Temporal Bone Computed Tomography Research Articles

Utilizing deep learning for automatic segmentation of the cochleae in temporal bone computed tomography.

Segmentation of the cochlea in temporal bone computed tomography (CT) is the basis for image-guided otologic surgery. Manual segmentation is time-consuming and laborious. To assess the utility of deep learning analysis in automatic segmentation of the cochleae in temporal bone CT to differentiate abnormal images from normal images. Three models (3D U-Net, UNETR, and SegResNet) were trained to segment the cochlea on two CT datasets (two CT types: GE 64 and GE 256). One dataset included 77 normal samples, and the other included 154 samples (77 normal and 77 abnormal). A total of 20 samples that contained normal and abnormal cochleae in three CT types (GE 64, GE 256, and SE-DS) were tested on the three models. The Dice similarity coefficient (DSC) and Hausdorff distance (HD) were used to assess the models. The segmentation performances of the three models improved after adding abnormal cochlear images for training. SegResNet achieved the best performance. The average DSC on the test set was 0.94, and the HD was 0.16 mm; the performance was higher than those obtained by the 3D U-Net and UNETR models. The DSCs obtained using the GE 256 CT, SE-DS CT, and GE 64 CT models were 0.95, 0.94, and 0.93, respectively, and the HDs were 0.15, 0.18, and 0.12 mm, respectively. The SegResNet model is feasible and accurate for automated cochlear segmentation of temporal bone CT images.

Characterization of jugular bulb position on computed tomography (CT) with implications for excision of vestibular schwannomas.

To describe the distribution of jugular bulb position and pneumatization of posterior lip of internal auditory meatus (IAM) in patients with vestibular schwannoma (VS). This retrospective study included 43 patients who had a thin slice (< 2mm) CT temporal bone for preoperative planning of retrosigmoid approach for excision of VS between March 2011 and March 2021. On computed tomography (CT), high riding jugular bulb was defined by its relationship to IAM and correlated with type of jugular bulb according to Manjila et al. classification. The most common position of the jugular bulb was type 2a on the side of the tumor (26/43, 60.5%) and contralateral to the side of the tumor (28/43, 65.1%). High riding jugular bulb was noted in 9 (20.9%) patients. Seven among the 9 (77.9%) patients with high riding jugular bulb had Manjila et al. type 4 jugular bulb. Pneumatization of posterior lip of IAM was noted in 8 (18.6%) patients. Avoidance of drilling of the IAM in the subgroup of 23 patients who underwent total excision of the tumor was significantly associated with Manjila et al. type 4 jugular bulb (3/4, 75%, p = 0.04) and pneumatization of posterior lip (3/4, 75%, p = 0.04). Ideally all patients with VS should undergo petrous bone CT of < 2mm slice thickness as it can help in qualifying the jugular bulb position and recognizing pneumatization of the IAM. The presence of Manjila et al. type 4 jugular bulb or pneumatization of the posterior lip in patients with VS should alert the surgeon to anticipate and prevent complications related to drilling the posterior lip of the IAM.

Otologic Manifestations in Patients with Achondroplasia: A Multicenter Study.

Achondroplasia, the most prevalent form of skeletal dysplasia involving short stature, necessitates a multidisciplinary approach that includes otology and auditory rehabilitation. Despite this, the clinical characteristics of hearing loss and otologic manifestations in achondroplasia patients remain poorly defined. This study aimed to explore the prevalence and treatment outcomes of otologic disease in individuals with achondroplasia. A retrospective review of medical records was conducted for 70 patients who visited the otolaryngology clinic at 3 institutions in South Korea from 1999 to 2023. Demographic and clinical characteristics, including audiometric findings, imaging studies, treatment modalities, and outcomes, were analyzed. Among 53 patients who underwent audiometry, 26 showed conductive hearing loss, 2 had mixed-type hearing loss, and 4 had sensorineural hearing loss. Fifty-one patients (72.9%) had middle ear effusion at least once. Myringotomy or ventilation tube insertion was performed on 33 patients (47.1%), and 16 patients (22.9%) required multiple insertions. Eighteen patients (25.7%) had adenoid hypertrophy, and 16 (22.9%) underwent adenoidectomy. Temporal bone computed tomography (TBCT) scans were taken in 9 patients (12.9%) for middle ear evaluation. Computed tomography (CT) scans showed a high jugular bulb and rotated inner ear structures. Chronic otitis media with cholesteatoma was diagnosed in 2 patients (2.9%), in whom tympanomastoidectomy was performed. Half of the children with achondroplasia experienced hearing loss, most commonly due to conductive hearing loss. Threequarters of these children exhibited otitis media with effusions, often necessitating the insertion of a ventilation tube and adenoidectomy. Given the anatomical variations present in these children, such as a high jugular bulb and rotated structures of the inner ear and facial nerve, a cautious approach is essential when performing middle ear surgery.

