Refining feasibility assessment of endoscopic ear surgery: a radiomics model utilizing machine learning on external auditory canal CT scans.

BACKGROUND: Feasibility assessment of endoscopic ear surgery (EES) relies solely on subjective evaluation by surgeons. OBJECTIVE: Extracting radiomic features from preoperative CT images of the external auditory canal, we aim to classify EES patients into easy and difficult groups and improve accuracy in determining surgery feasibility. METHODS: 85 patients' external auditory canal CT scans were collected and 139 radiomic features were extracted using PyRadiomics. The most relevant features were selected and three machine learning algorithms (logistic regression, support vector machine, and random forest) were compared using K-fold cross-validation (k = 5) to predict surgical feasibility. RESULTS: The best-performing machine learning model, the support vector machine (SVM), was selected to predict the difficulty of EES. The proposed model achieved a high accuracy of 86.5%, and F1 score of 84.6%. The area under the ROC curve was 0.93, indicating good discriminatory power. CONCLUSIONS AND SIGNIFICANCE: The proposed machine learning model provides a reliable and accurate method for classifying patients undergoing otologic surgery based on preoperative imaging data. The model can help clinicians to better prepare for challenging surgical cases and optimize treatment plans for individual patients.

Validation of Earphone-Type Sensors for Non-Invasive and Objective Swallowing Function Assessment.

Standard methods for swallowing function evaluation are videofluoroscopy (VF) and videoendoscopy, which are invasive and have test limitations. We examined the use of an earphone-type sensor to noninvasively evaluate soft palate movement in comparison with VF. Six healthy adults wore earphone sensors and swallowed barium water while being filmed by VF. A light-emitting diode at the sensor tip irradiated infrared light into the ear canal, and a phototransistor received the reflected light to detect changes in ear canal movement, including that of the eardrum. Considering that the soft palate movement corresponded to the sensor waveform, a Bland-Altman analysis was performed on the difference in time recorded by each measurement method. The average difference between the time taken from the most downward retracted position before swallowing to the most upward position during swallowing of the soft palate in VF was -0.01 ± 0.14 s. The Bland-Altman analysis showed no fixed or proportional error. The minimal detectable change was 0.28 s. This is the first noninvasive swallowing function evaluation through the ear canal. The earphone-type sensor enabled us to measure the time from the most retracted to the most raised soft palate position during swallowing and validated this method for clinical application.

Projected Cost Simulation in Chronic Ear Surgery: Cost in Chronic Ear Surgery.

OBJECTIVE: To examine the projected healthcare costs of intact canal wall (ICW) and canal wall down (CWD) tympanomastoidectomy surgery and associated clinic follow-up visits in the management of chronic ear disease. STUDY DESIGN: A review of literature was performed to analyze the cholesteatoma recidivism rates of ICW and CWD tympanomastoidectomy. Projected Medicare cost simulation applied to representative samples of patients undergoing otologic surgery and follow-up clinic appointments projected over 15 years with an annual 25% cholesteatoma recidivism rate. SETTING: Tertiary academic center. PATIENTS: Simulated patient population status postchronic ear surgery and representative follow-up clinic visits with or without in-office mastoid debridement procedures. INTERVENTIONS: Therapeutic and rehabilitative. MAIN OUTCOME MEASURES: Healthcare cost. RESULTS: Simulation of cost for chronic ear surgery with follow-up visits produced a higher mean cost for the ICW group compared with the CWD group at year 1 ($9112.06 versus $4954.16). However, CWD patients accumulate cost over time due to routine mastoid debridements. The accumulated costs for the CWD group surpassed the ICW group at 12.54 (CI: 12.02-13.11) years. CONCLUSIONS: Using a projected cost analysis model, intact canal wall tympanomastoidectomy incurs a larger upfront cost than the canal wall down technique. However, long-term mastoid cavity maintenance costs accumulate to surpass the intact canal wall group at 12.54 years.

Patient Use of Low-cost Digital Videoscopes and Smartphones for Remote Ear and Oropharyngeal Examinations.

