[The imaging appearances of stapical footplate fistula related to inner ear malformation].

Objective: To summarize the HRCT and MRI appearances of stapical footplate fistula related to inner ear malformation (SFF-Re-IEM). Methods: The HRCT and MRI materials of 48 cases (53 ears) SFF-Re-IEM were retrospectively analyzed. Among them, 25 SFF-Re-IEM ears were confirmed by surgery. Their CT and MRI findings including associated IEM type, internal auditory canal (IAC) malformation, tympanic fluid, its density and signal features, and accompanied labyrinthitis were recorded. Results: Among 48 cases (53 ears) with SFF-Re-IEM, 17 ears with incomplete partition type Ⅰ, accounting for 32.1%, 13 ears with common cavity for 24.5%, 13 ears with cochlear aplasia for 24.5%, 7 ears with cochlear dysplasia Ⅱ for 13.2%, and 3 ears with Mondini for 5.7%,were found respectively. 94.3% of them were associated with a defect or dysplasia in the found of the IAC. They were divided into 4 types according to the intact of the stapical footplate and accompanied CSF otorrhea: 22 ears were diagnosed as the stapical footplate leaking, of them, 2 ears might come from the stapical footplate bony defect, 6 ears were from the stapical footplate hernia. 1 ear belonged to the peristapical footplate leaking. 30 ears with the isolated the stapical footplate hernia were another found. The bony defect in 2 ears with the stapical footplate bony defect were not presented on CT and MRI.The focal bony defect of the affected stapical footplate of 36 ears with the stapical footplate hernia were demonstrated, which presented the hemispherical protruding into the tympana, the soft-tissue density on CT, and CSF-like signal on the MR heaved-T2WI images. Among 22 ears with the stapical footplate leaking, their imaging appearances varied from the different amount of the leaking CSF. Besides the focal bony defects of the affected stapical footplates, there were much more CSF-like density or signal in the ipsilateral tympanic cavity in 17 affected ears connecting with the vestibule through the defect area. In the CSF leaking ears with less CSF leaking in 5 ears, the CSF-like cysts like SFH were shown on the stapical footplate defect area, but their outer edges were irregular, and the CSF-like signal scattering in the tympanic cavity did not connect with the protruding cysts at the stapical area. Conclusion: The variable appearances of the SFF-Re-IEM ears based on the different subtypes are its characteristic HRCT and MRI appearances. This is helpful for the SFF-Re-IEM diagnosing to grasp its imaging features.

Cochlear Implantation: Small Cochlear Diameter May Indicate Degree of Abnormality.

Cochlear size variation was first reported in 1884, and since then, there have been various reports confirming the same. Yet, there is no single report that has displayed the wide variations in the cochlear size in a single layout capturing the cochlea in the oblique coronal view/ cochlear view. Basal turn diameter (A-value) was measured in the oblique coronal plane using the OTOPLAN® otological preplanning tool in 104 computed tomography (CT) scans of the temporal bones of cochlear implant (CI) recipients in a tertiary CI center. All CT scans with an image resolution of at least 0.5 mm and identified as having cochleae with normal anatomy were included in this study. A 3-dimensional (3D) segmentation was performed using the 3D slicer and visualized to evaluate the impact of cochlear size on the number of turns studied. The A-value was found to vary between 7.3 mm and 10.4 mm among the studied patients. Three-dimensional segmentation of the inner ear revealed only 2 turns of the cochlea in 4 ears, with A-values of 7.3, 8.8, 7.8, and 7.7 mm. One ear had only 11 /2 turns of the cochlea, with an A-value of 7.9 mm. As a further advancement in the assessment of cochlear size as determined by the A-value, 3D segmentation of the complete inner ear provides a full picture of the number of cochlear turns. Three-dimensional segmentation of the entire inner ear could help improve the preoperative planning of CI surgery and have implications for electrode array selection. Cochlear size could be a predictor of the number of cochlear turns, even in cases that look normal from the radiological findings. The findings of this study could help in improving the preoperative planning for a more successful CI surgery by differentiating between the normal and abnormal cochlea.

Evaluation of a Slim Modiolar Electrode Array: A Temporal Bone Study.

