On the accuracy of cochlear duct length measurement in computed tomographic images

Lexow, G. Jakob; Kluge, Mathias; Gellrich, Nils‐Claudius; Lenarz, Thomas; Majdani, Omid; Rau, Thomas S.

doi:10.1007/s00405-018-4930-7

Cited by 19 publications

(22 citation statements)

References 23 publications

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“…A general problem with manual measurements of the basal turn parameters is the inter- and intra-user variability 20,21 : with the proposed approach, the user is still required to manually measure A and B. Rivas et al 20 investigated the variability in manual A value assessments and found mean absolute deviations of 0.22 mm to an automated reference approach. In case of average values A = 9.04 mm and B = 6.33 mm, 8 this mean variability would yield deviations of the BTL (according to equation 1) up to 0.7 mm.…”

Section: Discussionmentioning

confidence: 99%

A Novel Method for Clinical Cochlear Duct Length Estimation toward Patient‐Specific Cochlear Implant Selection

et al. 2018

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ObjectiveIn the field of cochlear implantation, the current trend toward patient-specific electrode selection and the achievement of optimal audiologic outcomes has resulted in implant manufacturers developing a large portfolio of electrodes. The aim of this study was to bridge the gap between the known variability of cochlea length and this electrode portfolio.DesignRetrospective analysis on cochlear length and shape in micro–computed tomography and cone beam computed tomography data.SettingTertiary care medical center.Subjects and MethodsA simple 2-step approach was developed to accurately estimate the individual cochlear length as well as the projected length of an electrode array inside the cochlea. The method is capable of predicting the length of the cochlea and the inserted electrode length at any specific angle. Validation of the approach was performed with 20 scans of human temporal bones (micro–computed tomography) and 47 pre- and postoperative clinical scans (cone beam computed tomography).ResultsMean ± SD absolute errors in cochlear length estimations were 0.12 ± 0.10 mm, 0.38 ± 0.26 mm, and 0.71 ± 0.43 mm for 1, 1.5, and 2 cochlea turns, respectively. Predicted insertion angles based on clinical cone beam computed tomography data showed absolute deviations of 27° ± 18° to the corresponding postoperative measurements.ConclusionWith accuracy improvements of 80% to 90% in comparison with previously proposed approaches, the method is well suited for the use in individualized cochlear implantation.

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Section: Discussionmentioning

confidence: 99%

A Novel Method for Clinical Cochlear Duct Length Estimation toward Patient‐Specific Cochlear Implant Selection

et al. 2018

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“…A landmark was finally set every 30° to 60°. 14 , 15 The whole enrolled cochlea is presented by the software in an additional window. Herein, the CDL (A to C) and the 2TL (A to B; Figure 1 , D and D ′ ) were measured in millimeters.…”

Section: Methodsmentioning

confidence: 99%

Cochlear Duct Length Measurements in Computed Tomography and Magnetic Resonance Imaging Using Newly Developed Techniques

Taeger¹,

Müller-Graff²,

Ilgen³

et al. 2021

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Objective Growing interest in measuring the cochlear duct length (CDL) has emerged, since it can influence the selection of cochlear implant electrodes. Currently the measurements are performed with ionized radiation imaging. Only a few studies have explored CDL measurements in magnetic resonance imaging (MRI). Therefore, the presented study aims to fill this gap by estimating CDL in MRI and comparing it with multislice computed tomography (CT). Study Design Retrospective data analyses of 42 cochleae. Setting Tertiary care medical center. Methods Diameter (A value) and width (B value) of the cochlea were measured in HOROS software. The CDL and the 2-turn length were determined by the elliptic circular approximation (ECA). In addition, the CDL, the 2-turn length, and the angular length were determined via HOROS software by the multiplanar reconstruction (MPR) method. Results CDL values were significantly shorter in MRI by MPR ( d = 1.38 mm, P < .001) but not by ECA. Similar 2-turn length measurements were significantly lower in MRI by MPR ( d = 1.67 mm) and ECA ( d = 1.19 mm, both P < .001). In contrast, angular length was significantly higher in MRI ( d = 26.79°, P < .001). When the values were set in relation to the frequencies of the cochlea, no clinically relevant differences were estimated (58 Hz at 28-mm CDL). Conclusion In the presented study, CDL was investigated in CT and MRI by using different approaches. Since no clinically relevant differences were found, diagnostics with radiation may be omitted prior to cochlear implantation; thus, a concept of radiation-free cochlear implantation could be established.

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“…Eight (13%) studies employed direct histology, 10 (15%) employed indirect methods, 37 (57%) employed spiral coefficients, and 10 (15%) used 3D reconstructions. In addition, three studies measured the LW length and "A" values, 29,32,68 whereas three studies measured OC length and "A" values. 11,34,64…”

Section: Study Characteristics and Summary Measuresmentioning

confidence: 99%

Comprehensive Analysis of Factors Affecting Cochlear Size: A Systematic Review and Meta‐analysis

et al. 2021

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Objectives To determine the cochlea's average size in humans and evaluate the relationships between certain covariates and cochlear size. Methods A systematic search on articles on cochlear size and published in English was conducted using Cochrane, PubMed, Web of Science, and Scopus databases up to September 15, 2020. Data were pooled using random‐effects with three models. The effect of demographic, clinical, and measurement‐related parameters was specifically analyzed. Meta‐regression and subgroup analyses were conducted. The overall effect estimation was made for outcomes. Results The meta‐analysis included 4,708 cochleae from 56 studies. The overall length of the organ of Corti was 32.94 mm (95% confidence interval [CI]: 32.51–33.38). The first and second models revealed that age, gender, country, continent, measurement method (direct, indirect), measured structure (“A” value, cochlear lateral wall), origin (in vivo, in vitro), and type (histology specimens, plastic casts, imaging) of the cochlear material did not affect the cochlear size. However, study populations (general population, patients with a cochlear implant, and patients with congenital sensorineural hearing loss [CSNHL]) were found to affect the outcomes. Compared to the other populations, patients with CSNHL had shorter cochleae. Therefore, we developed a third model and found that the general population and patients with cochlear implants did not differ in cochlear size. Conclusion This meta‐analysis investigated the factors that could affect the cochlear size and found that patients with CSNHL had significantly shorter cochleae, whereas other covariates had no significant effect. Laryngoscope, 132:188–197, 2022

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On the accuracy of cochlear duct length measurement in computed tomographic images

Cited by 19 publications

References 23 publications

A Novel Method for Clinical Cochlear Duct Length Estimation toward Patient‐Specific Cochlear Implant Selection

A Novel Method for Clinical Cochlear Duct Length Estimation toward Patient‐Specific Cochlear Implant Selection

Cochlear Duct Length Measurements in Computed Tomography and Magnetic Resonance Imaging Using Newly Developed Techniques

Comprehensive Analysis of Factors Affecting Cochlear Size: A Systematic Review and Meta‐analysis

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