Exploration of different electrode types inserted in a 3D model of a patient with incomplete partition type III inner ear malformation.

BACKGROUND: Incomplete partition type III (IP III) represents a rare malformation of the inner ear, posing challenges during cochlear implantation due to inevitable cerebrospinal fluid (CSF) leaks and the potential misplacement of electrodes within the internal auditory canal (IAC). Despite the absence of a consensus on electrode selection, literature suggests both straight and perimodiolar electrodes as viable options for proper insertion. Limited implantation series contribute to the ambiguity in electrode choice. In this study, we evaluated the insertion performance of three electrode types in a 3D model simulating an IP III patient's inner ear. METHODS: A 3D model replicating the inner ear of a patient with IP III undergoing surgery was created, incorporating a canal wall up mastoidectomy and an enlarged round window approach. Insertions were carried out using a straight electrode, a perimodiolar electrode, and a slim perimodiolar electrode, inserted through a sheath in the basal turn of the cochlea. Electrode positions were assessed after each insertion, with each type being tested 20 times. RESULTS: Successful insertion rates were 95 % for the slim perimodiolar electrode, 85 % for the perimodiolar electrode, and 75 % for the slim straight electrode. Notably, the slim perimodiolar electrode required an adapted insertion technique due to the altered cochlear position in IP III cases. Statistical analysis revealed the slim perimodiolar electrode's superiority over the slim straight electrode in achieving successful insertions. CONCLUSIONS: The 3D model of the IP III inner ear proved to be an effective tool for electrode testing and insertion training prior to surgery. Following multiple insertions in the 3D model, the slim perimodiolar electrode demonstrated the highest success rate, emphasizing its potential as the preferred choice for cochlear implantation in IP III cases.

Variability in Inner Ear Morphology Among a Family With Pendred Syndrome Due to a SLC26A4 Gene Variant.

OBJECTIVES: Pendred syndrome, an autosomal recessive disorder, is often associated with pathogenic variants of the SLC26A4 gene that encodes the pendrin protein. Given its autosomal recessive inheritance, tracing the family history and screening siblings become crucial once a diagnosis of Pendred syndrome is confirmed. This case report aims to underscore the variability in inner ear morphology within a family diagnosed with Pendred syndrome, all carrying the same SLC26A4 gene mutation. METHODS: A chart review and a review of the literature. RESULTS: We present a family of 4, all of whom possess sensorineural hearing loss due to the same homozygous SLC26A4 variant c.919-2A>G. Intriguingly, clinical manifestations, especially inner ear deformities, displayed variability among family members. Notably, 1 family member exhibited a normal cochleovestibular structure morphology, which was rarely reported in the literature. CONCLUSIONS: This report highlights the significance of genetic testing and familial consultation when a proband exhibits typical Pendred syndrome symptoms. It also underscores that the inner ear morphology can exhibit variability among family members, even with the same homozygous SLC26A4 variant.

[Deep transfer learning radiomics model based on temporal bone CT for assisting in the diagnosis of inner ear malformations].

Objective:To evaluate the diagnostic efficacy of traditional radiomics, deep learning, and deep learning radiomics in differentiating normal and inner ear malformations on temporal bone computed tomography（CT）. Methods:A total of 572 temporal bone CT data were retrospectively collected, including 201 cases of inner ear malformation and 371 cases of normal inner ear, and randomly divided into a training cohort（n=458） and a test cohort（n=114） in a ratio of 4∶1. Deep transfer learning features and radiomics features were extracted from the CT images and feature fusion was performed to establish the least absolute shrinkage and selection operator. The CT results interpretated by two chief otologists from the National Clinical Research Center for Otorhinolaryngological Diseases served as the gold standard for diagnosis. The model performance was evaluated using receiver operating characteristic（ROC）, and the accuracy, sensitivity, specificity, and other indicators of the models were calculated. The predictive power of each model was compared using the Delong test. Results:1 179 radiomics features were obtained from traditional radiomics, 2 048 deep learning features were obtained from deep learning, and 137 features fusion were obtained after feature screening and fusion of the two. The area under the curve（AUC） of the deep learning radiomics model on the test cohort was 0.964 0（95%CI 0.931 4-0.996 8）, with an accuracy of 0.922, sensitivity of 0.881, and specificity of 0.945. The AUC of the radiomics features alone on the test cohort was 0.929 0（95%CI 0.882 2-0.974 9）, with an accuracy of 0.878, sensitivity of 0.881, and specificity of 0.877. The AUC of the deep learning features alone on the test cohort was 0.947 0（95%CI 0.898 2-0.994 8）, with an accuracy of 0.913, sensitivity of 0.810, and specificity of 0.973. The results indicated that the prediction accuracy and AUC of the deep learning radiomics model are the highest. The Delong test showed that the differences between any two models did not reach statistical significance. Conclusion:The feature fusion model can be used for the differential diagnosis of normal and inner ear malformations, and its diagnostic performance is superior to radiomics or deep learning models alone.