HYPOTHESIS: Evaluation of the Slim Modiolar (SM) electrode in temporal bones (TB) will elucidate the electrode's insertion outcomes. BACKGROUND: The SM electrode was designed for atraumatic insertion into the scala tympani, for ideal perimodiolar positioning and with a smaller caliber to minimize interference with cochlear biological processes. METHODS: The SM electrode was inserted into TBs via a cochleostomy. First, the axial force of insertion was measured. Next, TBs were inserted under fluoroscopy to study insertion dynamics, followed by histologic evaluation of electrode placement and cochlear trauma. A subset of TBs were inserted with the Contour Advance (CA) electrode for comparison. RESULTS: Sixteen of 22 insertions performed to measure the axial force of insertion had flat or near zero insertion force profiles. Six insertions had increased insertion forces, which were attributed to improper sheath depth before electrode insertion. Under real-time fluoroscopy, 23 of 25 TBs had uneventful insertion and good perimodiolar placement. There was 1 scala vestibuli insertion due to suboptimal cochleostomy position and 1 tip roll over related to premature electrode deployment. When compared with the CA electrode, 14 of 15 insertions with the SM electrode resulted in a more perimodiolar electrode position. No evidence of trauma was found in histologic evaluation of the 24 TBs with scala tympani insertions. CONCLUSION: TB evaluation revealed that the SM electrode exerts minimal insertion forces on cochlear structures, produces no histologic evidence of trauma, and reliably assumes the perimodiolar position. Nonstandard cochleostomy location, improper sheath insertion depth, or premature deployment of the electrode may lead to suboptimal outcomes.

Automatic localization of cochlear implant electrodes using cone beam computed tomography images.

BACKGROUND: Cochlear implants (CI) are implantable medical devices that enable the perception of sounds and the understanding of speech by electrically stimulating the auditory nerve in case of inner ear damage. The stimulation takes place via an array of electrodes surgically inserted in the cochlea. After CI implantation, cone beam computed tomography (CBCT) is used to evaluate the position of the electrodes. Moreover, CBCT is used in research studies to investigate the relationship between the position of the electrodes and the hearing outcome of CI user. In clinical routine, the estimation of the position of the CI electrodes is done manually, which is very time-consuming. RESULTS: The aim of this study was to optimize procedures of automatic electrode localization from CBCT data following CI implantation. For this, we analyzed the performance of automatic electrode localization for 150 CBCT data sets of 10 different types of electrode arrays. Our own implementation of the method by Noble and Dawant (Lecture notes in computer science (Including subseries lecture notes in artificial intelligence and lecture notes in bioinformatics), Springer, pp 152-159, 2015. https://doi.org/10.1007/978-3-319-24571-3_19 ) for automated electrode localization served as a benchmark for evaluation. Differences in the detection rate and the localization accuracy across types of electrode arrays were evaluated and errors were classified. Based on this analysis, we developed a strategy to optimize procedures of automatic electrode localization. It was shown that particularly distantly spaced electrodes in combination with a deep insertion can lead to apical-basal confusions in the localization procedure. This confusion prevents electrodes from being detected or assigned correctly, leading to a deterioration in localization accuracy. CONCLUSIONS: We propose an extended cost function for automatic electrode localization methods that prevents double detection of electrodes to avoid apical-basal confusions. This significantly increased the detection rate by 11.15 percent points and improved the overall localization accuracy by 0.53 mm (1.75 voxels). In comparison to other methods, our proposed cost function does not require any prior knowledge about the individual cochlea anatomy.

Superior Canal Dehiscence and the Risk of Additional Dehiscences: A Retrospective CT Cohort Study.