Importance: During the novel coronavirus disease 2019 pandemic, telehealth has become a vital component of health care delivery. For otolaryngology evaluations, examination of the ear and oropharynx is important but difficult to achieve remotely. Objective: To assess the feasibility of patient use of low-cost digital videoscopes and smartphones for examination of the ear and oropharynx. Design, Setting, and Participants: A prospective quality improvement study was conducted in an academic adult otolaryngology clinic including 23 patients who presented for an in-person appointment and owned a smartphone device. The study was conducted from July 1 to 15, 2020. Interventions: Participants were asked to capture pictures and videos of their ear canals and oropharynx with digital videoscopes and their smartphones under real-time guidance over a telehealth platform. They were then surveyed about their experience. Main Outcomes and Measures: The primary outcomes were ratings by health care clinicians and a blinded otolaryngologist reviewer of image acceptability. Secondary outcomes included participant time to image acquisition and willingness to purchase digital videoscopes for telehealth use. Results: Of the 23 participants included, 14 were women (61%); mean age was 50 years (range, 21 to 80 years). Of the images obtained using the digital otoscope ear examination, 95% were considered acceptable by the health care clinicians and 91% were considered acceptable by the blinded reviewer; 16 participants (70%) reported that the otoscope was easy to use. The mean time to acquire images for both ears was 114 seconds (95% CI, 84-145 seconds). Twenty-one participants (91%) were willing to pay for a digital otoscope for telehealth use. For the oropharyngeal examination, a greater proportion of smartphone video examinations were considered acceptable by clinicians (63% acceptability) and the blinded reviewer (55%) compared with the digital endoscope (clinicians, 40%; blinded reviewer, 14%). The mean time required for the oropharyngeal examination smartphone video capture was shorter at 35 seconds compared with both the digital endoscope (difference, -27 seconds; 95% CI, -7 to -47 seconds) and smartphone photo capture (difference, -53 seconds; 95% CI, -20 to -87 seconds). Conclusions and Relevance: Digital otoscopes and smartphones apparently can facilitate remote head and neck physical examination in telehealth. Digital otoscopes were useful for ear examinations, and smartphone videos appeared to be the most useful for oropharyngeal examinations. Further studies are required to determine specific diagnostic capabilities in various telehealth practice settings.

Objective assessment of autophony during phonation in the diagnosis of patulous Eustachian tube patients.

OBJECTIVE: A system enabling the objective assessment of the transmission of voice sounds to the external auditory canal (EAC) during phonation has recently been revised. Our aim was to evaluate the effectiveness of this new system in the diagnosis of patulous Eustachian tube (PET) patients by comparing the results obtained using this method with those obtained from conventional objective tests to diagnose PET. METHODS: A prospective survey of medical records was included with definite PET, possible PET, and sensorineural hearing loss as control. The measurement system consists of a personal computer, an AD/DA converter (NI 6361, National Instruments), a probe microphone system for recording voice sound (ER-10C, Etymotic Research) and two microphones for measuring noise sound in the EAC (ER-10B+, Etymotic Research). Pronouncing the "Ni" sound for 5 s were recorded with these three microphones. The ratio of the maximum sound pressure of voice sound and noise sound in EAC (EAC/Voice) was simultaneously calculated, and results were displayed on a personal computer for diagnosing. RESULTS: Thirty-one patients of 42 ears with definite PET, 26 patients of 38 ears with possible PET, and 12 patients of 24 ears with sensorineural hearing loss as control were included. The EAC/Voice were 8.63 ± 5.43, 25.41 ± 32.63, and 25.87 ± 24.93 in the control, definite PET, and possible PET group respectively. The control group was significantly different from the definite PET (p < 0.05) and possible PET group (p < 0.05). ROC curve analysis confirmed 14.7 as the best diagnostic cut-off value of EAC/Voice (area under the curve=0.782, 95% CI 0.671-0.894). By adopting this cut-off point, 25 (56.8%) and 22 (61.1%) ears were determined as positive findings in the definite PET and possible PET group, respectively. There was no significant correlation between the positive findings judged by the current method and that of sonotubometry in the control (r = -0.63, p = 0.769), definite PET (r = 0.12, p = 0.451), and possible PET group (r = 0.12, p = 0.451). CONCLUSION: The current system is more useful in the objective assessment of autophony during phonation by calculating the ratio of voice sound and elicited noise sound transmitted in the EAC (EAC/Voice). This method seems promising because it is able to detect cases eluding conventionally used test methods such as sonotubometry performed without phonation, thereby increasing the accuracy of PET diagnoses.