Management of Massive Iatrogenic Temporal Lobe Meningoencephalocele and Bacterial Meningitis Following Pediatric Cochlear Implant Surgery.

To review the management of meningitis, large lateral skull base defect, and meningoencephalocele following pediatric cochlear implant (CI) surgery. Case report. Patient demographics, medical and surgical history, computed tomography (CT). An 8-year-old male with congenital severe to profound sensorineural hearing loss underwent uncomplicated right CI surgery at 18 months of age. He returned to his home country and received a bilateral sequential left ear CI at age 2. Five years following his second CI surgery, he presented to his local emergency room with worsening fever, headache, back pain, and vomiting. Lumbar puncture confirmed bacterial meningitis, and he was managed with intravenous antibiotics. The hospital course was complicated by a right-sided facial nerve paresis, prompting a temporal bone CT. Imaging demonstrated a tegmen defect measuring 15 mm × 10 mm with soft tissue opacification involving the entire mastoid and CI harness. He was then referred by family back to our institution. Intraoperatively, we identified a massive temporal lobe meningoencephalocele involving the entire mastoid cavity and engulfing the entire proximal electrode harness. Following middle cranial fossa craniotomy and revision mastoidectomy, proximal and distal array were separated, encephalocele transected, and remaining temporal lobe reduced. The lateral skull base was reconstructed with calvarial bone, temporalis fascia, and bovine collagen graft. The remnant electrode array was removed, a new CI receiver stimulator was fixed postero-superiorly to the cranial defect, and a new multichannel array inserted. A titanium cranioplasty completed the repair. A lumbar drain was placed for 3 days. Recovery and CI activation occurred uneventfully. Risk of encephalocele and meningitis underscores the importance of early identification, adequate repair, and long-term radiologic follow-up of iatrogenic tegmen defects during pediatric CI surgery.

Radiographic Estimation of Superior Canal Dehiscence Area in a Prediction Model of Surgical Outcome.

Computed tomography (CT) imaging of the temporal bone constitutes an integral element in the diagnostic workup of superior canal dehiscence (SCD). This study explores the utility of a clinically efficient method of manually estimating SCD size on CT imaging in predicting surgical outcomes. Cohort study. Tertiary center. Consecutive middle fossa repairs of SCD between 2011 and 2022 were included. Measurements of approximate dehiscence area (ADA), a previously established estimation method, on temporal bone CT imaging were performed by trained raters blind to clinical information. Surgical outcomes, evaluated with symptom resolution and audiometric improvement following repair, were assessed in multivariable regression models with ADA as the primary predictor and patient demographics and other history factors as covariates. Among 311 cases included, mean ADA was 2.68 mm2, and 71% of cases achieved overall symptom improvement (OSI). Every 1 mm2 rise in ADA predicted on average 3 dB greater narrowing of low-frequency air-bone gap (β 95% confidence interval, CI [-5.4, -0.7]) but 50% lower odds of OSI (adjusted odds ratio: 95% CI [0.32, 0.78]) among unilateral SCD cases. A model incorporating ADA, patient demographics, and history factors predicted OSI with a sensitivity, specificity combination as high as 85%, 73% and a positive predictive value, negative predictive value combination as high as 85%, 82% (area under the curve: 95% CI: 0.76-0.93). Increased ADA predicts more pronounced audiometric improvement but poorer symptomatic response among unilateral SCD cases. ADA is an efficient and practical method of estimating SCD size and demonstrated clinical utility in accurately predicting surgical outcomes.

