Temporal Bone CT Research Articles

Prevalence and characteristics of facial nerve bifurcation in the mastoid segment: a retrospective analysis using temporal bone CT scans.

To investigate the prevalence and characteristics of bifurcation of the facial nerve (FN) in the mastoid segment using temporal bone CT scans. A total of 970 cases (1931 ears) of temporal bone CT scans were reviewed, including 463 females and 498 males, aged 1 to 95years (interquartile range: 20-69years). CT imaging with multiplanar reconstruction (MPR) was used to identify and evaluate the bifurcation of the FN. Cases showing branching were confirmed by consensus among three physicians. We identified 10 cases (10 ears) with facial nerve branching in the vertical segment, yielding an incidence rate of 0.52% (10/1931 ears). Every cases were unilateral, predominantly on the left side. Age analysis revealed 1 case (0.22%) in individuals under 20years and 9 cases (0.61%) in those over 20years. Bifurcation generally occurred near the middle to lower vertical segment, with the closest proximity to the second genu observed in a 15-year-old patient. Bifurcation of the FN in the mastoid segment, though rare, can be encountered in otologic surgery. Detailed preoperative imaging evaluations are crucial for surgical planning to minimize the risk of nerve damage. Our findings emphasize the importance of recognizing anatomical variations in the FN for improving surgical outcomes and patient safety.

Retrolabyrinthine approach to the lateral skull base: The value of preoperative temporal bone CT analysis

PurposeThe most used neurosurgical approach to reach cerebellar-pontine angle is the retrosigmoid route. This article describes the presigmoid approach which requires excellent knowledge of the labyrinthine block together with quantitative analysis of temporal bone CT. MethodsCT-based quantitative measurements were obtained in patients undergoing vestibular neurectomy with a presigmoid approach. Eighteen patients were enrolled, and five measures were taken: Trautmann’s area, the petro-clival angle, presigmoid dura length and its angle. The relationship between these measurements and hospitalization days, operating times, and complications was explored. ResultsThe posterior semicircilar canal (PSC)-sigmoid sinus (SS) distance, presigmoid dura- internal auditory canal (IAC)-PSC angle, and duration of surgery are predictors of complications. Specifically, a PSC-sigmoid sinus distance <11 mm, a dura presig-IAC-PSC angle <14 are associated with the highest risk of complications. ConclusionPreoperative temporal bone CT scan can guide the surgeon through the narrowest areas of the surgical approach. Trautmann’s triangle area and petro-clival angle reduction are challenging and can be faced with combined microscopic-endoscopic technique, and with optics angulation-rotation. The retrolabyrinthine approach can enable hearing preservation and minimal cerebellar retraction.

Minor's Syndrome or Dehiscence of the Superior Semicircular Canal: A Case Report

Semicircular canal dehiscence is a congenital syndrome that mainly affects the superior and, less commonly, the posterior semicircular canal in the temporal bone. This syndrome was first reported by Minor et al. in 1998. The prevalence is about 0.5% in the general population. The most characteristic symptom is the Tullio phenomenon, predominantly vertigo and nystagmus. Hearing loss (in particular conductive loss) often completes overall clinical picture. The dehiscence may be completely asymptomatic, in which case it is seen as an incidental finding on radiological investigations. Audiological evaluation includes audiometry and vestibular evoked myogenic potentials (VEMPs). Clinical symptoms are based on the pathophysiological concept of a third mobile window within the inner ear. Diagnosis is confirmed by high resolution petrous temporal bone CT with multiplanar reconstructions (MPRs) in the plane of the canal (Pöschls’ plane for the superior semicircular canal) and 3-D surface reconstructions. MR findings are less sensitive for this entity. The most common differential diagnosis is otosclerosis. Clinical–radiological correlations have therapeutic applications even though the indication for surgery depends on the severity of the vestibular symptoms.

