Tools for creating wide-field views of the human retina using Optical Coherence Tomography

TOOLS FOR CREATING WIDE-FIELD VIEWS OF THE HUMAN RETINA USING OPTICAL COHERENCE TOMOGRAPHY Ashavini M. Pavaskar, B.E. Marquette University, 2011 Optical Coherence Tomography (OCT) has allowed in-vivo viewing of details of retinal layers like never before. With the development of spectral domain OCT (SD-OCT) details of nearly 2μm axial resolution and higher imaging speed have been reported. Ne v rthel ss, a single volume scan of the retina is typically restricted to 6mm x 6mm in size. Having lar er field of view of the retina will definitely enhance the clinical utility of the OC T. A tool was developed for creating wide-field thickness maps of the retina by c ombining the use of already available tools like i2k RetinaTM (DualAlign, LLC, Clif ton Park, NY) and the thickness maps from Cirrus HD-OCT research browser (Carl Zeiss Medite c, Dublin, California, USA). Normal subjects (n=20) were imaged on Zeiss Cirrus HD-OCT using 512x128 M acular Cube scanning protocol. Sixteen overlapping volumetric images were obtained by movi ng the internal fixation target around such that the final stitched maps were 12mm x 14mm in size. The thickness maps were corrected for inter-individual differences in axial le ngths measured using Zeiss IOL Master and averaged to obtain a normative map. An algorithm was also developed for montaging 3-D volume scans. Using this algorit hm two OCT volume scans can be registered and stitched together to obtain a larger volume s can. The algorithm can be described as a two step process involving 3-D phase-correlat ion and 2-D Pseudo-polar Fourier transform (PPFT). In the first step, 3-D phase-correl ati n provides translation values in the x, y and z axis. The second step involves applying PPFT on ea ch overlapping pair of B-scans to find rotation in the x-y plane. Subsequent volumes can be st itched to obtain a large field of view. We developed a simple and robust method for creating wide-field views of the reti na using existing SD-OCT hardware. As segmentation algorithms improve, this me thod could be expanded to produce wide-field maps of retinal sub-layers, such as the outer nucle a layer or retinal nerve fiber layer. These wide-field views of the retina may prove useful in evaluating retinal diseases involving the peripheral retina ( e.g., retinitis pigmentosa and glaucoma).

[1]  Jan Flusser,et al.  Image Registration: A Survey and Recent Advances , 2005 .

[2]  Max A. Viergever,et al.  A survey of medical image registration , 1998, Medical Image Anal..

[3]  Stephan Saalfeld,et al.  Globally optimal stitching of tiled 3D microscopic image acquisitions , 2009, Bioinform..

[4]  R C Pruett,et al.  Monochromatic ophthalmoscopy and fundus photography. The normal fundus. , 1977, Archives of ophthalmology.

[5]  N. Congdon,et al.  Important causes of visual impairment in the world today. , 2003, JAMA.

[6]  A. Ardeshir Goshtasby,et al.  2-D and 3-D Image Registration: for Medical, Remote Sensing, and Industrial Applications , 2005 .

[7]  Vikram S Brar,et al.  Normative data for macular thickness by high-definition spectral-domain optical coherence tomography (spectralis). , 2009, American journal of ophthalmology.

[8]  G. Borgefors.  Distance transformations in arbitrary dimensions , 1984 .

[9]  T. Aleman,et al.  Identifying photoreceptors in blind eyes caused by RPE65 mutations: Prerequisite for human gene therapy success , 2005, Proceedings of the National Academy of Sciences of the United States of America.

[10]  A. Fercher,et al.  In vivo optical coherence tomography. , 1993, American journal of ophthalmology.

[11]  J. Duker,et al.  Ultrahigh speed 1050nm swept source/Fourier domain OCT retinal and anterior segment imaging at 100,000 to 400,000 axial scans per second. , 2010, Optics express.

[12]  Wolfgang Drexler,et al.  Cellular and functional optical coherence tomography of the human retina: the Cogan lecture. , 2007, Investigative ophthalmology & visual science.

