Diffusion spectrum imaging dsi yerkes imaging center. Diffusion weighted imaging, cystic brain lesions, adc mapping doi. Diffusion spectrum imaging dsi the human brain has the remarkable capacity to change in response to experience. Spectrum of reversible splenial lesions of corpus callosum fig. Tractography, diffusion tensor imaging, mri, pediatrics, brain, cost analysis, functional 1. Deconvolution in diffusion spectrum imaging sciencedirect. Diffusion mri is a key modality for microstructure imaging, because of its unique sensitivity to cellular architecture. Diffusion tensor imaging dti is a magnetic resonance imaging technique that enables the measurement of the restricted diffusion of water in tissue in order to produce neural tract images instead of using this data solely for the purpose of assigning contrast or colors to pixels in a crosssectional image. The technique sensitizes the mr signal to the random dispersion of signal.
The methods include diffusion spectrum imaging dsi, qball imaging qbi, and generalized qsampling imaging gqi. Kingsley department of radiology,north shore university hospital, 300 community drive,manhasset,new york 11030,and department of radiology,new york university school of medicine,new york,new york. Request pdf diffusion spectrum magnetic resonance imaging dsi tractography of crossing fibers mri tractography is the mapping of. Accelerated radial diffusion spectrum imaging using a multiecho stimulated echo diffusion sequence steven baete 1,2 and fernando emilio boada 1center for biomedical imaging, dept. Pdf of diffusion, representative of the average pattern of diffusion within each resolved volume. Tuch ds, reese tg, wiegell mr, makris n, belliveau jw, wedeen vj. Group comparison with diffusion imaging and application to. Diffusion spectrum imaging tractography in complex. Diffusion spectrum imaging in white matter microstructure in subjects. Water diffusion traces tissue fiber structurewater diffusion traces tissue fiber structure 2000. Noninvasively diffusion basis spectrum imaging dbsi. Connectometry analysis is based on diffusion spectrum imaging and. However, singleshell acquisitions, such as diffusion tensor imaging dti and high angular resolution diffusion imaging hardi, still remain the most common acquisition schemes in practice. Mri tractography is the mapping of neural fiber pathways based on diffusion mri of tissue diffusion anisotropy.
Diffusion imaging is a new twist on mri that uses magnetic resonance signals to track the movement of water molecules in the brain. Diffusion spectrum imaging dsi is a method for determining the average amount of molecular diffusion occurring within any enclosed space, such as the set of myo. Tractography based on diffusion tensor imaging dti cannot directly image multiple fiber orientations within a single voxel. The goal of dsi is to reconstruct the pdf for diffusion in each voxel. A novel diffusion tensor imagingbased computeraided. Wedeen 2 1department of neurology, 2martinos center for biomedical imaging, department of radiology, massachusetts general.
Stepbystep gdsi reconstruction of diffusion pdf and odf from multishell voxel data in matlab. Cortical diffusion imaging organization for human brain. In gray matter, water tends to diffuse multidirectionally. Lenaldekar, which inhibits tcell expansion in a noncytolytic manner, has been shown to suppress relapses and preserve white matter integrity in mice with experimental autoimmune encephalomyelitis. Diffusionweighted mr imaging in cystic brain lesions. Diffusion spectrum magnetic resonance imaging dsi tractography of crossing fibers. Mr diffusion tensor imaging dti and mr densely encoded diffusion imaging, such as diffusion spectrum imaging dsi 4, highangular resolution diffusion imaging hardi 5,6, or qball imaging 7 measure the 3d intravoxel spin displacement for each voxel in a 3d multislice mr scan. Introduction diffusion tensor imaging dti is currently the most sensitive mrtechnique utilized to assess white matter integrity 1. Speed school of engineering, university of louisville in partial ful. Deconvolution in diffusion spectrum imaging request pdf. Diffusion spectrum imaging shows the structural basis of functional cerebellar circuits in the human cerebellum in vivo ntributor. However, tongue fiber crossings or branching could not be.
