turn of the cochlea (CW), the cochlear height (CH), and the width of the bony canal for the cochlear nerve (WCN) were measured on a reference plane containing the modiolus, the posterior semicircular canal, the footplate, and the stapes arch. RESULTS Width of the canal measurements <or=1.7 mm or >or=2.5 mm supported the diagnosis of SNHL with a specificity of 97% and 91%, respectively. Cochlear width was found to be significantly smaller in the SNHL group (5.61 +/- 0.51 mm) than in the control group (5.75 +/- 0.31 mm, P < 0.02), a size <5.4 mm being highly suggestive of SNHL with a specificity of 90%. No significant variations of all measurements were found with age. CONCLUSION Appropriate measurements of WCN and CW are highly correlated with SNHL.
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Affiliation(s)
- Natacha Teissier
- Paediatric ENT, Robert Debré Hospital, 49 Bd Sérurier, Paris, France.
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Lareida A, Beckmann F, Schrott-Fischer A, Glueckert R, Freysinger W, Müller B. High-resolution X-ray tomography of the human inner ear: synchrotron radiation-based study of nerve fibre bundles, membranes and ganglion cells. J Microsc 2009; 234:95-102. [PMID: 19335460 DOI: 10.1111/j.1365-2818.2009.03143.x] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The combination of osmium tetroxide staining and high-resolution tomographic imaging using monochromatic X rays allows visualizing cellular structures of the human inner ear, that is, the organ of Corti, the stria vascularis and further soft tissues of the membranous labyrinth, in three-dimensional space with isotropic micrometre resolution. This approach permits to follow the course of nerve fibre bundles in a major part of the specimen and reveals the detailed three-dimensional arrangement of individual ganglion cells with distinct nuclei by means of X-ray tomography for the first time. The non-destructive neuron cell counting in a selected volume of 125 microm x 800 microm x 600 microm = 0.06 mm(3) gives rise to the estimate that 2000 ganglion cells are present along 1 mm organ of Corti.
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Affiliation(s)
- A Lareida
- Biomaterials Science Center, University of Basel, c/o University Hospital, Basel, Switzerland
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Gupta SS, Maheshwari SR, Kirtane MV, Shrivastav N. Pictorial review of MRI/CT Scan in congenital temporal bone anomalies, in patients for cochlear implant. Indian J Radiol Imaging 2009; 19:99-106. [PMID: 19881062 PMCID: PMC2765183 DOI: 10.4103/0971-3026.50825] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
High-resolution CT scan (HRCT) and MRI are routinely performed prior to cochlear implant surgery. These modalities help assess the status of the inner ear structures. A few patients have significant anomalies, which need to be assessed and understood in detail. We present a pictorial essay of these anomalies and described our HRCT and MRI techniques in patients being imaged prior to surgery.
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Affiliation(s)
- Santosh S Gupta
- Department of Radiology, P.D. Hinduja National Hospital and Medical Research Centre, Mumbai, India
| | - Shailendra R Maheshwari
- Department of Radiology, P.D. Hinduja National Hospital and Medical Research Centre, Mumbai, India
| | - Milind V Kirtane
- Department of ENT, P.D. Hinduja National Hospital and Medical Research Centre, Mumbai, India
| | - Nitin Shrivastav
- Department of ENT, P.D. Hinduja National Hospital and Medical Research Centre, Mumbai, India