[The value of HRCT in predicting cerebrospinal fluid gusher during cochlear implantation].

Objective:To investigate the predictive value of temporal bone high-resolution CT（HRCT） multiplanar reconstruction（MPR） for cerebrospinal fluid（CSF） gusher during cochlear implantation in patients with inner ear malformation. Methods:The clinical data of 33 patients（36 ears） with inner ear malformation who underwent cochlear implantation were retrospectively analyzed. The predictive value of HRCT for cerebrospinal fluid gusher during cochlear implantation was evaluated. Results:The width of the cochlear foramen（P=0.024, OR=1.735） and the diameter of the inner auditory meatus（P=0.022, OR=6.119） were independent risk factors for CSF gusher during cochlear implantation. The area under the curve（AUC） of cochlear foramen width in predicting intraoperative gusher was 0.851, the sensitivity was 93.33%, and the specificity was 61.90%. The AUC of the upper and lower diameter of the internal auditory canal for predicting intraoperative gusher was 0.848, the sensitivity was 80.00%, and the specificity was 80.95%. The AUC of cochlear foramen width combined with the upper and lower diameters of the internal auditory meatus for predicting intraoperative gusher was 0.930, the sensitivity was 80.00%, and the specificity was 95.24%. Conclusion:Based on temporal bone HRCT, the prediction model of cochlear foramen width combined with the upper and lower diameter of the internal auditory canal has crucial predictive value for the "gusher" during cochlear implantation in patients with inner ear malformation.

Research progress on incomplete partition type 3 inner ear malformation.

PURPOSE: This review aims to provides a comprehensive overview of the latest research progress on IP-III inner ear malformation, focusing on its geneticbasis, imaging features, cochlear implantation, and outcome. METHODS: Review the literature on clinical and genetic mechanisms associated with IP-III. RESULTS: Mutations in the POU3F4 gene emerge as the principal pathogenic contributors to IP-III anomalies, primarily manifesting through inner ear potential irregularities leading to deafness. While cochlear implantation stands as the primary intervention for restoring hearing, the unique nature of the inner ear anomaly escalates the complexity of surgical procedures and postoperative results. Hence, meticulous preoperative assessment to ascertain surgical feasibility and postoperative verification of electrode placement are imperative. Additionally, gene therapy holds promise as a prospective treatment modality. CONCLUSIONS: IP-III denotes X-linked recessive hereditary deafness, with cochlear implantation currently serving as the predominant therapeutic approach. Clinicians are tasked with preoperative assement and individualized postoperative rehabilitation.

A novel radiological software prototype for automatically detecting the inner ear and classifying normal from malformed anatomy.

