Temporal Bone Computed Tomography Images Research Articles

Synthetic temporal bone CT generation from UTE-MRI using a cycleGAN-based deep learning model: advancing beyond CT-MR imaging fusion.

The aim of this study is to develop a deep-learning model to create synthetic temporal bone computed tomography (CT) images from ultrashort echo-time magnetic resonance imaging (MRI) scans, thereby addressing the intrinsic limitations of MRI in localizing anatomic landmarks in temporal bone CT. This retrospective study included patients who underwent temporal MRI and temporal bone CT within one month between April 2020 and March 2023. These patients were randomly divided into training and validation datasets. A CycleGAN model for generating synthetic temporal bone CT images was developed using temporal bone CT and pointwise encoding-time reduction with radial acquisition (PETRA). To assess the model's performance, the pixel count in mastoid air cells was measured. Two neuroradiologists evaluated the successful generation rates of 11 anatomical landmarks. A total of 102 patients were included in this study (training dataset, n = 54, mean age 58 ± 14, 34 females (63%); validation dataset, n = 48, mean age 61 ± 13, 29 females (60%)). In the pixel count of mastoid air cells, no difference was observed between synthetic and real images (679 ± 342 vs 738 ± 342, p = 0.13). For the six major anatomical sites, the positive generation rates were 97-100%, whereas those of the five major anatomical structures ranged from 24% to 83%. We developed a model to generate synthetic temporal bone CT images using PETRA MRI. This model can provide information regarding the major anatomic sites of the temporal bone using MRI. The proposed algorithm addresses the primary limitations of MRI in localizing anatomic sites within the temporal bone. CT is preferred for imaging the temporal bone, but has limitations in differentiating pathology there. The model achieved a high success rate in generating synthetic images of six anatomic sites. This can overcome the limitations of MRI in visualizing key anatomic sites in the temporal skull.

Automated detection of otosclerosis with interpretable deep learning using temporal bone computed tomography images

ObjectiveThis study aimed to develop an automated detection schema for otosclerosis with interpretable deep learning using temporal bone computed tomography images. MethodsWith approval from the institutional review board, we retrospectively analyzed high-resolution computed tomography scans of the temporal bone of 182 participants with otosclerosis (67 male subjects and 115 female subjects; average age, 36.42 years) and 157 participants without otosclerosis (52 male subjects and 102 female subjects; average age, 30.61 years) using deep learning. Transfer learning with the pretrained VGG19, Mask RCNN, and EfficientNet models was used. In addition, 3 clinical experts compared the system's performance by reading the same computed tomography images for a subset of 35 unseen subjects. An area under the receiver operating characteristic curve and a saliency map were used to further evaluate the diagnostic performance. ResultsIn prospective unseen test data, the diagnostic performance of the automatically interpretable otosclerosis detection system at the optimal threshold was 0.97 and 0.98 for sensitivity and specificity, respectively. In comparison with the clinical acumen of otolaryngologists at P < 0.05, the proposed system was not significantly different. Moreover, the area under the receiver operating characteristic curve for the proposed system was 0.99, indicating satisfactory diagnostic accuracy. ConclusionOur research develops and evaluates a deep learning system that detects otosclerosis at a level comparable with clinical otolaryngologists. Our system is an effective schema for the differential diagnosis of otosclerosis in computed tomography examinations.

Low-Lying Tegmen and Surgical Outcomes Following the Middle Cranial Fossa Repair of Superior Canal Dehiscence.