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Naganawa S, Satake H, Iwano S, Sone M, Nakashima T. Communication between cochlear perilymph and cerebrospinal fluid through the cochlear modiolus visualized after intratympanic administration of Gd-DTPA. ACTA ACUST UNITED AC 2009; 26:597-602. [DOI: 10.1007/s11604-008-0286-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2008] [Accepted: 09/22/2008] [Indexed: 10/21/2022]
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NAGANAWA S, SONE M, OTAKE H, NAKASHIMA T. Endolymphatic Hydrops of the Labyrinth Visualized on Noncontrast MR Imaging: A Case Report. Magn Reson Med Sci 2009; 8:43-6. [DOI: 10.2463/mrms.8.43] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
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Abstract
OBJECTIVE Large endolymphatic duct and sac (LEDS) syndrome is the most common radiologically detectable form of inner ear malformation (IEM) associated with sensorineural hearing loss (SNHL). Nevertheless, it is relatively unknown in the German-speaking countries. METHODS Among all patients referred from ear, nose, and throat specialists to the radiology department with clinically suspected IEM between 1994 and 2003, we identified the cases of LEDS. The retrospective study included clinical records, high-resolution computed tomography, and magnetic resonance imaging. RESULTS Of 169 patients, 17 (median age 12 years; 12 females) showed LEDS. A total of 28 ears were affected. Ten patients (6%; 15 ears) had isolated LEDS, while seven patients showed additional IEM (4%; 13 ears). The most frequent of these was dysplastic vestibule (13/13 ears), followed by Mondini deformity (10/13 ears) and dilated semicircular canals (7/13 ears). Three of 13 ears revealed severe IEM of the cochlea, vestibule, and semicircular canals. No correlation could be demonstrated between the severity of morphological changes and the degree of SNHL. CONCLUSION LEDS may be an underestimated cause of SNHL. Imaging is necessary for a confident diagnosis.
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Affiliation(s)
- S Bartel-Friedrich
- Abteilung Phoniatrie und Pädaudiologie, Klinik und Poliklinik für Hals-Nasen-Ohren-Heilkunde, Kopf- und Halschirurgie, Universitätsklinikum der Martin-Luther-Universität Halle-Wittenberg, Deutschland.
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Krombach GA, Honnef D, Westhofen M, Di Martino E, Günther RW. Imaging of congenital anomalies and acquired lesions of the inner ear. Eur Radiol 2007; 18:319-30. [DOI: 10.1007/s00330-007-0759-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2006] [Revised: 08/10/2007] [Accepted: 08/27/2007] [Indexed: 02/01/2023]
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Vijayasekaran S, Halsted MJ, Boston M, Meinzen-Derr J, Bardo DME, Greinwald J, Benton C. When is the vestibular aqueduct enlarged? A statistical analysis of the normative distribution of vestibular aqueduct size. AJNR Am J Neuroradiol 2007; 28:1133-8. [PMID: 17569973 PMCID: PMC8134171 DOI: 10.3174/ajnr.a0495] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE The size of vestibular aqueducts (VAs) seen on CT studies varies. The current practice of calling a VA enlarged when it exceeds a certain threshold (eg, 1.5 mm at the midpoint) is arbitrary. Our hypothesis was that statistical analysis of the range of VA widths in a normal-hearing population would lead to a mathematic definition of the upper-limit-of-normal VA width. MATERIALS AND METHODS The VA midpoint and opercular widths were measured in 73 children with normal hearing. Statistical analysis yielded values of the 99 th, 97.5th, 95th, 90th, 75th, and 50th percentiles for this normal distribution. RESULTS The upper-limit-of-normal (95th percentile) values for the VA midpoint and opercular widths were 0.9 and 1.9 mm, respectively. The VAs with greater widths may reasonably be considered enlarged. CONCLUSION The VAs with midpoint or opercular widths of 1.0 and 2.0 mm or greater, respectively, are enlarged.
