The pdf represents the density of the average spin dis placement in a voxel, and is, therefore, also called ensem ble average propagator or diffusion propagator 17. Converting multishell and diffusion spectrum imaging to high. Diffusion spectrum imaging tractography in complex cerebral white matter. Diffusion is restricted anisotropic to describe anisotropic diffusion, diffusivity must be measured in more than one direction. A tool for unraveling disrupted structural connectivity in ptsd. Quantitative comparison between hybrid diffusion imaging and diffusion spectrum imaging yc. Suitable for in vivo application, it provides a sufficiently dense qspace signal sample. Comparison between diffusion tensor and diffusion spectrum imaging in regions containing fiber crossings. For each subject, full dti, diffusional kurtosis imaging, and diffusion spectrum imaging datasets were acquired during 2 independent sessions, and fiber bundle orientations were estimated by using the specific theoretic assumptions of each technique. 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. The impact of edema and fiber crossing on diffusion mri.
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. Quantitative comparison between hybrid diffusion imaging and. Optimal imaging parameters for minimum angular discrimination. Physics in cancer research diffusionweightedimagingincancer. Diffusion spectrum imaging dsi on the other hand, enables direct reconstruction of p, also referred to as the probability density function pdf wedeen et al. Index terms diffusion, diffusion spectrum imaging, diffusion tensor imaging, orientation distribution function, space. However, a long acquisition time is required for adequate space sampling to completely reconstruct the 3d diffusion probability density function. Wedeen 2 1department of neurology, 2martinos center for biomedical imaging, department of radiology, massachusetts general. Tractography based on diffusion tensor imaging dti cannot directly image multiple fiber orientations within a single voxel. Due to common mr hardware and scan time limitations, diffusion tensor imaging basser et al.
This disease is the second most common hematologic malignancy after lymphoma, and its spectrum of characteristic features are widely known by the acronym crab hypercalcemia, r. Halving imaging time of whole brain diffusion spectrum. Current clinical applications of diffusiontensor imaging in. Diffusion spectrum magnetic resonance imaging dsi tractography. Diffusion tensor imaging dti is an established diffusion weighted imaging method, which models the diffusion as a univariate gaussian distribution 1. Jul 15, 2008 these methods include diffusion spectrum mri dsi lin et al. 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. Noncontrast mr venography revealed signal void in posterior aspect of superior sagittal sinus figure 3a.
Noninvasively diffusion basis spectrum imaging dbsi. Meng and zhang, quantitative imaging in medicine and surgery, 2014, 42. Diffusion weighted imaging dwi has been at the forefront of cancer imaging since the early 2000s. Accelerated diffusion spectrum imaging with compressed. Diffusion spectrum imaging dsi conventional diffusion tensor imaging dti cannot directly image multiple fiber orientations within a single voxel. Use of diffusion spectrum imaging in preliminary longitudinal evaluation of amyotrophic lateral sclerosis. 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. Dsi accomplishes this by acquiring a full sampling of diffusion weighting gradient directions and magnitudes. To validate ex vivo diffusion relaxation correlation spectrum imaging drcsi in the characterization of microstructural tissue compartments in prostate specimens from men with pca by using registered wholemount digital histopathology wmhp as the reference standard. In dsi, diffusion weighted images are acquired along different directions that are organized in the qspace integral points of a cubic lattice within a sphere.
Diffusion imaging distinguishes tissue characteristics based on the diffusion random motion of water molecules gray matter. In the first group, 10 trigeminal nerves were organized. Multishell and diffusion spectrum imaging dsi are becoming increasingly popular methods of acquiring diffusion mri data in a research context. Mri tractography is the mapping of neural fiber pathways based on diffusion mri of tissue diffusion anisotropy. Diffusion weighted imaging dwi showed sharply delineated areas of diffusion restriction involving both gray and white matter of bilateral parietal and occipital regions. Jan 22, 2021 diffusion basis spectrum imaging has shown success in modeling nongaussian diffusion phenomena with multiple gaussian functions for biological tissues and environment in ms subjects and eae mice wang et al. Diffusion weighted dw magnetic resonance imaging mri, through manipulating the diffusion sensitive gradients, can detect the brownian motion of water molecules and provide the ensemble information of the complex local tissue structures by the measured diffusion probability density function pdf wedeen et al. Abstract diffusion spectrum imaging dsi can map complex. Granziera c, schmahmann jd, hadjikhani n, meyer h, meuli r, et al. Diffusion spectrum imaging in white matter microstructure in subjects.
Before its application in clinical oncology, this powerful technique had already achieved widespread recognition due to its utility in the diagnosis of cerebral infarction. 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. Space truncation and sampling in diffusion spectrum imaging. The goal of dsi is to reconstruct the pdf for diffusion in each voxel. Two groups of phantoms were built using the fixed mouse trigeminal nerves. Dsi thus appears to be a promising imaging method for characterizing anatomical disruptions that occur in cerebellar diseases, and for monitoring response to therapeutic interventions. Evaluation of fiber tracking from subsampled qspace data. Hybrid diffusion imaging hydi combines the approaches of diffusion tensor imaging, high angular resolution, multiple diffusion weighting levels. Converting multishell and diffusion spectrum imaging to.
Like all projection imaging techniques, the mapping between the 3d shape and its 1d projection is not necessarily one. One limitation of this model arises in the presence of fiber crossings, and this can be addressed by using a more involved imaging method. Mcdonald2, niky farid1, josh kuperman1, david karow1. Wednesday, february 24, 2016, at 12pm noon etby fernando e. Dsi accomplishes this by acquiring a full sampling of diffusion weighting gradient directions and magnitudes, which permits direct reconstruction of the average pdf. Diffusion imaging applications in neuropsychiatric disorders. Dsi is to reconstruct the pdf for diffusion in each voxel. Pdf deconvolution in diffusion spectrum imaging yasser. Acceler ated diffusion spectrum imaging with compressed s. Request pdf diffusion spectrum magnetic resonance imaging dsi tractography of crossing fibers mri tractography is the mapping of. Mapping the orientation of white matter fiber bundles.
