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## Approved for the Major Department (2009)

### Citations

4669 | A computational approach to edge detection
- Canny
- 1986
(Show Context)
Citation Context ... FA image of a tensor field and the corresponding structural image C. As discussed in early computer vision work, the second derivative of Gaussian serves as an efficient detector of ridge structures =-=[21]-=-. The Hessian serves as a computational approach for finding the direction of maximum ridge response. Let hi(x) be a mapping that gives the corresponding point in the subject image Ii for all x in the... |

976 |
Aspects of multivariate statistical theory
- Muirhead
- 1982
(Show Context)
Citation Context ...y and shows constant changes of FA with an anticorrelated change in FRO. 70 where S is the pooled covariance matrix given by, S = ∑nx i=1 (xi − x̄)(xi − x̄)T + ∑ny i=1 (yi − ȳ)(yi − ȳ)T nx + ny − 2 =-=[73]-=-. (6.12) In order to relax the normality assumptions associated with the parametric test, we apply a random permutation test based on the T 2 statistic to compute pvalues [74]. The permutation test is... |

959 | Functional Data Analysis
- Ramsay, Silverman
- 2005
(Show Context)
Citation Context ...continuity and spatial correlation of the samples. Statistics of the diffusion curves are computed as an infinite dimensional 66 extension to multivariate statistics known as functional data analysis =-=[84]-=-. The simplest extensions of ordinary statistics to the functional setting is the sample mean function f̄(t), parametrized by arc-length t for N samples, given by f̄(t) = 1 N N∑ i=1 fi(t), (6.1) and t... |

695 | Nonrigid registration using free-form deformations: application to breast MR images
- Rueckert, LI, et al.
- 1999
(Show Context)
Citation Context ...data was processed using the methods described in Chapter 4. To bring the separate atlases into register, the RView software was used with an affine initialization followed by a B-spline registration =-=[98, 86, 89]-=-. In this experiment, the FA image of the atlas template for each age group was registered to the atlas for the 1 year group. The registration employed is insufficient for quantitative analysis but gi... |

445 |
An overlap invariant entropy measure of 3D medical image alignment
- Studholme, DLG, et al.
(Show Context)
Citation Context ...data was processed using the methods described in Chapter 4. To bring the separate atlases into register, the RView software was used with an affine initialization followed by a B-spline registration =-=[98, 86, 89]-=-. In this experiment, the FA image of the atlas template for each age group was registered to the atlas for the 1 year group. The registration employed is insufficient for quantitative analysis but gi... |

383 | MR diffusion tensor spectroscopy and imaging
- Basser, Mattiello, et al.
- 1994
(Show Context)
Citation Context ...ally varying measurements of the diffusion rate of water [60]. Basser et al. later introduced the diffusion tensor formalism to characterize the anisotropic diffusion found in white matter structures =-=[9, 10]-=-. The development of DWI and diffusion tensor imaging (DTI) has enabled detailed investigation of white matter fiber bundles by mapping the anisotropic diffusion of water generated by axon fiber bundl... |

372 |
Tract-based spatial statistics: voxelwise analysis of multi-subject diffusion data.
- Smith, Jenkinson
- 2006
(Show Context)
Citation Context ...smoothing that can make localization of changes challenging to interpret [51]. One of the most popular frameworks for statistical analysis of DTI is the tract-based spatial statistics (TBSS) software =-=[93]-=-. TBSS is a modified voxelwise approach for analysis of diffusion properties using nonlinear registration to a template combined with a skeletonization of FA voxels. FA values are globally projected o... |

364 |
Microstructural and physiological features of tissues elucidated by quantitative diffusion-tensor MRI.
- Basser, Pierpaoli
- 1996
(Show Context)
Citation Context ...ally varying measurements of the diffusion rate of water [60]. Basser et al. later introduced the diffusion tensor formalism to characterize the anisotropic diffusion found in white matter structures =-=[9, 10]-=-. The development of DWI and diffusion tensor imaging (DTI) has enabled detailed investigation of white matter fiber bundles by mapping the anisotropic diffusion of water generated by axon fiber bundl... |

361 |
Brain development during childhood and adolescence: A longitudinal MRI study
- Giedd, Blumenthal, et al.
- 1999
(Show Context)
Citation Context ...age of 5 [29]. White matter structures increase in volume and develop well into early adulthood, while cortical gray matter regions undergo a period of growth followed by pruning in later adolescence =-=[39]-=-. MRI is an attractive tool for the investigation of development because of the minimal risk posed to healthy subjects. DTI, in particular, presents a safe method for investigating the myelination, de... |

344 | A fast algorithm for the minimum covariance determinant estimator
- Rousseeuw, VanDriessen
- 1999
(Show Context)
Citation Context ...ctive ellipsoids is shown in Fig. 5.4. Because streamline tractography is prone to outliers, the ellipsoid is computed by the fast implementation of the minimum covariance determinant (MCD) estimator =-=[85]-=-. The distance between the two ellipsoids is measured in two ways. First, the Euclidean distance between the centers of the two ellipsoids is referred to as EDc. Second, the Bhattacharyya coefficient ... |

320 | Spin diffusion measurements: spin echoes in the presence of a time dependent field gradient
- Stejskal, Tanner
- 1965
(Show Context)
Citation Context ...-Tanner equation Si = Si exp(−bgiDgTi ), (2.1) where Si is the observed intensity in a gradient direction gi, S0 is the intensity without diffusion weighting, and b is a constant proposed by Le-Bihan =-=[97, 60]-=-. b is defined as 11 b = γ2G2δ2 ( ∆− δ 3 ) , (2.2) where γ is the gyromagnetic ratio, G is the amplitude of the diffusion weighting gradient, δ is the duration of the gradient, and ∆−δ is the time bet... |

286 | A Riemannian Framework for Tensor Computing.
- Pennec, Fillard, et al.
- 2006
(Show Context)
Citation Context ...ural method for operating on diffusion tensors, which preserves the physical interpretation of the data, and constrains operations to remain in the valid space of symmetric positive-definite matrices =-=[33, 34, 81]-=-. In these methods, statistics are computed in a tangent space to the manifold of symmetric positive definite matrices. For the case of computing statistics of diffusion tensors, the mean is defined a... |

280 |
The divergence and Bhattacharyya distance measures in signal selection
- Kailath
- 1967
(Show Context)
Citation Context ...ways. First, the Euclidean distance between the centers of the two ellipsoids is referred to as EDc. Second, the Bhattacharyya coefficient EDρ is used to measure the difference between the ellipsoids =-=[54]-=-. For Gaussian distributions with means m1,m2 and covariances S1, S2 with pooled covariance S = (S1 + S2)/2, B = 1 8 (m2 −m1)TR−1(m2 −m1) + 1 2 ln ( |S|√|S1||S2| ) (5.2) EDρ = e −B. (5.3) EDρ is bound... |