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Affiliation(s)
- S Vijayasekaran
- Department of Otolaryngology, Cincinnati Children's Hospital Medical Center and the University of Cincinnati College of Medicine, Cincinnati, Ohio 45229-3039, USA
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Grimmer JF, Hedlund G. Vestibular symptoms in children with enlarged vestibular aqueduct anomaly. Int J Pediatr Otorhinolaryngol 2007; 71:275-82. [PMID: 17113162 DOI: 10.1016/j.ijporl.2006.10.010] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2006] [Revised: 10/12/2006] [Accepted: 10/15/2006] [Indexed: 11/28/2022]
Abstract
OBJECTIVE The objective of this study is to describe the vestibular symptoms in pediatric patients with enlarged vestibular aqueduct (EVA) anomaly. METHODS Retrospective chart review of pediatric and adult patients with EVA anomaly who were treated at the University of Utah Hospital or Primary Children's Medical Center, between 1995 and 2005. Radiographs were reviewed to confirm the diagnosis. Comparisons were made between adult and pediatric patients. RESULTS Thirty-two patients were included in the study, 17 females and 15 males. Twenty-one patients were under the age of 18 and 11 patients were age 18 or older. On initial audiometric evaluation at a tertiary hospital, the pure tone average in the right ear was 75.0 dB and the pure tone average in the left ear was 80.4 dB. The incidence of vestibular symptoms in adult patients was 45.5% and in pediatric patients was 48.0%. Fourteen patients underwent cochlear implantation. Four patients (28.6%) who previously denied vestibular symptoms experienced post-operative vertigo after cochlear implantation. CONCLUSIONS About half of the patients with EVA in our series experienced vestibular symptoms. Pediatric patients in our series experienced vertigo and vestibular symptoms with equal frequency when compared to adult patients. Some patients with EVA undergoing cochlear implantation experienced vestibular symptoms in the post-operative period.
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Affiliation(s)
- J Fredrik Grimmer
- Division of Otolaryngology, University of Utah, Primary Children's Medical Center, UT, USA.
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Abstract
OBJECTIVES/HYPOTHESIS Large vestibular aqueduct syndrome (LVAS) is one of the common causes of hearing loss (HL). All prior studies have reported some anomalies associated with LVAS by imaging techniques. This study was undertaken to determine prevalence of LVAS in our temporal bone (TB) collection and its relationship to other systemic or otologic anomalies. STUDY DESIGN Retrospective, TB histopathologic study. METHODS Anteroposterior diameters of internal (IA) and external (EA) apertures were measured in 40 normal TBs (40 cases). TBs were considered as large vestibular aqueduct (LVA) if width of apertures was 95% greater than "normals." Systemic and otologic anomalies and histopathology of ears with LVAS were noted. RESULT Of 1,608 non-"normal" TBs, 63 had LVA. There was negative correlation between IA and EA in 48 TBs with only enlarged IA. Fifteen TBs with enlarged EA always had enlarged IA and were therefore considered as LVAS. The most common pathologic condition was congenital heart anomaly. The most common syndrome or dysplasia was Mondini's. The most common anomalies of external and middle ears were dehiscent facial nerves, low set auricles, and ossicular deformities. Inner ear anomalies included modiolar deficiencies, hair cell loss, interscalar septum defects, and strial atrophy. There was no record of family history of HL, head injury, or craniofacial, branchial, or thyroidal abnormalities. CONCLUSION Because HL associated with LVAS may be attributed to other ear anomalies, it is important to investigate other inner ear problems and system diagnoses that may indicate a syndrome in patients with radiologically diagnosed LVAS.
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Affiliation(s)
- Shigeo Hirai
- International Hearing Foundation, Minneapolis, Minnesota, USA.