[13]  Jay B. West,et al.  Predicting error in rigid-body point-based registration , 1998, IEEE Transactions on Medical Imaging.

[14]  E Reichel,et al.  Quantitative assessment of macular edema with optical coherence tomography. , 1995, Archives of ophthalmology.

[15]  Michael D. Abràmoff,et al.  Image processing with ImageJ , 2004 .

[16]  B. N. Chatterji,et al.  An FFT-based technique for translation, rotation, and scale-invariant image registration , 1996, IEEE Trans. Image Process..

[17]  Teresa C. Chen,et al.  Ultrahigh-resolution high-speed retinal imaging using spectral-domain optical coherence tomography. , 2004, Optics express.

[18]  C. Girkin.  Differences in optic nerve structure between individuals of predominantly African and European ancestry: Implications for disease detection and pathogenesis , 2008, Clinical ophthalmology.

[19]  U. Schmidt-Erfurth,et al.  Retinal optical coherence tomography: past, present and future perspectives , 2010, British Journal of Ophthalmology.

[20]  Rob G L van der Heijde,et al.  RETINAL THICKNESS ANALYSIS (RTA): An Objective Method to Assess and Quantify the Retinal Thickness in Healthy Controls and in Diabetics Without Diabetic Retinopathy , 2002, Retina.

[21]  Hassan Foroosh,et al.  Extension of phase correlation to subpixel registration , 2002, IEEE Trans. Image Process..

[22]  W. Drexler.  Ultrahigh-resolution optical coherence tomography. , 2004, Journal of biomedical optics.

[23]  L. Ellwein,et al.  Use of eye care and associated charges among the Medicare population: 1991-1998. , 2002, Archives of ophthalmology.

[24]  Bernd Hamann,et al.  Cellular resolution volumetric in vivo retinal imaging with adaptive optics-optical coherence tomography. , 2009, Optics express.

[25]  M. Blumenkranz,et al.  The sensitivity and specificity of single-field nonmydriatic monochromatic digital fundus photography with remote image interpretation for diabetic retinopathy screening: a comparison with ophthalmoscopy and standardized mydriatic color photography. , 2002, American journal of ophthalmology.

[26]  W. Drexler,et al.  Adaptive optics optical coherence tomography at 120,000 depth scans/s for non-invasive cellular phenotyping of the living human retina. , 2009, Optics express.

[27]  Yoel Shkolnisky,et al.  The angular difference function and its application to image registration , 2005, IEEE Transactions on Pattern Analysis and Machine Intelligence.

[28]  Maciej Wojtkowski,et al.  High-speed optical coherence tomography: basics and applications. , 2010, Applied optics.

[29]  E. Berson.  Retinitis pigmentosa. The Friedenwald Lecture. , 1993, Investigative ophthalmology & visual science.

[30]  J. Pulido,et al.  Retinal topography and thickness mapping in atrophic age related macular degeneration , 2002, The British journal of ophthalmology.

[31]  L Frisén,et al.  Fundoscopy of nerve fiber layer defects in glaucoma. , 1973, Investigative ophthalmology.

[32]  D. Donoho,et al.  Fast and accurate Polar Fourier transform , 2006 .

[33]  J. Fujimoto,et al.  Ultrahigh-resolution ophthalmic optical coherence tomography , 2001, Nature Medicine.

[34]  J. Duker,et al.  Three-dimensional retinal imaging with high-speed ultrahigh-resolution optical coherence tomography. , 2005, Ophthalmology.

[35]  C. D. Kuglin,et al.  The phase correlation image alignment method , 1975 .

[36]  Amir Averbuch,et al.  Pseudopolar-based estimation of large translations, rotations, and scalings in images , 2005, IEEE Trans. Image Process..

[37]  S. Asrani,et al.  A new method for rapid mapping of the retinal thickness at the posterior pole. , 1996, Investigative ophthalmology & visual science.