273 | Advances in functional and structural MR image analysis and implementation as FSL.
- Smith, Jenkinson, et al.
- 2004
(Show Context)
Citation Context ...el that are typically smoothed and corrected for multiple comparisons. The most popular frameworks for voxelwise analysis are the statistical parametric mapping (SPM) and FMRIB software library (FSL) =-=[37, 94]-=-. Voxelwise analysis has been applied in DTI studies including autism [8] and schizophrenia [20]. The major challenge in voxel-based analysis is the need for multiple comparison correction and smoothi... |

216 | Log-euclidean metrics for fast and simple calculus on diffusion tensors. Magnetic Resonance in Medicine
- Arsigny, Pennec, et al.
- 2006
(Show Context)
Citation Context ...) Covariance statistics are computed in the tangent plane located at the mean D̂ on the manifold. Further simplifications have shown an efficient method for computation using the Log-Euclidean metric =-=[5, 6]-=-. This simplification assumes that the identity matrix is a close approximation to the mean, removing the need to 46 compute the mean via a gradient descent algorithm. Interpolation and averaging are ... |

216 | Unbiased diffeomorphic atlas construction for computational anatomy. Neuroimage 2004;23:S151–60
- Joshi, Davis, et al.
(Show Context)
Citation Context ... the tensor volumes. An unbiased, deformable atlas building procedure is then applied that produces mappings between each subject and a common atlas coordinate system using the method of Joshi et al. =-=[53]-=-. Deformed images are averaged to produce a template tensor atlas suitable for fiber tractography, as shown in Fig. 4.2. The atlas tracts may be mapped back into individual native space using the inve... |

213 | Automated modelbased tissue classification of MR images of the brain.
- Leemput, Maes, et al.
- 1999
(Show Context)
Citation Context ...of the background voxels. A white matter segmentation was created by coregistration of a T1 structural image to the averaged baseline image and applying a tissue segmentation tool to the two channels =-=[105, 104]-=-. A label image was created from the six direction image by identifying voxels within the white matter segmentation that are highly aligned or highly unaligned with the closest gradient direction. The... |

204 |
Toward a quantitative assessment of diffusion anisotropy,
- Pierpaoli, Basser
- 1996
(Show Context)
Citation Context ...tially proposed as part of the diffusion tensor model by Basser and Pierpaoli to avoid error introduced by the choice of laboratory reference frame when using a small number of measurement directions =-=[10, 83]-=-. Some of the initially proposed measures include fractional anisotropy (FA), mean diffusivity (MD), relative anisotropy (RA), the lattice index (LI), and the organization index. The purpose of these ... |

166 |
Statistical Parametric Mapping: The Analysis of Functional Brain Images.
- Friston
- 2007
(Show Context)
Citation Context ...el that are typically smoothed and corrected for multiple comparisons. The most popular frameworks for voxelwise analysis are the statistical parametric mapping (SPM) and FMRIB software library (FSL) =-=[37, 94]-=-. Voxelwise analysis has been applied in DTI studies including autism [8] and schizophrenia [20]. The major challenge in voxel-based analysis is the need for multiple comparison correction and smoothi... |

135 |
Spatial transformations of diffusion tensor magnetic resonance images.
- Alexander, Pierpaoli, et al.
- 2001
(Show Context)
Citation Context ... selected. Here, the atlas provides better anatomical correspondence, and the deformable atlas has sharper structures. 45 approximation of the transformation into a rotation and deformation component =-=[2]-=-. The local linear transformation, F , is found by computing the Jacobian matrix from the deformation field with finite differences. The rotation of each tensor is computed by performing singular valu... |

132 |
High angular resolution diffusion imaging reveals intravoxel white matter fiber heterogeneity.
- Tuch, Reese
- 2002
(Show Context)
Citation Context ... of the measured tensor. This problem was initially identified by Tuch et al. who showed that multiple fiber orientations per voxel could be resolved using high b-values and increase angular sampling =-=[103]-=-. The problem arises from multiple compartments of tissue within the relatively large spatial size of a voxel. Higher order distributions have been a recent area of research interest for instances whe... |

128 |
White matter structure in autism: preliminary evidence from diffusion tensor imaging.
- Barnea-Goraly, Kwon, et al.
- 2004
(Show Context)
Citation Context ...s [1]. BarneaGorlay et al. observed decrease tensor anisotropy in white matter in a variety of areas including white matter deep to the ventromedial prefrontal cortex and the anterior cingulate gyrus =-=[8]-=-. Krabbe disease is a degenerative disease characterized by loss of axon myelination, and there is hope that DTI can be a useful tool for characterizing the progress of the disease as well as potentia... |

126 | Principal Geodesic Analysis on Symmetric Spaces: Statistics of Diffusion Tensors. in Computer Vision Approaches to Medical Image Analysis.
- Fletcher, Joshi
- 2004
(Show Context)
Citation Context ...ural method for operating on diffusion tensors, which preserves the physical interpretation of the data, and constrains operations to remain in the valid space of symmetric positive-definite matrices =-=[33, 34, 81]-=-. In these methods, statistics are computed in a tangent space to the manifold of symmetric positive definite matrices. For the case of computing statistics of diffusion tensors, the mean is defined a... |

124 | In vivo fiber tractography using DT–MRI data.
- Basser, Pajevic, et al.
- 2000
(Show Context)
Citation Context ...an important challenge for DTI analysis. The most common approach, fiber tractography, integrates the field of tensor principal eigenvectors to create streamlines that sample anatomical fiber bundles =-=[14]-=-. The fiber tractography algorithm used in this thesis is a relatively simple streamline method based on 4th order Runge-Kutta integration. In this algorithm, a seed region is defined manually. Within... |

108 | Automated model-based bias field correction of MR images of the brain.
- Leemput, Maes, et al.
- 1999
(Show Context)
Citation Context ...of the background voxels. A white matter segmentation was created by coregistration of a T1 structural image to the averaged baseline image and applying a tissue segmentation tool to the two channels =-=[105, 104]-=-. A label image was created from the six direction image by identifying voxels within the white matter segmentation that are highly aligned or highly unaligned with the closest gradient direction. The... |