Modified infra-promontorium trans-channel approach to the petrous apex. Case report

This article describes the approach to the petrous pyramid developed at National Medical Research Center of Otorhinolaryngology, namely an endoscopy – microscopy-guided modified trans-channel infra-promontorium approach with internal carotid artery retraction maneuver in patients with lesions of the petrous pyramid but with preserved hearing. A clinical report describing the apical cholesteatoma of the petrous pyramid and the use of this approach are presented. Anatomical and functional features after the surgery are also described. The purpose of this paper is advancing of the surgical approach to the petrous pyramid with the possibility of hearing preservation. The results of surgical treatment in lesions of the petrous pyramid were evaluated in the immediate and distant periods. The functions of facial mimic muscles were evaluated immediately after the surgery, in 6 months, and in one year. The functions of facial mimic muscles remained at the baseline level during the whole follow-up period. The pure tone audiogram demonstrated the preserved hearing function in the postoperative period. Complete elimination of the pathological process was achieved in all cases (n=15); according to the MRI of the temporal bones, no relapses occurred in a year. The surgical approach proposed for patients with the lesions of the petrous pyramid enables complete removal of the pathological process from the petrous pyramid with the preservation of hearing and facial functions, based on the subjective examinations (audiometry, facial function diagnosis) and radiology (CT and MRI of temporal bones) at the preoperative stage.

Evaluation of Hearing Loss: Understanding Audiologic Testing to Refine Image Interpretation.

The standard of reference for diagnosing and characterizing hearing loss is audiologic testing. The results of audiologic testing inform the imaging algorithm and the differential diagnosis for the underlying cause. Pure-tone audiometry tests the ability to hear tones across different frequencies, and the results are displayed as an audiogram. Tympanometry measures tympanic membrane compliance as a function of pressure to generate a tympanogram. Acoustic reflex testing helps differentiate third window lesions from other causes of conductive hearing loss. Clinical and audiologic assessment of sensorineural hearing loss helps in differentiating cochlear from retrocochlear causes. Symmetrical sensorineural hearing loss is typical of cochlear disease. Asymmetry increases the likelihood of a retrocochlear lesion, the most common of which among adults is vestibular schwannoma. Unlike patients with sensorineural hearing loss, who commonly have normal imaging studies, patients with conductive hearing loss are expected to have abnormal temporal bone CT studies. By incorporating the results of audiologic testing into their evaluation, radiologists can perform a more informed and more intentional search for the structural cause of hearing loss. The authors describe several audiogram configurations that suggest specific underlying mechanisms of conductive hearing loss. By providing a practical and accessible summary of the basics of audiologic testing, the authors empower the radiologist to leverage relevant clinical information and audiologic test results to interpret temporal bone imaging more confidently and more accurately, particularly temporal bone CT in the setting of conductive hearing loss. ©RSNA, 2024.

Prediction of difficult round window visibility during cochlear implantation via a reformatted CT facial recess view: A retrospective study with surgical correlation.

Cochlear implant surgery is performed commonly through the facial recess via the round window (RW) approach. This study aims to evaluate the utility of reformatting the pre-operative CT temporal bone scan into a CT facial recess view in alerting surgeons to a potentially difficult surgery with poorly visualized round window. This is a retrospective study of 41 patients (43 ears), who had undergone cochlear implant surgery. Intraoperative findings of round window position relative to 2nd genu-mastoid portion of facial nerve, and round window membrane orientation were recorded by the surgeons. Pre-operative CTs were analyzed by two radiologists in axial and a reformatted facial recess plane that simulates the surgeon's view via the facial recess. Radiological assessment markers include the facial nerve-chorda tympani nerve width (FN-CTN) measured 1.2mm inferior to the exit point of the chorda tympani nerve into the tympanic cavity, round window position relative to 2nd genu-mastoid segment of the facial nerve and RW membrane's angle from the vertical axis. The best predictor for difficult round window intraoperative visibility is the RW position relative to the 2nd genu-mastoid segment of the facial nerve lying lateral to it on CT facial recess reformatted images. A RW that lies partially to completely posterior to the posterior border of the 2nd genu-mastoid segment of the facial nerve had up to 55.6% risk of encountering difficult access, while those positioned anterior to or partially anterior to the anterior edge of the 2nd genu-mastoid segment of the facial nerve had 0% risk of difficult access (p<0.05). There are substantial agreements in the intra-rater (Kappa=0.751, p<0.001) and inter-rater reliability (Kappa= 0.698, p<0.001). There is no significant association between surgical difficulty and facial nerve-chorda tympani distance or RW angle (p>0.05). Identification of round window positions in the reformatted CT facial recess view is a useful tool in predicting potentially difficult round window access in cochlear implant surgery. RW= Round window, FN-CTN= facial nerve to chorda tympani nerve width.

