@article {2179, title = {On the generalizability of diffusion MRI signal representations across acquisition parameters, sequences and tissue types: chronicles of the MEMENTO challenge}, journal = {NeuroImage}, volume = {240}, year = {2021}, doi = {https://doi.org/10.1016/j.neuroimage.2021.118367}, author = {Alberto De Luca and Andrada Ianus and Alexander Leemans and Marco Palombo and Noam Shemesh and Hui Zhang and Daniel C Alexander and Markus Nilsson and Martijn Froeling and Geert-Jan Biessels and Mauro Zucchelli and Matteo Frigo and Enes Albay and Sara Sedlar and Abib Alimi and Samuel Deslauriers-Gauthier and Rachid Deriche and Rutger Fick and Maryam Afzali and Tomasz Pieciak and Fabian Bogusz and Santiago Aja-Fernandez and Evren Ozarslan and Derek K. Jones and Haoze Chen and Mingwu Jin and Zhijie Zhang and Fenxiang Wang and Vishwesh Nath and Prasanna Parvathaneni and Jan Morez and Jan Sijbers and Ben Jeurissen and Shreyas and Fadnavis and Stefan Endres and Ariel Rokem and Eleftherios Garyfallidis and Irina Sanchez and Vesna Prchkovska and Paulo Rodrigues and Bennet A. Landman and Kurt G Schilling} } @article {1776, title = {Diffusion MRI fiber tractography of the brain}, journal = {NMR in Biomedicine}, year = {2019}, doi = {10.1002/nbm.3785}, author = {Ben Jeurissen and Maxime Descoteaux and Susumu Mori and Alexander Leemans} } @article {1909, title = {Reproducibility and intercorrelation of graph theoretical measures in structural brain connectivity networks}, journal = {Medical Image Analysis}, volume = {52}, year = {2019}, pages = {56-67}, doi = {https://doi.org/10.1016/j.media.2018.10.009}, author = {Timo Roine and Ben Jeurissen and Daniele Perrone and Jan Aelterman and Wilfried Philips and Jan Sijbers and Alexander Leemans} } @article {1915, title = {The arcuate fasciculus network and verbal deficits in psychosis}, journal = {Translational Neuroscience}, volume = {8}, year = {2017}, month = {Feb-11-2017}, pages = {117-126}, doi = {10.1515/tnsci-2017-0018}, author = {Kenney, Joanne P.M. and McPhilemy, Genevieve and Scanlon, Cathy and Najt, Pablo and McInerney, Shane and Arndt, Sophia and Scherz, Elisabeth and Byrne, Fintan and Alexander Leemans and Ben Jeurissen and Hallahan, Brian and McDonald, Colm and Cannon, Dara M.} } @mastersthesis {1777, title = {Improved reliability of fiber orientation estimation and graph theoretical analysis of structural brain networks with diffusion MRI}, volume = {Doctor of Science}, year = {2017}, school = {University of Antwerp}, type = {PhD thesis}, author = {Timo Roine} } @article {1651, title = {D-BRAIN: Anatomically Accurate Simulated Diffusion MRI Brain Data}, journal = {PlosOne}, volume = {11}, number = {3}, year = {2016}, pages = {1-23}, doi = {10.1371/journal.pone.0149778}, author = {Daniele Perrone and Ben Jeurissen and Jan Aelterman and Timo Roine and Jan Sijbers and Aleksandra Pizurica and Alexander Leemans and Wilfried Philips} } @article {kenney2016p, title = {P. 3.033 Lateralisation of the arcuate fasciculus in psychosis \& the role in verbal learning \& auditory verbal hallucinations}, journal = {European Neuropsychopharmacology}, volume = {26}, year = {2016}, pages = {S76{\textendash}S77}, author = {Kenney, J and McInerney, S and McPhilemy, G and Najt, P and Scanlon, C and Arndt, S and Scherz, E and Byrne, F and Alexander Leemans and Ben Jeurissen and G Donohoe and B Hallahan and C McDonald and D Cannon} } @article {1634, title = {Abnormal wiring of the connectome in adults with high-functioning autism spectrum disorder}, journal = {Molecular Autism}, volume = {6}, number = {1}, year = {2015}, pages = {65}, abstract = {Recent brain imaging findings suggest that there are widely distributed abnormalities affecting the brain connectivity in individuals with autism spectrum disorder (ASD). Using graph theoretical analysis, it is possible to investigate both global and local properties of brain{\textquoteright}s wiring diagram, i.e., the connectome. We acquired diffusion-weighted magnetic resonance imaging data from 14 adult males with high-functioning ASD and 19 age-, gender-, and IQ-matched controls. As with diffusion tensor imaging-based tractography, it is not possible to detect complex (e.g., crossing) fiber configurations, present in 60{\textendash}90 \% of white matter voxels; we performed constrained spherical deconvolution-based whole brain tractography. Unweighted and weighted structural brain networks were then reconstructed from these tractography data and analyzed with graph theoretical measures. In subjects with ASD, global efficiency was significantly decreased both in the unweighted and the weighted networks, normalized characteristic path length was significantly increased in the unweighted networks, and strength was significantly decreased in the weighted networks. In the local analyses, betweenness centrality of the right caudate was significantly increased in the weighted networks, and the strength of the right superior temporal pole was significantly decreased in the unweighted networks in subjects with ASD. Our findings provide new insights into understanding ASD by showing that the integration of structural brain networks is decreased and that there are abnormalities in the connectivity of the right caudate and right superior temporal pole in subjects with ASD.}, keywords = {Autism spectrum disorder, Brain networks, Connectivity, Connectome, Diffusion Magnetic Resonance Imaging, Graph theoretical analysis, Tractography, White matter tract}, issn = {2040-2392}, doi = {10.1186/s13229-015-0058-4}, url = {http://dx.doi.org/10.1186/s13229-015-0058-4}, author = {Roine, Ulrika and Timo Roine and Salmi, Juha and Nieminen-von Wendt, Taina and Tani, Pekka and Lepp{\"a}m{\"a}ki, Sami and Rintahaka, Pertti and Caeyenberghs, Karen and Alexander Leemans and Sams, Mikko} } @article {1518, title = {Constrained spherical deconvolution-based tractography and tract-based spatial statistics show abnormal microstructural organization in Asperger syndrome}, journal = {Molecular Autism}, volume = {6}, year = {2015}, pages = {4}, abstract = {Background: The aim of this study was to investigate potential differences in neural structure in individuals with Asperger syndrome (AS), high-functioning individuals with autism spectrum disorder (ASD). The main symptoms in AS are severe impairments in social interaction, and restricted or repetitive patterns of behavior, interests or activities. Methods: Diffusion weighted magnetic resonance imaging data was acquired for 14 adult males with AS and 19 age, gender and IQ-matched controls. Voxel-wise group differences in fractional anisotropy (FA) were studied with Tract-Based Spatial Statistics (TBSS). Based on the results of TBSS, a tract-level comparison was performed with constrained spherical deconvolution (CSD)-based tractography, which is able to detect complex (e.g. crossing) fiber configurations. In addition, to investigate the relationship between the microstructural changes and the severity of symptoms, we looked for correlations between FA and Autism Spectrum Quotient (AQ), Empathy Quotient and Systemizing Quotient. Results: TBSS revealed widely distributed local increases in FA bilaterally in individuals with AS, most prominent in the temporal part of superior longitudinal fasciculus, corticospinal tract, splenium of corpus callosum, anterior thalamic radiation, inferior fronto-occipital fasciculus (IFO), posterior thalamic radiation, uncinate fasciculus and inferior longitudinal fasciculus (ILF). CSD-based tractography also showed increases in the FA in multiple tracts. However, only the difference in the left ILF was significant after a Bonferroni correction. These results were not explained by the complexity of microstructural organization, measured using the planar diffusion coefficient. In addition, we found a correlation between AQ and FA in the right IFO in the whole group. Conclusions: Our results suggest that there are local and tract-level abnormalities in WM microstructure in our homogenous and carefully characterized group of adults with AS, most prominent in the left ILF.