scholarly journals Multimodal Atlas of the Murine Inner Ear: From Embryo to Adult

2021 ◽  
Vol 12 ◽  
Author(s):  
Jean-Paul Bryant ◽  
Vikram Chandrashekhar ◽  
Anthony J. Cappadona ◽  
Pashayar P. Lookian ◽  
Vibhu Chandrashekhar ◽  
...  

The inner ear is a complex organ housed within the petrous bone of the skull. Its intimate relationship with the brain enables the transmission of auditory and vestibular signals via cranial nerves. Development of this structure from neural crest begins in utero and continues into early adulthood. However, the anatomy of the murine inner ear has only been well-characterized from early embryogenesis to post-natal day 6. Inner ear and skull base development continue into the post-natal period in mice and early adulthood in humans. Traditional methods used to evaluate the inner ear in animal models, such as histologic sectioning or paint-fill and corrosion, cannot visualize this complex anatomy in situ. Further, as the petrous bone ossifies in the postnatal period, these traditional techniques become increasingly difficult. Advances in modern imaging, including high resolution Micro-CT and MRI, now allow for 3D visualization of the in situ anatomy of organs such as the inner ear. Here, we present a longitudinal atlas of the murine inner ear using high resolution ex vivo Micro-CT and MRI.

2018 ◽  
Vol 12 ◽  
Author(s):  
Thomas van den Boogert ◽  
Marc van Hoof ◽  
Stephan Handschuh ◽  
Rudolf Glueckert ◽  
Nils Guinand ◽  
...  

2020 ◽  
Vol 3 (01) ◽  
pp. 01-09
Author(s):  
Preeti Tiwari ◽  
Sheo Kumar ◽  
Prabhaker Mishra ◽  
Rajat Jain ◽  
Namita Mohindra ◽  
...  

Abstract Introduction Preoperative imaging is a standard practice for cochlear implant candidacy. We are discussing association between surgical feasibility and various anatomical details of middle and inner ear by both high-resolution computed tomography (HRCT) and 3T magnetic resonance imaging (MRI) in patients with bilateral sensorineural hearing loss (SNHL) and are used as a guide during surgery as well as foresee complications in cochlear implantation. Materials and Methods A total of 56 patients of aged 1 to 5 years (prelingual) and > 1 years (postlingual or perilingual) having bilateral SNHL were included in the study. HRCT temporal bone and MRI head was done in all candidates. Based on the imaging findings of CT and MRI, patients were divided into two categories (normal and abnormal). Demographic and clinical values were compared between two groups. Binary logistic regression analysis was used to identify the predictors of the outcome variable (surgical difficulty). Results Out of 56 patients, 55 underwent cochlear implantation by Veria technique, one patient having Michel’s deformity was denied surgery and was advised brain stem implant. Note that 69.1% patients had no radiological abnormality, while 30.9% patients showed abnormality including acquired disease and malformation. Out of the total study patients, 18% (n = 10) showed various type of congenital inner ear malformation. Large size of the external auditory canal (EAC), high basal turn angle (BTA), and increased distance between tympanic segment of facial canal to EAC (midpoint between level of I-S joint corresponding to EAC and exit of chordae tympanic at level of EAC), all these factors showed inverse relationship with difficulty in surgery, which were found to be statistically significant. Conclusion The imaging in cochlear implant patients is an essential tool for preoperative assessment of candidacy, surgical planning, and avoid intra- and postoperative complications. BTA and distance between tympanic segment of facial nerve and EAC (midpoint between level of I-S joint corresponding to EAC and exit of chordae tympanic at level of EAC) are important predictors for evaluating intra- and postoperative complications.


2003 ◽  
Vol 16 (3) ◽  
pp. 411-420 ◽  
Author(s):  
F. Calzolari ◽  
E. Sarti ◽  
A. Sensi ◽  
G. Garani ◽  
L. Clauser ◽  
...  