OBJECTIVE: Determine if superior canal dehiscence (SCD) found on flat-panel CT increases the risk for other defects in the otic capsule. STUDY DESIGN: Retrospective cohort study. SETTING: Tertiary care center. PATIENTS: One hundred ears (50 with SCD and 50 matched controls without SCD). INTERVENTIONS: Flat-panel CT imaging. MAIN OUTCOME MEASURES: (1) Prevalence of other dehiscences in SCD ears, (2) dehiscences in controls, and (3) otic capsule thickness in other reported dehiscence locations (cochlea-carotid, lateral semicircular canal [SCC] and mastoid, facial nerve-lateral SCC, vestibular aqueduct, posterior SCC-jugular bulb, posterior SCC-posterior fossa). Between-group comparisons were considered significant at p < 0.007 after applying the Bonferroni correction for multiple comparisons. RESULTS: Not including the SCD, there was a mean of 0.04 additional dehiscences in the SCD group (n = 2/50, 4%) and 0.04 non-SCD dehiscences in the controls (n = 2/50, 4%, p > 0.007). In the SCD group, there was one dehiscence between the cochlea and carotid artery and one between the posterior SCC and posterior fossa. The control group had one enlarged vestibular aqueduct and one dehiscence between the facial nerve and lateral SCC. As a group, SCD ears had wider vestibular aqueducts (0.68 ± 0.20 vs 0.51 ± 0.30 mm, p < 0.007) and thinner bone between the posterior SCC and posterior fossa (3.12 ± 1.43 vs 4.34 ± 1.67 mm, p < 0.007). The bone between the facial nerve and lateral SCC was thicker in SCD ears (0.77 ± 0.23 vs 0.55 ± 0.27 mm, p < 0.007) and no different for cochlea-carotid, and lateral SCC and mastoid (p > 0.007). CONCLUSIONS: SCD does not increase the likelihood of a second dehiscence in the same otic capsule. SCD patients may have congenitally thinner otic capsule bones compared to controls, particularly near the posterior SCC, where the vestibular aqueduct may be enlarged.

Association of audiovestibular findings with fluid-attenuated inversion recovery magnetic resonance imaging in patients with vestibular schwannoma.

BACKGROUND: Vestibular schwannoma (VS) is a benign tumor of the vestibular nerve. Flair-attenuated inversion recovery (FLAIR) of magnetic resonance imaging (MRI) images are sensitive in detecting high protein contents of fluids. OBJECTIVES: To investigate the association between signal intensity (SI) on FLAIR images and audiovestibular findings in patients with VS. METHODS: Medical records of twenty-five patients with VS were retrospectively analyzed. RESULTS: Larger tumors were associated with increased FLAIR SI of the cochlea, vestibule, and semicircular canal (SCC) on the affected side compared to those of the unaffected side. Pure-tone audiometry (PTA), and speech audiometry were associated with the SI of the affected cochlea. There was no significant correlation between the SI of the vestibule and vestibular evoked myogenic potential, SI of the SCC, and caloric test or video head impulse test results. CONCLUSION: Our study suggests that tumor size was significantly associated with high SI on FLAIR imaging, and audiological findings were associated with the SI of the affected cochlea. Further studies with larger cohorts are required to confirm the association between vestibular function and FLAIR imaging in VS.

Reduced Cochlear MRI Signal and Hearing Outcomes in Conservatively Managed Vestibular Schwannoma Patients.

OBJECTIVE: This study aimed to determine if hypointense cochlear magnetic resonance imaging (MRI) constructive interference in steady-state (CISS) signal correlates with hearing outcomes in conservatively managed vestibular schwannoma (VS) patients. STUDY DESIGN: Retrospective review of 657 cases from 1992 to 2020. SETTING: Tertiary academic referral center. PATIENTS: A retrospective review was performed to identify conservatively managed VS patients with appropriate baseline MRI, audiology, and at least 12-month audiological follow-up. Patients were excluded if they progressed to surgery or radiotherapy in less than 12 months, bilateral tumors, or surgery on the contralateral ear. INTERVENTION: Conservatively managed patients with CISS imaging studies and audiology testing. MAIN OUTCOME MEASURES: Primary outcome measure change in pure-tone average (PTA) and word recognition score (WRS). Secondary outcome measures tumor size, presence of lateral fluid cap, or cystic changes. RESULTS: A total of 92 individuals (47% male, 58 ± 11.6 yr) met the inclusion criteria, with 36 (39%) of patients demonstrating abnormal cochlear CISS signal. At baseline, abnormal cochlear CISS signal was associated with higher intracanalicular (IC) length (7.9 versus 6.6 mm, p = 0.0177) and lower WRS (55.7 versus 78.8 dBHL, p = 0.0054). During follow-up, individuals with abnormal cochlear CISS signal had significantly higher PTA (62.4 versus 46.4 dBHL, p = 0.0010). After adjusting for baseline covariates, abnormal cochlear CISS signal was consistently associated with a greater increase in PTA of 8.3 dBHL (95% confidence interval, 2.9-13.7; p = 0.0032) from baseline when compared with the normal group. CONCLUSIONS: Abnormal cochlear signal on MRI CISS sequences is associated with poorer hearing outcomes in conservatively managed VS patients.

