Ultra-high-resolution CT of the temporal bone: Comparison between deep learning reconstruction and hybrid and model-based iterative reconstruction.

PURPOSE: The purpose of this study was to evaluate the ability of ultra-high-resolution computed tomography (UHR-CT) to assess stapes and chorda tympani nerve anatomy using a deep learning (DLR), a model-based, and a hybrid iterative reconstruction algorithm compared to simulated conventional CT. MATERIALS AND METHODS: CT acquisitions were performed with a Mercury 4.0 phantom. Images were acquired with a 1024 × 1024 matrix and a 0.25 mm slice thickness and reconstructed using DLR, model-based, and hybrid iterative reconstruction algorithms. To simulate conventional CT, images were also reconstructed with a 512 × 512 matrix and a 0.5 mm slice thickness. Spatial resolution, noise power spectrum, and objective high-contrast detectability were compared. Three radiologists evaluated the clinical acceptability of these algorithms by assessing the thickness and image quality of the stapes footplate and superstructure elements, as well as the image quality of the chorda tympani nerve bony and tympanic segments using a 5-point confidence scale on 13 temporal bone CT examinations reconstructed with the four algorithms. RESULTS: UHR-CT provided higher spatial resolution than simulated conventional CT at the penalty of higher noise. DLR and model-based iterative reconstruction provided better noise reduction than hybrid iterative reconstruction, and DLR had the highest detectability index, regardless of the dose level. All stapedial structure thicknesses were thinner using UHR-CT by comparison with conventional simulated CT (P < 0.009). DLR showed the best visualization scores compared to the other reconstruction algorithms (P < 0.032). CONCLUSION: UHR-CT with DLR results in less noise than UHR-CT with hybrid iterative reconstruction and significantly improves stapes and tympanic chorda tympani nerve depiction compared to simulated conventional CT and UHR-CT with iterative reconstruction.

Anatomical Study of the Facial Recess with Implications in Round Window Visibility for Cochlear Implantation: Personal Observations and Review of the Literature

Abstract Introduction Posterior tympanotomy through facial recess (FR) is the conventional and most preferred approach to facilitate cochlear implantation, especially when the electrode is inserted through the round window. The complications of the FR approach can be minimized by proper understanding of the anatomy of the FR. Objective The present study was undertaken to assess the various parameters of FR and round window visibility, which may be of relevance for cochlear implant surgery. Methods Thirty-five normal wet human cadaveric temporal bones were studied by dissection for anatomy of FR and posterior tympanum. Photographs were taken with an 18megapixels digital camera, which were then imported to a computer to determine various parameters. Results The mean distance from the take-off point/crotch of the chorda tympani nerve (CTN) to the stylomastoid foramen was 4.08 ± 0.8 mm(range of 2.06 - 5.5mm). The variations in the course of the CTN included origin at the level of the lateral semicircular canal. Themean chorda-facial angle in our study was 26.91° ± 1.19°, with a range of 25° to 28.69°. The mean FR length ranged between 9.4 mm and 18.56 mm (mean of 12.41 ± 2.91mm) and varied with the origin of the CTN and pneumatization of temporal bone. The average maximum width of the FR was 2.93 ± 0.4 mm (range 2.24-3.45 mm) and the mean width of the FR at the level of the round window was 2.65 ± 0.41 mm. Conclusion The FR approach provides good access to the round windowmembrane in all cases. In some cases, table adjustment is required.

Trastornos del gusto posestapedostomías / Post stapedectomy taste disorders

Introducción: En su trayecto por el oído medio el nervio cuerda del tímpano (CT), se ve expuesto a lesiones quirúrgicas. Los trastornos del gusto se presentan como posibles secuelas del daño sobre la CT, lo cual puede afectar la calidad de vida de los pacientes. En las estapedostomías, la CT debe ser movilizada frecuentemente, y a veces seccionada para accederá la platina del estribo. Objetivo: Evaluar la evolución temporal de los trastornos del gusto posestapedostomías y su correlación con la preservación de la CT. Material y método: Estudio retrospectivo entre los años 2002 y 2007. Se analizaron las fichas clínicas y protocolos operatorios en busca de preservación o sección de la CT durante la cirugía. Se aplicó un mini cuestionario para evaluar la función gustativa y su evolución en el tiempo. Resultados: La CT fue preservada en 131 pacientes (93 por ciento) y seccionada en 10 pacientes (7 por ciento). La incidencia de alteraciones del gusto fue 7,6 por ciento> (10 pacientes) en el grupo con preservación de la CT y 20 por ciento> (2 pacientes) en el grupo que se seccionó (p >0,05). Todos los pacientes tuvieron una recuperación completa en su función gustativa antes de 12 meses luego de la cirugía, siendo más rápida en el grupo con preservación que en el que se seccionó la CT(5 meses versus 11 meses respectivamente). Conclusiones: Las alteraciones del gusto están presentes en pacientes sometidos a estapedostomías incluso cuando la CT es preservada. Cuando es seccionada no siempre se presentan trastornos del gusto, pero cuando están son más severos y duraderos.

