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Co-occurrence Statistical Medical Image Processing . Bradley D. Clymer Dept of Electrical & Computer Engineering Dept of Biomedical Informatics Participating Faculty in Biomedical Engineering. Outline. Brief overview of medical image research of Clymer’s group
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Co-occurrence Statistical Medical Image Processing Bradley D. Clymer Dept of Electrical & Computer Engineering Dept of Biomedical Informatics Participating Faculty in Biomedical Engineering
Outline • Brief overview of medical image research of Clymer’s group • Using in vivo resolution to infer hidden data in spatial statistics -- osteoporosis, microvessels • Using statistical co-occurrence methods for multispectral medical images -- dynamic contrast MRI • Using 4-D co-occurrence techniques to process raw dynamic contrast data for tissue characterization
Clymer Group Medical Image Research Activities • Image acquisition & reconstruction • Parallel channel MRI (SMASH) at ultrahigh Fields: Dr. P. Schmalbrock (MRI), P. Wassenaar (MS EE) • Electron Paramagnetic Resonance Imaging (EPRI): Dr. J. Zweier (DHLRI), Dr. Y. Deng (DHLRI), Dr. P. Kuppusamy (DHLRI), R. Ahmad (EE PhD Student) • Multimodal Data Fusion & Display • Temporal Bone Surgery Simulator: Dr. G. Wiet, (Children’s Hosp.), D Stredney (OSC), Dr. P. Schmalbrock (MRI), S Raghunathan (BME PhD Student) • Using audio/haptics for multimodal image data fusion and perception: Dr. M. Knopp, Hee Chun (ECE PhD Student).
Clymer Group Medical Image Research Activities(cont.) • Directionally sensitive co-occurrence textures for tissue characterization • Osteoporosis assessment: Dr. K. Powell (CCF), Chad Showalter (ECE PhD Student), plus pending NIH grant with 4 Colleges & 6 Depts. • Microvessel volume density from ultrahigh field MRI: Dr. G. Christoferidis (MRI), Dr. P. Schmalbrock (MRI), Dr. D. Chakeres (MRI), P. Barnes (BME PhD Student) • Dynamic Contrast MRI • Parameter pseudo-image spatial co-occurrence statistics: Dr. M. Knopp (MRI), Dr. J. Heverhagen (MRI), M. Kale, (ECE PhD Student) • 4-D spatial-temporal co-occurrence statistics on raw data: Dr. M. Knopp (MRI), Dr. J. Heverhagen (MRI), Dr. T. Kurc (BMI), B Woods (ECE MS Student)
Statistical Co-occurrence Image Textures (Haralick et al.) • Even when fine structures are not resolved completely, intravoxel mixing effects create statistical spatial patterns • Haralick’s methods can be directionally sensitive – can sense isotropy/anisotropy of statistics in image data • Microvessels: long tubes with diameters smaller than voxel (pixel) size. • Trabeculae: sheets and rods of calcified tissue with cross sections smaller than voxel (pixel) size.
Statistical Co-occurrence Image Textures (cont.) • Haralick’s general approach: • Build a co-occurrence matrix (joint histogram) of nearest neighbor values in a specific direction • Generate a group of moments and entropies to characterize local joint statistics in the given neighbor directions • Use combination of calculated moments and entropies to classify local image content • Have been used since 1973 on 2-D imagery, more recently on 3-D, we are extending to 4-D with parallel cluster computing approaches
Example from bone imaging • We used mCT images of bone core samples (calcaneus): • Simulated blurring to in vivo CT resolution by local averaging of mCT data • Calculated directionally sensitive co-occurrence textures on blurred images • Compared texture outcomes as predictors for morphometric parameters (accepted standard) using linear regression
Texture parameters vs Morphometric parameters at different resolutions
Next phase of bone imaging (pending NIH R21/R33 proposal) • Obtain in situ/vivo images from human cadavers and live thoroughbred horse remodeling with exercise and atrophy • Establish translational model to bone mechanics • Compare in situ/vivo CT & MRI via directional textures with • Morphometric measures from high resolution images after excision • Mechanical testing, localization of fracture sites • Participants: ECE/BME/BMI: Clymer (PI); Radiology: M Knopp, P Schmalbrock; BME/Orth Surg: A. Litsky; Veterinary Science: A. Bertone; Mech Eng: M. Dapino, OSC: D. Stredney
Co-occurrence Processing of Dynamic Contrast MRI – 4 approaches • Spatial pattern textures of diffusion model parameter pseudo-images (k21, kel, Amp) • Use co-occurrence technique to assess parameter combination statistics and moments and entropies similar to textures at matched points in k21-image, kel-image, Amp-image • Combine methods 1 & 2 • Use raw 4-D DCE MRI data and calculate co-occurrence textures in specific directions through hyperspace, build classifier without using diffusion model parameters
Approach 1 (spatial textures of parameter pseudoimages) • John David Fleig (MSEE, MSCIS 2003) • Joel Saltz, BMI • Tahsin Kurc, BMI • Bradley Clymer, ECE, BMI
Approach 2 (pixelwise co-occurrence across different parameter pseudo-images) • Mehmet Kale (MSEE 2004, ECE Phd Student) • Johannes Heverhagen, Radiology • Bradley Clymer, ECE, BMI
Approach 4 (4-D Image texture classification of raw DCE image sequences) • Brent Woods (ECE MS Student) • Tahsin Kurc, BMI • Johannes Heverhagen, Radiology • Bradley Clymer, ECE, BMI