Cochlear Apex Triangulation Utilizing Ct Measures And Middle Ear Landmarks.

To better characterize the cochlear apex in relation to surgically relevant landmarks to guide surgeons and improve procedural success of apical electrode placement. Retrospective image analysis. Tertiary referral center. Cochlear implant recipients with available preoperative computed tomography (CT) imaging. None. Cochlear dimensions and cochlear apex distance measures to surgically relevant middle ear landmarks and critical structures. Eighty-two temporal bone CT scans were analyzed utilizing multiplanar reformats. The average lateral width of promontory bone over the cochlear apex was 1.2 mm (standard deviation [SD], 0.3). The anteroposterior distance from the round window (avg, 4.2 mm; SD, 0.5), oval window (avg, 3.3 mm; SD, 0.3), cochleariform process (avg, 2.3; SD, 0.5), and superior-inferior distance from the cochleariform process (avg, -0.9; SD, 0.8) to the cochlear apex were measured. The relationship of the cochlear apex to critical structures was highly variable.A newly developed stapes vector was created and found to mark the posterior/superior boundary of the apex in 94% of patients. When a vector parallel to the stapes vector was drawn through the round window, it marked the anterior/inferior boundary of the cochlear apex in 89% of patients. This study assists in characterizing cochlear apex anatomy and its relation to surrounding structures as a means of improving procedural accuracy and reducing trauma during apical cochleostomy. Understanding both distance relationships and expected boundaries of the apex could help to inform future surgical approaches.

Radiologic evaluation of the internal carotid artery and jugular bulb in lateral temporal bone resection using 3D computed tomography.

This study investigated the internal carotid artery (ICA) and jugular bulb (JB) structures in terms of lateral temporal bone resection using 3D computed tomography (CT). We retrospectively investigated 80 ears of 40 patients using 3D reconstruction data from normal temporal bone CT. Ten critical points (P) in the temporal bone were marked in the 3D object with reference to the axial, coronal, and sagittal images of the CT scans. An imaginary plane of the facial nerve (PLf) course was also reconstructed in relation to the three points of the chorda-facial junction, P5 (second genu), and P3 (cochleariform) process. The distances (mean ± SD; mm) from points P3 to P1 (the highest level of the JB) and P2 (the posterior wall of the ascending petrous IAC at the level of the Eustachian tube) were 12.03 ± 2.56 and 9.79 ± 1.78, respectively. The distances from point P4 (chorda-facial junction) to P1 and P2 were 10.98 ± 2.70 and 17.66 ± 2.26, respectively. The angles (mean ± SD; degree) between the PLf to the line from Pa (point of the anterior bony canal) to P3 and P4 were 17.80 ± 10.05º and 8.93 ± 5.37º, respectively. The angles between the PLf to the line from P3 to P1 and P2 were - 36.35 ± 13.28º and - 24.78 ± 13.91º, respectively. The angles between the PLf to the line from P4 to P1 and P2 respectively were - 40.35 ± 15.37º and - 13.34 ± 7.63º. Understanding the anatomical relationships of P1 and P2 at P3 and P4 can be helpful in preventing iatrogenic trauma of the ICA and JB.

Middle ear-acquired cholesteatoma diagnosis based on CT scan image mining using supervised machine learning models

BackgroundDistinguishing between middle ear cholesteatoma and chronic suppurative otitis media (CSOM) is an ongoing challenge. While temporal bone computed tomography (CT) scan is highly accurate for diagnosing middle ear conditions, its specificity in discerning between cholesteatoma and CSOM is only moderate. To address this issue, we utilized trained machine learning models to enhance the specificity of temporal bone CT scan in diagnosing middle ear cholesteatoma. Our database consisted of temporal bone CT scan native images from 122 patients diagnosed with middle ear cholesteatoma and a control group of 115 patients diagnosed with CSOM, with both groups labeled based on surgical findings. We preprocessed the native images to isolate the region of interest and then utilized the Inception V3 convolutional neural network for image embedding into data vectors. Classification was performed using machine learning models including support vector machine (SVM), k-nearest neighbors (k-NN), random forest, and neural network. Statistical metrics employed to interpret the results included classification accuracy, precision, recall, F1 score, confusion matrix, area under the receiver operating characteristic curve (AUC), and FreeViz diagram.ResultsOur training dataset comprised 5390 images, and the testing dataset included 125 different images. The neural network, k-NN, and SVM models demonstrated significantly higher relevance in terms of classification accuracy, precision, and recall compared to the random forest model. For instance, the F1 scores were 0.974, 0.987, and 0.897, respectively, for the former three models, in contrast to 0.661 for the random forest model.ConclusionThe performance metrics of the presented trained machine learning models hold promising prospects as potentially clinically useful aids.