103 | Generalized diffusion tensor imaging and analytical relationships between diffusion tensor imaging and high angular resolution diffusion imaging
- Özarslan, Mareci
- 2003
(Show Context)
Citation Context ...t the time [11]. A variety of different models have been proposed to overcome the limitation of DTI including higher order diffusion 13 Figure 2.2. Example of noncrossing and crossing fibers. tensors =-=[77, 78]-=-, q-ball imaging [102], spherical harmonics [27], and mixtures of tensors [80, 56]. However, high angular resolution diffusion imaging (HARDI) imaging techniques are not yet widely used in clinical ne... |

98 | Valmet: A new validation tool for assessing and improving 3d object segmentation.
- Gerig, Jomier, et al.
- 2001
(Show Context)
Citation Context ... bundle rather than individual streamlines. 5.2.1 Volumetric Overlap As a preliminary measure of volumetric overlap, the probabilistic overlap metric implemented in Valmet was adapted to tractography =-=[38]-=-. This measure is referred to as the binary tractography overlap (BTO) and is defined by BTO = 1− ∑ i |PA(xi)− PB(xi)|∑ i PA(xi) + PB(xi) . (5.1) Here, PA(xi) is a measure of the probability that voxe... |

81 | Riemannian Geometry for the Statistical Analysis of Diffusion Tensor Data.
- Fletcher, Joshi
- 2007
(Show Context)
Citation Context ...ural method for operating on diffusion tensors, which preserves the physical interpretation of the data, and constrains operations to remain in the valid space of symmetric positive-definite matrices =-=[33, 34, 81]-=-. In these methods, statistics are computed in a tangent space to the manifold of symmetric positive definite matrices. For the case of computing statistics of diffusion tensors, the mean is defined a... |

79 | Population shape regression from random design data,” in Computer Vision,
- Davis, Fletcher, et al.
- 2007
(Show Context)
Citation Context ...s 107 with respect to a continuously varying parameter such as age. However, the problem of performing regression in multiple dimensions and especially on manifolds remains an active area of research =-=[26, 111]-=-. 8.4.5 Incorporating Covariates In addition to expanding tract oriented analysis to other statistical tools such as regression, future clinical studies will need to incorporate clinical covariates in... |

78 |
A Generic Framework for Non-rigid Registration Based on Non-uniform Multi-level Free-form Deformations.
- Schnabel, Rueckert, et al.
- 2001
(Show Context)
Citation Context ...data was processed using the methods described in Chapter 4. To bring the separate atlases into register, the RView software was used with an affine initialization followed by a B-spline registration =-=[98, 86, 89]-=-. In this experiment, the FA image of the atlas template for each age group was registered to the atlas for the 1 year group. The registration employed is insufficient for quantitative analysis but gi... |

78 |
Dysmyelination revealed through MRI as increased radial (but unchanged axial) diffusion of water.
- Song, Sun
- 2001
(Show Context)
Citation Context ...wed that mice with a genetic deficiency in myelin production with no additional axonal damage displayed higher values for λ⊥ than matched controls that would also correspond to lower FA and higher MD =-=[96]-=-. This study gives credibility to the use of anisotropy as a biomarker for changes in tissue myelination. In a related field to material presented later in this thesis, a negative correlation of MD wi... |

77 |
Apparent diffusion coefficients from high angular resolution diffusion imaging: Estimation and applications. Magnetic Resonance in
- DESCOTEAUX, ANGELINO, et al.
- 2006
(Show Context)
Citation Context ...been proposed to overcome the limitation of DTI including higher order diffusion 13 Figure 2.2. Example of noncrossing and crossing fibers. tensors [77, 78], q-ball imaging [102], spherical harmonics =-=[27]-=-, and mixtures of tensors [80, 56]. However, high angular resolution diffusion imaging (HARDI) imaging techniques are not yet widely used in clinical neuroscience studies. Given the focus of this thes... |

76 | Clinical DT-MRI estimation, smoothing and fiber tracking with Log-Euclidean metrics. In:
- Fillard, Arsigny, et al.
- 2006
(Show Context)
Citation Context ...gularization filter for diffusion weighted images [16]. Fillard et al. combined a maximum likelihood (ML) tensor estimator with a regularization function to jointly smooth and estimate a tensor field =-=[31, 32]-=-. This chapter builds on previous work by combining a comparison of gradient direction schemes with tensor estimation methods to study the error in diffusion tensors given the noisy image acquisition ... |

69 | Pajevic S. Statistical artifacts in diffusion tensor MRI (DT-MRI) caused by background noise. Magn Reson Med
- PJ
(Show Context)
Citation Context ...ser and Pajevic illustrated some of the nonlinearities in diffusion tensor statistics 21 by demonstrating the sorting bias associated with estimating the value of the eigenvalues of diffusion tensors =-=[12]-=-. Anderson presented a theoretical framework for investigating the effects of noise and developed some preliminary results on the implications for fiber tractography [4]. Hasan compared different grad... |

69 |
A Bayesian approach for stochastic white matter tractography
- Friman, Farneback, et al.
(Show Context)
Citation Context ...luate the connectivity between two regions of the brain. Friman et al. proposed a Bayesian approach for dealing with local uncertainty in fiber orientation to obtain a global measure of connectivitiy =-=[36]-=-. Later work by Zhang et al. developed a fast and efficient sampling method to solve this connectivity problem using a particle filter [113]. Both of these models are able to integrate information ove... |

65 |
Classification and quantification of neuronal fiber pathways using diffusion tensor MRI. Magnetic Resonance in Medicine
- Ding, Gore, et al.
- 2003
(Show Context)
Citation Context ...ression in clinical neuroimaging studies. Previous work has shown the importance of modeling the diffusion properties of a fiber tract as a function sampled by arc length along the axis of the bundle =-=[23, 35, 28]-=-. The major challenge in implementing tract oriented statistics in population studies is finding a consistent spatial parametrization within and between populations. Defining anatomically equivalent R... |

63 | Fiber tract-oriented statistics for quantitative diffusion tensor MRI analysis.
- Corouge, Fletcher, et al.
- 2006
(Show Context)
Citation Context ...tics in the pyramidal tract [63]. Corouge et al. proposed 19 to analyze tensors as a function sampled along arc length of fiber bundles using appropriate statistics for the space of diffusion tensors =-=[23]-=-. These methods will be extended in this thesis with the development of methods normalizing measures in a population and a novel statistical framework for populations of arc length functions. In work ... |