To compare treatment response from the middle cranial fossa repair of superior canal dehiscence (SCD) between cases with and cases without low-lying tegmen (LLT). Cohort study. Single tertiary care institution. Two investigators independently reviewed preoperative high-resolution temporal bone computed tomography images and classified the ipsilateral tegmen as either "low-lying" or "control." Patients completed a symptom questionnaire and underwent audiometric testing pre- and post-operatively. Multivariable regression models assessed for symptomatic resolution and audiometric improvement following surgery with tegmen status as the primary predictor. Models controlled for patient age, sex, bilateral SCD disease, dehiscence location, prior ear surgery status, surgery duration, and follow-up duration. Among a total of 410 cases included, we identified 121 (29.5%) LLT cases. Accounting for all control measures, patients with LLT were significantly less likely to experience overall symptom improvement (adjusted odds ratio: 0.32, 95% confidence interval [CI]: 0.18-0.57, p < .001) and reported a significantly lower proportion of preoperative symptoms that resolved following surgery (adjusted β: -25.6%, 95% CI: -37.0% to -14.3%, p < .001). However, audiometric outcomes following surgery did not differ significantly between patients with and patients without LLT. This is the first investigation on the relationship between LLT and surgical outcomes following the middle fossa repair of SCD. Patients with LLT reported less favorable symptomatic response but exhibited a similar degree of audiometric improvement.

Computed tomography approximated superior semicircular canal dehiscence size and location and their association with clinical presentation

ObjectiveThis study investigates the relationship of superior semicircular canal dehiscence (SSCD) size and location with patient symptomatology and audiometry. MethodsWe retrospectively reviewed SSCD cases presented to a tertiary institution between 2011 and 2022. Dehiscence length and width measured on high-resolution temporal bone computed tomography imaging were used to calculate an approximate dehiscence area (ADA). Dehiscence location was classified employing a six-grade system. Multivariable regression analyses were performed with symptomatology and audiogram metrics as outcome variables and ADA and dehiscence location as the primary covariates of interest. ResultsA total of 402 SSCD were included in the analysis. Controlling for patient age, sex, dehiscence laterality, and location, greater ADA was independently associated higher rates of autophony (aOR 1.39; 95% C.I. 1.14–1.71; P = 0.004) and hyper-amplification (aOR 1.39; 1.14–1.70; P = 0.004). Additionally, dehiscences with greater ADA exhibited significantly lower bone conduction threshold at 500 Hz (adjusted β –1.75, P = 0.006) and 1000 Hz (adjusted β –1.61, P = 0.018) and significantly wider air-bone gap at 500 Hz (adjusted β 2.22, P < 0.001) and 1000 Hz (adjusted β 1.00, P = 0.039). Dehiscence location was not independently associated with any outcome variable examined when accounting for dehiscence size. ConclusionThe size of dehiscence is more independently related to clinical presentations than the anatomical location of the dehiscence in the superior semicircular canal. Greater dehiscence size is associated with symptomatology and audiometry consistent with more severe bone conduction hyperacusis.

Deep learning-based approach for the automatic segmentation of adult and pediatric temporal bone computed tomography images.

Automatic segmentation of temporal bone computed tomography (CT) images is fundamental to image-guided otologic surgery and the intelligent analysis of CT images in the field of otology. This study was conducted to test a convolutional neural network (CNN) model that can automatically segment almost all temporal bone anatomy structures in adult and pediatric CT images. A dataset comprising 80 annotated CT volumes was collected, of which 40 samples were obtained from adults and 40 from children. A further 60 annotated CT volumes (30 from adults and 30 from children) were used to train the model. The remaining 20 annotated CT volumes were employed to determine the model's generalizability for automatic segmentation. Finally, the Dice coefficient (DC) and average symmetric surface distance (ASSD) were utilized as metrics to evaluate the performance of the CNN model. Two independent-sample t-tests were used to compare the test set results of adults and children. In the adult test set, the mean DC values of all the structures ranged from 0.714 to 0.912, and the ASSD values were less than 0.24 mm for 11 structures. In the pediatric test set, the mean DC values of all the structures ranged from 0.658 to 0.915, and the ASSD values were less than 0.18 mm for 11 structures. There was no statistically significant difference between the adult and child test sets in most temporal bone structures. Our CNN model shows excellent automatic segmentation performance and good generalizability for both adult and pediatric temporal bone CT images, which can help to advance otologist education, intelligent imaging diagnosis, surgery simulation, application of augmented reality, and preoperative planning for image-guided otology surgery.

Radiological dimensions of the Eustachian tube in patients with adhesive otitis media.

