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Copyright and Reprint Permission: Abstracting is permitted with credit to the source. Libraries are permitted to photocopy beyond the limit of US copyright law, for private use of patrons, those articles in this volume that carry a code at the bottom of the first page, provided that the per-copy fee indicated in the code is paid through the Copyright Clearance Center, 222 Rosewood Drive, Danvers,...
The 9th International Symposium on Biomedical Imaging (ISBI'12) was held Apr 30 - May 5, 2012, at the Centre Convencions International Barcelona (CCIB), in Barcelona, Spain. This is the third occasion that the meeting is held in Europe. The IEEE International Symposium on Biomedical Imaging (ISBI) is the premier forum for the presentation of technological advances in theoretical and applied biomedical...
Diffusion tensor imaging (DTI) is sensitive to the directionally-constrained flow of water, which diffuses preferentially along axons. Tractography programs may be used to infer matrices of connectivity (anatomical networks) between pairs of brain regions. Little is known about how these computed connectivity measures depend on the scans' spatial and angular resolutions. To determine this, we scanned...
Bipolar disorder is characterized by extreme mood swings, including both manic and depressive episodes commonly accompanied by psychosis. Many imaging studies have investigated white matter changes in bipolar illness, and the results have suggested abnormal intra- and inter-hemispheric white matter structures, particularly in the fronto-limbic and callosal systems. However, some inconsistency remains...
Fiber tracking techniques are essential for representing and visualizing the cardiac fiber architecture information encoded in diffusion-tensor imaging (DTI) data. We propose a neighborhood-based probabilistic fiber tracking method for cardiac DTI which accounts for spatial correlation and data uncertainty. The method consists in tracking fiber paths by sampling step directions from a normalized weighted...
Even if a number of methods have been proposed for resolving crossing fibres from diffusion-weighted (DW) MRI, other complex fibre geometries have drawn minimal attention. In this study, we focus on fibre orientation dispersion induced by within-voxel fanning. We use a multi-compartment, model-based approach to estimate fibre dispersion. A Bingham distribution is employed to represent a continuum...
In this paper we present a novel approach to extracting fibre orientation information from the diffusion signal. We start the process by expanding the diffusion signal using spherical harmonics (SH) basis. In theory, this could lead to a mapping between SH coefficients and fibre orientations. In practice, finding such a mapping is non-trivial. Instead, we simulate the diffusion signal for a limited...
Diffusion Tensor Imaging (DTI) has received increasing attention in the neuroimaging community. However, the complex Diffusion Weighted Images (DWI) acquisition protocol are prone to artifacts induced by motion and low signal-to-noise rations(SNRs). A rigorous quality control (QC) and error correction procedure is absolutely necessary for DTI data analysis. Most existing QC procedures are conducted...
In this paper, we explore the theory of tensor invariants as a mathematical framework for computing new biomarkers for HARDI. We present and explain the integrity basis, basic invariants and principal invariants of 2nd & 4th order tensors to expand on a recently proposed paper on 4th order tensor invariants. We present the mathematical results and compute the basic and principal invariants on...
Standard analysis techniques for Functional Magnetic Resonance Imaging (fMRI) assume a linear, time invariant model of underlying signal behaviour. These assumptions are valid for some but not all data. Hence each model characteristic should be formally tested for its validity when analysing particular data. Diagnosing model violations is a necessary step in statistical modeling but is not yet common...
We propose a novel real-time non central χ (nc-χ) noise correction method for diffusion-weighted MR data that are known to be particularly sensitive to noise, especially at high b-values. This technique aims to be real-time during the acquisition to get any map stemming from the Diffusion Tensor Imaging (DTI) and the High Angular Resolution Diffusion Imaging (HARDI) models corrected from nc-χ noise...
We consider the problem of aligning high angular resolution diffusion images characterized by orientation distribution functions (ODFs). We cast this problem as an optimization problem where we seek the rotation that aligns the source and target ODFs. This rotation induces a linear transformation of the spherical harmonic coefficients of the ODFs, which can be parametrized by the rotation Euler angles...
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