Nicolas Wiest-Daesslé's research while affiliated with Université de Rennes 1 and other places

Publications (17)

Article
Cerebral hemispheres represent both structural and functional asymmetry, which differs among right- and left-handers. The left hemisphere is specialised for language and task execution of the right hand in right-handers. We studied the corticospinal tract in right- and left-handers by diffusion tensor imaging and tractography. The present study aim...
Conference Paper
We propose an iterative two-step method to compute a diffeomorphic non-rigid transformation between images of anatomical structures with rigid parts, without any user intervention or prior knowledge on the image intensities. First we compute spatially sparse, locally optimal rigid transformations between the two images using a new block matching st...
Article
We propose and evaluate a new block-matching strategy for rigid-body registration of multimodal or multisequence medical images. The classical algorithm first matches points of both images by maximizing the iconic similarity of blocks of voxels around them, then estimates the rigid-body transformation best superposing these matched pairs of points,...
Article
Diffusion tensor imaging permits study of white matter fibre bundles; however, its main limitation is lack of validation on anatomical data, especially in crossing fibre regions. Our study aimed to compare four deterministic tractography algorithms used in clinical routine. We studied the corticospinal tract, the bundle mediating voluntary movement...
Conference Paper
Full-text available
In this paper, we build upon a new model, describing the random motion of water molecules in fibrous tissues, to develop a mul-tifiber deterministic tractography algorithm. We apply this algorithm to track the corticospinal tract of the human brain, in both controls and patients with tumors.
Article
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In this paper, we propose to compare three diffusion mod-els to track the portion of the corticospinal tract dedicated to the hand motor function (called hand motor fibers hereafter), using diffusion, func-tional and anatomical MRI. The clinical diffusion data have few gradient directions and low b-values. In this context, we show that a newly intr...
Article
Full-text available
Introduction : Si la substance grise a été largement étudiée en IRM fonctionnelle (IRMf), l'étude in vivo des tractus de substance blanche est plus récente. L'IRM en tenseur de diffusion permet désormais d'étudier son anatomie grâce à la tractographie. Notre objectif était l'étude du tractus cortico-spinal (TCS) en tenseur de diffusion et en tracto...
Article
Introduction. Si la substance grise a été largement étudiée en IRM fonctionnelle (IRMf), l'étude in vivo des tractus de substance blanche est plus récente. L'IRM en tenseur de diffusion permet désormais de l'étudier grâce à la tractographie. Notre objectif était l'étude du tractus cortico-spinal (TCS) en tenseur de diffusion et en tractographie che...
Conference Paper
Full-text available
In this paper we study the impact of denoising the raw high angular resolution diffusion imaging (HARDI) data with the Non-Local Means filter adapted to Rician noise (NLMr). We first show that NLMr filtering improves robustness of apparent diffusion coefficient (ADC) and orientation distribution function (ODF) reconstructions from synthetic HARDI d...
Conference Paper
Full-text available
Diffusion-Weighted MRI (DW-MRI) is subject to random noise yielding measures that are different from their real values, and thus biasing the subsequently estimated tensors. The Non-Local Means (NLMeans) filter has recently been proposed to denoise MRI with high signal-to-noise ratio (SNR). This filter has been shown to allow the best restoration of...
Conference Paper
Full-text available
This paper gives an overview of the evolution of clinical neuroinformatics in the domain of neurosurgery. It shows how image guided neurosurgery (IGNS) is evolving according to the integration of new imaging modalities before, during and after the surgical procedure and how this acts as the premise of the operative room of the future. These differe...
Conference Paper
Full-text available
A number of problems frequently encountered in brain image analysis can be conveniently solved within a registration framework, such as alignment of mono- or multi-sequence magnetic resonance images (MRI) for single or multiple subjects, computation of the cerebral mid-sagittal plane in anatomical or diffusion-tensor MRI, correction of acquisition...
Article
We propose a method for the automated computation of the mid-sagittal plane of the brain in diffusion tensor MR images. We estimate this plane as the one that best superposes the two hemispheres of the brain by reflection symmetry. This is done via the automated minimisation of a correlation-type global criterion over the tensor image. The minimisa...
Article
Full-text available
We propose to use a recently introduced optimisation method in the context of rigid registration of medical images. This optimisation method, introduced by Powell and called NEWUOA, is compared with two other widely used algorithms: Powell's direction set and Nelder-Mead's downhill simplex method. This paper performs a comparative evaluation of the...
Conference Paper
Full-text available
Diffusion tensor imaging (DT-MRI) is very sensitive to corrupting noise due to the non linear relationship between the diffusion-weighted image intensities (DW-MRI) and the resulting diffusion tensor. Denoising is a crucial step to increase the quality of the estimated tensor field. This enhanced quality allows for a better quantification and a bet...