BACKGROUND: To develop an effective radiological software prototype that could read Digital Imaging and Communications in Medicine (DICOM) files, crop the inner ear automatically based on head computed tomography (CT), and classify normal and inner ear malformation (IEM). METHODS: A retrospective analysis was conducted on 2053 patients from 3 hospitals. We extracted 1200 inner ear CTs for importing, cropping, and training, testing, and validating an artificial intelligence (AI) model. Automated cropping algorithms based on CTs were developed to precisely isolate the inner ear volume. Additionally, a simple graphical user interface (GUI) was implemented for user interaction. Using cropped CTs as input, a deep learning convolutional neural network (DL CNN) with 5-fold cross-validation was used to classify inner ear anatomy as normal or abnormal. Five specific IEM types (cochlear hypoplasia, ossification, incomplete partition types I and III, and common cavity) were included, with data equally distributed between classes. Both the cropping tool and the AI model were extensively validated. RESULTS: The newly developed DICOM viewer/software successfully achieved its objectives: reading CT files, automatically cropping inner ear volumes, and classifying them as normal or malformed. The cropping tool demonstrated an average accuracy of 92.25%. The DL CNN model achieved an area under the curve (AUC) of 0.86 (95% confidence interval: 0.81-0.91). Performance metrics for the AI model were: accuracy (0.812), precision (0.791), recall (0.8), and F1-score (0.766). CONCLUSION: This study successfully developed and validated a fully automated workflow for classifying normal versus abnormal inner ear anatomy using a combination of advanced image processing and deep learning techniques. The tool exhibited good diagnostic accuracy, suggesting its potential application in risk stratification. However, it is crucial to emphasize the need for supervision by qualified medical professionals when utilizing this tool for clinical decision-making.

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.

Long-term outcomes and electrophysiological measures of children with inner ear malformations and cochlear implants.

OBJECTIVES: To compared auditory and speech performance outcomes of children with cochlear implants (CI), between those with inner ear malformations (IEMs) and with normal ear anatomy; and to describe differences in electrophysiological measurements. STUDY DESIGN: A retrospective study. SETTING: A tertiary care pediatric medical center. PATIENTS: Forty-one children with IEMs who underwent CI during 2003-2017, and 41 age-matched CI recipients with normal ear anatomy (control group). MAIN OUTCOME MEASURES: Post-CI auditory performance outcomes including educational setting, Categories of Auditory Performance (CAP), and Speech Intelligibility Rating (SIR); and electrophysiological measurements, Including maximal comfortable electrical levels (CLs) and impedances along CI electrodes. RESULTS: The ANOVA on ranks revealed lower CAP scores in the study than control group: H3 = 18.8, P < 0.001. Among children with IEMs, CAP scores were better in children with enlarged vestibular aqueduct (EVA) (P < 0.04). SIR scores of the control group did not differ from those with isolated EVA; however, SIR scores of the IEMs without EVA subgroup were lower than all the other study subgroups (P < 0.01). The proportion of the control group that was integrated with full inclusion educational settings into the regular mainstream schools was higher than for those with IEMs without EVA (47 % vs. 15 %, P < 0.05), but similar to those with isolated EVA. For the study group versus control group, maximal comfortable electrical levels (CLs) were higher)P > 0.03) while impedance measurements were similar. CONCLUSIONS: Outcomes of pediatric recipients with normal anatomy were better than those with IEMs. Among pediatric recipients of CI with IEMs, auditory performance was better and CLs were lower among children with isolated EVA than all other IEM subgroups.

Evaluation of subarcuate canal on CT images in the perspective of clinical basis.

