Neuroimaging-based age prediction using machine learning is proposed as a biomarker of brain aging, relating to cognitive performance, health outcomes and progression of neurodegenerative disease. However, even leading age-prediction algorithms contain measurement error, motivating efforts to improve experimental pipelines. T1-weighted MRI is commonly used for age prediction, and the pre-proces...

OBJECTIVE The purpose of this study was to determine the accuracy and reliability of two methods of measurements of linear distances (multiplanar 2D and tridimensional reconstruction 3D) obtained from cone-beam computed tomography (CBCT) with different voxel sizes. MATERIAL AND METHODS Ten dry human mandibles were scanned at voxel sizes of 0.2 and 0.4 mm. Craniometric anatomical landmarks wer...

BACKGROUND AND PURPOSE Single-voxel MR spectroscopy is a widely used tool for evaluating brain tumors. Although extensive data are available on the MR spectral appearance of tumors, less is known about the effect of voxel position on the accuracy of single-voxel MR spectroscopy findings. The purpose of this study was to test the hypothesis that the accuracy of single-voxel MR spectroscopy in th...

We present a 3D brain MRI segmentation method in which a high resolution label image evolves under the influence of multiple constraints. The constraints are expressed in a versatile energy minimization framework which allows for evolutions only at label boundaries, effectively making it a surface evolution system. Constraints are defined using atlas-mapped parameters. The atlas, composed of a ...

Introduction: Diffusion tensor MRI (DTI) has become a powerful tool for the investigation into tissue architecture and integrity. However, there are numerous anatomical details in the brain that are undetectable at typical DTI image resolution, being 8mm3 voxels, due to partial volume effects and the sequence used in the majority of DTI studies, single -shot EPI, is sensitive to magnetic field ...

Active contour models are an efficient, accurate, and robust tool for the segmentation of 2D and 3D image data. In particular, geometric deformable models (GDM) that represent an active contour as the level set of an implicit function have proven to be very effective. GDMs, however, do not provide any topology control, i.e. contours may merge or split arbitrarily and hence change the genus of t...

Voxelisation is the process of converting a source object of any data type into a three-dimensional grid of voxel values. This voxel grid should represent the original object as closely as possible, although some inaccuracies will occur due to the discrete nature of the voxel grid representation. In this paper we report our on-going research into methods for representing objects as voxelised di...

There is a need to visualize multi-billion voxel data sets. Hardware accelerated rendering currently available on PCs provides a cost effective and scalable way to render these very large data sets. Very large voxel data can be rendered on systems with limited texture and system memory piecemeal by decomposing the data into a set of tiled sub-domains, which are sequentially read from disk. Henc...

The present study compared the efficacy of cone beam computed tomography using different voxel sizes in the diagnosis of simulated external root resorption. The presence or absence of simulated defects on buccal, mesial and distal root surfaces of 20 premolars was evaluated. The defects were small (0.26 mm in diameter and 0.08 mm deep), medium (0.62 mm in diameter and 0.19 mm deep) and large (1...