Oscar Acosta

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The Australian Imaging, Biomarkers and Lifestyle (AIBL) study of aging, a participant of the worldwide Alzheimer's Disease Neuroimaging Initiative (ADNI), performed (11)C-Pittsburgh Compound B (PiB) scans in 177 healthy controls (HC), 57 mild cognitive impairment (MCI) subjects, and 53 mild Alzheimer's disease (AD) patients. High PiB binding was present in(More)
Accurate cortical thickness estimation is important for the study of many neurodegenerative diseases. Many approaches have been previously proposed, which can be broadly categorised as mesh-based and voxel-based. While the mesh-based approaches can potentially achieve subvoxel resolution, they usually lack the computational efficiency needed for clinical(More)
Despite the increasing adoption of other imaging modalities, ultrasound guidance is widely used for surgical procedures and clinical imaging due to its low cost, non-invasiveness, and real-time visual feedback. Many ultrasound-guided procedures require extensive training and where possible training on simulations should be preferred over patients.(More)
We report in this communication a new formulation for the cost function of the well-known fuzzy C-means classification technique whereby we introduce weights. We derive the equations of this new weighted fuzzy C-means algorithm (WFCM) in the presence of additive and multiplicative bias field. We show that the weights can be designed in the same manner as(More)
Beta-amyloid (Abeta) deposition is one of the neuropathological hallmarks of Alzheimer's disease (AD), Abeta burden can be quantified using (11)C PiB PET. Neuropathological studies have shown that the initial plaques are located in the temporal and orbitofrontal cortices, extending later to the cingulate, frontal and parietal cortices (Braak and Braak,(More)
PURPOSE To describe the evolution and to assess the predictive value of metabolic parameters with different SUV threshold segmentations calculated from two 18F-FDG-PET/CT, one prior to and the other one during concomitant chemoradiation therapy (CCRT), for locally-advanced cervical cancer (LACC). MATERIAL AND METHODS 53 patients treated for LACC by CCRT(More)
IMPORTANCE β-amyloid (Aβ) deposition is one of the hallmarks of Alzheimer disease. Aβ deposition accelerates gray matter atrophy at early stages of the disease even before objective cognitive impairment is manifested. Identification of at-risk individuals at the presymptomatic stage has become a major research interest because it will allow early(More)
Results Atlas-based segmentation Atlas based approaches are commonly used, not only for obtaining a final segmentation but for initialization when further algorithms are applied. An atlas can be considered as a complete description of neighborhood relationships between several different structures. Thus, the atlas A is a mapping from n dimensional spatial(More)
Beta-amyloid (Abeta) plaques are one of the neuropathological hallmarks of Alzheimer's disease (AD) and can be quantified using the marker 11C PiB. As l1C PiB PET images have limited anatomical information, an Magnetic Resonance Image (MRI) is usually acquired to perform the spatial normalization needed for population analysis. We designed and evaluated a(More)