62 |
Correlation of white matter diffusivity and anisotropy with age during childhood and adolescence: a cross-sectional diffusion-tensor MR imaging study.
- Schmithorst, Wilke, et al.
- 2002
(Show Context)
Citation Context ...nation. In a related field to material presented later in this thesis, a negative correlation of MD with age and a positive correlation of FA with age has been shown in healthy developing adolescents =-=[88]-=-. These findings are unable to demonstrate the specificity of DTI invariant changes with biological causes. They do, however, provide credibility for the use of DTI as a biomarker for tissue change. 1... |

59 | Automatic tractography segmentation using a high-dimensional white matter atlas.
- O’Donnell, Westin
- 2007
(Show Context)
Citation Context ...rovides a statistical mechanism more appropriate for addressing global changes in tract statistics. O’Donnell and Westin used clustering to obtain a consistent set of fiber tracts across a population =-=[75]-=-. Further work used the population of fiber tracts to perform pointwise statistics along tract functions [76]. An alternative framework by Maddah et al. performs joint clustering and point matching of... |

56 | Fast and simple calculus on tensors in the log-euclidean framework,”
- Arsigny, Fillard, et al.
- 2005
(Show Context)
Citation Context ...) Covariance statistics are computed in the tangent plane located at the mean D̂ on the manifold. Further simplifications have shown an efficient method for computation using the Log-Euclidean metric =-=[5, 6]-=-. This simplification assumes that the identity matrix is a close approximation to the mean, removing the need to 46 compute the mean via a gradient descent algorithm. Interpolation and averaging are ... |

56 | Towards a shape model of white matter fiber bundles using diffusion tensor MRI
- Corouge, Gouttard, et al.
- 2004
(Show Context)
Citation Context ...there are typically a small number of streamlines, which diverge between the bundles that produce large distances. Previous research has considered the minimum, mean, or maximum of such distributions =-=[24, 115]-=-. However, the minimum and mean 55 Figure 5.2. Closest point distances for atlas and individual tractography results for the right cingulum in a subject. 0 1 2 3 4 5 6 7 8 0 1000 2000 3000 4000 5000 6... |

56 |
Q-ball imaging. Magnetic Resonance in
- Tuch
(Show Context)
Citation Context ...y of different models have been proposed to overcome the limitation of DTI including higher order diffusion 13 Figure 2.2. Example of noncrossing and crossing fibers. tensors [77, 78], q-ball imaging =-=[102]-=-, spherical harmonics [27], and mixtures of tensors [80, 56]. However, high angular resolution diffusion imaging (HARDI) imaging techniques are not yet widely used in clinical neuroscience studies. Gi... |

50 |
The effect of gradient sampling schemes on measures derived from diffusion tensor MRI: a Monte Carlo study.
- Jones
- 2004
(Show Context)
Citation Context ... tensor estimation to reduce motion artifacts in tensor statistics [66]. Derek Jones elaborated on the previous investigations by simulating the effect of noise under a variety of gradient directions =-=[49]-=-. Further investigation of the impact of imaging noise on fiber tractography was developed by Basser and Pajevic [13]. Jones and Basser showed how Rician noise tends to underestimate high values of th... |

49 |
The effect of filter size on VBM analyses of DT-MRI data.
- Jones, Symms, et al.
- 2005
(Show Context)
Citation Context ...ism [8] and schizophrenia [20]. The major challenge in voxel-based analysis is the need for multiple comparison correction and smoothing that can make localization of changes challenging to interpret =-=[51]-=-. One of the most popular frameworks for statistical analysis of DTI is the tract-based spatial statistics (TBSS) software [93]. TBSS is a modified voxelwise approach for analysis of diffusion propert... |

42 | Squashing peanuts and smashing pumpkins’: how noise distorts diffusion-weighted
- Jones, Basser
- 2004
(Show Context)
Citation Context ...mpact of imaging noise on fiber tractography was developed by Basser and Pajevic [13]. Jones and Basser showed how Rician noise tends to underestimate high values of the ADC along gradient directions =-=[50]-=-. Koay et al. describe methods to overcome negative eigenvalues in tensor estimation caused by imaging noise [55]. Basu et al. used the Rician noise model to demonstrate statistical bias and develop a... |

41 | Rician noise removal in diffusion tensor MRI. In:
- Basu, Fletcher, et al.
- 2006
(Show Context)
Citation Context ...igenvalues in tensor estimation caused by imaging noise [55]. Basu et al. used the Rician noise model to demonstrate statistical bias and develop a regularization filter for diffusion weighted images =-=[16]-=-. Fillard et al. combined a maximum likelihood (ML) tensor estimator with a regularization function to jointly smooth and estimate a tensor field [31, 32]. This chapter builds on previous work by comb... |

41 | Maximum-likelihood estimation of Rician distribution parameters,”
- Sijbers, Dekker, et al.
- 1998
(Show Context)
Citation Context ... in both the real and imaginary components of k-space is well-approximated by a Gaussian distribution, and noise in the magnitude signal Si is consequently well-characterized by a Rician distribution =-=[91, 90]-=-. A noisy measurement R of an underlying signal A in the diffusion weighted image is a random variable given by R = √ (A+X)2 + (Y i)2, X, Y ∼ N(0, σ2), (3.2) where X and Y are Gaussian random variable... |

39 |
Geometrically constrained two-tensor model for crossing tracts in DWI. Magn Reson Imaging 24:1263–1270.
- Peled, Friman, et al.
- 2006
(Show Context)
Citation Context ...limitation of DTI including higher order diffusion 13 Figure 2.2. Example of noncrossing and crossing fibers. tensors [77, 78], q-ball imaging [102], spherical harmonics [27], and mixtures of tensors =-=[80, 56]-=-. However, high angular resolution diffusion imaging (HARDI) imaging techniques are not yet widely used in clinical neuroscience studies. Given the focus of this thesis on population studies, the foll... |

38 | A unified framework for clustering and quantitative analysis of white matter fiber tracts. Med. Image Anal.,
- Maddah, Grimson, et al.
- 2008
(Show Context)
Citation Context ...used the population of fiber tracts to perform pointwise statistics along tract functions [76]. An alternative framework by Maddah et al. performs joint clustering and point matching of fiber bundles =-=[64]-=-. This framework has been applied to a study of schizophrenia in adults [65]. CHAPTER 3 DIFFUSION WEIGHTED IMAGE PREPROCESSING 3.1 Introduction Clinical neuroimaging studies that acquire DTI commonly ... |

37 |
Structural disconnectivity in schizophrenia: a diffusion tensor magnetic resonance imaging study.
- Burns, Job, et al.
- 2003
(Show Context)
Citation Context ...s methods such as statistical parametric mapping (SPM). For example, Burns et al. found reduced anisotropy in the left 7uncinate and arcuate fasciculus in adult schizophrenics versus matched controls =-=[20]-=-. The advantage of this method of analysis is efficient processing requiring minimal manual intervention. However, the major drawback is that the statistical analysis can only test the relatively weak... |