Treacher Collins Syndrome 2 caused by a novel pathogenic variant in PLOR1D: clinical report and literature review

Objective: To investigate the clinical features, molecular etiology, and treatment of a family with Treacher Collins Syndrome 2 (TCS2). Methods: Information of the proband (female, 8 years old) including medical history and family history was collected. Physical examination and examinations concerning laboratory, audiology, and radiology were performed on the proband. Physical examination was also performed on the family members. Genomic DNA of proband was extracted for whole exome sequencing, and then the genomic DNA of family members was extracted for Sanger sequencing. POLR1D and TCS2 related literatures published before August 31,2023 were searched and sifted in PubMed and CKNI databases. The clinical characteristics of TCS2 were summarized. Results: The proband had poor hearing since childhood, with pure tone audiometry indicating conductive hearing loss. She had a smaller jaw, bilateral preauricular fistulas and cup-shaped ear deformities. Temporal bone CT scan revealed deformities in the left external ear canal, bilateral middle ear and inner ear. A bone-conduction hearing aid device was surgically implanted, resulting in restoration of almost normal hearing levels. The proband's mother also had a slightly smaller jaw. Genetic analysis revealed a novel heterozygous variant NM_015972.4:c.38_47del in the POLR1D gene in the proband, which was inherited from her mother. A review of the literature revealed no clear evidence of genotype-phenotype correlation in TCS2. Conclusions: Molecular diagnosis plays a vital role in the diagnosis of TCS2. Patients with normal facial phenotype may be carriers of pathogenic variants in the POLR1D gene and have the risk of passing it to the offsprings with complete penetrance. Proper bone conductive hearing devices can improve the quality of life of TCS2 patients.

Clinical analysis of 50 patients with abnormal pulsatile tinnitus in sigmoid sinus

Objective: To analyze the disease characteristics, diagnosis and treatment methods of venous pulsatile tinnitus treated by intervention of sigmoid sinus. Methods: Fifty patients (from Shandong Provincial ENT Hospital, Shandong University between February 2014 and July 2020) with venous pulsatile tinnitus treated by sigmoid sinus surgery were analyzed retrospectively. The tinnitus characteristics, imaging findings, surgical methods, intraoperative findings and postoperative tinnitus changes were recorded. The patients were followed up for 6-12 months. The sign rank sum test was used to analyze the difference in tinnitus grading before and after surgery. There were 50 patients with unilateral venous pulsatile tinnitus, including 49 females and 1 male. The age ranged from 17 to 67 years, with a median age of 44 years. There were 45 cases of right tinnitus and 5 cases of left tinnitus. The degree of tinnitus before operation was grade Ⅱ or above, including 4 cases of gradeⅡ, 11 cases of grade Ⅲ, 22 cases of grade Ⅳ and 13 cases of grade Ⅴ. Results: Thirty-seven cases were cured, 8 cases were ineffective (no change in tinnitus), 3 cases were markedly effective (tinnitus grade decreased by 3 in 2 cases, 4 in 1 case), and 2 cases were effective (tinnitus grade decreased by 1). The difference of tinnitus grade before and after operation was statistically significant (Z=-5.70,P<0.05). Temporal bone CT showed 36 cases of sigmoid diverticulum (including 17 cases with sigmoid sinus dehiscence), 12 cases of sigmoid sinus dehiscence and 2 cases of absence of the temporal bone cortex abutting to sigmoid sinus. Thirty-five cases were performed with closure of sigmoid sinus diverticulum, 4 cases were performed with resurfacing of the sigmoid plate, 5 cases were performed with narrowing of sigmoid sinus, 4 cases were performed with simple opening of pre sigmoid mastoid air chamber, 1 case of opening was performed with pre sigmoid mastoid air chamber combined with narrowing of sigmoid sinus, and 1 case was performed with opening of pre sigmoid mastoid air chamber combined with closure of sigmoid sinus diverticulum. Conclusions: Venous pulsatile tinnitus is common in women. The common causes may be sigmoid sinus wall abnormalities such as sigmoid sinus diverticulum and perisigmoid bone defect. Imaging examinations are helpful for diagnosis. Venous pulsatile tinnitus can be treated with surgery.