The aim of this study is to describe external, middle and inner ear malformations in children with congenital craniofacial abnormalities. Seventeen patients with craniofacial and external ear anomalies, aged between 12 days and 15 years (mean 3.4 years), were studied. The majority of children had conductive hearing loss. High-resolution CT of the petrous bone was performed in all cases; in 9 cases three-dimensional reconstructions were done. For each child CT findings of external, middle, inner ear, facial nerve and skull base were analysed. Ear malformations have been correlated with anomalies of the auricle. The most serious auricular anomalies were more frequently associated with external auditory canal atresia, dysplasia of the tympanic cavity and malleo-incudal joint and aberration of the mastoid segment of the facial nerve. These anomalies are probably related through a common embryological origin. Inner ear malformations were diagnosed more rarely, but we emphasize that these malformations are more frequent in “syndromic” forms with craniofacial abnormalities rather than in isolated anomalies of the auricle; it is very important because inner ear abnormalities are considered a contraindication to functional surgery in patients with atresia. Diagnostic imaging is useful for an early and complete characterization of the craniofacial and ear malformations; a precise analysis of the ear abnormalities is necessary to give an indication for the eventual audiological treatment. High-resolution CT is the method of choice for the analysis of the external and middle ear; CT and MR should be integrated for the study of the inner ear and facial nerve. CT and MR are helpful to determine the extent of craniofacial abnormalities; MR should be done when encephalic malformations are suspected. Finally, three-dimensional CT is useful for the maxillofacial surgeon to plan surgical treatment.


Author(s):  
J. A. Pollock ◽  
M. Martone ◽  
T. Deerinck ◽  
M. H. Ellisman

Localization of specific proteins in cells by both light and electron microscopy has been facilitate by the availability of antibodies that recognize unique features of these proteins. High resolution localization studies conducted over the last 25 years have allowed biologists to study the synthesis, translocation and ultimate functional sites for many important classes of proteins. Recently, recombinant DNA techniques in molecular biology have allowed the production of specific probes for localization of nucleic acids by “in situ” hybridization. The availability of these probes potentially opens a new set of questions to experimental investigation regarding the subcellular distribution of specific DNA's and RNA's. Nucleic acids have a much lower “copy number” per cell than a typical protein, ranging from one copy to perhaps several thousand. Therefore, sensitive, high resolution techniques are required. There are several reasons why Intermediate Voltage Electron Microscopy (IVEM) and High Voltage Electron Microscopy (HVEM) are most useful for localization of nucleic acids in situ.


Author(s):  
Gary Bassell ◽  
Robert H. Singer

We have been investigating the spatial distribution of nucleic acids intracellularly using in situ hybridization. The use of non-isotopic nucleotide analogs incorporated into the DNA probe allows the detection of the probe at its site of hybridization within the cell. This approach therefore is compatible with the high resolution available by electron microscopy. Biotinated or digoxigenated probe can be detected by antibodies conjugated to colloidal gold. Because mRNA serves as a template for the probe fragments, the colloidal gold particles are detected as arrays which allow it to be unequivocally distinguished from background.


Author(s):  
Wenbing Yun ◽  
Steve Wang ◽  
David Scott ◽  
Kenneth W. Nill ◽  
Waleed S. Haddad

Abstract A high-resolution table-sized x-ray nanotomography (XRMT) tool has been constructed that shows the promise of nondestructively imaging the internal structure of a full IC stack with a spatial resolution better than 100 nm. Such a tool can be used to detect, localize, and characterize buried defects in the IC. By collecting a set of X-ray projections through the full IC (which may include tens of micrometers of silicon substrate and several layers of Cu interconnects) and applying tomographic reconstruction algorithms to these projections, a 3D volumetric reconstruction can be obtained, and analyzed for defects using 3D visualization software. XRMT is a powerful technique that will find use in failure analysis and IC process development, and may facilitate or supplant investigations using SEM, TEM, and FIB tools, which generally require destructive sample preparation and a vacuum environment.


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