OBJECTIVES: The aim of our study to contribute to the field of morphometrics by including measurements of the SAC and SAF and their distances from surrounding structures, particularly for surgeons involved in retrosigmoid approach for internal acoustic meatus tumor surgery and cerebellopontine angle surgery. Although there is limited information in the literature regarding the role of the subarcuate fossa (SAF) and subarcuate canal (SAC), it has been suggested that the SAC may be a potential pathway for infection from the middle ear to the posterior cranial fossa, and cerebellar abscesses may have this origin. METHODS: For the images of our study, computerized tomography images of 118 individuals (59 females and 59 males) between the ages of 18-65 who applied to Bayindir Health Group. RESULTS: The width of the cranial opening of the subarcuate canal was determined as 44 ± 0.54 mm, width of the labyrinth opening of the subarcuate canal was determined as 60 ± 0.42 mm, Length of the subarcuate canal was determined as 8.79 ± 2.31 mm, width of the subarcuate canal was determined as 5.54 ± 1.75 mm, and depth of subarcuate fossa was determined as 1.67 ± 0.69 mm. The distance of the cranial opening of the subarcuate canal to the superior semicircular canal (SSC-SAC/C) was measured as 5.33 ± 1.81 mm, The distance of the labyrinth opening of the subarcuate canal to the superior semicircular canal (SSC-SAC/L) was measured as 3.90 ± .98 mm, length of the petrous part of the temporal bone medial to the anterior semicircular canal measured from the apex to the SSCD (PLM) was measured as 33.56 ± 0.42 mm. No statistically significant differences were found between the right and left sides. CONCLUSIONS: The morphometric measurements obtained in this study can provide useful information for neurosurgeons, neurotologist and otolaryngologists involved in retrosigmoid approach for internal acoustic meatus tumor surgery and cerebellopontine angle surgery, and for patients undergoing cochlear implant planning with a retrofacial approach.

Congenital ear malformation (CEM).

BACKGROUND: At present, there are not international unified standards and reports on Congenital Ear Malformation (CEM) in the world, which makes it difficult to transfer information and compare the literature. AIMS/OBJECTIVES: Through the statistical analysis of a large sample of CEM, a unified standard of all aspects of CEM is proposed and the data are provided for reference, which is convenient for the international work and literature comparison in this field. MATERIALS AND METHODS: Based on the author's 30 years of clinical and scientific research work on CEM and the relevant cases of 3231 (4714 ears) in our hospital, and combined with literature, statistical analysis was made. RESULTS: This paper summarizes the classification, definition, epidemiology, embryonic development, pathogenic factors of CEM and elaborates on the clinical manifestations, examination and sequence therapy of representative Congenital Malformation of the Middle and Outer Ear (CMMOE). We also introduce malformation of the auricle and inner ear, so as to cover the outer, middle and inner ear. At the same time, we introduce our achievements and contributions in this field. CONCLUSIONS AND SIGNIFICANCE: This study provides reference to the international unified standard and treatment principle of the CEM.

Imaging Guide to Inner Ear Malformations: An Illustrative Review.

Inner ear malformation (IEM) with associated sensoryneural hearing loss (SNHL) is a major cause of childhood disability. Computed tomography (CT) and magnetic resonance imaging (MRI) imaging play important and often complementary roles in diagnosing underlying structural abnormalities and surgical planning allows for direct visualization of the cochlear nerve and is the preferred imaging modality prior to cochlear implantation. CT is helpful to assess osseous anatomy and when evaluating children with mixed hearing loss or syndromic associations. When reviewing these cases, it is important for the radiologist to be familiar with the key imaging features. In this article, we will present the imaging findings associated with different inner ear malformations associated with congenital sensorineural hearing loss.

Imaging in children with hearing loss. / Bildgebende Diagnostik bei Schwerhörigkeit im Kindesalter.

BACKGROUND: Since the introduction of hearing screening in Germany in 2009, pediatric hearing disorders are detected at an early stage. Early therapy is essential for language development. Imaging plays a central role in diagnosis and therapy planning. METHOD: Imaging findings of the most relevant causes of pediatric hearing disorders are presented. Specific attention is given to the method used in each case - CT or MRI. RESULTS AND CONCLUSIONS: While CT is the method of choice for conductive hearing loss, a combination of CT and MRI with high-resolution T2-3D sequences has been established as the best diagnostic method for sensorineural hearing loss. The most common causes of conductive hearing loss in childhood are chronic inflammation and cholesteatoma. Congenital malformations of the outer or middle ear are less frequent. In the case of sensorineural hearing loss, the cause is located in the inner ear and/or the cochlear nerve or the cerebrum. In these cases, congenital malformations are the most common cause. KEY POINTS: · CT and MRI are necessary to identify morphological causes of hearing disorders and to clarify the possibility of hearing-improving ear surgery or cochlear implantation.. · Contraindications for surgical procedures must be excluded.. · Anatomical variants that may be risk factors for surgery must be described.. CITATION FORMAT: · Sorge I, Hirsch F, Fuchs M et al. Imaging diagnostics for childhood hearing loss. Fortschr Röntgenstr 2023; 195: 896 - 904.