This study aimed to analyse the computed tomography parameters for effective ventilation in patients with adhesive otitis media. Twenty-six patients with unilateral adhesive otitis media were included in the study. The patients' temporal bone computed tomography images were retrospectively reviewed. Eustachian tube length and diameter were measured. Mastoid pneumatisation and middle-ear size were evaluated by measuring petroclival and Eustachian tube-tympanic cavity ventilation angles. The average Eustachian tube length was 38.4 mm and 38.9 mm in adhesive otitis media and healthy ears, respectively. The Eustachian tube diameter of the adhesive otitis media ears (1.47 mm) was significantly narrower than that of the healthy ears (1.83 mm). There were no significant differences in the angles between adhesive otitis media and healthy ears. A narrow Eustachian tube diameter was associated with developing adhesive otitis media. Measuring Eustachian tube diameter is simple and can be routinely performed when examining temporal bone computed tomography images for Eustachian tube function evaluation.

High-Resolution CT Imaging of the Temporal Bone: A Cadaveric Specimen Study.

Objective Super-high and ultra-high spatial resolution computed tomography (CT) imaging can be advantageous for detecting temporal bone pathology and guiding treatment strategies. Methods Six temporal bone cadaveric specimens were used to evaluate the temporal bone microanatomic structures utilizing the following CT reconstruction modes: normal resolution (NR, 0.5-mm slice thickness, 512 2 matrix), high resolution (HR, 0.5-mm slice thickness, 1,024 2 matrix), super-high resolution (SHR, 0.25-mm slice thickness, 1,024 2 matrix), and ultra-high resolution (UHR, 0.25-mm slice thickness, 2,048 2 matrix). Noise and signal-to-noise ratio (SNR) for bone and air were measured at each reconstruction mode. Two observers assessed visualization of seven small anatomic structures using a 4-point scale at each reconstruction mode. Results Noise was significantly higher and SNR significantly lower with increases in spatial resolution (NR, HR, and SHR). There was no statistical difference between SHR and UHR imaging with regard to noise and SNR. There was significantly improved visibility of all temporal bone osseous structures of interest with SHR and UHR imaging relative to NR imaging ( p < 0.001) and most of the temporal bone osseous structures relative to HR imaging. There was no statistical difference in the subjective image quality between SHR and UHR imaging of the temporal bone ( p ≥ 0.085). Conclusion Super-high-resolution and ultra-high-resolution CT imaging results in significant improvement in image quality compared with normal-resolution and high-resolution CT imaging of the temporal bone. This preliminary study also demonstrates equivalency between super-high and ultra-high spatial resolution temporal bone CT imaging protocols for clinical use.

Pneumolabyrinth as an Early Computed Tomographic Finding After Cochlear Implantation and its Clinical Significance.

To determine the incidence and volume of pneumolabyrinth using early temporal bone computed tomography (TBCT) findings and evaluate the correlation between pneumolabyrinth and various clinical variables. Retrospective case review. Tertiary academic center. Fifty-three consecutive adult cochlear implantation (CI) recipients (53 ears) with normal inner ears who underwent high-resolution TBCT within 3 days after CI were included. Axial TBCT images were used for detection and measurement of pneumolabyrinth. Incidence and volume of pneumolabyrinth were evaluated. In addition, the following clinical variables were analyzed to evaluate the correlation with pneumolabyrinth volume: demographics, implant type, surgical approach, postoperative dizziness, and preservation of functional residual hearing. Pneumolabyrinth was present in all patients, and the average volume was 8.496 mm3. Pneumolabyrinth was confined to the cochlea (pneumocochlea) in all patients except for one who also had pneumovestibule. The pneumolabyrinth volume in patients with postoperative dizziness was significantly larger than that in patients without postoperative dizziness (10.435 mm3 vs. 8.016 mm3; p = 0.029). Multivariate analysis showed that a larger volume of pneumolabyrinth was significantly associated with postoperative dizziness (odds ratio, 1.420; 95% confidence interval, 1.114-1.808; p = 0.005). A certain volume of pneumolabyrinth was always present in the early stage after CI, and the volume of pneumolabyrinth measured using early TBCT findings was significantly associated with the occurrence of postoperative dizziness.

Automated Registration-Based Temporal Bone Computed Tomography Segmentation for Applications in Neurotologic Surgery.