37 | Spatial normalization and averaging of diffusion tensor MRI data sets. Neuroimage,
- Jones
- 2002
(Show Context)
Citation Context ... models of diffusion. To solve both the needs for tract segmentation in individual cases as well as shape normalization for fiber tracts, we apply a population-based registration method. Jones et al. =-=[48]-=- and Xu et al. [110] described the advantages of spatial normalization for DTI population studies. Recent work has focused on the use of unbiased methods for mapping tensor images to a common coordina... |

36 | Uncinate fasciculus findings in schizophrenia: a magnetic resonance diffusion tensor imaging study.
- Kubicki, Westin, et al.
- 2002
(Show Context)
Citation Context ...used manually drawn ROI to investigate specific hypotheses about differences between white matter anatomy. Kubicki et al. found anisotropy differences in the uncinate fasciculus with manual selection =-=[58]-=-. Although these methods are able to test more specific hypotheses, they suffer from time consuming manual segmentation. The methods presented in this thesis are useful tools for future research in sc... |

35 |
Diffusion tensor imaging of the corpus callosum in Autism.
- Alexander, Lee, et al.
- 2007
(Show Context)
Citation Context ... et al. showed that after controlling for age, IQ, and other factors, there are significant differences between diffusion measurements in the corpus callosum between subjects with autism and controls =-=[1]-=-. BarneaGorlay et al. observed decrease tensor anisotropy in white matter in a variety of areas including white matter deep to the ventromedial prefrontal cortex and the anterior cingulate gyrus [8]. ... |

34 | Distortion correction and robust tensor estimation for MR diffusion imaging.
- Mangin, Poupon, et al.
- 2002
(Show Context)
Citation Context ... for DTI by developing metrics on the geometry of diffusion weighting gradients [46]. Mangin et al. combine distortion correction and tensor estimation to reduce motion artifacts in tensor statistics =-=[66]-=-. Derek Jones elaborated on the previous investigations by simulating the effect of noise under a variety of gradient directions [49]. Further investigation of the impact of imaging noise on fiber tra... |

33 | Orthogonal tensor invariants and the analysis of diffusion tensor magnetic resonance images.
- Ennis, Kindlmann
- 2006
(Show Context)
Citation Context .... The most commonly used measurements of tensor shape are FA and MD. However, Ennis and Kindlmann showed that FA and MD are not orthogonal and therefore not appropriate for joint statistical analysis =-=[30]-=-. The nonorthogonality implies that differences in FA have different meanings depending on the magnitude of the MD. In this framework, FA is used as a measure of anisotropy because of its common usage... |

31 | Generalized scalar measures for diffusion MRI using trace, variance, and entropy.
- Ozarslan, BC, et al.
- 2005
(Show Context)
Citation Context ...t the time [11]. A variety of different models have been proposed to overcome the limitation of DTI including higher order diffusion 13 Figure 2.2. Example of noncrossing and crossing fibers. tensors =-=[77, 78]-=-, q-ball imaging [102], spherical harmonics [27], and mixtures of tensors [80, 56]. However, high angular resolution diffusion imaging (HARDI) imaging techniques are not yet widely used in clinical ne... |

29 | Diffusion tensor imaging: Application to the study of the developing brain.
- Cascio, Gerig, et al.
- 2007
(Show Context)
Citation Context ...ifferences in development rates [40]. In a review of DTI applied to pediatric imaging, Casicio et al. found consistent reports of increased anisotropy and decreased total diffusion due to development =-=[22]-=-. Bonekamp et al. found DTI measurements to be reproducible in pediatric studies [18]. Clinical studies such as these have so far required time-consuming manual region of interest (ROI) segmentation t... |

29 | Anatomical MRI of the developing human brain: What have we learned?
- Durston, Hilleke, et al.
- 2001
(Show Context)
Citation Context ...ric disease. The rapid developmental changes in childhood are accompanied by significant development of the brain after birth. The brain increases in total volume after birth until about the age of 5 =-=[29]-=-. White matter structures increase in volume and develop well into early adulthood, while cortical gray matter regions undergo a period of growth followed by pruning in later adolescence [39]. MRI is ... |

29 | A volumetric approach to quantifying region-to-region white matter connectivity in diffusion tensor mri
- Fletcher, Tao, et al.
- 2007
(Show Context)
Citation Context ...d Finsler metrics to enable optimization of paths through a tensor field [68, 69]. A similar approach using a geodesic distance between points in an image is used to identify volumetric fiber bundles =-=[35]-=-. These methods provide more explicit segmentation of the volume of white matter fiber bundles. The focus of this thesis is statistical analysis of diffusion properties parametrized fiber bundles. The... |

28 | Theoretical analysis of the effects of noise on diffusion tensor imaging.
- Anderson
- 2001
(Show Context)
Citation Context ...envalues of diffusion tensors [12]. Anderson presented a theoretical framework for investigating the effects of noise and developed some preliminary results on the implications for fiber tractography =-=[4]-=-. Hasan compared different gradient encoding schemes for DTI by developing metrics on the geometry of diffusion weighting gradients [46]. Mangin et al. combine distortion correction and tensor estimat... |

27 |
Multitensor approach for analysis and tracking of complex fiber configurations. Magnetic Resonance in Medicine
- Kreher, Schneider, et al.
- 2005
(Show Context)
Citation Context ...limitation of DTI including higher order diffusion 13 Figure 2.2. Example of noncrossing and crossing fibers. tensors [77, 78], q-ball imaging [102], spherical harmonics [27], and mixtures of tensors =-=[80, 56]-=-. However, high angular resolution diffusion imaging (HARDI) imaging techniques are not yet widely used in clinical neuroscience studies. Given the focus of this thesis on population studies, the foll... |

27 | Finsler active contours.
- MELONAKOS, PICHON, et al.
- 2008
(Show Context)
Citation Context ...n of diffusion has been applied to enable segmentation of difficult structures such as the cingulum [7]. Other research has used Finsler metrics to enable optimization of paths through a tensor field =-=[68, 69]-=-. A similar approach using a geodesic distance between points in an image is used to identify volumetric fiber bundles [35]. These methods provide more explicit segmentation of the volume of white mat... |