Diffusion spectrum imaging data is reconstructed with a generalized qsampling imaging yeh et al. Diffusion imaging applications in neuropsychiatric disorders. This is a pdf file of an unedited manuscript that has been accepted for publication. Age and genderrelated changes in the normal human brain. Any information contained in this pdf file is automatically generated from digital material. Dtk is a complete software package that does reconstruction, fiber tracking, analysis and visualization. Diffusion spectrum imaging dsi is a method for determining the average amount of molecular diffusion occurring within any enclosed space, such as the set of myofibers within a given segment of tissue. Recently, we have described a novel approach to diffusion mri, diffusion spectrum imaging dsi which affords the capacity to accurately image multiple fiber. Accelerated radial diffusion spectrum imaging using a. We show how to apply diffusion spectrum imaging wedeen08 to diffusion mri. However, few studies have explored the effects of aging on diffusion imaging measures with higher b values. Recently, a novel diffusion basis spectrum imaging has been developed to quantitatively assess axonal injury, demyelination, and inflammation in a mouse model of inflammatory demyelination. However, the optimal imaging parameters for dsi to discriminate crossing fibers have not.
In this invivo 4t study, dsi parameters especially spatial resolution and diffusion encoding bandwidth were optimized on humans to segment. Wedeen vj, hagmann p, tseng wi, reese tg, weisskoff rm. Diffusion spectrum magnetic resonance imaging dsi citeseerx. Diffusion imaging distinguishes tissue characteristics based on the diffusion random motion of water molecules gray matter. Acceler ated diffusion spectrum imaging with compressed s.
Diffusion spectrum imaging shows the structural basis of. Introduction to diffusion tensor imaging mathematics. Diffusion spectrum imaging is a new technique at time of writing, which allows magnetic resonance brain imaging, at a much higher level of fidelity than fmri permits. Pdf deconvolution in diffusion spectrum imaging erick. It can not only handle diffusion tensor data but can also process high angular resolution diffusion imaging hardi data as well as diffusion spectrum imaging dsi data and qball imaging data. The orientation distribution functions were reconstructed to 642 discrete sampling directions for each pixel and with a diffusion distance scaling parameter of 1.
High angular resolution diffusion imaging reveals intravoxel white matter fiber heterogeneity. It provides a more general approach to disentangle complex fiber structures in biological tissues because it does not assume any particular. To recap on fmris function, this only slightly more elderly process by a mere few years works based on detection of the dynamic regulation of blood flow in the brain. A novel diffusion tensor imaging based computeraided diagnostic system for early diagnosis of autism by mahmoud mostapha b. After dsi data acquisition, the diffusion probability density function pdf was obtained according to the fourier relationship between the pdf. Dti is based on a mathematical description the tensor of the 3d shape of the water diffusion. Quantitative comparison between hybrid diffusion imaging. Matlab function to compute sampling density nonuniformity correction factor for multishell geometry. Dsi uses fourier transformation and numerical integration to calculate the orientation distribution function odf, which is the empirical distribution of water diffusion at different orientations of water diffusion. Diffusion tensor imaging dti representing the water diffusion within each. Diffusion mri processing for multicomportment characterization of. This motion is restricted by boundaries such as ligaments, membranes and macro molecules. Diffusion weighted imaging diffusion tensor imaging diffusion spectrum imaging biexponential diffusion age gender diffusion tensor imaging has been widely used to study brain diseases, disorders, development, and aging.