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Koesling S, Rasinski C, Amaya B. Imaging and clinical findings in large endolymphatic duct and sac syndrome. Eur J Radiol 2005; 57:54-62. [PMID: 16289429 DOI: 10.1016/j.ejrad.2005.09.005] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2005] [Revised: 09/20/2005] [Accepted: 09/23/2005] [Indexed: 11/25/2022]
Abstract
OBJECTIVE Large endolymphatic duct and sac syndrome (LEDS) is known as the most common kind of inner ear malformations, which is radiologically detectable. Nevertheless, nowadays many questions are not fully cleared and LEDS is relatively unknown among general radiologists. The aim of this study was to evaluate the incidence of LEDS in the own patient population and to present our experiences regarding imaging findings, clinical presentation and follow up. MATERIALS AND METHODS Based on a complete recording of all patients, sent from ENT department to radiology, we identified all radiological diagnosed cases of inner ear malformations including LEDS and all patients in whom an inner ear malformation was clinically suspected. The retrospective study included clinical records, HR-CT and MRI performed between 1994 and 2002. RESULTS Among 169 patients (338 ear), 17 of patients (median age: 12 years) and 28 ears, respectively, had enlarged endolymphatic structures. In 10 patients - 6% - (15 ears), no other abnormalities were detected, called isolated LEDS, seven patients showed additional inner ear abnormalities. One patient showed a labyrinthine hemorrhage after sudden hearing loss. Audiometric data revealed sensorineural hearing loss in 22 ears, deafness in 5 ears and normal hearing in 1 case of 28 ears. In 10 (67%) of 15 ears with isolated LEDS, the hearing loss was downward-fluctuating progressive. Twelve patients (eight with isolated LEDS) had partly repeated sudden hearing losses. A trigger for worsening of hearing was found in five patients. A correlation between the severity of morphological changes on imaging and the degree of hearing disturbances could not be detected. Only four young patients underwent a radiological examination within the first or second year after onset of hearing loss. Three patients received a cochlear implant. CONCLUSIONS LEDS might be the cause of progressive hearing loss and repeated acute hearing losses in children and young adults. Imaging plays an important role in making the diagnosis.
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Sugiura M, Sato E, Nakashima T, Sugiura J, Furuhashi A, Yoshino T, Nakayama A, Mori N, Murakami H, Naganawa S. Long-term follow-up in patients with Pendred syndrome: vestibular, auditory and other phenotypes. Eur Arch Otorhinolaryngol 2005; 262:737-43. [PMID: 15747138 DOI: 10.1007/s00405-004-0884-z] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2004] [Accepted: 09/23/2004] [Indexed: 10/25/2022]
Abstract
Fourteen patients with a Pendred syndrome gene (Pds) mutation and three patients without the mutation were studied to evaluate long-term vestibular and auditory manifestations among patients with bilateral enlarged vestibular aqueducts (EVA). Charts were reviewed retrospectively for age, gender, otological history, presence or absence of vertigo, results of magnetic resonance imaging, relevant gene mutations and perchlorate discharge test. A missense mutation, His 723 Arg (H723R), was identified in the homozygous state in six patients and in the heterozygous state in seven patients. Another missense mutation, Tyr 410 Met (T410 M), was identified in the heterozygous state in one patient. Patients with vertigo tended to have hearing fluctuation, compared with the patients without vertigo. Patients homozygous for H723R tended to have more episodes of vertigo than the heterozygous individuals. Only one patient who was homozygous for H723R had goiter. The long-term outcome of hearing level in patients with the H723R mutation was significantly better compared with published results for patients with a Pds mutation, but not for those with the H723R mutation. Whether environmental factors or a subtype of the Pds mutation H723R are related to the long-term outcome for these patients must be clarified.
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Affiliation(s)
- Makoto Sugiura
- Department of Otorhinolaryngology, Nagoya University School of Medicine, 466-8550 Nagoya, Japan.
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Naganawa S, Koshikawa T, Fukatsu H, Ishigaki T, Sato E, Sugiura M, Yoshino T, Nakashima T. Enlarged endolymphatic duct and sac syndrome: relationship between MR findings and genotype of mutation in pendred syndrome gene. Magn Reson Imaging 2004; 22:25-30. [PMID: 14972391 DOI: 10.1016/j.mri.2003.07.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2003] [Revised: 07/21/2003] [Accepted: 07/22/2003] [Indexed: 11/18/2022]
Abstract
Pendred syndrome (PDS) is characterized by profound deafness in childhood, positive perchlorate challenge, and goiter. PDS is often associated with enlarged endolymphatic duct and sac (EEDS), and recently, PDS gene mutations have been reported even in those patients with EEDS without classic Pendred syndrome. In a previous report, the number of mutant alleles was correlated with the degree of subclinical thyroid abnormality, but not with hearing loss, in patients with missense mutation H723R. It also has been reported that the hearing loss in EEDS was not correlated with the EEDS volume, cochlear modiolar area, or signal intensity of the endolymphatic sac. We evaluated the correlations between the number of mutant alleles and these parameters in patients with EEDS to investigate the mechanisms underlying this condition. The study group was comprised of 16 Japanese patients with EEDS diagnosed by MR imaging. The H723R mutation was homozygous in six patients and heterozygous in six patients, with no mutation found in four patients. The modiolar area, EEDS volume, and signal intensity ratio (sac signal/cerebrospinal fluid signal) were not significantly correlated with the number of mutant alleles. PDS gene mutations may not be the only cause of EEDS, and the mechanisms underlying EEDS remain unclear.