Retrolabyrinthine Bone Thickness as a Radiologic Marker for the Hypoplastic Endotype in Menière Disease.

Menière disease (MD) manifests in 2 major endotypes: one with a hypoplastic, underdeveloped endolymphatic sac (MD-hp) and the other with a normally developed sac that degenerates over time (MD-dg). Determining the specific endotype in patients is important for predicting disease progression, tailoring patient counseling, and optimizing treatment strategies. Endotype diagnosis involves measuring an angular trajectory of the vestibular aqueduct (ATVA), with an ATVA ≥140° indicative of MD-hp and an ATVA ≤120° of MD-dg. However, assessing the ATVA can be challenging. This study aimed to explore the link between ATVA and the thickness of the retrolabyrinthine bone as an alternative diagnostic measure that could provide differentiation between MD endotypes using CT and MR imaging. Retrospective review of CT temporal bone imaging from 32 adult patients with definite MD (60 ears) and 33 age-matched controls without MD or other inner ear symptoms (61 ears) was performed. The ATVA and retrolabyrinthine bone thickness were measured using uniform methodology on standardized axial CT images. Comparative analyses were performed to determine the correlation between ATVA and retrolabyrinthine bone thickness. Additionally, from a separate cohort of 11 patients (22 ears), CT and MR examinations of the temporal bone were retrospectively reviewed for retrolabyrinthine bone thickness measurements, to verify the correlation across the 2 modalities. The average retrolabyrinthine bone thickness was statistically significantly different between MD endotypes, being a mean of 0.8 (SD, 0.3) mm in patients with MD-hp (ATVA ≥140°) and 2.0 (SD, 0.9) mm in patients with MD-dg (ATVA ≤120°), with a consistent pattern of thin retrolabyrinthine bone in MD-hp and variable thickness in MD-dg. Receiver operating characteristic curve analysis within the MD cohort revealed that a retrolabyrinthine bone thickness ≥1.2 mm effectively rules out MD-hp. Excellent interrater reliability was noted for the retrolabyrinthine measurement, and there was near-perfect correlation between CT and MR measurements. Retrolabyrinthine bone thickness proved to be a useful and straightforward alternative marker for distinguishing MD endotypes, being particularly useful for excluding MD-hp. Including information on retrolabyrinthine bone thickness should be considered a routine part of reporting in the context of MD imaging.

The Photon-Counting CT Enters the Field of Cochlear Implantation: Comparison to Angiography DynaCT and Conventional Multislice CT.