26 | Relationships between diffusion tensor and q-space MRI.
- Basser
- 2002
(Show Context)
Citation Context ...nces where the microstructure of a voxel is substantially heterogeneous. Preliminary work on q-space MRI showed that more complex measurements could be made but were clinically unfeasible at the time =-=[11]-=-. A variety of different models have been proposed to overcome the limitation of DTI including higher order diffusion 13 Figure 2.2. Example of noncrossing and crossing fibers. tensors [77, 78], q-bal... |

26 |
Pediatric diffusion tensor imaging: normal database and observation of the white matter maturation in early childhood.
- Hermoye, Saint-Martin, et al.
- 2006
(Show Context)
Citation Context ...elopment present major challenges for traditional morphometry studies based on segmentation. The quantitative nature of diffusion imaging may provide a more stable reference for many of these studies =-=[47]-=-. Furthermore, DTI elucidates additional features of tissue microstructure, especially in white matter. A majority of myelination occurs 6before birth and during the first 2 years of life with some my... |

26 |
Formal characterization and extension of the linearized diffusion tensor model.
- Salvador, Peña, et al.
- 2005
(Show Context)
Citation Context ...n. Salvador et al. proposed a weighted least squares (WLS) estimator β̂wls = (X TW2X) −1 (XTW2(ln S)) (3.10) W = Diag(Xβ̂lls) (3.11) 26 based on an analysis of the log Rician probability distribution =-=[87]-=-. The implementation used in this work uses one iteration of weight computation. An ML estimate of the diffusion tensor using the log-likelihood function of the Rician distribution was proposed by Fil... |

25 | A Computational Framework for the Statistical Analysis of Cardiac Diffusion Tensors: Application to a Small Database of Canine Hearts.
- Peyrat, Sermesant, et al.
- 2007
(Show Context)
Citation Context ... al. [110] described the advantages of spatial normalization for DTI population studies. Recent work has focused on the use of unbiased methods for mapping tensor images to a common coordinate system =-=[114, 82]-=-. A reference atlas of fiber bundles visible in DTI was produced by [71]. Xu et al. [109] highlighted the need for smooth invertible mappings in a registration framework. Other work on DTI atlas build... |

24 |
Comparison of gradient encoding schemes for diffusion-tensor MRI
- Hasan, DL, et al.
(Show Context)
Citation Context ...e preliminary results on the implications for fiber tractography [4]. Hasan compared different gradient encoding schemes for DTI by developing metrics on the geometry of diffusion weighting gradients =-=[46]-=-. Mangin et al. combine distortion correction and tensor estimation to reduce motion artifacts in tensor statistics [66]. Derek Jones elaborated on the previous investigations by simulating the effect... |

24 | A Riemannian approach to diffusion tensor images segmentation
- Lenglet, Rousson, et al.
- 2005
(Show Context)
Citation Context ...y groups working on explicit volumetric segmentation of white matter tracts. Several groups have proposed distance metrics between tensors to enable levelset segmentation of white matter fiber tracts =-=[106, 61]-=-. Nonparametric methods for calculating the distribution of diffusion has been applied to enable segmentation of difficult structures such as the cingulum [7]. Other research has used Finsler metrics ... |

22 | A fuzzy, nonparametric segmentation framework for dti and mri analysis.
- Awate, Gee
- 2007
(Show Context)
Citation Context ...tation of white matter fiber tracts [106, 61]. Nonparametric methods for calculating the distribution of diffusion has been applied to enable segmentation of difficult structures such as the cingulum =-=[7]-=-. Other research has used Finsler metrics to enable optimization of paths through a tensor field [68, 69]. A similar approach using a geodesic distance between points in an image is used to identify v... |

22 |
The NIH MRI study of normal brain development.
- Evans
- 2006
(Show Context)
Citation Context ...fore birth and during the first 2 years of life with some myelination occurring throughout life [29]. There has been substantial interest recently in acquiring large databases of pediatric DTI images =-=[19]-=-. Preliminary analysis of DTI statistics in pediatric subjects has illustrated the capacity of DTI to quantify biological changes due to development such as changes in myelination and axon packing. Gi... |

22 |
Imagerie de diffusion in vivo par résonance magnétique nucléaire. Compte Rendu de l’Académie des Sciences
- Bihan, Breton
- 1985
(Show Context)
Citation Context ... the brain white matter. Pioneering work in the 1980s by Le Bihan et al. enabled the acquisition of diffusion weighted imaging (DWI) with spatially varying measurements of the diffusion rate of water =-=[60]-=-. Basser et al. later introduced the diffusion tensor formalism to characterize the anisotropic diffusion found in white matter structures [9, 10]. The development of DWI and diffusion tensor imaging ... |

22 | A.J.: Maximum likelihood estimation of signal amplitude and noise variance form MR data.
- Sijbers, Dekker
- 2004
(Show Context)
Citation Context ... in both the real and imaginary components of k-space is well-approximated by a Gaussian distribution, and noise in the magnitude signal Si is consequently well-characterized by a Rician distribution =-=[91, 90]-=-. A noisy measurement R of an underlying signal A in the diffusion weighted image is a random variable given by R = √ (A+X)2 + (Y i)2, X, Y ∼ N(0, σ2), (3.2) where X and Y are Gaussian random variable... |

21 |
Ingvar M. Noise considerations in the determination of diffusion tensor anisotropy. Magn Reson Imaging 2000;18:659–69
- Skare, TQ, et al.
(Show Context)
Citation Context ...fect of imaging noise and SNR on estimation of FA using Monte Carlo simulation [15]. Skare et al. later extended this work to show a comparison of the effect of noise on different anisotropy measures =-=[92]-=-. Basser and Pajevic illustrated some of the nonlinearities in diffusion tensor statistics 21 by demonstrating the sorting bias associated with estimating the value of the eigenvalues of diffusion ten... |

21 |
Voxel based versus region of interest analysis in diffusion tensor imaging of neurodevelopment.
- Snook, Plewes, et al.
- 2007
(Show Context)
Citation Context ...al DTI literature have relied on voxel-based analysis or manually drawn ROI. An overview of the differences between voxel-based and ROI analysis in DTI population studies was described by Snook et al =-=[95]-=-. ROI analysis typically uses manual segmentation of white matter structures. Within the ROIs, diffusion properties such as FA or MD are averaged to create a single statistic. Examples of studies usin... |

20 |
A general framework for experiment design in diffusion MRI and its application in measuring direct tissue-microstructure features
- Alexander
- 2008
(Show Context)
Citation Context ...ng the underlying biological causes for changes in diffusion parameters. Daniel Alexander has recently published a new experimental design for directly measuring tissue properties such as axon radius =-=[3]-=-. Sharon Peled recently proposed that incorporation of a term for free isotropic diffusion can improve the biological meaning of anisotropy measures [79]. Significant work also remains in the validati... |