Introduction: In its course through middle ear, the chorda tympani nerve (CTN) is potentially exposed to surgical injury. Possible sequels of CTN injury are taste disorders, which can affect the life quality of patients. During stepedectomies, the CTN often must be displaced or even severed in order to gain access to the stapes footplate. Aim: To assess the temporal evolution of post stepedectomy taste disorders and their correlation with CTN preservation. Material and Method: A retrospective study was conducted between 2002 and 2007. Medical records of 141 patients subjected to stapedectomy were analyzed in search for CTN preservation or section during surgery. A questionnaire was applied to evaluate postoperative taste function and its evolution over time. Results: CTN was preserved in 131 patients (93 percent) and sectioned in 10 patients (7 percent). The incidence of taste disorders was 7.6 percent (10 patients) in the CTN preserved group and 20 percent> (2 patients) in the CTN severed group (p>0.05). All patients had fully recovered taste function by 12 months after surgery, recovery being faster in the CTN preserved group than in the CTN severed group (5 months vs. 11 months respectively). Conclusions: Taste disorders may be present in patients subjected to stapedectomy even when CTN is preserved; taste disorders are more severe and long lasting in cases where the CTN is sectioned.

Miringoesclerose em pacientes renais crônicos: estudo em 116 pacientes / Miringoesclerosis in pacients with chronic renal faillure: study of 116 patients

A timpanoesclerose é uma alteração da lâmina própria da orelha média, resultante de processo inflamatório, que envolve a deposição de cálcio neste tecido. Com o objetivo de avaliar a influência de distúrbios do metabolismo do cálcio neste processo, os autores estudaram a freqüência de miringoesclerose em 116 pacientes portadores de insuficiência renal crônica, encontrando uma prevalência de índice de 9,5 por cento, o que reflete a possibilidade da influência desta doença na gênese da timpanosclerose

Variaçöes anatômicas do nervo corda do tímpano / Anatomic variations of chorda tympani nerve

Os autores apresentam um estudo das variaçöes anatômicas do nervo corda do tímpano encontradas em 30 ossos temporais humanos que foram dissecados. A seguir fazem uma revisäo bibliográfica e discutem o assunto, enfocando a correlaçäo anatômica entre o nervo facial e o nervo corda do tímpano

O seio sigmóide no acesso mastóide ao nervo facial e conduto-auditivo interno / Sigmoid sinus in mastoid access to facial nerve and internal auditory pathway

Os autores estudam as medidas anatômicas do seio sigmóide em relaçäo ao nervo facial, no seu segundo joelho e na emergência do nervo-corda do tímpano, com o intuito de prevenir-se para abordagem cirúrgica de mastóide, especialmente para ouvido interno. Foi elaborada uma relaçäo anatômica/radiográfica a partir de medidas de 52 ossos temporais humanos dissecados. A partir dessa previsäo pode o cirurgiäo prevenir-se quanto à possibilidade de ter que afastar o seio sigmóide para estes procedimentos

Autonomic nervous system regulation of murine immune responses as assessed by local surgical sympathetic and parasympathetic denervation

En ratones sometidos a gangliectomia simpática cervical superior (SCGx) unilateral se estudió el efecto de la desnervación local sobre la respuesta imune de ganglios linfáticos submaxilares (SmLN). El contenido de norepinefrina (NE) de SmLN disminuyó en un 90% a los 7-20 dias luego de la SCGx uni o bilateral. Los SmLN ipsilaterales de ratones SCGx unilateralmente 10-20 días antes e inyectados i.d. o i.p. con eritrocitos de carnero mostraron una respuesta de células formadoras de placa (PFC) significantivamente mayor que el control invervado contralateral. En ratones inyectados con eritrocitos de carnero en al fase temprana de parálisis neural simpática (2 h luego de la SCGx), se detectó una respuesta PFC aumentada mientras que durante la fase de degeneración anterógrada de los terminales (6-24 h luego de SCGx), se observó una disminucióm crecimente de PFC. En ratones crónicamente SCGx se detectó también un aumento significativo en la hipersensibilidad por contacto y reacción alogeneica retardada en al oreja ipsilateral a la operación. Al inyectar células de SmLN desnervados a F1 de (BALB/c x C57Bl/6) o de (BALB/c x AKR) se obtuvbieron índices esplénicos significativamente mayores que los observados luego de inyectar células controles. La estimulación mitogénica en diferentes protocolos experimentales no resultó en diferencias significativas entre SmLN desnervados e inervados. Luego de la descentralización local por sección unilateral del tronco lingual-cuerda del tímpano, los SmLN ipsilaterales exhibieron menor respuesta PFC 8-28 días luego de la cirugía. Estos resultados indican función modulatoria del sistema nervioso autónomo en la respuesta inmune

Alteraçöes morfológicas da glândula submandibular do rato, após secçäo do nervo corda do tímpano: observaçäo após um ano / Morphological alterations in rat submandibular glands after cutting the chorda tympani nerve

No presente trabalho foram estudadas as alteraçöes morfológicas das glândulas submandibulares de rato, após secçäo do nervo corda do tímpano. Com base nos resultados foi possível concluir: o peso médio das glândulas experimentais foi maior nos grupos de 1 e 2 dias para as que tiveram o corda do tímpano seccionado. Para todas as outras glândulas desnervadas, o peso da glândula experimental foi menor do que a controle. O aumento de peso inicial foi atribuído à uma retençäo ou acúmulo de secreçäo no interior das células acinares. A partir de 3 dias foram observadas regiöes de atrofia mais acentuada na regiäo acinar do que nas outras estruturas, as glândulas ficaram menores, fibrosadas, com reduçäo da parte glandular acinosa e com grande invasäo de polimorfonucleares. Nas glândulas com secçäo do nervo corda do tímpano foram observadas fibras nervosas e neurônios com características normais. A partir de 60 dias de observaçäo após secçäo do nervo, a glândula parece caminhar para uma regeneraçäo do parênquima