External auditory exostoses and early Neolithic aquatic resource procurement in Cyprus: Results from Cypro-PPNB Kissonerga-Mylouthkia in regional context.

OBJECTIVE: This research is designed to evaluate the occurrence of external auditory exostoses (EAEs) in skeletal remains from the oldest known water wells in the world (Kissonerga-Mylouthkia, Cyprus, 8,200-7,200 BCE). MATERIALS: Six individuals (MNI = 6), five fragmentary temporalia, two preserved auditory canals. METHODS: Macroscopic and microscopic (up to x30) observation, with illumination; presence, type, side, severity, occlusion, number, and position of bony growths recorded. RESULTS: Bony growths within two auditory canals were discovered. Differential diagnosis includes osteomata and external auditory exostoses, with the latter consistent with the bony growths (Grade 1 EAEs, two adult males, one with single, another with two EAEs). CONCLUSIONS: The emergence of the Neolithic in Southwest Asia is thought to involve increases in dietary breadth among foraging societies (Broad-Spectrum Revolution). EAEs likely indicate maritime activity in this context, given the lack of freshwater bodies, and zooarchaeological evidence points to dietary and other uses of maritime organisms. SIGNIFICANCE: This EAE evidence is the oldest known in maritime contexts in Eastern Mediterranean and the Middle East, and first in Cyprus. It contributes towards understanding the initial colonization events by Neolithic farming communities in the 9th millennium BC, and the emergence of broad-spectrum economies at the dawn of the Neolithic in Southwest Asia, crucial for re-considerations of paradigms on the transition to the Neolithic way of life in the Near East. LIMITATIONS: Only a few skeletal remains from these prehistoric contexts were available for observation. SUGGESTIONS FOR FURTHER RESEARCH: Further intensive review of Cypriot skeletal collections for EAEs is advised.

Can we predict the altered subjective quality assessment of sound after ear canal surgery?

PURPOSE: To correlate the subjective quality assessment of ear canal acoustics of the participants to the objective measurement of the ear canal acoustics. The objective ear canal acoustics is the frequency-dependent modulation of soundwaves through the ear canal. Our second objective is to design a model to predict the subjective quality of sound based on the altered objective ear canal acoustics. METHODS: To determine the frequency-dependent modulation of the soundwaves the real-ear unaided gain (REUG) of the ear canal is measured. 40 participants with normal hearing were presented six simulated sound fragments representing the acoustic properties of six different ear canals (REUG). These six sound fragments were built based on the difference between these six REUGs and the average REUG of a normal adult ear canal. Subjective sound quality was evaluated using a VAS score and a paired comparison score. RESULTS: We found a strong correlation between the objective ear canal acoustics and the subjective assessment of the quality of sound (Spearman's rho-0.89). Our linear mixed VAS model for individual participants has an intercept of 95.6 and a slope of - 4.2 (p < 0.001). The paired comparison analysis endorsed our findings that an increased difference in REUG is predictive for a decreased quality assessment of ear canal acoustics. CONCLUSION: There is a strong correlation between the subjective evaluation of ear canal acoustics and the objective quality assessment of ear canal acoustics. Our models show that an increased difference in REUG predicts a decreased quality of ear canal acoustics.

Endoscopic Assessment of the Isthmus Tympanicum and Tensor Tympani Fold and their Relationship with Mastoid Pneumatization in Chronic Otitis Media.

