Geometrically accurate real-time volumetric visualization of the middle ear using optical coherence tomography (original) (raw)
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Optical coherence tomography system requirements for clinical diagnostic middle ear imaging
Journal of Biomedical Optics, 2015
Noninvasive middle ear imaging using optical coherence tomography (OCT) presents some unique challenges for real-time, clinical use in humans. We present results from a two-dimensional/three-dimensional OCT system built to assess the imaging requirements of clinical middle ear imaging, and the technical challenges associated with them. These include the need to work at a low numerical aperture, the deleterious effects of transtympanic imaging on image quality at the ossicles, sensitivity requirements for clinical fidelity of images at real-time rates, and the high dynamic-range requirements of the ear. We validated the system by imaging cadaveric specimens with simulated disorders to show the clinical applicability of the images. We also provide additional insight into the likely role of OCT in clinical otology.
Biomedical optics express, 2016
We present the design, implementation and validation of a swept-source optical coherence tomography (OCT) system for real-time imaging of the human middle ear in live patients. Our system consists of a highly phase-stable Vernier-tuned distributed Bragg-reflector laser along with a real-time processing engine implemented on a graphics processing unit. We use the system to demonstrate, for the first time in live subjects, real-time Doppler measurements of middle ear vibration in response to sound, video rate 2D B-mode imaging of the middle ear and 3D volumetric B-mode imaging. All measurements were performed non-invasively through the intact tympanic membrane demonstrating that the technology is readily translatable to the clinic.
Optical Coherence Tomography-Based Atlas of the Human Cochlear Hook Region
Journal of Clinical Medicine
Advancements in intracochlear diagnostics, as well as prosthetic and regenerative inner ear therapies, rely on a good understanding of cochlear microanatomy. The human cochlea is very small and deeply embedded within the densest skull bone, making nondestructive visualization of its internal microstructures extremely challenging. Current imaging techniques used in clinical practice, such as MRI and CT, fall short in their resolution to visualize important intracochlear landmarks, and histological analysis of the cochlea cannot be performed on living patients without compromising their hearing. Recently, optical coherence tomography (OCT) has been shown to be a promising tool for nondestructive micrometer resolution imaging of the mammalian inner ear. Various studies performed on human cadaveric tissue and living animals demonstrated the ability of OCT to visualize important cochlear microstructures (scalae, organ of Corti, spiral ligament, and osseous spiral lamina) at micrometer re...
Investigation of middle ear anatomy and function with combined video otoscopy-phase sensitive OCT
Biomedical Optics Express, 2016
We report the development of a novel otoscopy probe for assessing middle ear anatomy and function. Video imaging and phasesensitive optical coherence tomography are combined within the same optical path. A sound stimuli channel is incorporated as well to study middle ear function. Thus, besides visualizing the morphology of the middle ear, the vibration amplitude and frequency of the eardrum and ossicles are retrieved as well. Preliminary testing on cadaveric human temporal bone models has demonstrated the capability of this instrument for retrieving middle ear anatomy with micron scale resolution, as well as the vibration of the tympanic membrane and ossicles with sub-nm resolution.
Reconstruction and exploration of virtual middle-ear models derived from micro-CT datasets
Hearing Research, 2010
Background-Middle-ear anatomy is integrally linked to both its normal function and its response to disease processes. Micro-CT imaging provides an opportunity to capture highresolution anatomical data in a relatively quick and non-destructive manner. However, to optimally extract functionally relevant details, an intuitive means of reconstructing and interacting with these data is needed. Materials and methods-A micro-CT scanner was used to obtain high-resolution scans of freshly explanted human temporal bones. An advanced volume renderer was adapted to enable real-time reconstruction, display, and manipulation of these volumetric datasets. A customdesigned user interface provided for semi-automated threshold segmentation. A 6-degrees-offreedom navigation device was designed and fabricated to enable exploration of the 3D space in a manner intuitive to those comfortable with the use of a surgical microscope. Standard haptic devices were also incorporated to assist in navigation and exploration. Results-Our visualization workstation could be adapted to allow for the effective exploration of middle-ear micro-CT datasets. Functionally significant anatomical details could be recognized and objective data could be extracted. Conclusions-We have developed an intuitive, rapid, and effective means of exploring otological micro-CT datasets. This system may provide a foundation for additional work based on middle-ear anatomical data.