Flocculus Herniation into the Internal Acoustic Canal in Incomplete Partition Type I: A Case Report.

In this study, we present the first case with cerebellar herniation into the internal acoustic canal in incomplete partition type I anomaly. Cerebellar herniation into the internal acoustic canal is very rare with only a few cases reported in the literature. Although it is a rare clinical situation, cerebellar herniation into the internal acoustic canal may be seen in patients with incomplete partition type I. We presented magnetic resonance imaging findings of a 3-year-old girl with a history of meningitis, middle ear effusion, and bilateral congenital sensorineural hearing loss. Magnetic resonance imaging showed bilateral incomplete partition type I malformation and an additional flocculus herniation into the right internal acoustic canal. In the presented case, predisposition to cerebrospinal fluid leak in incomplete partition type I anomaly may be the reason for cerebellar herniation into internal acoustic canal. Also, possible increased intracranial pressure due to meningitis may be a contributing factor.

[Imaging evaluation of cerebrospinal fluid otorrhea associated with inner ear malformation in children].

Objective: To explore the imaging evaluation of cerebrospinal fluid (CSF) otorrhea associated with inner ear malformation (IEM) in children. Methods: The clinical data of 28 children with CSF otorrhea associated with IEM confirmed by surgical exploration in Beijing Children's Hospital, from Nov, 2016 to Jan, 2021, were analyzed retrospectively,including 16 boys and 12 girls, aged from 8-month to 15-year and 8-month old, with a median age of 4-year old. The shapes of stapes were observed during the exploration surgery, and the imaging features of temporal bone high resolution CT(HRCT) and inner ear MRI pre- and post-operation were analyzed. Results: In 28 children with CSF otorrhea, 89.3%(25/28) had stapes footplates defect during exploration. Preoperative CT showed indirect signs such as IEM, tympanic membrane bulging, soft tissue in the tympanum and mastoid cavity. IEM included four kinds: incomplete partition type I (IP-Ⅰ), common cavity (CC), incomplete partition type Ⅱ (IP-Ⅱ), and cochlear aplasia (CA); 100%(28/28) presented with vestibule dilation; 85.7%(24/28) with a defect in the lamina cribrosa of the internal auditory canal. The direct diagnostic sign of CSF otorrrhea could be seen in 73.9%(17/23) pre-operative MRI: two T2-weighted hyperintense signals between vestibule and middle ear cavity were connected by slightly lower or mixed intense T2-weighted signals, and obvious in the coronal-plane; 100%(23/23) hyperintense T2-weighted signals in the tympanum connected with those in the Eustachian tube.In post-operative CT, the soft tissues in the tympanum and mastoid cavity decreased or disappeared as early as one week. In post-operative MRI, the hyperintense T2-weighted signals of tympanum and mastoid decreased or disappeared in 3 days to 1 month,soft tissues tamponade with moderate intense T2-weighted signal were seen in the vestibule in 1-4 months. Conclusions: IP-Ⅰ, CC, IP-Ⅱ and CA with dilated vestibule can lead to CSF otorrhea. Combined with special medical history, T2-weighted signal of inner ear MRI can provide diagnostic basie for most children with IEM and CSF otorrhea.HRCT and MRI of inner ear can also be used to evaluate the effect of surgery.

Cochlear Implantation: Systematic Approach to Preoperative Radiologic Evaluation.