This study investigates the accuracy of an automated method to rapidly segment relevant temporal bone anatomy from cone beam computed tomography (CT) images. Implementation of this segmentation pipeline has potential to improve surgical safety and decrease operative time by augmenting preoperative planning and interfacing with image-guided robotic surgical systems. Descriptive study of predicted segmentations. Academic institution. We have developed a computational pipeline based on the symmetric normalization registration method that predicts segmentations of anatomic structures in temporal bone CT scans using a labeled atlas. To evaluate accuracy, we created a data set by manually labeling relevant anatomic structures (eg, ossicles, labyrinth, facial nerve, external auditory canal, dura) for 16 deidentified high-resolution cone beam temporal bone CT images. Automated segmentations from this pipeline were compared against ground-truth manual segmentations by using modified Hausdorff distances and Dice scores. Runtimes were documented to determine the computational requirements of this method. Modified Hausdorff distances and Dice scores between predicted and ground-truth labels were as follows: malleus (0.100 ± 0.054 mm; Dice, 0.827 ± 0.068), incus (0.100 ± 0.033 mm; Dice, 0.837 ± 0.068), stapes (0.157 ± 0.048 mm; Dice, 0.358 ± 0.100), labyrinth (0.169 ± 0.100 mm; Dice, 0.838 ± 0.060), and facial nerve (0.522 ± 0.278 mm; Dice, 0.567 ± 0.130). A quad-core 16GB RAM workstation completed this segmentation pipeline in 10 minutes. We demonstrated submillimeter accuracy for automated segmentation of temporal bone anatomy when compared against hand-segmented ground truth using our template registration pipeline. This method is not dependent on the training data volume that plagues many complex deep learning models. Favorable runtime and low computational requirements underscore this method's translational potential.

Could computed tomography histogram analysis add value to the diagnosis of cholesteatoma?

To investigate the potential role of computed tomography (CT) histogram analysis in differentiating cholesteatoma (CHS) and non-cholesteatoma (NCHS). We evaluated 77 temporal bone CT images (from November 2016 to February 2020) that were obtained preoperatively (mean age, 37.10±17.27 years in CHS; 36.72±16.08 years in NCHS group). Histogram analyses of the resulting XML files were conducted using the R Project 3.3.2 program. ROC analysis was used to find threshold values, and the diagnostic efficiency of these values in differentiating CHS-NCHS was determined. The CT images of 41 CHS (53.25%) and 36 NHCS cases (46.75%) were evaluated. There was a statistically significant difference between the CHS and NCHS group in terms of the mean, maximum, and median values (p = 0.036, p = 0.006, p = 0.043). When examining the ROC curve obtained from the mean of these parameters, area under the curve (AUC) is determined as 0.638, and when the threshold value is selected as 42.55, the mean value was determined to have a sensitivity of 86.50% and specificity of 56.10% in differentiating CHS-NCHS.

Anatomical Measurement of Normal Eustachian Tube on the Temporal Bone Computed Tomography Imaging

Tujuan: Menggambarkan pengukuran anatomis tuba Eustachius normal pada pencitraan Computed Tomography (CT) tulang temporal. Metode: Ini adalah penelitian deskriptif tuba Eustachius normal dengan mengukur diameter pretimpani, sudut tubotimpani dan panjang pars kartilago tuba Eustachius normal menggunakan teknik rekonstruksi multiplanar pada pencitraan CT tulang temporal dari 58 sampel di beberapa rumah sakit di Makassar. Semua sampel dibagi lagi menjadi kelompok laki-laki dan perempuan, serta kelompok sisi kanan dan kiri. Kami juga membagi sampel menjadi 6 kelompok usia. Hasil: Rerata diameter pretimpani pada kelompok pria adalah 4,62 mm dan pada kelompok wanita adalah 4,36 mm. Rerata diameter pretimpani adalah 4,59 mm pada kelompok sisi kanan dan 4,36 mm pada kelompok sisi kiri. Rerata sudut tubotimpani adalah 143,5o pada kelompok pria dan 143,3o pada kelompok wanita. Nilai rerata sudut tubotimpani tidak memiliki perbedaan di kedua sisi telinga. Rerata panjang pars kartilago tidak memiliki perbedaan antara kelompok pria dan wanita dan juga antara sisi kanan dan kiri. Simpulan: Diameter pretimpani lebih besar pada kelompok pria dan kelompok sisi kanan. Sudut tubotimpani dan panjang kartilago tuba Eustachius tidak memiliki perbedaan yang signifikan pada semua kelompok.Kata kunci: tuba eustachius, diameter pretimpani, sudut tubotimpani, panjang kartilago, CT tulang tempor