}, doi = {10.1186/2040-2392-6-4}, url = {http://www.molecularautism.com/content/6/1/4}, author = {Roine, Ulrika and Salmi, Juha and Timo Roine and Nieminen-von Wendt, Taina and Lepp{\"a}m{\"a}ki, Sami and Rintahaka, Pertti and Tani, Pekka and Alexander Leemans and Sams, Mikko} } @article {perrone2015effect, title = {The effect of Gibbs ringing artifacts on measures derived from diffusion MRI}, journal = {NeuroImage}, volume = {120}, year = {2015}, pages = {441{\textendash}455}, publisher = {Academic Press}, author = {Daniele Perrone and Jan Aelterman and Pi{\.z}urica, Aleksandra and Ben Jeurissen and Wilfried Philips and Alexander Leemans} } @article {1519, title = {Informed constrained spherical deconvolution (iCSD)}, journal = {Medical Image Analysis}, volume = {24}, year = {2015}, pages = {269{\textendash}281}, type = {Original research}, chapter = {269}, abstract = {Diffusion-weighted (DW) magnetic resonance imaging (MRI) is a noninvasive imaging method, which can be used to investigate neural tracts in the white matter (WM) of the brain. However, the voxel sizes used in DW-MRI are relatively large, making DW-MRI prone to significant partial volume effects (PVE). These PVEs can be caused both by complex (e.g. crossing) WM fiber configurations and non-WM tissue, such as gray matter (GM) and cerebrospinal fluid. High angular resolution diffusion imaging methods have been developed to correctly characterize complex WM fiber configurations, but significant non-WM PVEs are also present in a large proportion of WM voxels. In constrained spherical deconvolution (CSD), the full fiber orientation distribution function (fODF) is deconvolved from clinically feasible DW data using a response function (RF) representing the signal of a single coherently oriented population of fibers. Non-WM PVEs cause a loss of precision in the detected fiber orientations and an emergence of false peaks in CSD, more prominently in voxels with GM PVEs. We propose a method, informed CSD (iCSD), to improve the estimation of fODFs under non-WM PVEs by modifying the RF to account for non-WM PVEs locally. In practice, the RF is modified based on tissue fractions estimated from high-resolution anatomical data. Results from simulation and in-vivo bootstrapping experiments demonstrate a significant improvement in the precision of the identified fiber orientations and in the number of false peaks detected under GM PVEs. Probabilistic whole brain tractography shows fiber density is increased in the major WM tracts and decreased in subcortical GM regions. The iCSD method significantly improves the fiber orientation estimation at the WM-GM interface, which is especially important in connectomics, where the connectivity between GM regions is analyzed.}, keywords = {Connectomics, constrained spherical deconvolution, Diffusion MRI, fiber orientation, gray matter, partial volume effect, Response function, Tractography}, doi = {10.1016/j.media.2015.01.001}, url = {http://www.sciencedirect.com/science/article/pii/S1361841515000080}, author = {Timo Roine and Ben Jeurissen and Daniele Perrone and Jan Aelterman and Wilfried Philips and Alexander Leemans and Jan Sijbers} } @article {roine2015isotropic, title = {Isotropic non-white matter partial volume effects in constrained spherical deconvolution}, journal = {Information-based methods for neuroimaging: analyzing structure, function and dynamics}, year = {2015}, pages = {112}, publisher = {Frontiers Media SA}, author = {Timo Roine and Ben Jeurissen and Daniele Perrone and Jan Aelterman and Alexander Leemans and Wilfried Philips and Jan Sijbers} } @article {forde2015structural, title = {Structural brain network analysis in families multiply affected with bipolar I disorder}, journal = {Psychiatry Research: Neuroimaging}, volume = {234}, number = {1}, year = {2015}, pages = {44{\textendash}51}, publisher = {Elsevier}, author = {Forde, Natalie J and O{\textquoteright}Donoghue, Stefani and Scanlon, Cathy and Louise Emsell and Chaddock, Chris and Alexander Leemans and Ben Jeurissen and Gareth J. Barker and Dara M. Cannon and Murray, Robin M and others} } @article {1484, title = {Automated correction of improperly rotated diffusion gradient orientations in diffusion-weighted MRI}, journal = {Medical Image Analysis}, volume = {18}, number = {7}, year = {2014}, pages = {953-962}, doi = { 10.1016/j.media.2014.05.012}, author = {Ben Jeurissen and Alexander Leemans and Jan Sijbers} } @conference {roine2014ismrm, title = {Improving fiber orientation estimation in constrained spherical deconvolution under non-white matter partial volume effects}, year = {2014}, month = {05/2014}, pages = {4492}, author = {Timo Roine and Ben Jeurissen and Wilfried Philips and Alexander Leemans and Jan Sijbers} } @conference {1443, title = {Isotropic non-white matter partial volume effects in constrained spherical deconvolution}, year = {2014}, author = {Timo Roine and Ben Jeurissen and Wilfried Philips and Alexander Leemans and Jan Sijbers} } @article {roine2014frontiers, title = {Isotropic non-white matter partial volume effects in constrained spherical deconvolution}, journal = {Frontiers in Neuroinformatics}, volume = {8}, number = {28}, year = {2014}, month = {03/2014}, pages = {1-9}, publisher = {Frontiers}, type = {Original Research}, abstract = {Diffusion-weighted (DW) magnetic resonance imaging (MRI) is a noninvasive imaging method, which can be used to investigate neural tracts in the white matter (WM) of the brain. Significant partial volume effects (PVE) are present in the DW signal due to relatively large voxel sizes. These PVEs can be caused by both non-WM tissue, such as gray matter (GM) and cerebrospinal fluid (CSF), and by multiple nonparallel WM fiber populations. High angular resolution diffusion imaging (HARDI) methods have been developed to correctly characterize complex WM fiber configurations, but to date, many of the HARDI methods do not account for non-WM PVEs. In this work, we investigated the isotropic PVEs caused by non-WM tissue in WM voxels on fiber orientations extracted with constrained spherical deconvolution (CSD). Experiments were performed on simulated and real DW-MRI data. In particular, simulations were performed to demonstrate the effects of varying the diffusion weightings, signal-to-noise ratios (SNR), fiber configurations, and tissue fractions. Our results show that the presence of non-WM tissue signal causes a decrease in the precision of the detected fiber orientations and an increase in the detection of false peaks in CSD. We estimated 35-50 \% of WM voxels to be affected by non-WM PVEs. For HARDI sequences, which typically have a relatively high degree of diffusion weighting, these adverse effects are most pronounced in voxels with GM PVEs. The non-WM PVEs become severe with 50 \% GM volume for maximum spherical harmonics orders of 8 and below, and already with 25 \% GM volume for higher orders. In addition, a low diffusion weighting or SNR increases the effects. The non-WM PVEs may cause problems in connectomics, where reliable fiber tracking at the WM-GM interface is especially important. We suggest acquiring data with high diffusion-weighting 2500-3000 s/mm2, reasonable SNR (~30) and using lower SH orders in GM contaminated regions to minimize the non-WM PVEs in CSD. }, keywords = {constrained spherical deconvolution, Diffusion MRI, fiber orientation, gray matter, partial volume effect}, doi = {10.3389/fninf.2014.00028}, url = {http://journal.frontiersin.org/Journal/10.3389/fninf.2014.00028/abstract}, author = {Timo Roine and Ben Jeurissen and Daniele Perrone and Jan Aelterman and Alexander Leemans and Wilfried Philips and Jan Sijbers} } @article {1547, title = {Recursive calibration of the fiber response function for spherical deconvolution of diffusion MRI data.}, journal = {NeuroImage}, volume = {86}, year = {2014}, month = {2014 Feb 1}, pages = {67-80}, abstract = {There is accumulating evidence that at current acquisition resolutions for diffusion-weighted (DW) MRI, the vast majority of white matter voxels contains "crossing fibers", referring to complex fiber configurations in which multiple and distinctly differently oriented fiber populations exist. Spherical deconvolution based techniques are appealing to characterize this DW intra-voxel signal heterogeneity, as they provide a balanced trade-off between constraints on the required hardware performance and acquisition time on the one hand, and the reliability of the reconstructed fiber orientation distribution function (fODF) on the other hand. Recent findings, however, suggest that an inaccurate calibration of the response function (RF), which represents the DW signal profile of a single fiber orientation, can lead to the detection of spurious fODF peaks which, in turn, can have a severe impact on tractography results. Currently, the computation of this RF is either model-based or estimated from selected voxels that have a fractional anisotropy (FA) value above a predefined threshold. For both approaches, however, there are user-defined settings that affect the RF and, consequently, fODF estimation and tractography. Moreover, these settings still rely on the second-rank diffusion tensor, which may not be the appropriate model, especially at high b-values. In this work, we circumvent these issues for RF calibration by excluding "crossing fibers" voxels in a recursive framework. Our approach is evaluated with simulations and applied to in vivo and ex vivo data sets with different acquisition settings. The results demonstrate that with the proposed method the RF can be calibrated in a robust and automated way without needing to define ad-hoc FA threshold settings. Our framework facilitates the use of spherical deconvolution approaches in data sets in which it is not straightforward to define RF settings a priori.