Computer-Generated Three-Dimensional Reconstruction of the Cochlea

1989 ◽  
Vol 100 (2) ◽  
pp. 87-91 ◽  
Author(s):  
Laurence Ariyasu ◽  
Frank R. Galey ◽  
Raymond Hilsinger ◽  
Frederick M. Byl
Keyword(s):  
Cochlear Implant ◽  
Spiral Ganglion ◽  
Three Dimensional ◽  
Organ Of Corti ◽  
Nerve Fibers ◽  
Cochlear Nerve ◽  
Three Dimensional Reconstruction ◽  
Optimum Length ◽  
Dimensional Reconstruction ◽  
Cochlear Damage

Computer-generated three-dimensional reconstructions of the nerve fibers from the organ of Corti to the spiral ganglion were used to determine the optimum maximal length of the cochlear implant electrode. The spiral ganglion within the modiolus is much shorter than the organ of Corti. The spiral ganglion has turns and reaches no higher than the middle of the second turn of the organ of Corti, which has turns. The spiral ganglion is concentric and basal with respect to the organ of Corti. The spiral ganglion dendrites within the osseous spiral lamina of the basal turn project radially, nearly perpendicular to the central axis of the modiolus. Upon entering the modiolus, they turn basally at an angle of approximately 120 degrees. The projection of dendrites within the osseous spiral lamina became increasingly oblique as the ganglion extended apically. The organization of the cochlear nerve results from the spiraling of the ganglion. These findings are in agreement with previous reports. Implications of these findings and their possible relevance to the optimum length of the cochlear implant electrode are discussed with reference to cochlear damage resulting from longer electrodes.

Temporal Bone Histopathology in Deafness Due to Cryptococcal Meningitis

1979 ◽  
Vol 88 (5) ◽  
pp. 630-636 ◽  
Author(s):  
Takehiko Harada ◽  
Isamu Sando ◽  
Eugene N. Myers
Keyword(s):  
Temporal Bone ◽  
Cryptococcal Meningitis ◽  
Ganglion Cells ◽  
Spiral Ganglion ◽  
Organ Of Corti ◽  
Nerve Fibers ◽  
Vestibular Nerve ◽  
Cochlear Nerve ◽  
Internal Auditory Meatus ◽  
Temporal Bones

This paper reports on a patient who survived an attack of cryptococcal meningitis eight years prior to his death. A bilateral sensorineural hearing loss had been noted a short time before the patient was admitted to the hospital, and was the only complication after he recovered from the disease. Histopathologic study of the temporal bones showed a similar pattern of pathology in both ears, the most striking finding being a severe loss of spiral ganglion cells in Rosenthal's canal, and of cochlear nerve fibers in the osseous spiral lamina and internal auditory meatus. The vestibular nerve was mostly free from pathology. The organ of Corti was atrophic but the hair cell population appeared to be almost normal. A slight number of cryp-tococci were observed in limited areas of the cochlear and the saccular nerves in the internal auditory meatus. The severe pathology of the cochlear nerve was compatible with audiologic evaluations, which pointed to a retrocochlear lesion. Thus, this case demonstrates some characteristic aspects of cryptococcal infection of the temporal bone: The primary site of invasion was the cochlear nerve in the internal auditory meatus and the modiolus, leading to the loss of ganglion cells and nerve fibers, while the vestibular nerve appears to have been resistant to infection.

scholarly journals Computer-Aided Three-Dimensional Reconstruction in Human Cochlear Maps: Measurement of the Lengths of Organ of Corti, Outer Wall, Inner Wall, and Rosenthal's Canal

1996 ◽  
Vol 105 (9) ◽  
pp. 701-709 ◽  
Author(s):  
Atsushi Kawano ◽  
H. Lee Seldon ◽  
Graeme M. Clark
Keyword(s):  
Three Dimensional ◽  
Organ Of Corti ◽  
Outer Wall ◽  
Two Dimensional ◽  
Three Dimensional Reconstruction ◽  
Scala Tympani ◽  
Geometric Difference ◽  
Computer Aided ◽  
Angle Difference ◽  
Dimensional Reconstruction

This paper describes the application of computer-aided three-dimensional reconstruction to measurements of the length of the organ of Corti (mean ± SD, 35.58 ±1.41 mm), scala tympani outer wall (40.81 ± 1.97 mm), scala tympani inner wall (18.29 ± 1.47 mm), and Rosenthal's canal center (15.98 ± 1.33 mm) in eight adult male cochleas. The Rosenthal's canal center ranged between 1 3/4 and 2 turns, did not appear to be linearly related to the organ of Corti, and lay near the basal end of the latter. The length of the organ of Corti measured with three-dimensional reconstruction differed by 7.6% ± 3.2% (“cutting angle difference”) from that derived from traditional two-dimensional reconstruction on the plane perpendicular to the plane of section, and by 2.6% ± 1.7% (“geometric difference”) from that derived from two-dimensional reconstruction on the axial plane at right angles to the modiolar axis.

Methods for three-dimensional reconstruction of cellular components within a thick section

1986 ◽  
Vol 44 ◽  
pp. 18-21
Author(s):  
J. Frank ◽  
B. F. McEwen ◽  
M. Radermacher ◽  
C. L. Rieder
Keyword(s):  
Tilt Angle ◽  
Tomographic Reconstruction ◽  
3D Structure ◽  
Three Dimensional ◽  
Thick Section ◽  
Three Dimensional Reconstruction ◽  
Axis Ratio ◽  
Dimensional Reconstruction ◽  
Cellular Components

The tomographic reconstruction from multiple projections of cellular components, within a thick section, offers a way of visualizing and quantifying their three-dimensional (3D) structure. However, asymmetric objects require as many views from the widest tilt range as possible; otherwise the reconstruction may be uninterpretable. Even if not for geometric obstructions, the increasing pathway of electrons, as the tilt angle is increased, poses the ultimate upper limitation to the projection range. With the maximum tilt angle being fixed, the only way to improve the faithfulness of the reconstruction is by changing the mode of the tilting from single-axis to conical; a point within the object projected with a tilt angle of 60° and a full 360° azimuthal range is then reconstructed as a slightly elliptic (axis ratio 1.2 : 1) sphere.

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