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Affiliation(s)
- Shinji Naganawa
- Department of Radiology, Nagoya University School of Medicine, Nagoya, Japan.
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Abstract
OBJECTIVE To evaluate the diagnostic accuracy of magnetic resonance imaging for assessment of the endolymphatic sac and vestibular aqueduct. STUDY DESIGN Imaging and histological study of the cadaver. METHODS Five cadavers were studied by a 1.5-T magnetic resonance imaging system with a 3-inch-diameter surface coil. Magnetic resonance imaging scans were obtained with proton density-weighted and T2-weighted fast spin-echo sequences. Histological sections were made with an epoxy resin-embedding method and were compared with magnetic resonance imaging scans. RESULTS The visibility of the endolymphatic sac on both sequences corresponded well to the presence of the endolymphatic sac on histological sections. On the histological sections, the width of the external aperture of vestibular aqueduct (endolymphatic sac including surrounding connective tissue) was 0.96 +/- 0.18 mm (mean +/- SD) and the width of lumen of endolymphatic sac at the same point was 0.47 +/- 0.17 mm. The width of the endolymphatic sac was 1.02 +/- 0.19 mm on proton density-weighted images and was 0.81 +/- 0.15 mm on T2-weighted images. The widths of endolymphatic sac measured on proton density-weighted image and those of vestibular aqueduct on histological section did not show statistically significant differences (P >.05). On the other hand, the endolymphatic sac as measured on T2-weighted image tended to be smaller than the vestibular aqueduct (P <.05) and tended to be larger than the lumen of the endolymphatic sac (P <.0005). CONCLUSION Both sequences can precisely depict the endolymphatic sac; however, the proton density-weighted image is a more appropriate indicator of the actual anatomical configuration of the endolymphatic sac with surrounding connective tissue and vestibular aqueduct.
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Affiliation(s)
- Mari Kobayashi
- Department of Otolaryngology, School of Medicine, Tokyo Medical and Dental University, Japan
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Abstract
OBJECTIVES High-resolution MRI (MRI) of human inner ear structures provides several advantages over other imaging modalities. High-resolution visualization of inner ear ultrastructure in a noninvasive manner may provide important information about inner ear disease that is not obtainable in other ways. The study was performed to demonstrate the capabilities of MRI at high resolution on the human cochlea, vestibular structures, and facial nerve. Comparative analyses of MRI anatomy with that seen on histological dissection were made. The aim of the study was to define the anatomy of human cadaveric cochlea using a 9.4-Tesla magnetic resonance scanner, currently the most powerful magnetic resonance magnet available. STUDY DESIGN Experimental pilot study of cadaveric human cochleae. METHODS Serial scanning using a 9.4-Tesla magnetic resonance imager on normal preserved and fresh cadaveric inner ears was performed in different planes. RESULTS The images revealed detailed anatomy of the modiolus, utricle, saccule, semicircular canals, and facial nerve. Specifically, identifiable structures within the cochlea included the osseous spiral lamina, Reissner's membrane, membranous spiral lamina, spiral ligament, and others. CONCLUSIONS Data established through the acquisition of images from cadaver cochlea, facial nerve, and vestibular complex provide a foundation for developing steps for testing temporal bones and, eventually, patients with Meniere's disease and other inner ear disease. The present ongoing project will provide information on baseline images of the inner ear using high-resolution MRI.