}, keywords = {Adult, Algorithms, Brain, Calibration, diffusion tensor imaging, Humans, Image Enhancement, Image Interpretation, Computer-Assisted, Imaging, Three-Dimensional, Male, Nerve Fibers, Myelinated, Pattern Recognition, Automated, Reproducibility of Results, Sensitivity and Specificity}, issn = {1095-9572}, doi = {10.1016/j.neuroimage.2013.07.067}, author = {Chantal M W Tax and Ben Jeurissen and Vos, Sjoerd B. and Viergever, Max A. and Alexander Leemans} } @conference {1554, title = {Structural brain network analysis in families multiply affected with bipolar 1 disorder}, year = {2014}, address = {Athens, Greece}, author = {Forde, Natalie J and Scanlon, Cathy and Louise Emsell and O{\textquoteright}Donoghue, S and Chaddock, Chris and Alexander Leemans and Ben Jeurissen and Dara M. Cannon and Murray, R M and Colm McDonald} } @article {1546, title = {Structural neuroimaging correlates of allelic variation of the BDNF val66met polymorphism.}, journal = {NeuroImage}, volume = {90}, year = {2014}, month = {2014 Apr 15}, pages = {280-9}, abstract = {BACKGROUND: The brain-derived neurotrophic factor (BDNF) val66met polymorphism is associated with altered activity dependent secretion of BDNF and a variable influence on brain morphology and cognition. Although a met-dose effect is generally assumed, to date the paucity of met-homozygotes have limited our understanding of the role of the met-allele on brain structure. METHODS: To investigate this phenomenon, we recruited sixty normal healthy subjects, twenty in each genotypic group (val/val, val/met and met/met). Global and local morphology were assessed using voxel based morphometry and surface reconstruction methods. White matter organisation was also investigated using tract-based spatial statistics and constrained spherical deconvolution tractography. RESULTS: Morphological analysis revealed an "inverted-U" shaped profile of cortical changes, with val/met heterozygotes most different relative to the two homozygous groups. These results were evident at a global and local level as well as in tractography analysis of white matter fibre bundles. CONCLUSION: In contrast to our expectations, we found no evidence of a linear met-dose effect on brain structure, rather our results support the view that the heterozygotic BDNF val66met genotype is associated with cortical morphology that is more distinct from the BDNF val66met homozygotes. These results may prove significant in furthering our understanding of the role of the BDNF met-allele in disorders such as Alzheimer{\textquoteright}s disease and depression.}, keywords = {Adolescent, Adult, Alleles, Brain, Brain-Derived Neurotrophic Factor, diffusion tensor imaging, Female, Genotype, Heterozygote, Homozygote, Humans, Image Processing, Computer-Assisted, Male, Middle Aged, Polymorphism, Single Nucleotide, Young Adult}, issn = {1095-9572}, doi = {10.1016/j.neuroimage.2013.12.050}, author = {Forde, Natalie J and Ronan, Lisa and Suckling, John and Scanlon, Cathy and Neary, Simon and Holleran, Laurena and Alexander Leemans and Tait, Roger and Rua, Catarina and Fletcher, Paul C and Ben Jeurissen and Dodds, Chris M and Miller, Sam R and Bullmore, Edward T and Colm McDonald and Nathan, Pradeep J and Dara M. Cannon} } @conference {1433, title = {Analysis and modeling of isotropic partial volume effects in diffusion MRI}, volume = {7}, year = {2013}, month = {2013}, doi = {10.3389/conf.fninf.2013.10.00027}, author = {Timo Roine and Ben Jeurissen and Alexander Leemans and Wilfried Philips and Jan Sijbers} } @article {1369, title = {Comprehensive framework for accurate diffusion MRI parameter estimation}, journal = {Magnetic Resonance in Medicine}, volume = {81}, year = {2013}, pages = {972-984}, doi = {10.1002/mrm.24529}, author = {Jelle Veraart and Jeny Rajan and Ron R Peeters and Alexander Leemans and Stefan Sunaert and Jan Sijbers} } @article {1361, title = {Does the use of hormonal contraceptives cause microstructural changes in cerebral white matter? Preliminary results of a DTI and tractography study.}, journal = {European radiology}, volume = {23}, year = {2013}, month = {2012 Jul 20}, pages = {57-64}, abstract = {OBJECTIVE: To evaluate the effect of monophasic combined oral contraceptive pill (COCP) and menstrual cycle phase in healthy young women on white matter (WM) organization using diffusion tensor imaging (DTI). METHODS: Thirty young women were included in the study; 15 women used COCP and 15 women had a natural cycle. All subjects underwent DTI magnetic resonance imaging during the follicular and luteal phase of their cycle, or in different COCP cycle phases. DTI parameters were obtained in different WM structures by performing diffusion tensor fibre tractography. Fractional anisotropy and mean diffusivity were calculated for different WM structures. Hormonal plasma concentrations were measured in peripheral venous blood samples and correlated with the DTI findings. RESULTS: We found a significant difference in mean diffusivity in the fornix between the COCP and the natural cycle group. Mean diffusivity values in the fornix were negatively correlated with luteinizing hormone and estradiol blood concentrations. CONCLUSION: An important part in the limbic system, the fornix, regulates emotional processes. Differences in diffusion parameters in the fornix may contribute to behavioural alternations related to COCP use. This finding also suggests that the use of oral contraceptives needs to be taken into account when designing DTI group studies. KEY POINTS: {\textbullet} Diffusion tensor MRI offers new insights into brain white matter microstructure. {\textbullet} The effects of oral hormonal contraception were examined in young women. {\textbullet} Diffusion tensor images and hormone blood concentrations were evaluated. {\textbullet} Women using hormonal contraception demonstrated higher mean diffusivity in the fornix. {\textbullet} These changes may contribute to behavioural alternations related to contraception use.}, issn = {1432-1084}, doi = {10.1007/s00330-012-2572-5}, author = {De Bondt, Timo and Wim Van Hecke and Jelle Veraart and Alexander Leemans and Jan Sijbers and Stefan Sunaert and Jacquemyn, Yves and Paul M Parizel} } @conference {1389, title = {How to make sure you are using the correct gradient orientations in your diffusion MRI study?}, year = {2013}, month = {April}, pages = {2047}, address = {Salt Lake City, USA}, author = {Ben Jeurissen and Alexander Leemans and Jan Sijbers} } @article {1412, title = {Increased coherence of white matter fiber tract organization in adults with Asperger syndrome: A diffusion tensor imaging study}, journal = {Autism Research}, volume = {6}, year = {2013}, pages = {642-650}, chapter = {642}, doi = {10.1002/aur.1332}, author = {Roine, Ulrika and Timo Roine and Salmi, Juha and Nieminen-von Wendt, Taina and Lepp{\"a}m{\"a}ki, Sami and Rintahaka, Pertti and Tani, Pekka and Alexander Leemans and Sams, Mikko} } @article {1348, title = {Investigating the prevalence of complex fiber configurations in white matter tissue with diffusion magnetic resonance imaging.}, journal = {Human Brain Mapping}, volume = {34}, number = {11}, year = {2013}, pages = {2747-66}, abstract = {It has long been recognized that the diffusion tensor model is inappropriate to characterize complex fiber architecture, causing tensor-derived measures such as the primary eigenvector and fractional anisotropy to be unreliable or misleading in these regions. There is however still debate about the impact of this problem in practice. A recent study using a Bayesian automatic relevance detection (ARD) multicompartment model suggested that a third of white matter (WM) voxels contain crossing fibers, a value that, whilst already significant, is likely to be an underestimate. The aim of this study is to provide more robust estimates of the proportion of affected voxels, the number of fiber orientations within each WM voxel, and the impact on tensor-derived analyses, using large, high-quality diffusion-weighted data sets, with reconstruction parameters optimized specifically for this task. Two reconstruction algorithms were used: constrained spherical deconvolution (CSD), and the ARD method used in the previous study. We estimate the proportion of WM voxels containing crossing fibers to be \~{}90\% (using CSD) and 63\% (using ARD). Both these values are much higher than previously reported, strongly suggesting that the diffusion tensor model is inadequate in the vast majority of WM regions. This has serious implications for downstream processing applications that depend on this model, particularly tractography, and the interpretation of anisotropy and radial/axial diffusivity measures.}, issn = {1097-0193}, doi = {10.1002/hbm.22099}, author = {Ben Jeurissen and Alexander Leemans and Jacques-Donald Tournier and Derek K. Jones and Jan Sijbers} } @article {1368, title = {Limbic and callosal white matter changes in euthymic bipolar I disorder: an advanced diffusion MRI tractography study}, journal = {Biologicial Psychiatry}, volume = {73}, year = {2013}, pages = {194-201}, doi = {http://dx.doi.org/10.1016/j.biopsych.2012.09.023}, author = {Louise Emsell and Alexander Leemans and Camilla Langan and Wim Van Hecke and Gareth J. Barker and Peter McCarthy and Ben Jeurissen and Jan Sijbers and Stefan Sunaert and Dara M. Cannon and Colm McDonald} } @conference {1557, title = {Recursive calibration of the fiber response function for spherical deconvolution diffusion ODF sharpening}, year = {2013}, address = {Podstrana, Croatia}, author = {Chantal M W Tax and Ben Jeurissen and Vos, Sjoerd B. and Viergever, Max A. and Alexander Leemans} } @conference {1556, title = {Robust fiber response function estimation for deconvolution based diffusion MRI methods}, volume = {21}, year = {2013}, pages = {3149}, address = {Salt Lake City, Utah}, author = {Chantal M W Tax and Ben Jeurissen and Viergever, Max A. and Alexander Leemans} } @conference {1555, title = {Robust fiber response function estimation for deconvolution based diffusion MRI methods}, volume = {5}, year = {2013}, pages = {55}, address = {Rotterdam, The Netherlands}, author = {Chantal M W Tax and Ben Jeurissen and Viergever, Max A. and Alexander Leemans} } @article {1397, title = {Weighted linear least squares estimation of diffusion MRI parameters: Strengths, limitations, and pitfalls.