Forward-projected Model-based Iterative Reconstruction SoluTion in Temporal Bone Computed Tomography: A Comparison Study of All Reconstruction Modes.

Identify appropriate reconstruction modes of Forward-projected model-based Iterative Reconstruction SoluTion (FIRST) in temporal bone computed tomography (CT) and investigate the contribution of spatial resolution and noise to the visual assessment. Sixteen temporal bone CT images were reconstructed. Two blinded radiologists assessed 8 anatomical structures and classified the visual assessment. These visual scores were compared across reconstruction modes among each anatomical structure. Visual scores and contrast-to-noise ratio, noise power spectrum (NPS) at low (NPSLow) and high (NPSHigh) spatial frequencies, and 50% modulation transfer function relationships were evaluated. Visual scores differed significantly for the stapedius muscle and osseous spiral lamina, with CARDIAC SHARP, BONE, and LUNG modes for the osseous spiral lamina scoring highest. Visual scores significantly positively correlated with NPSLow, NPSHigh, and 50% modulation transfer function but negatively with contrast-to-noise ratio. Modes providing higher spatial resolution and lower noise reduction showed an improved visual assessment of CT images reconstructed with FIRST.

Combining Stereoscopic Video and Virtual Reality Simulation to Maximize Education in Lateral Skull Base Surgery.

Mastery of lateral skull base (LSB) surgery requires thorough knowledge of complex, 3-dimensional (3D) microanatomy and techniques. While supervised operation under binocular microscopy remains the training gold standard, concerns over operative time and patient safety often limit novice surgeons' stereoscopic exposure. Furthermore, most alternative educational resources cannot meet this need. Here we present proof of concept for a tool that combines 3D-operative video with an interactive, stereotactic teaching environment. Stereoscopic video was recorded with a microscope during translabyrinthine approaches for vestibular schwannoma. Digital imaging and communications in medicine (DICOM) temporal bone computed tomography images were segmented using 3D-Slicer. Files were rendered using a game engine software built for desktop virtual reality. The resulting simulation was an interactive immersion combining a 3D operative perspective from the lead surgeon's chair with virtual reality temporal bone models capable of hands-on manipulation, label toggling, and transparency modification. This novel tool may alter LSB training paradigms.

Utilization of Computed Tomography in Temporal Bone Fractures at a Large Level I Trauma Center.

To identify which patients with temporal bone fractures who have already undergone trauma pan-scan computed tomography (CT) do not require an additional dedicated temporal bone CT. To determine the added cost of dedicated temporal bone CT in a lower-risk group of patients. Retrospective chart review. A chart review was conducted of adult patients at a large level I trauma center with temporal bone fractures who underwent both trauma pan-scan CT and dedicated temporal bone CT. Patients were risk stratified into lower- and higher-risk groups based on imaging and physical exam findings. Imaging findings regarding five critical anatomic structures were compared between the two types of CT scans. There were 180 patients who met inclusion criteria, with 120 patients stratified to the lower-risk group. The negative predictive values of trauma pan-scan CT within the lower-risk group for fracture involvement with the five critical anatomic structures were as follows: otic capsule (1.000), carotid canal (0.960), facial nerve canal (1.000), ossicular chain (0.992), and tegmen (0.856). The annual out-of-pocket cost to patients for dedicated temporal bone CT imaging in the lower-risk group was estimated to be approximately $34,000, for a total of $190,000 during the complete study period. Trauma pan-scan CT may be sufficient in lower-risk patients to identify temporal bone fracture involvement with critical anatomic structures of the temporal bone. Reductions in dedicated temporal bone imaging will decrease both radiation exposure to trauma patients and strain on radiology departments. 4 Laryngoscope, 131:E278-E282, 2021.