Citations

... The angular and spatial resolutions of the data are very low: 20 or 30 diffusion sensitizing gradient (DSG) encoding directions distributed on a single shell at b = 1000s/mm 2 and slices of 5mm thickness, raising the demand for new appropriate diffusion models and/or tractography algorithms that may manage that type of data and propose an accurate reconstruction of the CST. We proposed a diffusion model coined Diffusion Directions Imaging (DDI) [8– 10] that meets these requirements even when using a simple deterministic streamline algorithm [11, 12] . We also recently design a probabilistic tractography algorithm based on an adaptive multi-modal particle filter [13] that is able to tract multiple fascicles over extended volumes. ...
... First, each sequence was denoised using the non local means algorithm [ Coupé et al. (2008) ]. Second, a rigid registration of each modality on the FLAIR was performed [ Commowick et al. (2012) ]. Then, skull stripping of T1w was performed using the volBrain platform [ Manjón and Coupé (2016) ], the same mask is applied to other modalities. ...
... Laterality in fiber volume, number of streamlines, or even their characteristics are a common finding in neuroimaging studies. For example, laterality has been seen in arcuate fasciculus (Lebel and Beaulieu 2009), corticospinal tract (Seizeur et al. 2014), and superior longitudinal fasciculus (Amemiya et al. 2021) in healthy, disease-unaffected brains. Interestingly, changes in this laterality seems to be . ...
... However, there are no systemic studies of core versus periphery of lesions in MS, and use of a single tensor model in DTI, which does not provide compartmental information, limits its ability to detect specific processes of neuronal pathology. High angular resolution diffusion imaging (HARDI) tackles this problem by using advanced models which enable intravoxel analysis through increased angular sampling of diffusion signals acquired typically with different diffusion weightings (multi-shell HARDI) (Descoteaux, 2015). A range of multi-shell HARDI models exist, divided mainly by the approach used to model the properties of nerve fibers, such as the cylinder model used in ActiveAx (Alexander et al., 2010), and the stick model in neurite orientation dispersion and density index (NODDI) (Zhang et al., 2012). ...
... The block-matching (BM) strategy looks for a transformation by finding a local correspondence between small blocks (typically 3×3×3 voxels) in the original and the target image [18,19]. This method, applied to field inhomogeneity-induced distortion correction in EPI [15], follows the registration method introduced in [20]. ...
... In this paper we compare the effects of distortion correction using linear, polynomial second order and polynomial third order transformations, and no distortion correction on DTI invariants of MSL and their contralateral counterparts. The contralateral ROIs are automatically computed using the mid-sagittal plane as a reference [26]. The comparison was performed using ANOVA and multiple comparison procedure in two main groups : 1) MSL and 2) contralateral ROI as well as for each of the combination of pre-processing (12 groups), resulting in 24 entries in our multiple comparisons procedure. ...
... The T 1 -weighted images were filtered using the NL-means algorithm to remove noise [Coupé et al., 2008]. The mean ASL control image was then coregistered with the T 1 -weighted image of the same subject using 3D rigid-body registration with a normalized mutual-information cost function and NEWUOA optimization [Wiest-Daesslé et al., 2007]. The inhomogeneity bias in the T 1 -weighted images was corrected and the images were segmented into gray matter (GM), white matter (WM) and cerebrospinal fluid (CSF) classes using the SPM8 toolbox [Ashburner and Friston, 2005]. ...
... We proposed a diffusion model coined Diffusion Directions Imaging (DDI) [8][9][10] that meets these requirements even when using a simple deterministic streamline algorithm [11,12]. We also recently design a probabilistic tractography algorithm based on an adaptive multi-modal particle filter [13] that is able to tract multiple fascicles over extended volumes. ...
... Endonasal endoscopy (EE) has almost become the standard of care in managing pituitary tumors [21]. Advanced intraoperative technological adjuncts to the standard 0°endoscopes, such as neuronavigation and angled endoscopes, have benefited neurosurgeons mainly in terms of precision and field of view, respectively, in addition to sheer convenience [3]. Despite the widespread availability of these, and scattered technical reports on their use, there are hardly few studies which have assessed the efficacy of either navigation or angled endoscopes with the surgical outcome in terms of extent of resection or endocrinological remission, and the need for retreatment [1,22]. ...
... These areas were defined using both the anatomic and functional definitions of 3DVA. This method has been employed by our team in previous studies [31]. For each subject, the functional activation map was registered to the anatomical map. ...