External auditory canal cholesteatoma in children: clinical manifestations

PurposeThe purpose of this study was to explore the characteristics of external auditory canal cholesteatoma (EACC) among children and to describe its radiological findings on high-resolution computed tomography (CT) of the temporal bone in order to improve the diagnostic accuracy of primary EACC.MethodsThe clinical records and CT imaging features of 44 patients who were diagnosed with EACC between January 2017 and May 2022 at Shenzhen Children’s Hospital were retrospectively reviewed. Clinical features, including external auditory canal wall findings, hearing damage, symptoms and physical examination findings, were analysed against the level of lesion involvement. The correlation between different types of EACC and the incidence of different clinical symptoms was analysed, and the degree of hearing impairment and the rate of bone wall destruction were examined using CT.ResultsThe mean age at EACC onset was 9.02 ± 3.15 years, and the mean age at onset for EACC involving the right ear was older than that of EACC involving the left ear (P < 0.05). There were 44 patients (46 ears), including 10 ears with type I EACC, 23 ears with type II EACC, and 13 ears with type III EACC. Conductive hearing loss was the main type of hearing impairment observed among EACC patients. There were differences in types I, II and III EACC in terms of hearing impairment; specifically, there was a significant difference in moderate hearing impairment between type II and type III EACC patients (P < 0.05). The four most common symptoms were otorrhea, otalgia, itching and bleeding. The incidence of itching symptoms was greater in type I EACC than the incidence of otorrhea, and the incidence of otorrhea symptoms in type II and type III EACC was significantly greater than that in type I EACC(P < 0.05). There were no significant differences in the fracture rates of the anterior, posterior, superior or inferior walls of the external auditory canal within or between type II and type III EACC patients (P > 0.05). The failure rate of scute damage was significantly higher in type III EACC patients than in type II EACC patients (P < 0.05).ConclusionThe presence of otorrhea and hearing loss as well as the identification of granulation tissue during otoscopy suggest the need for a temporal bone CT scan. This imaging modality can aid in the early detection and accurate classification of EACC, thereby guiding the selection of appropriate surgical interventions and greatly assisting in preventing further progression of hearing impairment.

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.

Artificial Intelligence for Otosclerosis Detection: A Pilot Study.

The gold standard for otosclerosis diagnosis, aside from surgery, is high-resolution temporal bone computed tomography (TBCT), but it can be compromised by the small size of the lesions. Many artificial intelligence (AI) algorithms exist, but they are not yet used in daily practice for otosclerosis diagnosis. The aim was to evaluate the diagnostic performance of AI in the detection of otosclerosis. This case-control study included patients with otosclerosis surgically confirmed (2010-2020) and control patients who underwent TBCT and for whom radiological data were available. The AI algorithm interpreted the TBCT to assign a positive or negative diagnosis of otosclerosis. A double-blind reading was then performed by two trained radiologists, and the diagnostic performances were compared according to the best combination of sensitivity and specificity (Youden index). A total of 274 TBCT were included (174 TBCT cases and 100 TBCT controls). For the AI algorithm, the best combination of sensitivity and specificity was 79% and 98%, with an ideal diagnostic probability value estimated by the Youden index at 59%. For radiological analysis, sensitivity was 84% and specificity 98%. The diagnostic performance of the AI algorithm was comparable to that of a trained radiologist, although the sensitivity at the estimated ideal threshold was lower.

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.