SN Comprehensive Clinical Medicine
The aim of the study was to obtain volumetric data of the components of the inner ear using three-dimensional reconstruction of high-resolution cone-beam computed tomography (CBCT) images. Two hundred three CBCT image series of the temporal bone from 118 anatomically normal patients (55 women and 63 men; mean age: 49.4 ± 20.4 years) with different suspected disorders were included in this study. Normative volumetric measurements of the inner ear, the cochlea, the semicircular canals (SSC), and the vestibule were determined using a semi-automated reconstruction method of the Workstation. Volumetric measurements were successfully completed in all 118 patients. Mean inner ear, cochlear, and vestibule volumes were statistically significantly larger in males than in females on both sides (p 0.05). There was no significant difference between mean bony inner ear volumes when the clinical diagnoses were compared (p > 0.05 for all clinical diagnoses and volumes). Our study concluded that...
Preparation of Human Inner Ear Structures for High Resolution Imaging Studies
Archives of Neuroscience
Background: Introduction of the novel imaging modalities such as optical coherence tomography and scanning laser optical tomography allow the morphological and functional evaluation of the intracochlear structures up to the histological details. The prerequisite of these modalities is the preparation of the membranous labyrinth by removing the dense otic capsule to enhance the optical penetration depth. In the present study, a combination of the chemical decalcification and bone drilling method was explained for the preparation of the human inner ear structures for further studies. Methods: In this study, nine human temporal bones were used and trimmed in cubes containing middle and inner ear structures. The samples were immersed in 5% nitric acid, 20% EDTA, and 10% EDTA solutions, respectively. The samples were brought out and rinsed every 90 minutes, and mechanical removal of the softened bone was performed with surgical drill system until the complete decalcification of the samples was confirmed by X-ray imaging. The prepared samples were evaluated by microcomputed tomography imaging for anatomical distortions caused by the preparation process. Results: Complete decalcification and preparation of the samples were obtained in average of 10.5 ± 0.5 hours. No obvious morphological changes were observed in microcomputed tomography images, except for fracture of the remnant bony shell at the apex of cochlea in one sample. Conclusions: The combination of the chemical decalcification and mechanical removal of the softened bone can accelerate the sample preparation for high resolution imaging studies without significant morphological changes.
Journal of Biomedical Optics, 2010
There is considerable interest in developing new methods for in vivo imaging of the complex anatomy of the mammalian cochlea for clinical as well as fundamental studies. In this study, we explored, the feasibility of spectral domain optical coherence tomography ͑SD-OCT͒ for 3-D in vivo imaging of the cochlea in mice. The SD-OCT system employed in this study used a broadband light source centered at 1300 nm, and the imaging speed of the system was 47,000 A-scans per second using the InGaAs camera. The system was capable of providing fully processed, high-resolution B-scan images ͓512 ͑axial͒ ϫ 128 ͑lateral͒ pixels͔ at 280 frames per sec. The 3-D imaging acquisition time for a whole cochlea was ϳ0.45 sec. The traditional SD-OCT structural imaging algorithm was used to reconstruct 3-D cochlear morphology. We demonstrated that SD-OCT can be successfully used for in vivo imaging of important morphological features within the mouse cochlea, such as the otic capsule and structures within, including Reissner's membrane, the basilar membrane, tectorial membrane, organ of Corti, and modiolus of the apical and middle turns.
Combining Optical Coherence Tomography (OCT) with an Operating Microscope
Springer Proceedings in Physics
Optical coherence tomography (OCT) is an emerging biomedical imaging technology which gives high-resolution sectional images of light scattering tissue down to a depth of a few millimeter. The objective of this work is to combine OCT with an operation microscope. A spectral domain OCT was adapted via a specially designed scanning optics to the camera port of an operation microscope. This enables a non-contact on-line OCT during different medical applications. Hidden tissue structures were visualized with a resolution below 30 µm. As a first example for an application in otolaryngology we demonstrated that the OCT operation microscope is basically able to reveal parts of the cochlear morphology without opening its enveloping membranes. Thus it may serve as a helpful guide for the surgeon to exactly localize the scala tympani before opening the fluid-filled inner ear for inserting the electrode array of cochlear implants.
BMC Medical Imaging
Background Multi slice computed tomography (MSCT) is the most common used method in middle ear imaging. However, MSCT lacks the ability to distinguish the ossicular chain microstructures in detail resulting in poorer diagnostic outcomes. Novel cone beam computed tomography (CBCT) devices’ image resolution is, on the other hand, better than MSCT resolution. The aim of this study was to optimize imaging parameters of a novel full body CBCT device to obtain optimal contrast to noise ratio (CNR) with low effective dose, and to optimize its clinical usability. Methods Imaging of five anonymous excised human cadaver temporal bones, the acquisition of the effective doses and the CNR measurements were performed for images acquired on using Planmed XFI® full body CBCT device (Planmed Oy, Helsinki, Finland) with a voxel size of 75 µm. All images acquired from the specimens using 10 different imaging protocols varying from their tube current exposure time product (mAs) and tube voltage (kVp) w...