Biomedical subjects
Alok Gupta
Publications and source records attributed to Alok Gupta.
An information fusion framework for robust shape tracking.
Abstract-Existing methods for incorporating subspace model constraints in shape tracking use only partial information from the measurements and model distribution. We propose a unified framework for robust shape tracking, optimally fusing heteroscedastic uncertainties or noise from measurement, system dynamics, and a subspace model. The resulting nonorthogonal subspace projection and fusion are natural extensions of the traditional model constraint using orthogonal projection. We present two motion measurement algorithms and introduce alternative solutions for measurement uncertainty estimation. We build shape models offline from training data and exploit information from the ground truth initialization online through a strong model adaptation. Our framework is applied for tracking in echocardiograms where the motion estimation errors are heteroscedastic in nature, each heart has a distinct shape, and the relative motions of epicardial and endocardial borders reveal crucial diagnostic features. The proposed method significantly outperforms the existing shape-space-constrained tracking algorithm. Due to the complete treatment of heteroscedastic uncertainties, the strong model adaptation, and the coupled tracking of double-contours, robust performance is observed even on the most challenging cases.
Synchronous cystic teratomas of the craniofacial region.
A case of synchronous cystic teratomas presented with the complaints of a slow-growing facial mass and forward protrusion of the right eye since birth. The patient was examined thoroughly and subjected to magnetic resonance imaging (MRI) scan. The MRI scan revealed the presence of two separate cysts in the right orbit and right temporal fossa. The patient was operated by a combined effort of ophthalmologists and otorhinolaryngologists. The cysts were excised and subjected to pathological examination. The histopathological survey revealed both the cysts to be mature cystic teratomas similar to each other. This coexistence of a primary temporal fossa teratoma with an orbital teratoma is the first of its kind and to the best of our knowledge has not been reported before.
Global access to treatment: achievements and challenges.
As mentioned in the previous issue, this section of the Review addresses issues related to improving access to adequate and affordable care, treatment, and support everywhere. It replaces the section previously called "Patents and Prices." In this issue, we feature a review of achievements and challenges in recent years in opening global access to HIV/AIDS treatments. The article - one of a series commissioned to mark the tenth anniversary of the Canadian HIV/AIDS Legal Network, discussing past developments and future directions in areas of policy and law related to HIV/AIDS - describes the developments that recast the debate about access to treatment from one focused on patent entitlements to one focused on the right to health and treatment. It analyzes the role of national and international activism, strategically constructed alliances, and principled leadership in achieving this change. And it discusses continuing obstacles to equitable access to HIV/AIDS treatments for the world's population.
Fistula of the fourth branchial pouch.
Most of the congenital anomalies of the branchial apparatus are from the second arch, pouch, and cleft; some are from the first and third arches. Fourth branchial pouch remnants are very rare. We present a rare case of fourth branchial fistula, with characteristic clinical features of recurrent left-sided neck abscess that burst spontaneously, forming a fistula. Diagnosis of fourth branchial pouch fistula was confirmed by contrast radiography (ie, fistulogram and barium swallow) revealing the internal opening in the apex of the left pyriform fossa.