}, journal = {NeuroImage}, volume = {81}, year = {2013}, month = {2013 May 16}, pages = {335-346}, abstract = {PURPOSE: Linear least squares estimators are widely used in diffusion MRI for the estimation of diffusion parameters. Although adding proper weights is necessary to increase the precision of these linear estimators, there is no consensus on how to practically define them. In this study, the impact of the commonly used weighting strategies on the accuracy and precision of linear diffusion parameter estimators is evaluated and compared with the nonlinear least squares estimation approach. METHODS: Simulation and real data experiments were done to study the performance of the weighted linear least squares estimators with weights defined by (a) the squares of the respective noisy diffusion-weighted signals; and (b) the squares of the predicted signals, which are reconstructed from a previous estimate of the diffusion model parameters. RESULTS: The negative effect of weighting strategy (a) on the accuracy of the estimator was surprisingly high. Multi-step weighting strategies yield better performance and, in some cases, even outperformed the nonlinear least squares estimator. CONCLUSION: If proper weighting strategies are applied, the weighted linear least squares approach shows high performance characteristics in terms of accuracy/precision and may even be preferred over nonlinear estimation methods.}, issn = {1095-9572}, doi = {10.1016/j.neuroimage.2013.05.028}, author = {Jelle Veraart and Jan Sijbers and Stefan Sunaert and Alexander Leemans and Ben Jeurissen} } @conference {1558, title = {{\textquotedblleft}The weighted linear least squares for estimating diffusion (kurtosis) tensors: Revisited}, year = {2013}, address = {Podstrana, Croatia}, author = {Jelle Veraart and Jan Sijbers and Stefan Sunaert and Alexander Leemans and Ben Jeurissen} } @conference {1341, title = {Assessing the implications of complex fiber configurations for DTI metrics in real data sets}, year = {2012}, month = {May}, pages = {3584}, address = {Melbourne, Australia}, author = {Ben Jeurissen and Alexander Leemans and Jacques-Donald Tournier and Derek K. Jones and Jan Sijbers} } @conference {1325, title = {Correction of Gibbs ringing in diffusion MRI data using total variation regularization}, year = {2012}, month = {January}, pages = {99}, keywords = {MRI distortion artefacts}, author = {Daniele Perrone and Jan Aelterman and Maryna Kudzinava and Jan Sijbers and Aleksandra Pizurica and Wilfried Philips and Alexander Leemans} } @conference {1340, title = {HARDI-based methods for fiber orientation estimation}, year = {2012}, note = {Received the Summa Cum Laude Merit Award for the 20th Annual ISMRM meeting.}, month = {May}, pages = {3585}, address = {Melbourne, Australia}, author = {Ben Jeurissen and Alexander Leemans and Jacques-Donald Tournier and Jan Sijbers} } @mastersthesis {1337, title = {Improved analysis of brain connectivity using high angular resolution diffusion MRI}, volume = {PhD in Sciences}, year = {2012}, month = {03/2012}, pages = {208}, school = {University of Antwerp}, type = {PhD thesis}, keywords = {complex WM architecture, constrained spherical deconvolution, crossing fibers, CSD, Diffusion MRI, diffusion tensor imaging, DTI, HARDI, high angular resolution diffusion imaging, Magnetic Resonance Imaging, MRI, probabilistic tractography, Spherical deconvolution, Tractography, white matter, WM}, author = {Ben Jeurissen} } @article {1516, title = {Improved sensitivity to cerebral white matter abnormalities in Alzheimer{\textquoteright}s disease with spherical deconvolution based tractography.}, journal = {PloS one}, volume = {7}, year = {2012}, month = {2012}, pages = {e44074}, abstract = {Diffusion tensor imaging (DTI) based fiber tractography (FT) is the most popular approach for investigating white matter tracts in vivo, despite its inability to reconstruct fiber pathways in regions with "crossing fibers." Recently, constrained spherical deconvolution (CSD) has been developed to mitigate the adverse effects of "crossing fibers" on DTI based FT. Notwithstanding the methodological benefit, the clinical relevance of CSD based FT for the assessment of white matter abnormalities remains unclear. In this work, we evaluated the applicability of a hybrid framework, in which CSD based FT is combined with conventional DTI metrics to assess white matter abnormalities in 25 patients with early Alzheimer{\textquoteright}s disease. Both CSD and DTI based FT were used to reconstruct two white matter tracts: one with regions of "crossing fibers," i.e., the superior longitudinal fasciculus (SLF) and one which contains only one fiber orientation, i.e. the midsagittal section of the corpus callosum (CC). The DTI metrics, fractional anisotropy (FA) and mean diffusivity (MD), obtained from these tracts were related to memory function. Our results show that in the tract with "crossing fibers" the relation between FA/MD and memory was stronger with CSD than with DTI based FT. By contrast, in the fiber bundle where one fiber population predominates, the relation between FA/MD and memory was comparable between both tractography methods. Importantly, these associations were most pronounced after adjustment for the planar diffusion coefficient, a measure reflecting the degree of fiber organization complexity. These findings indicate that compared to conventionally applied DTI based FT, CSD based FT combined with DTI metrics can increase the sensitivity to detect functionally significant white matter abnormalities in tracts with complex white matter architecture.}, keywords = {Aged, 80 and over, Alzheimer Disease, Cerebrum, Cognition, Corpus Callosum, diffusion tensor imaging, Female, Humans, Male, Memory, Nerve Fibers, Myelinated}, issn = {1932-6203}, doi = {10.1371/journal.pone.0044074}, author = {Reijmer, Yael D and Alexander Leemans and Heringa, Sophie M and Wielaard, Ilse and Ben Jeurissen and Koek, Huiberdina L and Biessels, Geert Jan} } @article {1336, title = {The influence of complex white matter architecture on the mean diffusivity in diffusion tensor MRI of the human brain}, journal = {NeuroImage}, volume = {59}, year = {2012}, month = {2/2012}, pages = {2208 - 2216}, issn = {10538119}, doi = {10.1016/j.neuroimage.2011.09.086}, author = {Vos, Sjoerd B. and Derek K. Jones and Ben Jeurissen and Viergever, Max A. and Alexander Leemans} } @conference {1551, title = {Constrained spherical deconvolution based tractography and cognition in Alzheimer{\textquoteright}s disease}, year = {2011}, address = {Qu{\'e}bec, Canada}, author = {Reijmer, Yael D and Alexander Leemans and Heringa, Sophie M and Wielaard, Ilse and Ben Jeurissen and Koek, Huiberdina L and Biessels, Geert Jan} } @conference {1552, title = {Constrained spherical deconvolution based tractography and cognition in Alzheimer{\textquoteright}s disease}, year = {2011}, address = {Paris, France}, author = {Reijmer, Yael D and Alexander Leemans and Heringa, Sophie M and Wielaard, Ilse and Ben Jeurissen and Koek, Huiberdina L and Biessels, Geert Jan} } @conference {1549, title = {Constrained spherical deconvolution based tractography and cognition in Alzheimer{\textquoteright}s disease}, volume = {5}, year = {2011}, address = {Lille, France}, author = {Reijmer, Yael D and Alexander Leemans and Heringa, Sophie M and Wielaard, Ilse and Ben Jeurissen and Koek, Huiberdina L and Biessels, Geert Jan} } @conference {bjeurissM.aleemansjsijbers2011, title = {Correction of DWI gradient orientations using registration techniques}, year = {2011}, month = {January}, author = {Ben Jeurissen and Maarten Naeyaert and Alexander Leemans and Jan Sijbers} } @conference {1550, title = {Diffusion tensor imaging and cognition in Alzheimer{\textquoteright}s disease: the influence of crossing fibers}, year = {2011}, address = {Lunteren, The Netherlands}, author = {Wielaard, Ilse and Reijmer, Yael D and Alexander Leemans and Heringa, Sophie M and Ben Jeurissen and Koek, Huiberdina L and Biessels, Geert Jan} } @conference {1307, title = {Distortion correction of DKI data: affine approach}, year = {2011}, month = {December}, abstract = {In this work, the performance of FMRIB{\textquoteright}s Linear Registration Tool (FLIRT) is evaluated with respect to motion and distortion correction of diffusion kurtosis imaging (DKI) data. FLIRT is tested on two DKI datasets heavily distorted by motion and eddy currents artefacts. Six different criteria are used for evaluation. Our results show that distortion correction using FLIRT substantially improves the original data. However, being an affine registration tool, FLIRT cannot cope with the amount of non-linear distortion present in DKI datasets. Hence, we conclude that, for correction of DKI data, non-linear registration techniques are more suitable.