Congenital Unilateral Hearing Loss from Cochlear Nerve Canal Stenosis

A 2-month-old baby girl presented with a failed neonatal otoacoustic emission (OAE) hearing screening in the left ear. Combined Auditory Brainstem Response/Auditory Steady-State Response (ABR/ASSR) testing confirmed the presence of a unilateral left moderate to severe hearing loss. No Joint Committee on Infant Hearing (JCIH) risk factors for early childhood hearing loss1 were identified. She subsequently underwent computed tomography (CT) of the temporal bones to determine the presence of any inner ear malformation. No abnormalities of the internal auditory canal, cochlea, semicircular canals and ossicles were noted by the radiologist, and the study was officially reported as a “normal temporal bone CT scan.” Independent review of the CT imaging revealed the presence of a visually apparent disparity in the width of the cochlear nerve canals. (Figure 1) Measurement of the cochlear nerve canal width in the axial plane parallel to the infraorbitomeatal line2 using the length measurement tool in the DICOM imaging software (RadiAnt DICOM Viewer, Version 2024.1, Medixant) indicated a cochlear nerve canal width of 2.18 mm on the right and 1.02 mm on the left. (Figure 2) Applying the suggested cutoff point of 1.2 mm as described by Lin et al.,2 we identified the presence of left cochlear nerve canal stenosis as the etiology of the congenital unilateral hearing loss. The cochlear nerve canal, which has also been referred to as the bony canal for the cochlear nerve (BCNC), cochlear aperture, and cochlear fosette, is the bony transition point between the internal auditory canal and the cochlear modiolus. A relationship between a hypoplastic cochlear nerve canal and congenital sensorineural hearing loss was first suggested by Fatterpekar et al. in 2000.3 Subsequent studies confirmed the association between cochlear nerve canal stenosis and sensorineural hearing loss that ranges from near-normal to profound, with a statistically significant relationship between the degree of hearing loss and the degree of stenosis.4 Various cutoff points to define stenosis of the cochlear nerve canal have been identified in the medical literature. These cutoff points range from 1.2 mm to 1.7 mm when the canal width is measured in the axial plane.2 This particular case demonstrated clear-cut evidence of cochlear nerve canal stenosis, as it satisfied the smallest cutoff criteria (&lt; 1.2 mm) seen in the medical literature. The identification of cochlear nerve canal stenosis as the cause of congenital sensorineural hearing loss is important not only from a diagnostic point, but also from a prognostic perspective. Cochlear nerve deficiency has been noted to be highly prevalent among pediatric patients with cochlear nerve canal stenosis,5 and this has significant negative implications in relation to rehabilitation with external hearing devices and cochlear implants.

Fungal carotiditis with aneurysm - a rare complication of mucormycosis: presentation and management

During the COVID-19 pandemic, cases of mucormycosis (ROCM) had increased drastically, especially in the second wave. Most of these cases involved the paranasal sinuses, orbit and occasionally brain. This case report presents a rare case of mucormycosis complicated with a mycotic aneurysm of the petrous part of the internal carotid artery (ICA). A 43-year-old man presented with left-sided facial weakness for which high resolution computed tomography scan of the Temporal bones was done. A scrutiny of the computed tomography temporal bone showed evidence of osteomyelitis extending to the petrous apex around the foramen Lacerum. Computed tomography and magnetic resonance imaging of the paranasal sinus done later confirmed the diagnosis of mucormycosis. The patient underwent endoscopic surgical debridement of the nose and sinuses, with post-operative amphotericin B. After 3 weeks, the patient presented with bouts of profuse nasal bleed. Computed tomography angiogram showed an aneurysm in the petrous segment of the ICA suggestive of mycotic carotiditis complicated from mucormycosis spread along the skull base. It was successfully managed neurosurgically by a bypass shunting procedure. Mucormycosis is a disease that typically has an aggressive and startling fatality rate. ICA aneurysm is an uncommon occurrence in mucormycosis. Subjects with ROCM should be examined for brain and vascular involvement. Computed tomography angiogram should be performed as soon as possible if the skull base is involved in the ICA area. Morbidity and mortality can often be reduced by early diagnosis and interventions by a multidisciplinary team.