Sensorineural hearing loss results from abnormalities that affect the hair cells of the membranous labyrinth, inner ear malformations, and conditions affecting the auditory pathway from the cochlear nerve to the processing centers of the brain. Cochlear implantation is increasingly being performed for hearing rehabilitation owing to expanding indications and a growing number of children and adults with sensorineural hearing loss. An adequate understanding of the temporal bone anatomy and diseases that affect the inner ear is paramount for alerting the operating surgeon about variants and imaging findings that can influence the surgical technique, affect the choice of cochlear implant and electrode type, and help avoid inadvertent complications. In this article, imaging protocols for sensorineural hearing loss and the normal inner ear anatomy are reviewed, with a brief description of cochlear implant devices and surgical techniques. In addition, congenital inner ear malformations and acquired causes of sensorineural hearing loss are discussed, with a focus on imaging findings that may affect surgical planning and outcomes. The anatomic factors and variations that are associated with surgical challenges and may predispose patients to periprocedural complications also are highlighted. © RSNA, 2023 Quiz questions for this article are available through the Online Learning Center. Online supplemental material and the slide presentation from the RSNA Annual Meeting are available for this article.

Identification of a homozygous frameshift mutation in the FGF3 gene in a consanguineous Iranian family: First report of labyrinthine aplasia, microtia, and microdontia syndrome in Iran and literature review.

BACKGROUND: To date, over 400 syndromes with hearing impairment have been identified which altogether constitute almost 30% of hereditary hearing loss (HL) cases around the globe. Manifested as complete or partial labyrinthine aplasia (severe malformations of the inner ear structure), type I microtia (smaller outer ear with shortened auricles), and microdontia (small and widely spaced teeth), labyrinthine aplasia, microtia, and microdontia (LAMM) syndrome (OMIM 610706) is an extremely rare autosomal recessive condition caused by bi-allelic mutations in the FGF3 gene. METHODS: Using the whole-exome sequencing (WES) data of the proband, we analyzed a consanguineous Iranian family with three affected members presenting with congenital bilateral HL, type I microtia, and microdontia. RESULTS: We discovered the homozygous deletion c.45delC in the first exon of the FGF3 gene, overlapping a 38.72 Mb homozygosity region in chromosome 11. Further investigations using Sanger sequencing revealed that this variant co-segregated with the phenotype observed in the family. CONCLUSION: Here, we report the first identified case of LAMM syndrome in Iran, and by identifying a frameshift variant in the first exon of the FGF3 gene, our result will help better clarify the phenotype-genotype relation of LAMM syndrome.

Cochlear implantation in children with congenital inner ear malformations - Our experience.

OBJECTIVE: To share our experience of the surgical challenges faced in cochlear implanted patients with inner ear malformation and to assess the auditory and speech perception outcomes. MATERIAL AND METHOD: Clinical records of 502 cochlear implant procedures were reviewed and data of 122 patients who had inner ear malformations were enrolled in the study. Their auditory and speech performances were evaluated post implantation for 3 years. RESULT: Cerebrospinal fluid gusher was encountered during opening of cochlea in 42 patients (34.4%) and one patient was re-explored within 24 h. In 30.3% of cases facial anomaly was found. Significant improvement in average performance was seen in all malformation types except in cochlear hypoplasia at 12 months postoperatively. CONCLUSION: Surgical challenges can be overcome with expertise and giving special attention to preoperative imaging. Our experience suggests that outcomes are favourable in patients with inner ear malformations too.

The effect of bony cochlear nerve canal (BCNC) diameter on the degree of sensorineural hearing loss.

PURPOSE: This study investigated the correlation between the diameter of the bony cochlear nerve canal (BCNC), as determined by Temporal bone CT, and MRI findings of cochlear nerves (CN) in children with sensorineural hearing loss (SNHL). MATERIALS AND METHODS: A prospective study design was followed. Radiological data (Temporal bone CT and MRI) of fifty children with sensorineural hearing loss (age <18 y) were included in the study. All patients (100 ears) underwent routine MRI protocol in addition to 3D CISS (3-D constructive interference in steady state). RESULTS: Based on CT findings, the BCNC was classified according to its diameter into three groups; group 1 (<1.4 mm), group 2 (1.4-2.0 mm), and group 3 (>2.0 mm). A significant difference between the three groups at degrees of SNHL (p < 0.001) was observed. Significant difference (p < 0.001) was also observed in the mean level of pure tone audiometry (PTA) average in group 1 compared to group 2. The CN was absent in 20 ears of group 1 CT results (29%), CN hypoplasia was noticed in 40 ears of group 1 CT (58%). However, CN was present in 9 ears of group 1 CT (13%), while in group 2 and 3, CN was present in 100% of the cases (27, and 4 ears, respectively, p < 0.001). CONCLUSIONS: MRI and CT imaging are valuable in the diagnosis of SNHL in children. Moreover, with BCNC stenosis, there was a high probability of CN aplasia or hypoplasia.