Cochlear duct length (CDL) measurement plays a role in the context of individualized cochlear implant (CI) surgery regarding an individualized selection and implantation of the CI electrode carrier and an efficient postoperative anatomy-based fitting process. The level of detail of the preoperative temporal bone CT scan depends on the imaging modality with major impact on CDL measurements and CI electrode contact position determination. The aim of this study was to evaluate the accuracy of perioperative CDL measurements and electrode contact determination in photon-counting CT (PCCT). Ten human fresh-frozen petrous bone specimens were examined with a first-generation PCCT. A clinically applicable radiation dose of 27.1 mGy was used. Scans were acquired before and after CI insertion. Postoperative measurement of the CDL was conducted using an otological planning software and 3D-curved multiplanar reconstruction. Investigation of electrode contact position was performed by two respective observers. Measurements were compared with a conventional multislice CT and to a high-resolution flat-panel volume CT with secondary reconstructions. Pre- and postoperative CDL measurements in PCCT images showed no significant difference to high-resolution flat-panel volume CT. Postoperative CI electrode contact determination was also as precise as the flat-panel CT-based assessment. PCCT and flat-panel volume CT were equivalent concerning interobserver variability. CDL measurement with PCCT was equivalent to flat-panel volume CT with secondary reconstructions. PCCT enabled highly precise postoperative CI electrode contact determination with substantial advantages over conventional multislice CT scanners.

Computed tomographyScan Size Analysis of stapedius and tensor tympani muscles in middle ear myoclonic tinnitus.

To analyze the sizes of the stapedius and tensor tympani (TT) muscles using a temporal bone CT (TBCT) scan in patients with middle ear myoclonic tinnitus (MEMT) and investigate their value for the diagnosis of this rare cause of tinnitus. Medical records and TBCT of patients with MEMT or vascular tinnitus (VT) at Seoul St. Mary's Hospital from January 2012 to December 2022 were reviewed. The stapedius and TT muscles were analyzed. Thirty-eight patients with unilateral MEMT and 39 patients with VT were included. More males were in the MEMT group compared to the VT group (MEMT: n = 24, VT: n = 8, p = .001). The mean age of the MEMT group was younger compared to the VT group (MEMT: 35 ± 12 years, VT: 44 ± 14.3 years, p = .005). The mean BMI for the MEMT group was less than the VT group (MEMT: 22.3 ± 2.5, VT: 24.8 ± 4.36, p = .010). The mean length and width of the stapedius in the MEMT group were larger than those of the VT group (Length MEMT: 1.47 ± 0.60 mm, VT: 0.98 ± 0.24 mm, p = .001; Width MEMT: 0.89 ± 0.32 mm, VT: 0.72 ± 0.19 mm, p = .009). The mean length and width of the TT in the MEMT group were larger than that of the VT group (Length MEMT: 3.10 ± 0.50 mm, VT: 2.27 ± 0.42, p = .001; Width MEMT: 2.02 ± 0.36, VT: 1.75 ± 0.26 p = .001). The mean length and width of the stapedius and TT muscles measured in the MEMT group were longer and wider than the VT group. This suggests the use TBCT scan as a diagnostic tool for MEMT. Further studies with a larger study group to validate the results of this study are recommended.Level of Evidence: 4.

Retrolabyrinthine approach to the lateral skull base: The value of preoperative temporal bone CT analysis

PurposeThe most used neurosurgical approach to reach cerebellar-pontine angle is the retrosigmoid route. This article describes the presigmoid approach which requires excellent knowledge of the labyrinthine block together with quantitative analysis of temporal bone CT. MethodsCT-based quantitative measurements were obtained in patients undergoing vestibular neurectomy with a presigmoid approach. Eighteen patients were enrolled, and five measures were taken: Trautmann’s area, the petro-clival angle, presigmoid dura length and its angle. The relationship between these measurements and hospitalization days, operating times, and complications was explored. ResultsThe posterior semicircilar canal (PSC)-sigmoid sinus (SS) distance, presigmoid dura- internal auditory canal (IAC)-PSC angle, and duration of surgery are predictors of complications. Specifically, a PSC-sigmoid sinus distance <11 mm, a dura presig-IAC-PSC angle <14 are associated with the highest risk of complications. ConclusionPreoperative temporal bone CT scan can guide the surgeon through the narrowest areas of the surgical approach. Trautmann’s triangle area and petro-clival angle reduction are challenging and can be faced with combined microscopic-endoscopic technique, and with optics angulation-rotation. The retrolabyrinthine approach can enable hearing preservation and minimal cerebellar retraction.