Cochlear implantation for rare Streptococcus suis meningitis with hearing loss.

OBJECTIVES: This study aimed to explore the diagnostic sensitivity of 3D heavily weighted T2-weighted MRI (T2MRI) and high-resolution computed tomography (HRCT) in patients with cochlear fibrosis associated with Streptococcus suis (S. suis) meningitis and the practicality of Cochlear implantation (CI) treatments. METHODS: Between January 2020 and December 2022, we enrolled four patients with rare cochlear S. suis meningitis with associated hearing loss despite aggressive or non-aggressive follow-up antibiotic treatment. Clinical imaging data, surgical performances and post-surgical-electrode impedance were evaluated. RESULTS: Combined with HRCT and T2MRI, the cochlea had varying degrees of fibrosis and ossification in different cases. However, the electrodes were successfully and wholly inserted after intraoperative removal of the ossified and fibrotic foci. Post-surgical electrode impedance values of MP1 + 2 mode were normal in all 4 cases at initial activation. CONCLUSION: In patients with S. suis meningitis and associated cochlear fibrosis, T2MRI examination of the inner ear was more sensitive than HRCT. This research highlights the feasibility of CI treatment in S. suis meningitis patients with severe cochlear fibrosis.

Importance of preoperative HRCT temporal bone in the orientation of the cochlea and its relation to intra-operative difficulties in cochlear implantation - predicting the grades of difficulty.

OBJECTIVE: This study emphasizes the role of preoperative high-resolution computed tomography (HRCT) temporal bone in evaluating the variation in cochlear orientation and proposes a grading system to determine the level of intraoperative difficulties encountered. METHODS: Preoperative correlation of middle ear and inner ear structures along with the basal turn angle (BTA) was done to assess the orientation. Patients were divided into three groups depending on BTA and radiology findings. RESULTS: Group A (BTA = 55°-60°) had statistically significant (p < 0.05) correlation between middle ear to inner ear structures on HRCT, whereas group B (BTA >60°) and C (BTA <55°) had variations in the alignment of middle ear structures to their corresponding inner ear structures. CONCLUSION: The association of BTA to the correlation between middle ear and inner ear structures can determine the orientation of the cochlea. This evaluation makes the surgeon aware of intraoperative challenges and helps in surgical planning.

[Comprehensive literature review on the application of the otological-surgical planning software OTOPLAN® for cochlear implantation. German version]. / Umfassender Literaturüberblick über die Anwendung der otologisch-chirurgischen Planungssoftware OTOPLAN® bei der Cochleaimplantation.

BACKGROUND: The size of the human cochlear, measured by the diameter of the basal turn, varies between 7 and 11 mm. For hearing rehabilitation with cochlear implants (CI), the size of the cochlear influences the individual frequency map and the choice of electrode length. OTOPLAN® (CAScination AG [Bern, Switzerland] in cooperation with MED-EL [Innsbruck, Austria]) is a software tool with CE marking for clinical applications in CI treatment which allows for precise pre-planning based on cochlear size. This literature review aims to analyze all published data on the application of OTOPLAN®. MATERIALS AND METHODS: The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were applied to identify relevant studies published in the PubMed search engine between January 2015 and February 2023 using the search terms "otoplan" [title/abstract] OR "anatomy-based fitting" [title/abstract] OR "otological software tool" [title/abstract] OR "computed tomography-based software AND cochlear" [title/abstract]. RESULTS: The systematic review of the literature identified 32 studies on clinical use of OTOPLAN® in CI treatment. Most studies were reported from Germany (7 out of 32), followed by Italy (5), Saudi Arabia (4), the USA (4), and Belgium (3); 2 studies each were from Austria and China, and 1 study from France, India, Norway, South Korea, and Switzerland. In the majority of studies (22), OTOPLAN® was used to assess cochlear size, followed by visualizing the electrode position using postoperative images (5), three-dimensional segmentation of temporal bone structures (4), planning the electrode insertion trajectory (3), creating a patient-specific frequency map (3), planning of a safe drilling path through the facial recess (3), and measuring of temporal bone structures (1). CONCLUSION: To date, OTOPLAN® is the only DICOM viewer with CE marking in the CI field that can process pre-, intra-, and postoperative images in the abovementioned applications.