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Affiliation(s)
- Robert D Silver
- Department of Otolaryngology-Head and Neck Surgery, University of Minnesota, Minneapolis, Minnesota 55455, USA
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Abstract
Orthogonal-plane fluorescence optical sectioning (OPFOS) microscopy was developed for the purpose of making quantitative measurements of the intact mammalian cochlea and to facilitate 3D reconstructions of complex features. A new version of this imaging apparatus was built with a specimen chamber designed to accommodate samples as large as the intact guinea pig bulla. This method left the cochlear connections with the vestibular system and with the ossicles of the middle ear undisturbed, providing views within the cochlea with no breaches of its structural integrity. Since the features within the bulla were not physically touched during the preparation process, the risk of damage was minimized, and were imaged in relatively pristine condition with spatial resolution to 16 microm. A description of the imaging method and specimen preparation procedure is presented, as are images of features from the cochlea, ossicles, and vestibular system.
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Affiliation(s)
- Arne H Voie
- Spencer Technologies, 701 16th Ave., Seattle, WA 98122, USA.
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Sato E, Nakashima T, Lilly DJ, Fausti SA, Ueda H, Misawa H, Uchida Y, Furuhashi A, Asahi K, Naganawa S. Tympanometric findings in patients with enlarged vestibular aqueducts. Laryngoscope 2002; 112:1642-6. [PMID: 12352679 DOI: 10.1097/00005537-200209000-00021] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
OBJECTIVES The purpose of this study was to study systematically some relationships between the resonance frequency of the middle-ear transmission system and the volume of the endolymphatic duct and sac in patients with an enlarged vestibular aqueduct (EVA). STUDY DESIGN Prospective study. METHODS Thirteen patients (24 ears) with EVA, 17 subjects (29 ears) with normal hearing, and 17 patients (21 ears) with sensorineural hearing loss without EVA served as experimental subjects. Standard pure-tone audiometry, standard clinical tympanometry (using a 226-Hz probe tone), and multifrequency tympanometry were performed on each ear. Magnetic resonance imaging was used to determine the area of the cochlear modiolus and the volume of the endolymphatic duct and sac. RESULTS The audiometric configurations for most patients sloped downward from the low to the high frequencies. A significant air-bone gap was computed at each of these test frequencies. Multifrequency tympanometry yielded resonance frequencies for the patients with EVA that was significantly lower than those measured for the control subjects. In general, for patients with EVA, the resonance frequency of the middle ear system decreased as the volume of the endolymphatic duct and sac increased. This inverse relation was significant (correlation coefficient = -0.483, P =.0157). However, there was no correlation between resonance frequency and the degree of cochlea modiolar deficiency. CONCLUSIONS Clinically, our findings suggest that EVA probably should be included in the differential diagnosis for a patient who presents with a moderate to severe mixed hearing loss, a normal tympanogram at 226 Hz, and a resonance frequency that is abnormally low.
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Affiliation(s)
- Eisuke Sato
- Department of Otorhinolaryngology, Nagoya University School of Medicine, Japan
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Naganawa S, Iwayama E, Koshikawa T, Fukatsu H, Ishigaki T, Ninomiya A, Aoki I. Virtual endoscopy of the labyrinth, using a 3D-FastASE sequence. J Magn Reson Imaging 2001; 13:792-6. [PMID: 11329203 DOI: 10.1002/jmri.1110] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Virtual endoscopy (VE) of the labyrinth was performed using three-dimensional (3D)-fast asymmetric spin-echo MR imaging. The spatial resolution requirements and the usefulness of zero-fill interpolation (ZIP) were evaluated, and VE was used to examine three patients. The (0.6-mm) voxel data with ZIP satisfies the minimum requirements for VE for evaluation of the complex 3D anatomy and pathology of the labyrinth. J. Magn. Reson. Imaging 2001;13:792-796.
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Affiliation(s)
- S Naganawa
- Department of Radiology, Nagoya University School of Medicine, 65 Tsurumai-cho, Shouwa-ku, Nagoya 466-8550, Japan.
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