OBJECTIVES: To endoscopically evaluate the patency of the isthmus tympanicum and integrity of the tensor tympani fold as routes of ventilation of the attic and mastoid in chronic otitis media (COM) and to assess their effects on mastoid pneumatization. MATERIALS AND METHODS: Sixty patients with COM were categorized into two groups: (1) Group A: 36 patients with tympanic membrane perforation (2) Group B: 24 patients with limited attic disease of whom 14 patients had attic retraction pockets and 10 with limited attic cholesteatoma. A multislice computed tomography scan of the temporal bone was performed for each patient to assess the degree of mastoid pneumatization. Notably, either myringoplasty or tympanomastoid surgery was performed in all patients. An endoscope was inserted into the middle ear for evaluation of the isthmus tympanicum and tensor fold area. RESULTS: The isthmus tympanicum was patent in most ears (83.3%) of group A, whereas it was blocked in most ears (83.3%) of group B. The tensor fold was complete in 77.8% of ears in group A and 83.3% of ears in group B. It was observed that 94.1% of ears with patent isthmus in both groups had normal mastoid pneumatization and 5.9% of ears had poorly pneumatized mastoid. By contrast, 7.7% of ears with blocked isthmus tympanicum had normal mastoid pneumatization and 92.3% had poor mastoid pneumatization. Normal mastoid pneumatization was observed in 50% of ears in both groups with complete tensor fold, and 83.3% of ears with an incomplete tensor fold. CONCLUSION: A significant correlation was observed between COM with limited attic disease and obstruction of the isthmus tympanicum. Obstruction of isthmus tympanicum was associated with poor mastoid pneumatization. Furthermore, an incomplete tensor fold was associated with well pneumatized mastoid.

In vitro assessment of the antimicrobial susceptibility of caprine isolates of Mycoplasma mycoides subsp. capri.

The minimum inhibitory concentration (MIC) and minimum mycoplasmacidal concentration (MMC) of 17 antimicrobials against 41 Spanish caprine isolates of Mycoplasma mycoides subsp. capri (Mmc) obtained from different specimens (milk, external auricular canal and semen) were determined using a liquid microdilution method. For half of the isolates, the MIC was also estimated for seven of the antimicrobials using an epsilometric test (ET), in order to compare both methods and assess the validity of ET. Mutations in genes gyrA, gyrB, parC and parE conferring fluoroquinolone resistance, which have been recently described in Mmc, were investigated using PCR. The anatomical origin of the isolate had no effect on its antimicrobial susceptibility. Moxifloxacin and doxycycline had the lowest MIC values. The rest of the fluoroquinolones studied (except norfloxacin), together with tylosin and clindamycin, also had low MIC values, although the MMC obtained for clindamycin was higher than for the other antimicrobials. For all the aminoglycosides, spiramycin and erythromycin, a notable level of resistance was observed. The ET was in close agreement with broth microdilution at low MICs, but not at intermediate or high MICs. The analysis of the genomic sequences revealed the presence of an amino acid substitution in codon 83 of the gene gyrA, which has not been described previously in Mmc.

Safety assessment of trans-tympanic photobiomodulation.

We evaluated functional and morphological changes after trans-tympanic laser application using several different powers of photobiomodulation (PBM). The left (L) ears of 17 rats were irradiated for 30 min daily over 14 days using a power density of 909.1 (group A, 5040 J), 1136.4 (group B, 6300 J), and 1363.6 (group C, 7560 J) mW/cm(2). The right (N) ears served as controls. The safety of PBM was determined by endoscopic findings, auditory brainstem response (ABR) thresholds, and histological images of hair cells using confocal microscopy, and light microscopic images of the external auditory canal (EAC) and tympanic membrane (TM). Endoscopic findings revealed severe inflammation in the TM of C group; no other group showed damage in the TM. No significant difference in ABR threshold was found in the PBM-treated groups (excluding the group with TM damage). Confocal microscopy showed no histological difference between the AL and AN, or BL and BN groups. However, light microscopy showed more prominent edema, inflammation, and vascular congestion in the TM of BL ears. This study found a dose-response relationship between laser power parameters and TM changes. These results will be useful for defining future allowance criteria for trans-tympanic laser therapies.