A 3D deep supervised densely network for small organs of human temporal bone segmentation in CT images

Computed Tomography (CT) has become an important way for examining the critical anatomical organs of the human temporal bone in the diagnosis and treatment of ear diseases. Segmentation of the critical anatomical organs is an important fundamental step for the computer assistant analysis of human temporal bone CT images. However, it is challenging to segment sophisticated and small organs. To deal with this issue, a novel 3D Deep Supervised Densely Network (3D-DSD Net) is proposed in this paper. The network adopts a dense connection design and a 3D multi-pooling feature fusion strategy in the encoding stage of the 3D-Unet, and a 3D deep supervised mechanism is employed in the decoding stage. The experimental results show that our method achieved competitive performance in the CT data segmentation task of the small organs in the temporal bone.

A Retrospective Review of Temporal Bone Computed Tomography to Present Safe Guideline for Bone-Anchored Hearing Aids

ObjectivesBone-anchored hearing device (BAHD) is contraindicated in patients younger than 5 years because their calvarial bones are not thick enough to be implanted site. However, it has not been studied in the Korean population. This study was not only to establish a safe guideline for depth of implant device in all age groups who undergo BAHD implant surgery, but also to investigate whether implantation of currently used BAHDs could be done safely in Korean children, especially those younger than 5.MethodsTwo hundred eighty patients, who underwent high-resolution temporal bone computed tomography (TBCT) images between August 2010 and October 2018 were randomly enrolled in all ages. We retrospectively reviewed TBCT imaging to measure skull bone thickness at the recommended BAHD implant site.ResultsThe average skull bone thickness was 2.87 mm in patients younger than 5 years and 6.72 mm in patients older than 5 years, respectively, which conforms to the current guideline. The results indicate nearly 50% of calvarial bone thicknesses were less than 3 mm in patients under 5 years old, while 92.78% of the patients older than 5 years of age showed bone thickness greater than 4 mm. Of note, calvarial bone thickness was thicker than 3 mm in all patients who are older than 6 years.ConclusionThis study confirms that the currently approved BAHD implantation guideline is suitable in the Korean population. For safety, we suggest taking TBCTs prior to surgery, especially in pediatric patients. Besides, noninvasive applications are recommended for patients younger than 5.

Transmastoid access in branchio-oto-renal syndrome: A reappraisal of computed tomography imaging

ObjectiveTo evaluate for temporal bone abnormalities that might affect transmastoid surgery such as cochlear implantation in cases of branchio-oto-renal syndrome (BOR). Study designRetrospective review. MethodsQualitative assessment of temporal bone computed tomography imaging was performed by a neuroradiologist for 30 individuals with BOR (60 ears) and 20 controls with normal hearing (20 ears). Transmastoid access was assessed categorically across 4 features: tip development, cortex pneumatization, tegmen height, and facial recess pneumatization. The appearance of 4 standard landmarks (Koerner's septum, antrum, prominence of the horizontal semicircular canal, incudal short process) was also dichotomized as normal or abnormal. Data were compared using Fisher's exact testing. ResultsMastoid height differed between the groups with tip underdevelopment noted in 72% of BOR ears vs. 40% of controls (p = 0.02), and a low tegmen was seen in 68% of BOR ears and 25% of controls (p < 0.01). Significant differences in pneumatization were also found for the mastoid cortex (28% non-pneumatized in BOR vs. 5% in controls; p = 0.03) and the facial recess (27% non-pneumatized in BOR vs. 0% in controls; p = 0.01). Standard landmarks were easily identified in all of the control mastoids. In the BOR group, Koerner's septum was abnormally located or absent in 45%, and the antrum was severely hypoplastic or absent in 50%. Similarly, the prominence of the horizontal semicircular canal and the short process of the incus were dysplastic in 73% (44/60) and 62% (37/60), respectively. ConclusionsMastoid abnormalities are common in BOR syndrome. Restricted transmastoid access and abnormal or absent mastoid landmarks should be anticipated in those patients with BOR who become cochlear implant candidates. Level of evidence4.

