Ramkrishnan Narayanan

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Many types of transformations are used to model deformations in medical image registration. While some focus on modeling local changes, some on continuity and invertibility, there is no closed-form nonlinear parametric approach that addresses all these properties. This paper presents a class of nonlinear transformations that are local, continuous and(More)
OBJECTIVE Image-guided prostate biopsy has become routine in medical diagnosis. Although it improves biopsy outcome, it mostly operates in 2 dimensions, therefore lacking presentation of information in the complete 3-dimensional (3D) space. Because prostatic carcinomas are nonuniformly distributed within the prostate gland, it is crucial to accurately guide(More)
The interest in registering a set of images has quickly risen in the field of medical image analysis. Mutual information (MI) based methods are well-established for pairwise registration but their extension to higher dimensions (multiple images) has encountered practical implementation difficulties. We extend the use of alpha mutual information (alphaMI) as(More)
It is widely established that prostate cancer is a multifocal disease and cancerous lesions are not uniformly distributed within the gland. Current imaging methods cannot detect prostate cancer with sufficient sensitivity and specificity, especially localized cancers. A cancer atlas was previously demonstrated. However the atlas must be registered with a(More)
OBJECTIVE For a follow-up prostate biopsy procedure, it is useful to know the previous biopsy locations in anatomic relation to the current transrectal ultrasound (TRUS) scan. The goal of this study was to validate the performance of a 3-dimensional TRUS-guided prostate biopsy system that can accurately relocate previous biopsy sites. METHODS To correlate(More)
ACKNOWLEDGEMENTS The last five years at Michigan has been a huge learning experience, academically and personally. I have had the chance to meet some of the best faculty in my area of interest and have had great friends both in and out of the DIPL lab who have played a vital role in this experience. None of this would have been possible without the(More)
Prostate cancer is the most commonly diagnosed cancer in males in the United States and the second leading cause of cancer death. While the exact cause is still under investigation, researchers agree on certain risk factors like age, family history, dietary habits, lifestyle and race. It is also widely accepted that cancer distribution within the prostate(More)