High Prevalence of Cochlear Nerve Deficiency in Pediatric Patients With Cochlear Aperture Stenosis.

OBJECTIVE: Cochlear nerve deficiency (CND) is a common radiologic finding among unilateral sensorineural hearing loss (USNHL) patients. It is generally detected with magnetic resonance imaging (MRI), which is associated with higher cost, less availability, and possible need for sedation. Therefore, identifying computed tomography (CT) findings, such as cochlear aperture stenosis (CAS), that can reliably predict CND is valuable. Our study aimed to determine the prevalence of CND in pediatric patients with CT-diagnosed CAS. STUDY DESIGN: Retrospective study. SETTING: Tertiary care center. METHODS: We included pediatric patients diagnosed with CAS on temporal bone CT and with available temporal bone MRI. For each patient, an otolaryngologist and a pediatric neuroradiologist measured the cochlear aperture width on CT to confirm CAS (cochlear aperture < 1.4 mm) and assessed the status of the cochlear nerve on MRI. RESULTS: Fifty-five patients, representing 65 ears, had CAS on CT measurement. Median cochlear aperture width in CAS ears was 0.70 mm (interquartile range [IQR]: 0.40-1.05 mm) versus 2.00 mm in non-CAS ears (IQR: 1.80-2.30 mm, P < .001). CND was found in 98.5% (n = 64/65) of CAS ears, while a normal cochlear nerve was found in 1.5% (n = 1/65) of CAS ears. CONCLUSION: CND is highly prevalent among pediatric patients with CAS. This suggests that MRI may not be needed to assess for CND in USNHL patients with CAS, as initial CT may provide sufficient information to determine cochlear implant candidacy. We recommend thoughtful shared decision-making with parents of USNHL patients when determining whether to pursue MRI in the setting of a CAS diagnosis.

Preoperative Imaging in Cochlear Implants.

OBJECTIVE: To determine the utility of computed tomography (CT) and magnetic resonance imaging (MRI) in cochlear implant candidates. STUDY DESIGN: Retrospective case review. SETTING: Tertiary referral hospital. PATIENTS: A total of 207 cochlear implanted patients with CT and/or MRI. INTERVENTIONS: N/A. MAIN OUTCOME MEASURES: Age versus abnormal radiologic findings, imaging abnormality versus postoperative outcomes, postoperative outcomes versus electrode design, Cambridge Cochlear Implant Protocol (CCIP) status for imaging abnormalities, sensitivity and specificity of CT and MRI for round-window/cochlear occlusion, and MRI for incomplete partitions. RESULTS: A total of 207 patients with CT, MRI, or both were reviewed retrospectively. Less than half (15.5%) of CT scans had findings that might affect surgical intervention compared with 5.9% of MRI. No significant difference was found between children and adults for relevant imaging abnormalities (grade 4 or higher) with either CT (p = 0.931) or MRI (p = 0.606). CCIP status correlated with cochlear abnormalities (p = 0.040); however, only 46.2% of radiographic abnormalities on CT would be identified by these criteria. For detecting cochlear occlusion requiring surgical intervention, the sensitivity and specificity for CT were 40% (4 of 10; 95% confidence interval [CI], 12.16-73.76) and 95.73% (95% CI, 91.40-98.27), respectively. For MRI, the sensitivity and specificity were 33.33% (1 of 3; 95% CI, 0.84-90.57) and 96.97% (63 of 65; 95% CI, 89.32-99.63), respectively. There was no difference for postoperative AzBio scores for higher-grade imaging abnormalities (p = 0.6012) or for electrode designs (p = 0.3699). CONCLUSIONS: Significant radiographic abnormalities were relatively uncommon in cochlear implant patients on either CT or MRI at our single-center institution. If present, abnormal imaging findings rarely translated to management changes. CCIP status does not reliably predict which patients are likely to have abnormalities. Both MRI and CT have low sensitivity for round-window or cochlear occlusion, but detection likely leads to changes in surgical management.

