Details of human middle ear morphology based on micro-CT imaging of phosphotungstic acid stained samples.

A multitude of morphological aspects of the human middle ear (ME) were studied qualitatively and/or quantitatively through the postprocessing and interpretation of micro-CT (micro X-ray computed tomography) data of six human temporal bones. The samples were scanned after phosphotungstic acid staining to enhance soft-tissue contrast. The influence of this staining on ME ossicle configuration was shown to be insignificant.

Full-field thickness distribution of human tympanic membrane obtained with optical coherence tomography.

The full-field thickness distribution, three-dimensional surface model and general morphological data of six human tympanic membranes are presented. Cross-sectional images were taken perpendicular through the membranes using a high-resolution optical coherence tomography setup. Five normal membranes and one membrane containing a pathological site are included in this study.

MicroCT versus sTSLIM 3D imaging of the mouse cochlea.

We made a qualitative and quantitative comparison between a state-of-the-art implementation of micro-Computed Tomography (microCT) and the scanning Thin-Sheet Laser Imaging Microscopy (sTSLIM) method, applied to mouse cochleae. Both imaging methods are non-destructive and perform optical sectioning, respectively, with X-rays and laser light. MicroCT can be used on fresh or fixed tissue samples and is primarily designed to image bone rather than soft tissues.

The OPFOS Microscopy Family: High-Resolution Optical Sectioning of Biomedical Specimens.

We report on the recently emerging (laser) light-sheet-based fluorescence microscopy field (LSFM). The techniques used in this field allow to study and visualize biomedical objects nondestructively in high resolution through virtual optical sectioning with sheets of laser light. Fluorescence originating in the cross-section of the sheet and sample is recorded orthogonally with a camera.

Open access high-resolution 3D morphology models of cat, gerbil, rabbit, rat and human ossicular chains.

High-resolution 3D morphology models of cat, gerbil, rabbit, rat and human ossicular chains are presented. The models are based on high-resolution CT measurements. The resolution of the CT images, from which the models are segmented, varies from 5.

Realistic 3D computer model of the gerbil middle ear, featuring accurate morphology of bone and soft tissue structures.

In order to improve realism in middle ear (ME) finite-element modeling (FEM), comprehensive and precise morphological data are needed. To date, micro-scale X-ray computed tomography (μCT) recordings have been used as geometric input data for FEM models of the ME ossicles. Previously, attempts were made to obtain these data on ME soft tissue structures as well.

Anatomical boundary of the tympanic membrane pars flaccida of the Meriones unguiculatus (Mongolian gerbil).

The pars flaccida of the Meriones unguiculatus (Mongolian gerbil) was in previous studies shown to bulge almost spherically when pressurized, a behavior suggesting that it is suspended by a fixed circular boundary. The question arises whether this "functional" boundary is based on an underlying circular anatomical boundary, an important issue for modeling the middle-ear mechanics. In this article, the boundaries of the Mongolian gerbil pars flaccida were visualized in situ with otomicroscopy and in slides with light microscopy and by micro-CT radiology.

Tomographic imaging of macroscopic biomedical objects in high resolution and three dimensions using orthogonal-plane fluorescence optical sectioning.

A new optical-fluorescence microscopy technique, called HR-OPFOS, is discussed and situated among similar OPFOS-implementations. OPFOS stands for orthogonal-plane fluorescence optical sectioning and thus is categorized as a laser light sheet based fluorescence microscopy method. HR-OPFOS is used to make tomographic recordings of macroscopic biomedical specimens in high resolution.

Evaluation of a model for studies on sequelae after acute otitis media in the Mongolian gerbil.

Conclusions: The model appears relevant for studies on sequelae after acute otitis media (AOM), and may be the seed of a new, chronic tympanic membrane perforation model in the gerbil.

Objectives: To evaluate an experimental model for abortive otitis media and to assess the structural and functional changes of the tympanic membrane in the resolving phase.

Materials And Methods: The middle ears of 16 Mongolian gerbils were inoculated with type 6a Streptococcus pneumoniae.

Moiré profilometry using liquid crystals for projection and demodulation.

A projection moiré profilometer is presented in which both projection and optical demodulation are realized with liquid crystal light modulators. The computer generated grids, realized on thin film transistor matrices, allow phase-stepping and discrete grid averaging without the need for any mechanically moving component. Spatial line pitch and phase steps can thus be readily adjusted to suit the measurement precision and object geometry.

Design considerations in projection phase-shift moiré topography based on theoretical analysis of fringe formation.

Moiré topography is a well-established optical technique to measure the shape of three-dimensional surfaces, based on the geometric interference between an optical grid and its image deformed by an object surface. The technique produces fringes that represent contours of equal height, and from the recordings of several phase-shifted topograms surface height coordinates can be calculated. To perform these calculations, it is assumed that object height variation is small in comparison with the measurement setup dimensions, and this approximation leads to systematic errors in measurement accuracy.

Design and quantitative resolution measurements of an optical virtual sectioning three-dimensional imaging technique for biomedical specimens, featuring two-micrometer slicing resolution.

Several well-established techniques are available to obtain 3-D image information of biomedical specimens, each with their specific advantages and limitations. Orthogonal plane fluorescence optical sectioning (OPFOS), or selective plane illumination microscopy (SPIM), are additional techniques which, after adequate specimen preparation, produce high quality, autoaligned sectional images in nearly real time, of bone as well as soft tissue. Up until now, slicing resolutions down to 14 microm have been obtained.

Quasi-static transfer function of the rabbit middle ear' measured with a heterodyne interferometer with high-resolution position decoder.

Due to changes in ambient pressure and to the gas-exchange processes in the middle ear (ME) cavity, the ear is subject to ultra-low-frequency pressure variations, which are many orders of magnitude larger than the loudest acoustic pressures. Little quantitative data exist on how ME mechanics deals with these large quasi-static pressure changes and because of this lack of data, only few efforts could be made to incorporate quasi-static behavior into computer models. When designing and modeling ossicle prostheses and implantable ME hearing aids, the effects of large ossicle movements caused by quasi-static pressures should be taken into account.