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

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. Retrospective study. Tertiary care center. 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. Fifty-five patients, representing 65 ears, had CAS on CT measurement. Median cochlear aperture width in CAS ears was 0.70 mm (interquartilerange [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. 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.

Topographic Radioanatomical Analysis of the Singular Canal: Computed Tomography Study

Purpose: The singular canal (SC) is where the singular nerve, a branch of the inferior vestibular nerve, which carries afferent information from the posterior semicircular canal (PSCC), passes and is important in the surgical approach of the presigmoid retrolabyrinthine. This study was carried out to evaluate the visibility of the SC on standard computed tomography (CT) images, its distance to the surrounding structures, and to investigate the variations of its anatomy and its relationship with the meatus acusticus internus. Materials and Methods: The study was carried out retrospectively using images of 194 temporal bones on temporal bone CT scans of 44 men and 53 women aged 18–65. In the study, various measurements were made, especially the presence of the SC, its length, its angle with the internal acoustic canal (IAC), and the distance between the internal acoustic pore (IAP) and the singular foramen. In addition, the presence of the high jugular bulb and PSCC dehiscence images were investigated. Results: The SC was detected in 85.1% of the analyzed images. The mean canal length was 3.93 ± 1.22 mm, the angle between the SC and the IAC was 22.68° ±3.60°, and the distance between the SC and the IAP was 7.70 ± 0.83 mm. While no difference was found between the sides, it was determined that the length and diameter of the SC did not differ according to gender. Conclusion: Detailed morphometric analysis of the SC and a thorough understanding of its relationship with the IAC, vestibulum, and PSCC will help to accurately define the posterior and lateral borders of the dissection for this region.

Diagnostic Accuracy of Plain Computed Tomography Temporal Bone in Detection of Pre-operative Ossicular Status versus Per-operative Findings in Chronic Otitis Media.

Ossicular destruction is a common phenomenon in chronic otitis media due to an imbalance between osteoblasts and osteoclasts. Computed tomography helps us in the assessment of ossicular status, extent of pneumatization, and early identification of complications. This study aims to check the diagnostic accuracy of computed tomography temporal bone for the detection of ossicular erosion in comparison with the surgical findings taken as a gold standard. The use of this investigation as an adjunct can prove to be helpful in planning mastoid exploration as well as a primary reconstruction surgery especially in mucosal and early squamosal diseases. It's a cross-sectional validation study done on 50 patients with chronic otitis media (both mucosal and squamous type) from July 2022 to November 2023. Patients underwent CT scanning of temporal bone and ossicular status was reported by the radiologist. Later on, mastoid surgery was carried out and per operative findings were documented. 2 × 2 tables were formed and diagnostic accuracy of CT temporal bone was checked in terms of sensitivity, specificity, negative predictive value, and positive predictive value. The results revealed that CT temporal bone has a high diagnostic accuracy with a sensitivity of 92.5% and specificity of 100% for malleus (p value < 0.001). For incus and stapes, sensitivity came out to be 93.5% and 76% respectively and specificity values were 94.7% and 100% (p value < 0.001 for all) giving a verdict that the pre-operative use of this radiological investigation should be encouraged by otologists.

Correlative Study of High-Resolution Computed Tomography Temporal Bone with Intraoperative Findings in Tympanomastoid Surgery

Abstract Introduction: The global incidence of chronic otitis media (COM) is approximately 4.76 per thousand, with 31 million cases causing various complications. Most of these patients require one of the various forms of mastoid surgeries. High-resolution computed tomography (HRCT) has greatly improved the ability to assess both bony architecture and soft-tissue status. Aim: The aim is to assess the correlation of HRCT temporal bone with intraoperative findings in tympanomastoid surgery and to evaluate the sensitivity, specificity, positive predictive value, and negative predictive value of HRCT temporal bone. Materials and Methods: This prospective study was conducted in the Department of Otorhinolaryngology, SDM College of Medical Sciences and Hospital, Dharwad from November 2012–April 2014. Fifty patients of COM were taken up for study who underwent preoperative HRCT temporal bone followed by appropriate tympanomastoid surgery. Results: HRCT temporal bone showed increased sensitivity and specificity in detecting ossicular chain erosion and soft tissue abnormality within the middle ear and mastoid air cells. Facial nerve canal erosion was correctly detected in 62.50%, and overall agreement between surgical findings and the scan was high (90%). It also showed a very high specificity of 95.24%. For semicircular canal erosion and dural plate erosion, sensitivity was 50% each, specificity was 100% and had a very good correlation with surgical findings. Two cases of erosion of the posterior bony wall of the external auditory canal were correctly detected by the HRCT scan. Conclusion: HRCT temporal bone was found to have a high overall correlation with surgical findings and can be a useful method for early diagnosis of complications of COM and preoperative assessment.