A novel radiomics nomogram based on T2-sampling perfection with application-optimized contrasts using different flip-angle evolutions (SPACE) images for predicting cochlear and vestibular endolymphatic hydrops in Meniere's disease patients.

OBJECTIVES: To construct and validate a radiomics nomogram based on T2-sampling perfection with application-optimized contrasts using different flip-angle evolutions (SPACE) images for predicting cochlear and vestibular endolymphatic hydrops (EH) in Meniere's disease patients. METHODS: A total of 156 patients (312 affected ears) with bilateral definite Meniere's disease who underwent delayed enhancement MRI scans were enrolled in this study. All ears of the patients were divided into a training set (n = 218) and an internal validation set (n = 94). A radiomics nomogram was constructed from radiomics features extracted from the T2-SPACE images, and a radiomics score was calculated. Performance of the radiomics nomogram was assessed using receiver operating characteristics analysis. RESULTS: Five features were selected for the construction of the cochlear radiomics nomogram, and seven features for the vestibular radiomics nomogram. The radiomics nomograms exhibited robust performance in differentiating between EH-positive and EH-negative statuses in both training and validation cohorts, with the area under the receiver operating characteristics curve values for cochlear and vestibular radiomic nomograms being 0.703 and 0.728 in the training set, and 0.718 and 0.701 in the validation set, respectively. CONCLUSION: The novel radiomics nomograms based on T2-SPACE images were successfully constructed to predict cochlear and vestibular EH in Meniere's disease. The models showed a solid and superior performance and may play an important role in the EH prediction. CLINICAL RELEVANCE STATEMENT: We constructed a novel radiomics nomogram, which can be a very useful tool for predicting cochlear and vestibular endolymphatic hydrops in Meniere's disease patients. KEY POINTS: • This is the first T2-SPACE-based nomogram to predict cochlear and vestibular endolymphatic hydrops. • The nomogram is of great value to patients who are unable to undergo delayed enhancement MRI scans.

OCT-based intra-cochlear imaging and 3D reconstruction: ex vivo validation of a robotic platform.

PURPOSE: The small size of the cochlea, and its location deeply embedded in thick temporal bone, poses a challenge for intra-cochlear guidance and diagnostics. Current radiological imaging techniques are not able to visualize the cochlear microstructures in detail. Rotational optical coherence tomography (OCT) fibers show great potential for intra-cochlear guidance. The generated images could be used to map, and study, the tiny cochlear microstructures relevant for hearing. METHODS: This work describes the design of a rotational OCT probe with an outer diameter of 0.9 mm. It further discusses a robotic system, which features a remote center of motion mechanism, dedicated to the probe's positioning, fine manipulation and stable insertion into the cochlear micro-spaces. Furthermore, the necessary calibration steps for 3D reconstruction are described, followed by a detailed quantitative analysis, comparing the 3D reconstructions using a synthetic, 2:1 scaled scala tympani model with a reconstruction from micro-CT, serving as the ground truth. Finally, the potential of the system is demonstrated by scanning a single ex vivo cadaveric human cochlea. RESULTS: The study investigates five insertions in the same 2:1 scaled tympani model, along with their corresponding 3D reconstruction. The comparison with micro-CT results in an average root-mean-square error of 74.2 µm, a signed distance error of 38.1 µm and a standard deviation of 63.6 µm. The average F-score of the reconstructions, using a distance threshold of 100 and 74.2 µm, resulted in 83.0% and 71.8%, respectively. Insertion in the cadaveric human cochlea showed the challenges for straight insertion, i.e., navigating the hook region. CONCLUSION: Overall, the system shows great potential for intra-cochlear guidance and diagnostics, due to the system's capability for precise and stable insertion into the basal turn in the scala tympani. The system, combined with the calibration procedure, results in detailed and precise 3D reconstructions.