The spectrum of cochlear malformations in CHARGE syndrome and insights into the role of the CHD7 gene during embryogenesis of the inner ear.

PURPOSE: We reviewed the genotypes and the imaging appearances of cochleae in CHARGE patients from two large tertiary centres and analysed the observed cochlear anomalies, providing detailed anatomical description and a grading system. The goal was to gain insight into the spectrum of cochlear anomalies in CHARGE syndrome, and thus, in the role of the CHD7 gene in otic vesicle development. METHODS: We retrospectively reviewed CT and/or MR imaging of CHARGE patients referred to our institutions between 2005 and 2022. Cochlear morphology was analysed and, when abnormal, divided into 3 groups in order of progressive severity. Other radiological findings in the temporal bone were also recorded. Comparison with the existing classification system of cochlear malformation was also attempted. RESULTS: Cochlear morphology in our CHARGE cohort ranged from normal to extreme hypoplasia. The most common phenotype was cochlear hypoplasia in which the basal turn was relatively preserved, and the upper turns were underdeveloped. All patients in the cohort had absent or markedly hypoplastic semicircular canals and small, misshapen vestibules. Aside from a stenotic cochlear aperture (fossette) being associated with a hypoplastic or absent cochlear nerve, there was no consistent relationship between cochlear nerve status (normal, hypoplasia, or aplasia) and cochlear morphology. CONCLUSION: Cochlear morphology in CHARGE syndrome is variable. Whenever the cochlea was abnormal, it was almost invariably hypoplastic. This may shed light on the role of CHD7 in cochlear development. Accurate morphological description of the cochlea contributes to proper clinical diagnosis and is important for planning surgical treatment options.

Internal auditory canal volume in normal and malformed inner ears.

PURPOSE: A narrow bony internal auditory canal (IAC) may be associated with a hypoplastic cochlear nerve and poorer hearing performances after cochlear implantation. However, definitions for a narrow IAC vary widely and commonly, qualitative grading or two-dimensional measures are used to characterize a narrow IAC. We aimed to refine the definition of a narrow IAC by determining IAC volume in both control patients and patients with inner ear malformations (IEMs). METHODS: In this multicentric study, we included high-resolution CT (HRCT) scans of 128 temporal bones (85 with IEMs: cochlear aplasia, n = 11; common cavity, n = 2; cochlear hypoplasia type, n = 19; incomplete partition type I/III, n = 8/8; Mondini malformation, n = 16; enlarged vestibular aqueduct syndrome, n = 19; 45 controls). The IAC diameter was measured in the axial plane and the IAC volume was measured by semi-automatic segmentation and three-dimensional reconstruction. RESULTS: In controls, the mean IAC diameter was 5.5 mm (SD 1.1 mm) and the mean IAC volume was 175.3 mm3 (SD 52.6 mm3). Statistically significant differences in IAC volumes were found in cochlear aplasia (68.3 mm3, p < 0.0001), IPI (107.4 mm3, p = 0.04), and IPIII (277.5 mm3, p = 0.0004 mm3). Inter-rater reliability was higher in IAC volume than in IAC diameter (intraclass correlation coefficient 0.92 vs. 0.77). CONCLUSIONS: Volumetric measurement of IAC in cases of IEMs reduces measurement variability and may add to classifying IEMs. Since a hypoplastic IAC can be associated with a hypoplastic cochlear nerve and sensorineural hearing loss, radiologic assessment of the IAC is crucial in patients with severe sensorineural hearing loss undergoing cochlear implantation.