Development of bone-conduction mobile phones: assessment of hearing mechanisms by measuring psychological characteristics and acoustical properties in the outer ear canal.

We have been developing novel mobile phones using bone conduction, with flat-panel loudspeakers that convey speech sound by vibrating the pinna. In bone conduction via the pinna, i.e., pinna conduction, it is thought that speech sounds are conveyed via both air- and bone-conduction pathways. To obtain useful information for further development of bone-conduction mobile phones, peripheral mechanisms of the pinna conduction need to be clarified. In this study, hearing thresholds, sound field in the outer ear canals, and vibrations of the inner wall of the outer ear canals were measured while normal-hearing participants used pinna-conduction mobile phones. Thresholds decreased linearly as contact pressure increased below 1 kHz, but contact pressure did not affect thresholds above 2 kHz. Additionally, sound fields in the ipsilateral ear canal showed similar results. These results indicate that there is a considerable degree of bone-conduction components from the pinna to the inner ear, which only allow sounds below 1 kHz through. Because similar characteristics were observed in the threshold and the sound field in the outer ear canal, we suggest that osseotympanic emission, sound emission into the ear canal from the inner wall, and air conduction via external auditory foramen are the dominant components of pinna conduction. However, in the vibration measurement, differences between the ipsi- and contra-lateral responses were smaller than the sound field measurement. The smaller inter-lateral differences of the vibration in the outer ear canal suggest the existence of a significant amount of bone-conduction components that directly reach the middle or inner ear. Although the amount of such bone-conduction components does not seem sufficient for pinna.

A new soft material based in-the-ear EEG recording technique.

Long-term electroencephalogram (EEG) is important for seizure detection, sleep monitoring and etc. In-the- ear EEG device makes such recording robust to noise and privacy protected (invisible to other people). However, the state-of-art techniques suffer from various drawbacks such as customization for specific users, manufacturing difficulties and short life cycle. To address these issues, we proposed silvered glass silicone based in-the-ear electrode which can be manufactured using conventional compression moulding. The material and in-the-ear EEG are evaluated separately, showing that the proposed method is durable, low-cost and easy-to-make.

Assessment of thermal treatment via irrigation of external ear to reduce cisplatin-induced hearing loss.

Systemic and local changes in body temperature can have a profound effect on traumatic injuries including those to the inner ear. Therefore, we investigated the effects of acutely increasing or decreasing the temperature of the external ear canal on cisplatin-induced hearing loss. The external auditory canals of male guinea pigs were acutely irrigated with warm (44 °C), euthermic (37 °C), or cool (30 °C) water and subsequently injected with cisplatin (12 mg/kg, i.p.). Hearing was assessed by the auditory brainstem response and cochleograms were prepared to determine loss of hair cells. Ear canal irrigation with warm water potentiated cisplatin-induced hearing loss and outer hair cell loss whereas cool ear canal irrigation showed significant protection from cisplatin-induced hearing loss and outer hair cell loss. These results suggest that non-invasive cool water ear canal irrigation may be highly effective clinical procedure for protecting against cisplatin-induced hearing loss.

Assessment of the feasibility and clinical value of further research to evaluate the management options for children with Down syndrome and otitis media with effusion: a feasibility study.