20 |
A theoretical study of the effect of experimental noise on the measurement of anisotropy in diffusion imaging,"
- Bastin, Armitage, et al.
- 1998
(Show Context)
Citation Context ... effects of noise on tensor measurements through theory and Monte Carlo simulation. Early on, Bastin et al. showed the effect of imaging noise and SNR on estimation of FA using Monte Carlo simulation =-=[15]-=-. Skare et al. later extended this work to show a comparison of the effect of noise on different anisotropy measures [92]. Basser and Pajevic illustrated some of the nonlinearities in diffusion tensor... |

20 |
DTI and MTR abnormalities in schizophrenia: Analysis of white matter integrity.
- Kubicki, HJ, et al.
- 2005
(Show Context)
Citation Context ... Within the ROIs, diffusion properties such as FA or MD are averaged to create a single statistic. Examples of studies using ROI methods can be found in normal development [18, 40, 47], schizophrenia =-=[57]-=-, and Krabbe’s disease [44]. The major drawback of ROI analysis is the time consuming and unreliable manual identification of regions, especially the challenge to identify the long, curved structures ... |

18 | PASTA: pointwise assessment of streamline tractography attributes.
- Jones, Travis, et al.
- 2005
(Show Context)
Citation Context ...racted by fiber tractography. Jones et al. created the pointwise assessment of streamline tractography attributes (PASTA) tool, a graphical tool for visualizing diffusion statistics of a fiber bundle =-=[52]-=-. Lin et al. used a length normalized framework for investigating diffusion statistics in the pyramidal tract [63]. Corouge et al. proposed 19 to analyze tensors as a function sampled along arc length... |

16 |
Early Postnatal Development of Corpus Callosum and Corticospinal White Matter Assessed with Quantitative Tractography.
- Gilmore, Lin, et al.
- 2007
(Show Context)
Citation Context ...ue to development such as changes in myelination and axon packing. Gilmore et al. quantified differences in DTI images of neonates between fiber tracts to investigate differences in development rates =-=[40]-=-. In a review of DTI applied to pediatric imaging, Casicio et al. found consistent reports of increased anisotropy and decreased total diffusion due to development [22]. Bonekamp et al. found DTI meas... |

16 | The application of dti to investigate white matter abnormalities in schizophrenia
- Kubicki, Westin, et al.
- 2005
(Show Context)
Citation Context ... approximately 1% of the worlds population and accounts for a large percentage of public health resources [72]. Clinical symptoms of the disease include delusions, apathy, and auditory hallucinations =-=[59]-=-. There is some evidence that schizophrenia involves deficits in connectivity between different functional regions. Because of this hypothesis, recent studies have made extensive use of DTI in the inv... |

16 |
Neuropsychiatric applications of DTI: A review
- Lim, Helpern
- 2002
(Show Context)
Citation Context ...ogress of the disease as well as potential treatments [44]. Other disorders such as Alzheimers, drug addiction, alcoholism, etc. may involve deceits of white matter that can be investigated using DTI =-=[99, 107, 62]-=-. Although this thesis will not focus on any of these other application areas, the methods of this thesis are potentially valuable in any of these investigations. 81.4 Thesis and Contributions Thesis:... |

16 | Finsler tractography for white matter connectivity analysis of the cingulum bundle
- Melonakos, Mohan, et al.
(Show Context)
Citation Context ...n of diffusion has been applied to enable segmentation of difficult structures such as the cingulum [7]. Other research has used Finsler metrics to enable optimization of paths through a tensor field =-=[68, 69]-=-. A similar approach using a geodesic distance between points in an image is used to identify volumetric fiber bundles [35]. These methods provide more explicit segmentation of the volume of white mat... |

14 |
Diffusion tensor imaging in children and adolescents: reproducibility, hemispheric, and age-related differences.
- Bonekamp, LM, et al.
- 2007
(Show Context)
Citation Context ..., Casicio et al. found consistent reports of increased anisotropy and decreased total diffusion due to development [22]. Bonekamp et al. found DTI measurements to be reproducible in pediatric studies =-=[18]-=-. Clinical studies such as these have so far required time-consuming manual region of interest (ROI) segmentation to identify regions for statistical analysis. This thesis provides an improved technol... |

13 | Improved Correspondence for DTI Population Studies via Unbiased Atlas Building.
- Goodlett, Davis, et al.
- 2006
(Show Context)
Citation Context ...ngth of steps = 2.0 Similarity measure = NMI Lambda = 0 A.3.2 Feature Image As described by Goodlett et al., a feature image based on the Hessian of the FA image is used as the basis for registration =-=[43]-=-. The program used to compute the feature image is maxcurvature. The program is used as follows: $ maxcurvature <inputimage> -o <outputimage> -s <sigma> For most adult images, a sigma of 2.0 is recomm... |

13 |
Quantitative analysis along the pyramidal tract by length-normalized parameterization based on diffusion tensor tractography: application to patients with relapsing neuromyelitis optica
- Lin, Yu, et al.
- 2006
(Show Context)
Citation Context ...(PASTA) tool, a graphical tool for visualizing diffusion statistics of a fiber bundle [52]. Lin et al. used a length normalized framework for investigating diffusion statistics in the pyramidal tract =-=[63]-=-. Corouge et al. proposed 19 to analyze tensors as a function sampled along arc length of fiber bundles using appropriate statistics for the space of diffusion tensors [23]. These methods will be exte... |

12 |
Investigation of anomalous estimates of tensor-derived quantities in diffusion tensor imaging. Magnetic Resonance in Medicine
- Koay, Carew, et al.
- 2006
(Show Context)
Citation Context ...w Rician noise tends to underestimate high values of the ADC along gradient directions [50]. Koay et al. describe methods to overcome negative eigenvalues in tensor estimation caused by imaging noise =-=[55]-=-. Basu et al. used the Rician noise model to demonstrate statistical bias and develop a regularization filter for diffusion weighted images [16]. Fillard et al. combined a maximum likelihood (ML) tens... |

10 |
Comparison of fiber tracts derived from in-vivo dti tractography with 3d histological neural tract tracer reconstruction on a macaque brain. Neuroimage
- Dauguet, Peled, et al.
- 2007
(Show Context)
Citation Context ...ne tractography methods. Previous work on comparing histology to fiber tractography has shown the difficulty in using dice coefficients and their dependence on the various parameters for tractography =-=[25]-=-. After generation of the atlas template tracts, data from the individual subject images were mapped to these tracts using the transformations created during atlas building. Tract oriented functions w... |