Effect analysis of facial nerve decompression surgery in the treatment of Bell's palsy and Hunt syndrome

Objective:To summarize and analyze the effect of facial nerve decompression surgery for the treatment of Bell's palsy and Hunt syndrome. Methods:The clinical data of 65 patients with facial nerve palsy who underwent facial nerve decompression in our center from October 2015 to October 2022 were retrospectively analyzed, including 54 patients with Bell's palsy and 11 patients with Hunter syndrome. The degree of facial paralysis（HB grade） was evaluated before surgery, and ENoG, pure tone audiometry, temporal bone CT and other examinations were completed. All patients had facial palsy with HB grade V or above after conservative treatment for at least 1 month, and ENoG decreased by more than 90%. All patients underwent facial nerve decompression surgery through the transmastoid approach within 3 months after onset of symptoms. The recovery effect of facial nerve function after surgery in patients with Bell's palsy and Hunter syndrome was summarized and analyzed. In addition, 15 cases in group A（operated within 30-60 days after onset） and 50 cases in group B（operated within 61-90 days after onset） were grouped according to the course of the disease（the interval between onset of symptoms and surgery） to explore the effect of surgical timing on postoperative effect. Results:There was no significant difference between the two groups of patients with Chi-square test（P=0.54） in 42 patients（77.8%, 42/54） with Bell's palsy and 7 patients（63.6%, 7/11） in patients with Hunter syndrome who recovered to grade Ⅰ-Ⅱ. According to the course of the disease, 10 cases（66.7%, 10/15） in group A recovered to grade Ⅰ-Ⅱ after surgery. In group B, 39 patients（78.0%, 39/50） recovered to grade Ⅰ-Ⅱ after surgery, and there was no statistically significant difference between the two groups by Chi-square test（P=0.58）. Conclusion:Patients with Bell's palsy and Hunter syndrome can achieve good results after facial nerve decompression within 3 months of onset, and there is no significant difference in the surgical effect between the two types of patients.

Radiation dose reduction and image quality improvement with ultra-high resolution temporal bone CT using deep learning-based reconstruction: An anatomical study

PurposeThe purpose of this study was to evaluate the achievable radiation dose reduction of an ultra-high resolution computed tomography (UHR-CT) scanner using deep learning reconstruction (DLR) while maintaining temporal bone image quality equal to or better than high-resolution CT (HR-CT). Materials and methodsUHR-CT acquisitions were performed with variable tube voltages and currents at eight different dose levels (volumic CT dose index [CTDIvol] range: 4.6–79 mGy), 10242 matrix, and 0.25 mm slice thickness and reconstructed using DLR and hybrid iterative reconstruction (HIR) algorithms. HR-CT images were acquired using a standard protocol (120 kV/220 mAs; CTDI vol, 54.2 mGy, 5122 matrix, and 0.5 mm slice thickness). Two radiologists rated the image quality of seven structures using a five point confidence scale on six cadaveric temporal bone CTs. A global image quality score was obtained for each CT protocol by summing the image quality scores of all structures. ResultsWith DLR, UHR-CT at 120 kV/220 mAs (CTDIvol, 50.9 mGy) and 140 kV/220 mAs (CTDIvol, 79 mGy) received the highest global image quality scores (4.88 ± 0.32 [standard deviation (SD)] [range: 4–5] and 4.85 ± 0.35 [range: 4–5], respectively; P = 0.31), while HR-CT at 120 kV/220 mAs and UHR-CT at 120 kV/20 mAs received the lowest (i.e., 3.14 ± 0.75 [SD] [range: 2–5] and 2.97 ± 0.86 [SD] [range: 1–5], respectively; P = 0.14). All the DLR protocols had better image quality scores than HR-CT with HIR. ConclusionUHR-CT with DLR can be performed with up to a tenfold reduction in radiation dose compared to HR-CT with HIR while maintaining or improving image quality.