BACKGROUND: There is clinical uncertainty of the benefits and costs of different treatment options for children with Down syndrome who have glue ear. This study was designed to assess the extent of this lack of knowledge and determine if pursuing further information would be practical, beneficial and cost-effective. OBJECTIVES: To assess the level and practical effect of current uncertainty around treatment options for children with Down syndrome and glue ear. To assess the feasibility of studying the options for management of glue ear in children with Down syndrome via a randomised controlled trial (RCT) or multicentre prospective cohort study by evaluating the willingness of (1) parents to agree to randomisation for their children and (2) clinicians to recruit participants to a definitive study. To undertake value of information analyses to demonstrate the potential economic benefit from undertaking further research. DESIGN: A feasibility study exploring the views of parents of children with Down syndrome and professionals who have responsibility for the health and education of children with Down syndrome, on the participation in, and value of, future research into interventions for glue ear. Data were collected from parents via self-completed questionnaires, face-to-face interviews and focus groups and from professionals via online questionnaires and a Delphi review exercise. Development of economic models to represent clinical pathways of care and a RCT informed a value of information (VOI) analysis. SETTING: UK (professionals); East Midlands region of the UK (parents). PARTICIPANTS: Parents of children aged 1-11 years with Down syndrome (n = 156). Professionals including audiologists, ear, nose and throat surgeons, audiological physicians, speech and language therapists, and teachers of the deaf (n = 128). MAIN OUTCOME MEASURES: Quantitative and qualitative data on parental views and experiences of glue ear and its effects; interventions and treatment received; taking part in research and factors that would encourage or discourage participation; and the importance of various outcome domains to them and for their children. For professionals: information on caseloads; approaches to clinical management; opinions on frequency and significance of the consequences of glue ear for this population; importance of different outcome measures; opinions of interventions and their role in future research; views on health research; facilitators and barriers to recruitment, and participation in research involving RCTs. RESULTS: The complexity of the experience and individual characteristics of children with Down syndrome poses challenges for the design of any future research but these challenges were not considered by professionals to raise sufficient barriers to prevent it being undertaken. Parents were generally supportive of the need for, and value of, research but identified practical and emotional issues that would need addressing. Glue ear was considered to impact more on speech, language and communication than on hearing. Outcome measures for future research would need to evaluate these elements but measures should be designed specifically for the population. Parents and professionals identified randomisation as a significant barrier to participation. The VOI analyses identified lack of data as problematic but concluded that a future trial involving surgical intervention would be feasible at costs of < £650,000. CONCLUSIONS: Future research into the benefits of interventions for glue ear in children with Down syndrome would be feasible and could be cost-effective but should be carefully designed to facilitate and maximise participation from parents and professionals responsible for recruitment. FUNDING: The National Institute for Health Research Health Technology Assessment programme.

Earbud-based sensor for the assessment of energy expenditure, HR, and VO2max.

INTRODUCTION/PURPOSE: The goal of this program was to determine the feasibility of a novel noninvasive, highly miniaturized optomechanical earbud sensor for accurately estimating total energy expenditure (TEE) and maximum oxygen consumption (VO2max). The optomechanical sensor module, small enough to fit inside commercial audio earbuds, was previously developed to provide a seamless way to measure blood flow information during daily life activities. The sensor module was configured to continuously measure physiological information via photoplethysmography and physical activity information via accelerometry. This information was digitized and sent to a microprocessor where digital signal-processing algorithms extract physiological metrics in real time. These metrics were streamed wirelessly from the earbud to a computer. METHODS: In this study, 23 subjects of multiple physical habitus were divided into a training group of 14 subjects and a validation group of 9 subjects. Each subject underwent the same exercise measurement protocol consisting of treadmill-based cardiopulmonary exercise testing to reach VO2max. Benchmark sensors included a 12-lead ECG sensor for measuring HR, a calibrated treadmill for measuring distance and speed, and a gas-exchange analysis instrument for measuring TEE and VO2max. The earbud sensor was the device under test. Benchmark and device under test data collected from the 14-person training data set study were integrated into a preconceived statistical model for correlating benchmark data with earbud sensor data. Coefficients were optimized, and the optimized model was validated in the 9-person validation data set. RESULTS: It was observed that the earbud sensor estimated TEE and VO2max with mean ± SD percent estimation errors of -0.7 ± 7.4% and -3.2 ± 7.3%, respectively. CONCLUSION: The earbud sensor can accurately estimate TEE and VO2max during cardiopulmonary exercise testing.

Aplasia of the cochlea: radiologic assessment and options for hearing rehabilitation.