}, keywords = {medical imaging}, author = {Maryna Kudzinava and Alexander Leemans and Wilfried Philips and Daniele Perrone and Jan Aelterman and J. Dudink and Jan Sijbers} } @article {wvheckealeemansC.jveraartjsijbersS.2011, title = {The effect of template selection on diffusion tensor voxel based analysis results}, journal = {NeuroImage}, volume = {55}, number = {2}, year = {2011}, pages = {566-573}, author = {Wim Van Hecke and Alexander Leemans and Caroline A Sage and Jelle Veraart and Jan Sijbers and Stefan Sunaert} } @conference {M.J.bjeurissP.J.K.J.aleemans2011, title = {Fiber architecture of the female pelvic floor: An exploratory investigation using different diffusion MRI tractography algorithms}, year = {2011}, month = {May}, address = {Montreal, Canada}, author = {Martijn Froeling and Strijkers G. J. and Ben Jeurissen and van der Paardt M. P. and J. Stoker and K. Nicolay and A. J. Nederveen and Alexander Leemans} } @conference {1308, title = {Gibbs artifact suppression for DT-MRI data}, year = {2011}, month = {December}, keywords = {medical imaging}, author = {Daniele Perrone and Jan Aelterman and Maryna Kudzinava and Jan Sijbers and Aleksandra Pizurica and Wilfried Philips and Alexander Leemans} } @article {1258, title = {Probabilistic fiber tracking using the residual bootstrap with constrained spherical deconvolution}, journal = {Human Brain Mapping}, volume = {32}, year = {2011}, month = {March, 2011}, pages = {461 - 479}, keywords = {Diffusion MRI, Spherical deconvolution, Tractography}, doi = {10.1002/hbm.21032}, author = {Ben Jeurissen and Alexander Leemans and Derek K. Jones and Jacques-Donald Tournier and Jan Sijbers} } @conference {bjeurissM.aleemansjsijbers2011, title = {Registration based correction of DWI gradient orientations}, year = {2011}, month = {May}, address = {Montreal, Canada}, author = {Ben Jeurissen and Maarten Naeyaert and Alexander Leemans and Jan Sijbers} } @conference {1553, title = {White Matter Tract Deficits in Schizophrenia}, volume = {7}, year = {2011}, address = {Dublin, Ireland}, author = {Forde, Natalie J and Ellison-Wright, I and Nathan, Pradeep J and Zaman, R and Dudas, R and Agius, M and Fernandez-Egea, E and Alexander Leemans and Ben Jeurissen and Scanlon, Cathy and Colm McDonald and Dara M. Cannon} } @article {wvheckeAleemanssdbackerBjeurisspmparizejsijbers2010, title = {Comparing isotropic and anisotropic smoothing for voxel-based DTI analyses: A simulation study}, journal = {Human Brain Mapping}, volume = {31}, number = {1}, year = {2010}, pages = {98-114}, author = {Wim Van Hecke and Alexander Leemans and Steve De Backer and Ben Jeurissen and Paul M Parizel and Jan Sijbers} } @article {wvheckeNagelsaleemansVandervlietjsijbersParizel2010, title = {Correlation of cognitive dysfunction and diffusion tensor MRI measures in patients with mild and moderate multiple sclerosis}, journal = {Journal of magnetic resonance imaging}, volume = {31}, number = {6}, year = {2010}, month = {May}, pages = {1492-1498}, author = {Wim Van Hecke and Guy Nagels and Alexander Leemans and Everhard Vandervliet and Jan Sijbers and Paul M Parizel} } @conference {bjeurissaleemansdkjonesjdtournierjsijbers2010, title = {Counting the number of fiber orientations in diffusion MRI voxels using constrained spherical deconvolution}, year = {2010}, month = {January}, address = {Utrecht, The Netherlands}, author = {Ben Jeurissen and Alexander Leemans and Derek K. Jones and Jacques-Donald Tournier and Jan Sijbers} } @conference {bjeurissaleemansdkjonesjdtournierjsijbers2010, title = {Estimating the number of fiber orientations in diffusion MRI voxels: a constrained spherical deconvolution study}, year = {2010}, month = {May}, address = {Stockholm, Sweden}, author = {Ben Jeurissen and Alexander Leemans and Derek K. Jones and Jacques-Donald Tournier and Jan Sijbers} } @article {wvheckejsijberssdbackerdpootParizelaleemans2009, title = {On the construction of a ground truth framework for evaluating voxel-based diffusion tensor MRI analysis methods}, journal = {NeuroImage}, volume = {46}, number = {3}, year = {2009}, month = {July}, pages = {692-707}, doi = {10.1016/j.neuroimage.2008.07.006}, author = {Wim Van Hecke and Jan Sijbers and Steve De Backer and Dirk H J Poot and Paul M Parizel and Alexander Leemans} } @article {1376, title = {A diffusion tensor imaging group study of the spinal cord in multiple sclerosis patients with and without T2 spinal cord lesions.}, journal = {Journal of magnetic resonance imaging : JMRI}, volume = {30}, year = {2009}, month = {2009 Jul}, pages = {25-34}, abstract = {PURPOSE: To examine the T(2)-normal appearing spinal cord of patients with multiple sclerosis (MS) using diffusion tensor imaging. MATERIALS AND METHODS: Diffusion tensor images of the spinal cord were acquired from 21 healthy subjects, 11 MS patients with spinal cord lesions, and 10 MS patients without spinal cord lesions on the T(2)-weighted MR images. Different diffusion measures were evaluated using both a region of interest (ROI) -based and a diffusion tensor tractography-based segmentation approach. RESULTS: It was observed that the FA, the transverse diffusivity lambda(perpendicular), and the ratio of the longitudinal and transverse diffusivities (lambda(parallel)/lambda (perpendicular)) were significantly lower in the spinal cord of MS patients with spinal cord lesions compared with the control subjects using both the ROI method (P = 0.014, P = 0.028, and P = 0.039, respectively) and the tractography-based approach (P = 0.006, P = 0.037, and P = 0.012, respectively). For both image analysis methods, the FA and the lambda (parallel)/lambda (perpendicular) values were significantly different between the control group and the MS patient group without T(2) spinal cord lesions (P = 0.013). CONCLUSION: Our results suggest that the spinal cord may still be affected by MS, even when lesions are not detected on a conventional MR scan. In addition, we demonstrated that diffusion tensor tractography is a robust tool to analyze the spinal cord of MS patients.}, keywords = {Adult, Analysis of Variance, anisotropy, Diffusion Magnetic Resonance Imaging, Female, Humans, Image Processing, Computer-Assisted, Male, Multiple Sclerosis, Observer Variation, Reproducibility of Results, Spinal Cord, Spinal Cord Diseases, Thoracic Vertebrae}, issn = {1053-1807}, doi = {10.1002/jmri.21817}, author = {Wim Van Hecke and Guy Nagels and Emonds, Griet and Alexander Leemans and Jan Sijbers and van Goethem, Johan and Paul M Parizel} } @article {1375, title = {Diffusion tensor imaging in a rat model of Parkinson{\textquoteright}s disease after lesioning of the nigrostriatal tract.}, journal = {NMR in biomedicine}, volume = {22}, year = {2009}, month = {2009 Aug}, pages = {697-706}, abstract = {Parkinson{\textquoteright}s disease (PD) is characterised by degeneration of the nigrostrial connection causing dramatic changes in the dopaminergic pathway underlying clinical pathology. Till now, no MRI tools were available to follow up any specific PD-related neurodegeneration. However, recently, diffusion tensor imaging (DTI) has received considerable attention as a new and potential in vivo diagnostic tool for various neurodegenerative diseases. To assess this in PD, we performed DTI in the acute 6-hydroxydopamine (6-OHDA) rat model of PD to evaluate diffusion properties in the degenerating nigrostriatal pathway and its connecting structures. Injection of a neurotoxin in the striatum causes retrograde neurodegeneration of the nigrostriatal tract, and selective degeneration of nigral neurons. The advantage of this model is that the lesion size is well controllable by the injected dose of the toxin. The degree of functional impairment was evaluated in vivo using the amphetamine rotation test and microPET imaging of the dopamine transporter (DAT). Despite a nearly complete lesion of the nigrostriatal tract, DTI changes were limited to the ipsilateral substantia nigra (SN). In this study we demonstrate, using voxel-based statistics (VBS), an increase in fractional anisotropy (FA), whereas all eigenvalues were significantly decreased. VBS enabled us to visualise neurodegeneration of a cluster of neurons but failed to detect degeneration of more diffuse microstructures such as the nigrostriatal fibres or the dopaminergic endings in the striatum. VBS without a priori information proved to be better than manual segmentation of brain structures as it does not suffer from volume averaging and is not susceptible to erroneous segmentations of brain regions that show very little contrast on MRI images such as SN.