Is the Position of the Basal-Most Electrode Depending on Electrode Array Design and Influencing Postoperative Speech Perception? A Retrospective Analysis of 495 Ears.

OBJECTIVE: The objective of this study is to examine the influence of electrode array design on the position of the basal-most electrode in cochlear implant (CI) surgery and therefore the stimulability of the basal cochlea. Specifically, we evaluated the angular insertion depth of the basal-most electrode in perimodiolar and straight electrode arrays in relation to postoperative speech perception. MATERIALS AND METHODS: We conducted a retrospective analysis of 495 patients between 2013 and 2018 using the Cochlear™ Contour Advance® (CA), Cochlear™ Slim Straight® (SSA), or Cochlear™ Slim Modiolar® (SMA) electrode arrays, as well as the MED-EL Flex24 (F24), MED-EL Flex28 (F28), and MED-EL FlexSoft (F31.5) electrode arrays. Cochlear size and the position of the basal-most electrode were measured using rotational tomography or cone beam computed tomography, and the results were compared with postoperative speech perception in monosyllables and numbers. RESULTS: The straight electrode arrays, specifically the F31.5 (31.5 mm length) and the F28 (28 mm length), exhibited a significantly greater angular insertion depth of the basal-most electrode. No significant correlation was found between cochlear morphology measurements and the position of the basal-most electrode artifact. Cochleostomy-inserted electrode arrays showed a significantly higher insertion depth of the basal-most electrode. Nevertheless, the position of the basal-most electrode did not have a significant impact on postoperative speech perception. CONCLUSION: Straight electrode arrays with longer lengths achieved deeper angular insertion depths of the basal-most electrode. Cochlear morphology does not have a substantial influence on the position of basal-most electrode. The study confirms that the basal area of the cochlea, responsible for high-frequency range during acoustic stimulation, is not the primary region for speech understanding via electrical stimulation with CI.

Cochleo-carotid dehiscence as a third window syndrome: a review of an unusual presentation and its clinical-radiological approach / Dehiscencia cócleo-carotídea como síndrome de la tercera ventana: una revisión de una presentación inusual y su enfoque clínico-radiológico

When examining patients who present both fluctuating auditory symptoms and vestibular symptoms, which can be mistaken for an ear disease, it is important to consider cochlear-carotid fistula as a condition that could generate these clinical manifestations. In this case, additional imaging tests should be performed to demonstrate the lack of continuity at that level and rule out other entities. The objective is to describe the cochleo-carotid dehiscence in a 39-year-old woman and propose it as a possible etiology of a third window syndrome, in order to discuss the relationship between clinical findings, neurotologic examination, and magnetic resonance imaging.

Al examinar a pacientes que presentan síntomas auditivos fluctuantes y síntomas vestibu-lares, que pueden ser confundidos con una enfermedad del oído, es importante considerar la fístula coclear-carotídea como una condición que podría generar estas manifestaciones clínicas. En este caso, se deben realizar pruebas de imagen adicionales para demostrar la falta de continuidad en ese nivel y descartar otras entidades. El objetivo es describir la dehiscencia cocleo-carotídea en una mujer de 39 años y proponerla como una posible etiología del síndrome de la tercera ventana, con el fin de discutir la relación entre los hallazgos clínicos, el examen neurotológico y la resonancia magnética.

Machine learning-based prediction of the outcomes of cochlear implantation in patients with inner ear malformation.