Does the Degree of the Mastoid Pneumatization Affect the Side of Bell Palsy?

The aim is to investigate the impact of degree of mastoid pneumatization on the affected side of Bell palsy (BP). Retrospective study in tertiary academic hospital. In total, 52 patients who were diagnosed with as BP were included in the study. Each patient was staged using House-Brackmann (HB) staging system. All patients underwent temporal bone computed tomography imaging. House-Brackmann scores, side of the BP, and mastoid pneumatization of all of patients were evaluated in the present study. Regarding the degree of the mastoid pneumatization, there were no significant differences between the affected side and the unaffected side (P = 0.439). The degree of the mastoid pneumatization of the affected side and the unaffected side did not differ between males and females (P = 0.918 for the affected side, P = 0.765 for the unaffected side, respectively). A negative correlation between the age and mastoid pneumatization of each side was found (P = 0.001, P = 0.025, respectively). There was no significant correlation between HB score and the degree of the mastoid pneumatization of each side (P = 0.789, P = 0.703). As a conclusion, the degree of the mastoid pneumatization is not one of the risk factors for BP. Further randomized studies with larger numbers of patients are needed to confirm these findings.

Progression of Unilateral Hearing Loss in Children With and Without Ipsilateral Cochlear Nerve Canal Stenosis: A Hazard Analysis.

To investigate the risk of hearing loss progression in each ear among children with unilateral hearing loss associated with ipsilateral bony cochlear nerve canal (BCNC) stenosis. Tertiary pediatric referral center. Children diagnosed with unilateral hearing loss who had undergone temporal bone computed tomography imaging and had at least 6 months of follow-up audiometric testing were identified from a prospective audiological database. Two pediatric radiologists blinded to affected ear evaluated imaging for temporal bone anomalies and measured bony cochlear canal width independently. All available audiograms were reviewed, and air conduction thresholds were documented. Progression of hearing loss was defined by a 10 dB increase in air conduction pure-tone average. One hundred twenty eight children met inclusion criteria. Of these, 54 (42%) had a temporal bone anomaly, and 22 (17%) had ipsilateral BCNC stenosis. At 12 months, rates of progression in the ipsilateral ear were as follows: 12% among those without a temporal bone anomaly, 13% among those with a temporal bone anomaly, and 17% among those with BCNC stenosis. Children with BCNC stenosis had a significantly greater risk of progression in their ipsilateral ear compared with children with no stenosis: hazard ratio (HR) 2.17, 95% confidence interval (CI) (1.01, 4.66), p value 0.046. When we compared children with BCNC stenosis to those with normal temporal bone imaging, we found that the children with stenosis had nearly two times greater risk estimate for progression, but this difference did not reach significance, HR 1.9, CI (0.8, 4.3), p = 0.1. No children with BCNC stenosis developed hearing loss in their contralateral year by 12 months of follow-up. Children with bony cochlear nerve canal stenosis may be at increased risk for progression in their ipsilateral ear. Audiometric and medical follow-up for these children should be considered.

Enlarged vestibular aqueducts and other inner-ear abnormalities in patients with Down syndrome.

Histopathological anomalies of inner-ear structures in individuals with Down syndrome have been well documented; however, few studies have examined the radiological features. A retrospective study was conducted of temporal bone computed tomography images in 38 individuals (75 ears) with Down syndrome to evaluate the prevalence of inner-ear abnormalities and assess vestibular aqueduct widths. Inner-ear anomalies were identified in 20 of the 38 individuals (52.6 per cent). Seven of the 75 temporal bones (9.3 per cent) were found to have higher than previously reported. A dilated internal auditory canal and vestibule were more common among the present study group, while prior studies have demonstrated internal auditory canal stenosis and decreased vestibule size. Down syndrome patients exhibit a high prevalence of dysplastic inner-ear features that confer substantial risk of sensorineural hearing loss. Computed tomography is a useful screening aid to detect inner-ear abnormalities, particularly enlarged vestibular aqueducts, which cause preventable sensorineural hearing loss in this population.