Low-dose versus standard-dose normal temporal bone CT in children: a comparison study

ObjectiveTo compare the image quality of normal anatomical structures and radiation dose on low-dose (LDCT) and standard-dose (SDCT) temporal bone CT in children.MethodsThe study included 45 LDCT (80 kV and 130 mAs) and 45 SDCT (120 kV and 170 mAs) scans in children, 1–15 years of age. LDCT and SDCT scans were analyzed on H60s and H70h reconstruction kernels, respectively. Two readers assessed the image quality for 25 anatomical structures, using a 5-point scale. A score of 3 and above was considered “sufficient” and 2 and below was considered “insufficient” image quality. Image noise, contrast, age and size-specific effective doses were calculated.ResultsDespite an increase in image noise on LDCT, image quality remained sufficient for most structures owing to increased image contrast. The median effective dose on LDCT, calculated with age-specific conversion factor, decreased by 72.9% and that calculated with size-specific conversion factor decreased by 81.8% compared to the dose on SDCT.ConclusionLDCT provides comparable image quality for evaluation of temporal bone with significant reduction in radiation dose in children.

Comparison of Image Quality and Radiation Dose in Pediatric Temporal Bone CT Using Photon-Counting Detector CT and Energy-Integrating Detector CT.

Currently, there is a lack of research directly comparing photon-counting detector CT (PCD-CT) and energy-integrating detector CT (EID-CT) in pediatric temporal bone CT imaging. The purpose of this study was to compare the image quality and radiation dose of temporal bone CT scans in pediatric patients acquired with PCD-CT and EID-CT. The retrospective study included a total of 110 pediatric temporal bone CT scans (PCD-CT, n = 52; EID-CT, n = 58). Two independent readers evaluated the spatial resolution of 4 anatomic structures (tympanic membrane, incudostapedial joint, stapedial crura, and cochlear modiolus) and overall image quality by using a 4-point scale. Interreader agreement was assessed. Dose-length product for each CT was compared, and subgroup analyses were performed based on age (younger than 3 years, 3-5 years, 6-11 years, and 12 years and above). PCD-CT demonstrated statistically significantly higher scores than EID-CT for all items (tympanic membrane, 2.9 versus 2.4; incudostapedial joint, 3.6 versus 2.6; stapedial crura, 3.2 versus 2.4; cochlear modiolus, 3.4 versus 2.8; overall image quality, 3.6 versus 2.8; P < .05). Interreader agreement ranged from good to excellent (interclass correlation coefficients, 0.6-0.81). PCD-CT exhibited a 43% dose reduction compared with EID-CT, with a particularly substantial reduction of over 70% in the subgroups of children younger than 6 years. PCD temporal bone CT achieves significantly superior imaging quality at a lower radiation dose compared with EID-CT.

Postoperative complications in cochlear implant surgery and their possible risk factors