}, keywords = {Animals, Behavior, Animal, Diffusion Magnetic Resonance Imaging, Disease Models, Animal, Female, Imaging, Three-Dimensional, Immunohistochemistry, Parkinson Disease, Positron-Emission Tomography, Rats, Rats, Wistar, Substantia Nigra}, issn = {1099-1492}, doi = {10.1002/nbm.1381}, author = {N. Van Camp and Ines Blockx and Marleen Verhoye and Casteels, Cindy and Coun, Frea and Alexander Leemans and Jan Sijbers and Veerle Baekelandt and Koen Van Laere and Annemie Van Der Linden} } @conference {aleemansbjeurissjsijbersdkjones2009, title = {ExploreDTI: A Graphical Toolbox for Processing, Analyzing, and Visualizing Diffusion MR Data}, year = {2009}, month = {April}, address = {Honolulu, USA}, author = {Alexander Leemans and Ben Jeurissen and Jan Sijbers and Derek K. Jones} } @inproceedings {bjeurissaleemansjdtournierjsijbers2009, title = {Fiber Tracking on the {\textquoteright}Fiber Cup Phantom{\textquoteright} using Constrained Spherical Deconvolution}, booktitle = {MICCAI workshop on Diffusion Modelling and the Fiber Cup (DMFC{\textquoteright}09)}, year = {2009}, address = {London, United Kingdom}, author = {Ben Jeurissen and Alexander Leemans and Jacques-Donald Tournier and Jan Sijbers} } @conference {bjeurissaleemansjdtournierjsijbers2009, title = {Probabilistic Fiber Tracking using the Residual Bootstrap with Constrained Spherical Deconvolution MRI}, year = {2009}, month = {April}, address = {Honolulu, USA}, author = {Ben Jeurissen and Alexander Leemans and Jacques-Donald Tournier and Jan Sijbers} } @article {1374, title = {Quantitative diffusion tensor imaging in amyotrophic lateral sclerosis: revisited.}, journal = {Human brain mapping}, volume = {30}, year = {2009}, month = {2009 Nov}, pages = {3657-75}, abstract = {Voxel-based analyses (VBA) are increasingly being used to detect white matter abnormalities with diffusion tensor imaging (DTI) in different types of pathologies. However, the validity, specificity, and sensitivity of statistical inferences of group differences to a large extent depend on the quality of the spatial normalization of the DTI images. Using high-dimensional nonrigid coregistration techniques that are able to align both the spatial and orientational diffusion information and incorporate appropriate templates that contain this complete DT information may improve this quality. Alternatively, a hybrid technique such as tract-based spatial statistics (TBSS) may improve the reliability of the statistical results by generating voxel-wise statistics without the need for perfect image alignment and spatial smoothing. In this study, we have used (1) a coregistration algorithm that was optimized for coregistration of DTI data and (2) a population-based DTI atlas to reanalyze our previously published VBA, which compared the fractional anisotropy and mean diffusivity maps of patients with amyotrophic lateral sclerosis (ALS) with those of healthy controls. Additionally, we performed a complementary TBSS analysis to improve our understanding and interpretation of the VBA results. We demonstrate that, as the overall variance of the diffusion properties is lowered after normalizing the DTI data with such recently developed techniques (VBA using our own optimized high-dimensional nonrigid coregistration and TBSS), more reliable voxel-wise statistical results can be obtained than had previously been possible, with our VBA and TBSS yielding very similar results. This study provides support for the view of ALS as a multisystem disease, in which the entire frontotemporal lobe is implicated.}, keywords = {Adult, Aged, Algorithms, Amyotrophic Lateral Sclerosis, anisotropy, Brain, Brain Mapping, Case-Control Studies, diffusion tensor imaging, Female, Humans, Image Processing, Computer-Assisted, Male, Middle Aged, Reproducibility of Results, Sensitivity and Specificity, Statistics as Topic}, issn = {1097-0193}, doi = {10.1002/hbm.20794}, author = {Caroline A Sage and Wim Van Hecke and Ron R Peeters and Jan Sijbers and Robberecht, Wim and Paul M Parizel and Marchal, Guy and Alexander Leemans and Stefan Sunaert} } @conference {bjeurissaleemansjdtournierjsijbers2008, title = {Bootstrap methods for estimating uncertainty in Constrained Spherical Deconvolution fiber orientations}, year = {2008}, month = {May}, pages = {3324}, address = {Toronto, Canada}, author = {Ben Jeurissen and Alexander Leemans and Jacques-Donald Tournier and Jan Sijbers} } @conference {bjeurissaleemansjdtournierjsijbers2008, title = {Can residual bootstrap reliably estimate uncertainty in fiber orientation obtained by spherical deconvolution from diffusion-weighted MRI?}, volume = {41}, year = {2008}, month = {June}, address = {Melbourne, Australia}, author = {Ben Jeurissen and Alexander Leemans and Jacques-Donald Tournier and Jan Sijbers} } @inproceedings {wvheckealeemanssdbackerParizeljsijbers2008, title = {On the construction of a ground truth methodology to evaluate VBM analysis results of diffusion tensor images}, booktitle = {European Society for Magnetic Resonance in Medicine and Biology}, year = {2008}, month = {October}, address = {Valencia, Spain}, author = {Wim Van Hecke and Alexander Leemans and Steve De Backer and Paul M Parizel and Jan Sijbers} } @article {wvheckejsijbersDagostinoMaessdbackerVandervlietParizelaleemans2008, title = {On the construction of an inter-subject diffusion tensor magnetic resonance atlas of the healthy human brain}, journal = {NeuroImage}, volume = {43}, number = {1}, year = {2008}, pages = {69-80}, doi = {0.1016/j.neuroimage.2008.07.006}, author = {Wim Van Hecke and Jan Sijbers and E. Dagostino and F. Maes and Steve De Backer and Everhard Vandervliet and Paul M Parizel and Alexander Leemans} } @inproceedings {bjeurissaleemansjdtournierjsijbers2008, title = {Estimation of Uncertainty in Constrained Spherical Deconvolution Fiber Orientations}, booktitle = {5th IEEE International Symposium on Biomedical Imaging: From Nano to Macro}, year = {2008}, pages = {907-910}, address = {Paris, France}, author = {Ben Jeurissen and Alexander Leemans and Jacques-Donald Tournier and Jan Sijbers} } @inproceedings {wvheckealeemansAgostinosdbackerVandervlietParizeljsijbers2008, title = {The evaluation of a population based diffusion tensor image atlas using a ground truth method}, booktitle = {Proceedings of SPIE Medical Imaging}, volume = {6914}, year = {2008}, month = {February}, address = {San Diego, USA}, author = {Wim Van Hecke and Alexander Leemans and E. Dagostino and Steve De Backer and Everhard Vandervliet and Paul M Parizel and Jan Sijbers} } @conference {bjeurissaleemansefieremajsijbers2008, title = {Fiber Tractography on a Crossing Fiber Phantom using Constrained Spherical Deconvolution MRI}, year = {2008}, address = {Li{\`e}ge, Belgium}, author = {Ben Jeurissen and Alexander Leemans and Els Fieremans and Jan Sijbers} } @conference {wvheckealeemanssdbackerVandervlietjsijberspmparize2008, title = {A Ground Truth Analysis of the Preservation of Diffusion Tensor Information in a Population Specific Atlas}, year = {2008}, month = {May}, address = {Toronto, Canada}, author = {Wim Van Hecke and Alexander Leemans and Steve De Backer and Everhard Vandervliet and Jan Sijbers and Paul M Parizel} } @article {wvheckealeemansjsijbersVandervlietGoethemParizel2008, title = {A tracking based DTI segmentation method for the detection of diffusion-related changes of the cervical spinal cord with aging}, journal = {Journal of Magnetic Resonance Imaging}, volume = {27}, number = {5}, year = {2008}, month = {March}, pages = {978-991}, doi = {10.1002/jmri.21338}, author = {Wim Van Hecke and Alexander Leemans and Jan Sijbers and Everhard Vandervliet and J. Van Goethem and Paul M Parizel} } @inproceedings {wvheckeDagostinoaleemansParizelMaesjsijbers2007, title = {On the construction of a healthy brain inter-subject diffusion tensor image and tractography atlas}, booktitle = {32nd Congress of the Europea Society of NeuroRadiolog}, year = {2007}, pages = {146}, author = {Wim Van Hecke and E. Dagostino and Alexander Leemans and Paul M Parizel and F. Maes and Jan Sijbers} } @inproceedings {wvheckealeemansBrabanderLaridonClaeysCeulemansGoethemParizeljsijbers2007, title = {Diffusion Tensor Fiber Tracking Reveals Probst Bundles in Patients with Agenesis of the Corpus Callosum}, booktitle = {32nd Congress of the Europea Society of NeuroRadiolog}, year = {2007}, pages = {135}, author = {Wim Van Hecke and Alexander Leemans and N. De Brabander and A. Laridon and K. Claeys and B. Ceulemans and J. Van Goethem and Paul M Parizel and Jan Sijbers} } @inproceedings {wvheckealeemansjsijbersParizelGoethem2007, title = {Diffusion Tensor Tractoghraphy Reaveals Spinal Cord Alterations in Patients with Multiple Sclerosis}, booktitle = {32nd Congress of the Europea Society of NeuroRadiolog}, year = {2007}, pages = {129}, author = {Wim Van Hecke and Alexander Leemans and Jan Sijbers and Paul M Parizel and J. Van Goethem} } @article {ParizelRompaeyLoockwvheckeGoethemaleemansjsijbers2007, title = {Influence of User-Defined Parameters on Diffusion Tensor Tractography of the Corticospinal Tract}, journal = {The Neuroradiology Journal}, number = {20}, year = {2007}, pages = {139-147}, author = {Paul M Parizel and V. Van Rompaey and R. Van Loock and Wim Van Hecke and J. Van Goethem and Alexander Leemans and Jan Sijbers} } @inproceedings {aleemanswvheckeLebelWalkerjsijbersBeaulieu2007, title = {A model based approach for voxelwise analysis of multi-subject diffusion