In this study, we compare two brain imaging techniques, the traditional diffusion tensor imaging dti method and the recently proposed method, diffusion spectrum imaging dsi. Halving imaging time of whole brain diffusion spectrum. But in white matter, it diffuses along the length of neural wires, called axons, and scientists can use these diffusion measurements to map the fibers. Alexander1,2 1medical physics, university of wisconsinmadison, madison, wi, united states, 2psychiatry, university of wisconsinmadison, madison, wi, united states background at higher levels of diffusion weighting, the diffusion tensor model is inadequate for describing nongaussian. Diffusion tensor imaging dti can trace some of the fiber tracts of the human tongue noninvasively. Dsi accomplishes this by acquiring a full sampling of diffusion weighting gradient directions and magnitudes. One limitation of this model arises in the presence of fiber crossings, and this can be addressed by using a more involved imaging method 2,3. Because the imaging contrast derives from the transport of laserpolarized gases via flow and diffusion, direct snapshots of gas flow and diffusion in the porous samples can be obtained. Both are diffusion weighted imaging techniques that use. Threedimensional myoarchitecture of the bovine tongue.
Multishell and diffusion spectrum imaging dsi are becoming increasingly popular methods of acquiring diffusion mri data in a research context. Introduction diffusion spectrum mri dsi can define complex oriented coherence accurately by mapping 3d probability density function pdf of water molecular diffusion within each mri voxel 1, 2. The goal of dsi is to reconstruct the probability distribution function pdf for diffusion in each voxel. Qspace truncation and sampling in diffusion spectrum imaging. Diffusion mri reconstruction in dsi studio dsi studioa. Visualization of gas flow and diffusion in porous media. Mapping complex tissue architecture with diffusion spectrum magnetic resonance imaging. Deriving diffusion based parameters several models for quantifying voxelwise diffusion were proposed based on. Quantitative comparison between hybrid diffusion imaging and diffusion spectrum imaging yc. What is the difference between diffusion spectrum magnetic. In comparison, diffusion spectrum imaging dsi can detect the multiple fiber orientation within a voxel and allows for delineating crossing and touching fibers in the brain. Development of an imaging biomarker abhinav, k and yeh, fc and eldokla, a and ferrando, lm and chang, yf and lacomis, d and friedlander, rm and fernandezmiranda, jc 2014 use of diffusion spectrum imaging in preliminary longitudinal. Diffusion is measurement of water mobility, when cells swell and absorb water from the.
Although diffusion tensor imaging dti has been successfully applied to noninvasively evaluate white matter integrity, it is recognized that dti fails to correctly track crossing fibers, or accurately evaluate axon integrity in the presence of csf contamination or edema, i. Diffusion is restricted anisotropic to describe anisotropic diffusion, diffusivity must be measured in more than one direction. This ability to change function and structure is called. Diffusion tensor imaging dti is an established diffusion weighted imaging method, which models the diffusion as a univariate gaussian distribution 1. Diffusion basis spectrum imaging detects and distinguishes. Converting multishell and diffusion spectrum imaging to. Use of diffusion spectrum imaging in preliminary longitudinal evaluation of amyotrophic lateral sclerosis. Diffusion spectrum imaging dsi is a generalization of diffusion tensor imaging to map fibrous structure of white matter and potentially very sensitive to alterations of the cingulum bundles in dementia. As demonstrated below, transcallosal fiber tracts of adult macaque brains are examined with dsi and compared with those from. Diffusion spectrum magnetic resonance imaging dsi tractography. We can use diffusion weighted imaging in mri to determine whether the water content of the brain and other organs moves or not in an imaged slice due to physiological processess. If we do this measurement in many directions at least 6, but oft. High angular resolution diffusionweighted imaging hardi. Refereces 1 tian q, yang g, leuze c, rokem a, edlow bl, mcnab ja.
Pdfs and orientation distribution functions odfs were reconstructed with different qspace filtering and pdf integration lengths, and from down. Illustrate diffusion weighted imaging dwi findings of various cns pathological. Diffusion spectrum magnetic resonance imaging dsi allows the estimation of the displacement probability density function pdf of water molecules, which contain valuable information about the microgeometry of the medium where the diffusion process occurs. In a similar fashion it is possible to calculate the pdfs of all voxels in one call.
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