10 |
Tract-based morphometry for white matter group analysis.
- O’Donnell, Westin, et al.
- 2009
(Show Context)
Citation Context ... and Westin used clustering to obtain a consistent set of fiber tracts across a population [75]. Further work used the population of fiber tracts to perform pointwise statistics along tract functions =-=[76]-=-. An alternative framework by Maddah et al. performs joint clustering and point matching of fiber bundles [64]. This framework has been applied to a study of schizophrenia in adults [65]. CHAPTER 3 DI... |

8 |
Mild ventriculomegaly detected in utero with ultrasound: clinical associations and implications for schizophrenia. Schizophr Res
- JH, Tol, et al.
- 1998
(Show Context)
Citation Context ...nd MVMs in Neonates Prenatal MVM is a condition characterized by enlargement of the lateral ventricles diagnosed by ultrasound and has been associated with increased risk of neuropsychatric disorders =-=[42]-=-. Previous investigation of DTI quantities in MVM have found a significant decrease in FA from controls in manually identified regions of splenium as well as significant increase in MD in regions of t... |

8 | New perspectives on the sources of white matter DTI signal
- Peled
- 2007
(Show Context)
Citation Context ...measuring tissue properties such as axon radius [3]. Sharon Peled recently proposed that incorporation of a term for free isotropic diffusion can improve the biological meaning of anisotropy measures =-=[79]-=-. Significant work also remains in the validation of fiber tractography. Some initial work using histology of a macaque brain has attempted to validate DTI tractography [25]. Further development of si... |

6 | Findings in schizophrenia by tract-oriented DT-MRI analysis
- Maddah, Kubicki, et al.
- 2008
(Show Context)
Citation Context ...act functions [76]. An alternative framework by Maddah et al. performs joint clustering and point matching of fiber bundles [64]. This framework has been applied to a study of schizophrenia in adults =-=[65]-=-. CHAPTER 3 DIFFUSION WEIGHTED IMAGE PREPROCESSING 3.1 Introduction Clinical neuroimaging studies that acquire DTI commonly rely on derived tensor measures such as FA or MD for statistical analysis. M... |

5 |
Looking into the Functional Architecture of the Brain with Diffusion MRI. Nature reviews Neuroscience
- Bihan
- 2003
(Show Context)
Citation Context ...ns Functional Statistics Figure 6.2. Schematic diagram of tract analysis procedure. however, rotationally invariant measures such as anisotropy and MD have been linked to changes in tissue properties =-=[17]-=-. The most commonly used measurements of tensor shape are FA and MD. However, Ennis and Kindlmann showed that FA and MD are not orthogonal and therefore not appropriate for joint statistical analysis ... |

5 |
Diffusion tensor imaging of the developing mouse brain.
- Mori, Itoh, et al.
- 2001
(Show Context)
Citation Context ...nd was shown to be more sensitive than standard T2 imaging [44]. Experiments in diffusion imaging of the developing mouse brain showed a correlation between anisotropy and development of brain tissue =-=[70]-=-. Song et al. showed that mice with a genetic deficiency in myelin production with no additional axonal damage displayed higher values for λ⊥ than matched controls that would also correspond to lower ... |

4 |
Dealing with uncertainty in diffusion tensor MR data
- Basser, Pajevic
(Show Context)
Citation Context ...tigations by simulating the effect of noise under a variety of gradient directions [49]. Further investigation of the impact of imaging noise on fiber tractography was developed by Basser and Pajevic =-=[13]-=-. Jones and Basser showed how Rician noise tends to underestimate high values of the ADC along gradient directions [50]. Koay et al. describe methods to overcome negative eigenvalues in tensor estimat... |

4 | A method for registering diffusion weighted magnetic resonance images
- Tao, Miller
- 2006
(Show Context)
Citation Context ... also has no impact on the shape of the diffusion model, because the transformation is projected to a pure rotation. 103 The normalized gradient approach is similar to that proposed by Tao and Miller =-=[100]-=-. In this method, the local transformation is applied to the gradient directions, which are then renormalized to be of unit length. g′ = Ag ‖Ag‖ (8.3) The motivation for this method is an analysis of ... |

3 |
Prenatal mild ventriculomegaly predicts abnormal development of the neonatal brain.
- Gilmore, Smith, et al.
- 2008
(Show Context)
Citation Context ...l region of the tract provides more discriminative power between the 2 groups. These results are similar to differences that have been found between neonates and 1-year-old subjects in the same tract =-=[41]-=-. The results in the motor tract indicate a similar constant increase in FA across the whole tract. The FRO increases towards the inferior region of the tract, and decreases at a specific location 72 ... |

3 |
Nonparametric analysis of functional neuroimaging: A primer with examples
- Nichols, Holmes
(Show Context)
Citation Context ...̄)(yi − ȳ)T nx + ny − 2 [73]. (6.12) In order to relax the normality assumptions associated with the parametric test, we apply a random permutation test based on the T 2 statistic to compute pvalues =-=[74]-=-. The permutation test is run on the multivariate T 2 statistic and does not require multiple comparison correction. A large number of random permutations are applied to the true group labels and the ... |

2 |
Evaluation of White Matter Anisotropy
- Guo, Petrella, et al.
- 2001
(Show Context)
Citation Context ...ase is a degenerative disease characterized by loss of axon myelination, and there is hope that DTI can be a useful tool for characterizing the progress of the disease as well as potential treatments =-=[44]-=-. Other disorders such as Alzheimers, drug addiction, alcoholism, etc. may involve deceits of white matter that can be investigated using DTI [99, 107, 62]. Although this thesis will not focus on any ... |

2 |
Alzheimer’s disease: A diffusion tensor imaging and voxel-based morphometry study
- Sydykova, Stahl, et al.
(Show Context)
Citation Context ...ogress of the disease as well as potential treatments [44]. Other disorders such as Alzheimers, drug addiction, alcoholism, etc. may involve deceits of white matter that can be investigated using DTI =-=[99, 107, 62]-=-. Although this thesis will not focus on any of these other application areas, the methods of this thesis are potentially valuable in any of these investigations. 81.4 Thesis and Contributions Thesis:... |

1 |
Fundamental Neuroscience for Basic and Clinical
- Haines
- 2005
(Show Context)
Citation Context ...to as the splenium. Other smaller commissural connections include the anterior and posterior commisures. For further information on the anatomy of the nervous system, the reader is referred to Haines =-=[45]-=-. 51.3 Application Areas A wide variety of application areas in medicine and neuroscience exist for the methods presented in this thesis. These methods enable researchers to build a normative model of... |