tensor data}, booktitle = {Joint Annual Meeting ISMRM-ESMRMB}, year = {2007}, address = {Berlin}, author = {Alexander Leemans and Wim Van Hecke and C. Lebel and L. Walker and Jan Sijbers and C. Beaulieu} } @article {wvheckealeemansD{\textquoteright}AgostinosdbackerVandervlietParizeljsijbers2007, title = {Nonrigid Coregistration of Diffusion Tensor Images Using a Viscous Fluid Model and Mutual Information}, journal = {IEEE Transactions on Medical Imaging}, volume = {26}, number = {11}, year = {2007}, pages = {1598-1612}, author = {Wim Van Hecke and Alexander Leemans and E. Dagostino and Steve De Backer and Everhard Vandervliet and Paul M Parizel and Jan Sijbers} } @inproceedings {wvheckealeemansVandervlietParizeljsijbers2007, title = {An optimized tensor orientation strategy for non-rigid alignment of DT-MRI data}, booktitle = {Joint Annual Meeting ISMRM-ESMRMB}, year = {2007}, address = {Berlin}, author = {Wim Van Hecke and Alexander Leemans and Everhard Vandervliet and Paul M Parizel and Jan Sijbers} } @inproceedings {VandervlietNagelsHeineckewvheckealeemansjsijbersParizel2006, title = {On the cause and mechanisms of the negative BOLD response in fMRI}, booktitle = {23rd Annual Scientific Meeting of the European Society for Magnetic Resonance in Medicine and Biology}, year = {2006}, pages = {308}, address = {Warsaw, Poland}, author = {Everhard Vandervliet and Guy Nagels and A. Heinecke and Wim Van Hecke and Alexander Leemans and Jan Sijbers and Paul M Parizel} } @inproceedings {wvheckealeemansjsijbersParizelGoethem2006, title = {A comparison of diffusion tensor analysis methods for detecting age-related changes of the normal appearing spinal cord}, booktitle = {23rd Annual Scientific Meeting of the European Society for Magnetic Resonance in Medicine and Biology}, year = {2006}, pages = {293-294}, address = {Warsaw, Poland}, author = {Wim Van Hecke and Alexander Leemans and Jan Sijbers and Paul M Parizel and J. Van Goethem} } @inproceedings {wvheckealeemansBrabanderLaridonCeulemansJParizel2006, title = {Diffusion tensor fiber tracking in patients with agenesis of the corpus callosum}, booktitle = {23rd Annual Scientific Meeting of the European Society for Magnetic Resonance in Medicine and Biology}, year = {2006}, pages = {34-35}, address = {Warsaw, Poland}, author = {Wim Van Hecke and Alexander Leemans and N. De Brabander and A. Laridon and B. Ceulemans and Jan Sijbers and Paul M Parizel} } @inproceedings {wvheckealeemansjsijbersParizelGoethem2006, title = {DTI of normal appearing spinal cord in elderly}, booktitle = {44th Annual Meeting of the American Society of Neuroradiology}, year = {2006}, month = {May}, pages = {380-381}, address = {San Diego, USA}, author = {Wim Van Hecke and Alexander Leemans and Jan Sijbers and Paul M Parizel and J. Van Goethem} } @article {GroofmverhoyeMeirTindemansaleemansavdlinde2006, title = {In vivo diffusion tensor imaging (DTI) of brain subdivisions and vocal pathways in songbirds}, journal = {NeuroImage}, volume = {29}, year = {2006}, pages = {754-763}, author = {G. De Groof and Marleen Verhoye and V. Van Meir and I. Tindemans and Alexander Leemans and Annemie Van Der Linden} } @mastersthesis {1274, title = {Modeling and Processing of Diffusion Tensor Magnetic Resonance Images for Improved Analysis of Brain Connectivity}, volume = {PhD in Sciences: Physics}, year = {2006}, author = {Alexander Leemans} } @mastersthesis {1273, title = {Modeling and Processing of Diffusion Tensor Magnetic Resonance Images for Improved Analysis of Brain Connectivity}, year = {2006}, school = {University of Antwerp}, type = {PhD thesis}, address = {Antwerp}, author = {Alexander Leemans} } @inproceedings {wvheckealeemanssdbackerVandervlietParizelAgostinojsijbers2006, title = {Multi-channel coregistration of diffusion tensor images based on a viscous fluid model}, booktitle = {Belgian Day on Biomedical Engineering - IEEE/EMBS Benelux Symposium}, year = {2006}, pages = {139-142}, address = {Brussels, Belgium}, author = {Wim Van Hecke and Alexander Leemans and Steve De Backer and Everhard Vandervliet and Paul M Parizel and E. Dagostino and Jan Sijbers} } @inproceedings {aleemansjsijberssdbackerVandervlietParizel2006, title = {Multiscale white matter fiber tract coregistration: a new feature-based approach to align diffusion tensor data}, booktitle = {14th Scientific Meeting - International Society for Magnetic Resonance in Medicine}, year = {2006}, pages = {437}, address = {Seattle, USA}, author = {Alexander Leemans and Jan Sijbers and Steve De Backer and Everhard Vandervliet and Paul M Parizel} } @article {aleemansjsijberssdbackerVandervlietParizel2006, title = {Multiscale white matter fiber tract coregistration: a new feature-based approach to align diffusion tensor data}, journal = {Magnetic Resonance in Medicine}, volume = {55}, number = {6}, year = {2006}, pages = {1414-1423}, author = {Alexander Leemans and Jan Sijbers and Steve De Backer and Everhard Vandervliet and Paul M Parizel} } @inproceedings {wvheckealeemanssdbackerVandervlietParizeljsijbersAgostino2006, title = {Non-rigid coregistration of diffusion tensor images using a viscous fluid model.}, booktitle = {23rd Annual Scientific Meeting of the European Society for Magnetic Resonance in Medicine and Biology}, year = {2006}, pages = {191-192}, address = {Warsaw, Poland}, author = {Wim Van Hecke and Alexander Leemans and Steve De Backer and Everhard Vandervliet and Paul M Parizel and Jan Sijbers and E. Dagostino} } @inproceedings {Groofmverhoyealeemansjsijbersavdlinde2006, title = {Paired voxel-wise statistical mapping of in vivo Diffusion Tensor Imaging (DTI) data to assess the seasonal neuronal plasticity in the brain of a songbird}, booktitle = {1st Annual Meeting - European Society of Molecular Imaging}, year = {2006}, address = {Paris, France}, author = {G. De Groof and Marleen Verhoye and Alexander Leemans and Jan Sijbers and Annemie Van Der Linden} } @inproceedings {wvheckealeemansjsijbersParizelGoethem2006, title = {A preliminary study of diffusion tensor imaging and tractography of the spinal cord in elderly}, booktitle = {21th Annual Symposium - Belgian Hospital Physicists Association}, year = {2006}, pages = {61}, address = {Ghent, Belgium}, author = {Wim Van Hecke and Alexander Leemans and Jan Sijbers and Paul M Parizel and J. Van Goethem} } @inproceedings {Groofmverhoyealeemansavdlinde2006, title = {Using diffusion tensor imaging (DTI) to assess the neuronal plasticity in the brain of a songbird}, booktitle = {XXeme Congres du Groupement d{\textquoteright}Etudes de Resonance Magnetique}, year = {2006}, address = {Blankenberge, Belgium}, author = {G. De Groof and Marleen Verhoye and Alexander Leemans and Annemie Van Der Linden} } @inproceedings {Groofmverhoyealeemansavdlinde2006, title = {Using diffusion tensor imaging (DTI) to assess the neuronal plasticity and neuroconnectivity in the brain of a songbird}, booktitle = {Molecular \& Cellular Basis of Neuroconnectivity}, year = {2006}, address = {Leuven, Belgium}, author = {G. De Groof and Marleen Verhoye and Alexander Leemans and Annemie Van Der Linden} } @inproceedings {CampBlockxCamonVeramverhoyealeemansMartinezjsijbersPlanasavdlinde2006, title = {White and grey matters changes in a rat model for Huntington{\textquoteright}s disease discerned with in vivo DTI}, booktitle = {23rd Annual Scientific Meeting of the European Society for Magnetic Resonance in Medicine and Biology}, year = {2006}, pages = {210-211}, address = {Warsaw, Poland}, author = {N. Van Camp and Ines Blockx and L. Camon and N. de Vera and Marleen Verhoye and Alexander Leemans and E. Martinez and Jan Sijbers and A. Planas and Annemie Van Der Linden} } @article {aleemansjsijberssdbackerVandervlietParizel2005, title = {Affine Coregistration of Diffusion Tensor Magnetic Resonance Images Using Mutual Information}, journal = {Lecture Notes in Computer Science}, volume = {3708}, year = {2005}, pages = {523-530}, author = {Alexander Leemans and Jan Sijbers and Steve De Backer and Everhard Vandervliet and Paul M Parizel} } @article {ParizelGoethemHauweSalgadoVandervlietaleemans2005, title = {Characterization of brain tumors}, journal = {NeuroRadiology}, volume = {47}, year = {2005}, pages = {80-83}, author = {Paul M Parizel and J. Van Goethem and L. van den Hauwe and R. Salgado and Everhard Vandervliet and Alexander Leemans} } @inproceedings {DelputtealeemansFieremansDeeneDAsselerLemahieuAchtenjsijbersWalle2005, title = {Density Regularized Fiber Tractography of the Brain White Matter using Diffusion Tensor MRI}, booktitle = {13th Scientific Meeting - International Society for Magnetic Resonance in Medicine}, year = {2005}, pages = {1309}, address = {Miami, USA}, author = {S. Delputte and Alexander Leemans and Els Fieremans and Y. De Deene and Y. D{\textquoteright}Asseler and I. Lemahieu and Eric Achten and Jan Sijbers and R. Van de Walle} } @inproceedings {Groofmverhoyealeemansavdlinde2005, title = {DTI parameters: Fractional Anisotropy, Radial and Axial Diffusivity reveal seasonal neuroplasticity in the adult songbird brain}, booktitle = {4th annual meeting of the Society of Molecular Imaging}, year = {2005}, address = {Keulen, Germany}, author = {G. De Groof and Marleen