OBJECTIVE: Hearing rehabilitation of patients with severe inner ear malformations remains controversial. Our objective was to describe the radiologic findings of aplasia of the cochlea (AC) and evaluate the existing therapeutic options in such patients. STUDY DESIGN: Retrospective cohort study. SETTING: Tertiary referral center. PATIENTS: Pediatric and adult patients with AC evaluated at our institution from 1995 to 2010. INTERVENTIONS: The precise radiologic findings were identified using high-resolution computed tomography (HRCT) and magnetic resonance imaging (MRI) scans of the inner ear. In cases of auditory implantation on the AC side, the achieved outcome was recorded using categories of auditory performance (CAP). Related surgical aspects were analyzed. RESULTS: Twenty-three patients (28 ears) with AC were found. In 5 patients AC was bilateral. The remaining unilateral cases had contralateral normal ears (2 patients), cochlea hypoplasia (5 patients), common cavity (6 patients), incomplete partition Type I (4 patients), and atresia of the internal auditory canal (1 patient). Four patients (3 bilateral, 1 unilateral ACs) were treated with cochlear implants in ears with AC, and 1 patient underwent auditory brainstem implantation. All implanted patients achieved speech perception with limited vocabulary (CAP scores between 4 and 5). CONCLUSION: AC is defined as the total absence of the cochlea, with a present, although malformed, vestibule. Although a distinct auditory nerve was not seen in these cases of AC, results following cochlear implantation suggest functional cochlear nerve fibers in the remaining dysplastic inner ear structures. In selected cases, cochlear implantation may be a reasonable option for the habilitation of deafness associated with AC.

MRI assessment of internal acoustic canal variations using 3D-FIESTA sequences.

Magnetic resonance imaging (MRI) of the internal acoustic canal is the standard diagnostic tool for a wide range of indications in patients. This study aims to investigate the vascular variations and compression of the cranial nerves (CNs) VII and VIII at the cerebellopontine angle in patients with neuro-otologic symptoms using 3D-fast imaging employing steady-state acquisition (FIESTA) MR imaging. One hundred and eighty-seven patients (374 temporal bones) were examined on a 1.5-T MRI. In addition to conventional MR sequences, a 3D-FIESTA MR imaging was acquired. Magnetic resonance images thus obtained were evaluated with special regard to the presence of vascular contact to the CNs VII and VIII, as well as the presence of the vascular variations of the anterior inferior cerebellar artery (AICA) causing the compression of CNs. The Chi-squared test was used for statistical analysis. No statistically significant differences were found between the presence and absence of the AICA loop and/or vascular contact for the clinical symptoms of patients (P > 0.05). The cisternal and canalicular segments of CNs VII and VIII and adjacent vascular variations are well identified using 3D-FIESTA, especially by determining the relationship of the AICA variations between CNs.

Laser Doppler vibrometric assessment of middle ear motion in Thiel-embalmed heads.

HYPOTHESIS: Thiel-embalmed human whole head specimens represent an alternative model in middle ear research. BACKGROUND: Research into middle ear mechanics and the evaluation of active middle ear implants are generally performed on fresh human temporal bone specimens. A drawback of this method is the limited period during which the specimen can be used before tissue decay begins. Tissue conservation that preserves mechanical properties is desirable. METHODS: Using laser Doppler vibrometry, the movement of the tympanic membrane, stapes, and round window were measured in 23 ears from 15 human whole head specimens embalmed according to Thiel. The ears were acoustically stimulated through the intact external auditory canal. The measurement results were compared with data from the literature. RESULTS: The results were similar to those measured in living subjects and from fresh temporal bones, after excluding measurements with nontypical shapes or low amplitudes, that is, 9% for tympanic membrane, 38% for stapes, and 67% for round window. The best agreement was found for the tympanic membrane (mean difference between 0 and 5.2 dB) and for the stapes measurements (mean difference between 0 and 7.4 dB). Larger differences were found for the round window measurements (mean difference between 3 and 19 dB). For the stimulation levels used, the Thiel specimens behaved linearly in amplitude. The results remained reproducible for more than 20 hours in ambient air, and when the specimen was put back into Thiel solution, the measurements were stable for up to several months between measurements. CONCLUSION: Our results showed that the middle ears of Thiel-embalmed human whole head specimens can be used to study human middle ear mechanics; however, significant differences in some frequencies, particularly at the round window, have to be considered.