Deep learning reconstruction improves the image quality of low-dose temporal bone CT with otitis media and mastoiditis patients

ObjectiveTo evaluate the image quality of low-dose temporal bone computed tomography (CT) in otitis media and mastoiditis patients by using deep learning reconstruction (DLR). Materials and methodsA total of ninety-seven temporal bones from 53 consecutive adult patients who had suspected otitis media and mastoiditis and underwent temporal bone CT were prospectively enrolled. All patients underwent high resolution CT protocol (group A) and an additional low-dose protocol (group B). In group A, high resolution data were reconstructed by filter back projection (FBP). In group B, low-dose data were reconstructed by DLR mild (B1), DLR standard (B2) and DLR strong (B3). The objective image quality was analyzed by measuring the CT value and image noise on the transverse image and calculating the signal-to-noise ratio (SNR) on incudomallear joint, retroauricular muscle, vestibule and subcutaneous fat. Subjective image quality was analyzed by using a five-point scale to evaluate nine anatomical structures of middle and inner ear. The number of temporal bone lesions which involved in five structures of middle ear were assessed in group A, B1, B2 and B3 images. ResultsThere were no significant differences in the CT values of the four reconstruction methods at four structures (all p > 0.05). The DLR group B1, B2 and B3 had significantly less image noise and a significantly higher SNR than group A at four structures (all p < 0.001). The group B1 had comparable subjective image quality as group A in nine structures (all p > 0.05), however, the group B3 had lower subjective image quality than group A in modiolus, spiral osseous lamina and stapes (all p < 0.001), the group B2 had lower subjective image quality than group A in modiolus and spiral osseous lamina (both p < 0.05). The number of temporal bone lesions which involved in five structures for group A, B1 and B2 images were no significant difference (all p > 0.05), however, the number of temporal bone lesions which involved in mastoid for group B3 images were significantly more than group A (p < 0.05). The radiation dose of high resolution CT protocol and low-dose protocol were 0.55 mSv and 0.11 mSv, respectively. ConclusionCompared with high resolution CT protocol, in the low-dose protocol of temporal bone CT, DLR mild and standard could improve the objective image quality, maintain good subjective image quality and satisfy clinical diagnosis of otitis media and mastoiditis patients.

Quantification of Mastoid Air Cells and Opacification of the Middle Ear in Primary Ciliary Dyskinesia.

To evaluate pneumatization and opacification of the temporal bone on computed tomography (CT) images in patients with primary ciliary dyskinesia (PCD). Retrospective case-control study. Tertiary referral center. Fifteen patients with PCD (30 ears) and 45 age-matched individuals without PCD (90 ears) as controls. Diagnostic only. Quantification of mastoid air cells in the PCD and control groups and comparison between them. Degree of middle ear opacification on CT images of the temporal bone in the PCD group. The volume of the mastoid air cells was 30% smaller in the PCD group than in the control group ( p < 0.05). The suppression ratio, which is defined to indicate how much the average volume of mastoid air cells in the PCD group is suppressed relative to the control group, was 64% lower in the PCD group ( p < 0.05). Opacification was noted in 47% of the mastoid air cells and 63% of the tympanic cavity on CT images of the temporal bone in the PCD group, which were significantly higher frequencies than in the control group (1.1% and 1.1%, respectively). Compared with individuals without PCD, those with PCD showed a significantly smaller volume of mastoid air cells and a significantly higher frequency of opacification of mastoid air cells and tympanic cavity on temporal bone CT. Otitis media raises suspicion for PCD, and the otological manifestations of PCD reported here could help to narrow the differential diagnosis and facilitate early treatment.