OBJECTIVE: The objectives of this study are twofold: first, to visualize the structure of malformed cochleae through image reconstruction; and second, to develop a predictive model for postoperative outcomes of cochlear implantation (CI) in patients diagnosed with cochlear hypoplasia (CH) and incomplete partition (IP) malformation. METHODS: The clinical data from patients diagnosed with cochlear hypoplasia (CH) and incomplete partition (IP) malformation who underwent cochlear implantation (CI) at Beijing Tongren Hospital between January 2016 and August 2020 were collected. Radiological features were analyzed through 3D segmentation of the cochlea. Postoperative auditory speech rehabilitation outcomes were evaluated using the Categories of Auditory Performance (CAP) and the Speech Intelligibility Rating (SIR). This study aimed to investigate the relationship between cochlear parameters and postoperative outcomes. Additionally, a predictive model for postoperative outcomes was developed using the K-nearest neighbors (KNN) algorithm. RESULTS: In our study, we conducted feature selection by using patients' imaging and audiological attributes. This process involved methods such as the removal of missing values, correlation analysis, and chi-square tests. The findings indicated that two specific features, cochlear volume (V) and cochlear canal length (CDL), significantly contributed to predicting the outcomes of hearing and speech rehabilitation for patients with inner ear malformations. In terms of hearing rehabilitation, the KNN classification achieved an accuracy of 93.3%. Likewise, for speech rehabilitation, the KNN classification demonstrated an accuracy of 86.7%. CONCLUSION: The measurements obtained from the 3D reconstruction model hold significant clinical relevance. Despite the considerable variability in cochlear morphology across individuals, radiological features remain effective in predicting cochlear implantation (CI) prognosis for patients with inner ear malformations. The utilization of 3D segmentation techniques and the developed predictive model can assist surgeons in conducting preoperative cochlear structural measurements for patients with inner ear malformations. This, in turn, can offer a more informed perspective on the anticipated outcomes of cochlear implantation.

Cochlear-facial dehiscence - the most common cause of facial nerve stimulation from a cochlear implant? A case-control study.

Objectives: To investigate the prevalence of cochlear-facial dehiscence (CFD) and other radiographical pathologies in ears with facial nerve stimulation (FNS) from a cochlear implant (CI). Methods: Retrospective case-control study of 27 patients with CI and FNS on either ear (study group) and 27 patients without FNS, matched for age, sex and type of electrode array (control group). Preoperative CT scans of all 108 ears were re-evaluated. Subanalyses included comparisons between the study and control groups and associations between FNS and radiographic pathologies. Results: CFDs were detected in 20 of 54 ears (37%) in the study group and in 3 of 54 ears (6%) in the control group (P < 0.001). The corresponding numbers of otosclerosis were 10 (18%) and 0 (P = 0.011) and of developmental anomalies 16 (30%) and 8 (15%) (not significant). FNS was present in 33 ears in the study group, of which 14 (42%) had a CFD. FNS was absent in six ears with CFD and CI, four of which contralateral to an ear with FNS. Eight of 14 ears with FNS and CFD had a lateral electrode array and six had a perimodiolar electrode array. We found no association between the presence of CFD and stimulation thresholds for FNS. The adjusted odds ratio for developing FNS in the presence of a CFD was 9.9 (95% CI 2.7-36.0). Conclusions: CFD was the most common radiographic pathology in ears with FNS, with a 10-fold increased risk of FNS. To avoid CI-related FNS, preoperative CT scan and awareness of typical dehiscence symptoms are strongly recommended.

Patterns of Signal Intensity in CISS MRI of the Inner Ear and Eye.

BACKGROUND: Constructive interference in steady state (CISS) is a gradient echo magnetic resonance imaging (MRI) pulse sequence that provides excellent contrast between cerebrospinal fluid and adjacent structures but is prone to banding artifacts due to magnetic field inhomogeneities. We aimed to characterize artifacts in the inner ear and eye. METHODS: In 30 patients (60 ears/eyes) undergoing CISS sequence MRI, nine low-signal intensity regions were identified in the inner ear and compared to temporal bone histopathology. The number and angle of bands across the eye were examined. RESULTS: In the cochlea, all ears had regions of low signal corresponding to anatomy (modiolus (all), spiral lamina (n = 59, 98.3%), and interscalar septa (n = 50, 83.3%)). In the labyrinth, the lateral semicircular canal crista (n = 42, 70%) and utricular macula (n = 47, 78.3%) were seen. Areas of low signal in the vestibule seen in all ears may represent the walls of the membranous utricle. Zero to three banding artifacts were seen in both eyes (right: 96.7%, mean 1.5; left: 93.3%, mean 1.3). CONCLUSION: Low signal regions in the inner ear on CISS sequences are common and have consistent patterns; most in the inner ear represent anatomy, appearing blurred due to partial volume averaging. Banding artifacts in the eye are more variable.