Verhoye and Alexander Leemans and Annemie Van Der Linden} } @inproceedings {aleemanssdbackerjsijbersVandervlietParizel2005, title = {End point clustering for diffusion tensor white matter fiber bundle tractography}, booktitle = {22th Annual Scientific Meeting - European Society for Magnetic Resonance in Medicine and Biology}, year = {2005}, pages = {129-130}, address = {Basle, Switzerland}, author = {Alexander Leemans and Steve De Backer and Jan Sijbers and Everhard Vandervliet and Paul M Parizel} } @inproceedings {aleemansjsijbersmverhoyeavdlinde2005, title = {Entropy-based coregistration for DT-MR images using an efficient tensor shape preserving reorientation strategy}, booktitle = {13th Scientific Meeting - International Society for Magnetic Resonance in Medicine}, year = {2005}, pages = {227}, address = {Miami, USA}, author = {Alexander Leemans and Jan Sijbers and Marleen Verhoye and Annemie Van Der Linden} } @inproceedings {aleemansjsijbersParizel2005, title = {A Graphical Toolbox for Exploratory Diffusion Tensor Imaging and Fiber Tractography}, booktitle = {14th Annual Meeting - Section for Magnetic Resonance Technologists}, year = {2005}, address = {Miami, USA}, author = {Alexander Leemans and Jan Sijbers and Paul M Parizel} } @inproceedings {GroofmverhoyeMeirTindemansaleemansavdlinde2005, title = {In Vivo Visualization of the Neuroanatomy and Brain Connectivity of Starling Brain Through Diffusion Tensor Imaging}, booktitle = {6th Bi-Annual Meeting {\textendash} Belgian Society for Neuroscience}, year = {2005}, address = {Brussels, Belgium}, author = {G. De Groof and Marleen Verhoye and V. Van Meir and I. Tindemans and Alexander Leemans and Annemie Van Der Linden} } @article {aleemansjsijbersmverhoyeavdlindedvandyck2005, title = {Mathematical Framework for Simulating Diffusion Tensor MR Neural Fiber Bundles}, journal = {Magnetic Resonance in Medicine}, volume = {53}, year = {2005}, pages = {944-953}, author = {Alexander Leemans and Jan Sijbers and Marleen Verhoye and Annemie Van Der Linden and Dirk Van Dyck} } @inproceedings {aleemansjsijbersmverhoyeavdlinde2005, title = {Optimized Fiber Tractography based on Diffusion Tensor Magnetic Resonance Simulations}, booktitle = {20th Annual Symposium - Belgian Hospital Physicists Association}, year = {2005}, address = {Namur, Belgium}, author = {Alexander Leemans and Jan Sijbers and Marleen Verhoye and Annemie Van Der Linden} } @inproceedings {Groofmverhoyealeemansavdlinde2005, title = {Seasonal changes in neuronal connectivity in the songbird brain discerned by repeated in vivo DTI}, booktitle = {13th Scientific Meeting - International Society for Magnetic Resonance in Medicine}, year = {2005}, pages = {715}, address = {Miami, USA}, author = {G. De Groof and Marleen Verhoye and Alexander Leemans and Annemie Van Der Linden} } @inproceedings {aleemanssdbackerjsijbersVandervlietParizel2005, title = {TRACT: Tissue Relative Anisotropy based Curvature Thresholding for deterministic MR diffusion tensor tractography}, booktitle = {22th Annual Scientific Meeting - European Society for Magnetic Resonance in Medicine and Biology}, year = {2005}, pages = {289}, address = {Basle, Switzerland}, author = {Alexander Leemans and Steve De Backer and Jan Sijbers and Everhard Vandervliet and Paul M Parizel} } @inproceedings {Groofmverhoyealeemansavdlinde2005, title = {Using diffusion tensor imaging (DTI) to assess the neuronal plasticity in the brain of a songbird}, booktitle = {4th Annual Symposium {\textendash} Young Belgian Magnetic Resonance Scientists}, year = {2005}, address = {Brussels, Belgium}, author = {G. De Groof and Marleen Verhoye and Alexander Leemans and Annemie Van Der Linden} } @inproceedings {jsijbersCampaleemansajdendekmverhoyeavdlinde2004, title = {Coregistration of Micro-MRI, microCT and microPET}, booktitle = {Workshop on non Invasive 3D Microscopy}, year = {2004}, month = {August}, pages = {16}, address = {University of Antwerp, Belgium}, author = {Jan Sijbers and N. Van Camp and Alexander Leemans and Arnold Jan den Dekker and Marleen Verhoye and Annemie Van Der Linden} } @inproceedings {aleemansjsijbersmverhoyeavdlinde2004, title = {Experimental Evaluation of Synthetic DT-MRI Models}, booktitle = {21th Annual Scientific Meeting - European Society for Magnetic Resonance in Medicine and Biology}, year = {2004}, pages = {40-41}, address = {Copenhagen, Denmark}, author = {Alexander Leemans and Jan Sijbers and Marleen Verhoye and Annemie Van Der Linden} } @inproceedings {aleemansjsijbersmverhoyeavdlindedvandyck2004, title = {A Geometric Color Scheme for Visualizing Diffusion Tensor Magnetic Resonance Fiber Pathways}, booktitle = {19th Annual Symposium - Belgian Hospital Physicists Association}, year = {2004}, address = {Brussels, Belgium}, author = {Alexander Leemans and Jan Sijbers and Marleen Verhoye and Annemie Van Der Linden and Dirk Van Dyck} } @inproceedings {CampmverhoyealeemansPostnovBequeEyndenNuytsLauwersVerbruggenDebyzerBaekelandtClerckjsijbersLaereavdlinde2004, title = {In vivo multimodal imaging of a rat model for Parkinson{\textquoteright}s disease: high resolution micro-MRI, micro-SPECT and micro-CT}, booktitle = {21th Annual Scientific Meeting - European Society for Magnetic Resonance in Medicine and Biology}, year = {2004}, pages = {22-23}, address = {Copenhagen, Denmark}, author = {N. Van Camp and Marleen Verhoye and Alexander Leemans and A. Postnov and Dirk Beque and J. Van den Eynden and Johan Nuyts and E. Lauwers and Alfons Verbruggen and Zeger Debyser and Veerle Baekelandt and N. De Clerck and Jan Sijbers and Koen Van Laere and Annemie Van Der Linden} } @inproceedings {mverhoyeGroofMeirTindemansaleemansavdlinde2004, title = {In vivo neuroanatomy of the songbird brain, visualized through diffusion tensor imaging}, booktitle = {21th Annual Scientific Meeting - European Society for Magnetic Resonance in Medicine and Biology}, year = {2004}, pages = {161}, address = {Copenhagen, Denmark}, author = {Marleen Verhoye and G. De Groof and V. Van Meir and I. Tindemans and Alexander Leemans and Annemie Van Der Linden} } @inproceedings {mverhoyeGroofMeirTindemansaleemansavdlinde2004, title = {In vivo visualization of the neuroanatomy and brain connectivity of starling brain through diffusion tensor imaging}, booktitle = {34rd Annual Meeting of the Society for Neuroscience}, year = {2004}, address = {San Diego, USA}, author = {Marleen Verhoye and G. De Groof and V. Van Meir and I. Tindemans and Alexander Leemans and Annemie Van Der Linden} } @inproceedings {aleemansjsijberswvdbroekYang2004, title = {An Interactive Curvature Based Rigid-body Image Registration Technique: an Application to EFTEM}, booktitle = {13th European Microscopy Congress}, year = {2004}, address = {Antwerp, Belgium}, author = {Alexander Leemans and Jan Sijbers and Wouter Van den Broek and Z. Yang} } @inproceedings {aleemansjsijbersmverhoyeavdlinde2004, title = {A Library of 3D synthetic DT-MRI models for testing White Matter fiber Tractography Algorithms}, booktitle = {21th Annual Scientific Meeting - European Society for Magnetic Resonance in Medicine and Biology}, year = {2004}, pages = {42}, address = {Copenhagen, Denmark}, author = {Alexander Leemans and Jan Sijbers and Marleen Verhoye and Annemie Van Der Linden} } @inproceedings {aleemansjsijbers2004, title = {Multiresolutional rigid-body registration for space curves}, booktitle = {IEEE Advanced Concepts for Intelligent Vision Systems}, year = {2004}, pages = {215-221}, address = {Brussels, Belgium}, author = {Alexander Leemans and Jan Sijbers} } @inproceedings {aleemansjsijbersmverhoyeavdlindedvandyck2004, title = {White Matter Fiber Bundle Coregistration for Diffusion Tensor Magnetic Resonance Tractography}, booktitle = {13th Annual Meeting - Section for Magnetic Resonance Technologists}, year = {2004}, address = {Kyoto, Japan}, author = {Alexander Leemans and Jan Sijbers and Marleen Verhoye and Annemie Van Der Linden and Dirk Van Dyck} } @inproceedings {WaarsingaleemansDayEderveendvandyckBuelensClerckSasovWeinans2003, title = {Effects of Growth and OVX in the Tibia of Individual Rats: an in-vivo Micro-CT Study}, booktitle = {49th Annual Meeting - Orthopaedic Research Society}, year = {2003}, address = {New Orleans, LA, USA}, author = {J. H. Waarsing and Alexander Leemans and J. Day and A. G. H. Ederveen and Dirk Van Dyck and E. Buelens and N. De Clerck and A. Sasov and H. Weinans} } @inproceedings {aleemansjsijbersmverhoyeavdlindedvandyck2003, title = {A Simulated Phantom for Diffusion Tensor Fiber Tracking}, booktitle = {IEEE Advanced Concepts for Intelligent Vision Systems}, year = {2003}, pages = {281-285}, address = {Ghent University, Belgium}, author = {Alexander Leemans and Jan Sijbers and Marleen Verhoye and Annemie Van Der Linden and Dirk Van Dyck} } @inproceedings {aleemansjsijbersmverhoyeavdlindedvandyck2003, title = {Simulating Neuronal Fiber Bundles for DT-MRI Tractography}, booktitle = {20th Annual Scientific Meeting - European Society for Magnetic Resonance in Medicine and Biology}, year = {2003}, pages = {278}, address = {Rotterdam, The Netherlands}, author = {Alexander Leemans and Jan Sijbers and Marleen Verhoye and Annemie Van Der Linden and Dirk Van Dyck} }