ObjectiveThis is a retrospective analysis of the major and minor complications of cochlear implants, as well as the Risk Factors (RF) involved. MethodsWe analyzed the medical records of patients submitted to cochlear implants at public University from 2006 to July 2019, and list here the major and minor complications found, and their risk factors. ResultsThere were 193 ears, 100 (51.3%) from females and 93 (48.2%) from males, with a mean age of 23.63 years. In 54 of them (28%), there were alterations seen in the Temporal Bone CT scan, and 44 (22.8%) in the brain MRI. There were 158 (81.9%) insertions performed; 127 (65.8%) of them through the round window. There were 78 complications: 19 (9.8%) major and 56 (29%) minor complications. Among the major complications, there were 3 (1.6%) Surgical Site infections (SS); 5 (2.6%) hematomas/seromas; 5 (2.6%) electrode extrusion; 5 (2.6%) device faults; 1 (0.5%) wrong path. Among the minor complications, there were 6 (3.1%) Acute Otitis Media (AOM); 9 (4.7%) SS infections; 4 (2.1%) facial paresis; 17 (8.8%) vertigos; 9 (4.7%) with tinnitus. The most important RF was age. Patients younger than 2.5 years had more major complications: SS infection (p = 0.018) and electrode extrusion (p = 0.017). There was a higher rate of vertigo in adults (p = 0.003), and it was more often associated with comorbidities (p = 0.008). The insertion route, the presence of changes in CT and MRI and the CI brand used did not impact the number of complications. ConclusionAmong the minor complications, those involving the vestibular system were the most common, especially in adults with comorbidities. Regarding major complications, there was an emphasis on SS infections, hematomas, seromas, electrode extrusion, especially in children under two years of age. There were implanted device faults (2.6%), with none of the brands evaluated standing out.

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.

Measurement of stapes footplate thickness using ultra-high-resolution computed tomography: stapes axial plane correlates better with otosclerosis than lateral semicircular canal plane

Background, Aims Stapes footplate thickness measurement using ultra-high-resolution CT has been described only in the lateral semicircular canal plane. The purpose of this study was to compare stapes footplate thickness between the lateral semicircular canal and stapes axial planes in patients with otosclerosis compared to controls. Material and methods We performed a retrospective single-center study of patients undergoing high-resolution temporal bone CT. Two radiologists measured stapes footplate thickness in both the lateral semicircular canal and stapes axial planes. Results Between February 2020 and October 2022, we collected 81 ears from 49 patients (75% of women; mean age 51.22 ± 16.6 years, 17 otosclerosis, and 64 controls). In the stapes axial plane, there was a significant anterior thickening in otosclerosis patients (Reader 1: 0.52 ± 0.12 [0.3-0.7] vs. 0.41 ± 0.08 [0.3-0.6], p = 0.001; Reader 2: 0.54 ± 0.06 [0.5-0.7] vs. 0.39 ± 0.08 [0.2-0.6], P < 0.001) compared to controls. These differences were not significant using the lateral semicircular canal plane. Conclusion The stapes footplate was thickened at its AC in otosclerosis patients using only the stapes axial plane. Significance We propose to use the stapes axial plane instead of the lateral semicircular canal plane when analyzing the stapes.

Wideband acoustic immittance characteristics and machine learning-based diagnostic model for children with large vestibular aqueduct syndrome

Objective:This study was to investigate the wideband acoustic immittance（WAI） characteristics of children with large vestibular aqueduct syndrome（LVAS） and to construct a diagnostic model for LVAS based on WAI and machine learning（ML） techniques. Methods:We performed a retrospective analysis of the data from 38 children（76 ears） with LVAS and 44 children（88 ears） with normal hearing. The data included conventional audiological examination, temporal bone CT scan and WAI test. We performed statistical analysis and developed multivariate diagnostic models based on different ML techniques. Results:The two groups were balanced in terms of ear, gender, and age（P>0.05）. The wideband absorbance（WBA） of the LVAS group was significantly lower than that of the control group at 1 000-2 519 Hz, while the WBA of the LVAS group was significantly higher than that of the control group at 4 000-6 349 Hz（P<0.05）. WBA at 5 039 Hz under ambient pressure had a certain diagnostic value（AUC=0.767）. The multivariate diagnostic model had a high diagnostic value（AUC>0.8）, among which the KNN model performed the best（AUC=0.961）. Conclusion:The WAI characteristics of children with LVAS are significantly different from those of normal children. The diagnostic model based on WAI and ML techniques has high accuracy and reliability, and provides new ideas and methods for intelligent diagnosis of LVAS.