Frontiers diffusion basis spectrum imaging detects. Diffusion spectrum imaging using bodycentercubic sampling. Following this initial success, the ability of dwi to detect inherent tissue contrast began to be exploited in the field of. Prostate microstructure in prostate cancer using 3t mri with. 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. To overcome this limitation, advanced acquisition methods, such as diffusion spectrum imaging dsi tuch et al. Further these studies have shown that dti can be used longitudinally to track pathology over time, making white matter pathology a candidate as an outcome measure in future trials. Pdf optic neuritis is a frequent first symptom of multiple sclerosis ms for which corticosteroids are a widely employed treatment option. In this invivo 4t study, dsi parameters especially spatial resolution and diffusion encoding bandwidth were optimized on humans to segment.
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. In this investigation, we addressed the reliability and validity of deterministic tractography results based on diffusion spectrum imaging dsi. Use of diffusion spectrum imaging in preliminary longitudinal. Accelerated diffusion spectrum imaging in the human brain. Demonstration of the transcallosal fiber tracts for various cortical areas in an adult monkey brain using ex vivo dsi on a bruker 7t. Unlike the principal direction of the dti that points to a direction somewhere between the crossing. Diffusion spectrum imaging dsi 6, 910 is a model free technique that considers diffusion pattern in each voxel using the odf. Understanding diffusion mr imaging techniques rsna. Diffusion spectrum imaging dsi results in magnitude representation of the full qspace and yields a complete description of the diffusion probability density function pdf 4,5. Previous diffusion tensor imaging dti studies have shown white matter pathology in amyotrophic lateral sclerosis als, predominantly in the motor pathways. Pdf diffusion basis spectrum imaging detects axonal loss.
Space truncation and sampling in diffusion spectrum. 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. Diffusion spectrum imaging dsi yerkes imaging center. We show how to apply diffusion spectrum imaging wedeen08 to diffusion mri datasets of cartesian keyhole diffusion gradients. Hardy,2 and luca marinelli2 we developed a novel method to accelerate diffusion spec. Diffusion spectrum imaging dsi and qball imaging qbi the concept of dsi is based on the fourier relationship between the attenuated echo signal in qspace eq and the probability density function pdf of water molecular diffusion p sr eq r p sr. Qspace truncation and sampling in diffusion spectrum imaging qiyuan tian,1,2 ariel rokem,3 rebecca d. Deconvolution in diffusion spectrum imaging request pdf. Frontiers diffusion basis spectrum imaging detects axonal. Qspace imaging uses the fourier transform relationship to derive the probability density function pdf for spin displacement from the motiondependent attenuation of the. Diffusion tensor imaging korean journal of radiology.
Asymmetry spectrum imaging for baby diffusion tractography. Diffusion spectrum imaging dsi samples the full qspace and yields a complete description of the diffusion probability density function pdf. Different neural substrates for executive functions in youths. Diffusion spectrum imaging shows the structural basis of functional cerebellar circuits in the human cerebellum in vivo. Deconvolution in diffusion spectrum imaging sciencedirect. Interrogation of living myocardium in multiple static.
Introduction d iffusion measurements with magnetic resonance imaging mri is a useful tool for the noninvasive study of microstructural architecture in the brain and other tissues. Among them, diffusion tensor imaging dti reveals diffusion anisotropy and the directional distribution of water diffusivity and so it enables physiciansscientists. Fa and snr according to change of b value of diffusion tensor imaging sequence. 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. In this study, we used dbsi to assess the effects of 2week dex treatment on optic. In this study, montecarlo simulation was used to optimize the dsi imaging parameters, such as diffusion time, duration of diffusion. The goal of dsi is to reconstruct the probability distribution function pdf for diffusion in each voxel. It provides a more general approach to disentangle complex fiber structures in. Diffusion spectrum imaging may be described as the reference standard of diffusion imaging because it is the practical implementation of the principles derived earlier and is the diffusion imaging technique that has a sound basis in physical theory, 12. While dsi is capable of resolving complex distributions of intravoxel fiber orientations, full q space coverage comes at the expense of substantially long scan times 1 hour. It allows the mapping of the diffusion process of molecules, mainly water, in biological tissues, in vivo and noninvasively. While dsi is capable of resolving complex distributions of intravoxel fiber orientations, full q space coverage comes. Threedimensional myoarchitecture of the bovine tongue.
Mapping complex tissue architecture with diffusion spectrum. Diffusion spectrum imaging dsi is a method for determining the. Granziera, cristina, jeremy dan schmahmann, nouchine hadjikhani, heiko meyer, reto meuli, van wedeen, and gunnar krueger. Physicalfoundations and applications of restriction spectrum imaging nathan s. Quantitative comparison between hybrid diffusion imaging. Different neural substrates for executive functions in. Diffusiontensor imaging dti is a relatively new magnetic resonance imaging mri tech nique that has mostly been used to evaluate.
Diffusion spectrum imaging shows the structural basis of. Mar 01, 2010 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. Although many diffusion imaging modalities such as diffusion kurtosis image 3, 4 have been proposed, we will concentrate on the methods for analysis diffusion tensor imaging dti, qball imaging qbi, and diffusion spectrum imaging dsi 6, 7. A diffusion weighted image is one of the components needed to reconstruct the complete probability density function as in diffusion spectrum imaging. Diffusion spectrum imaging using bodycentercubic sampling scheme wy. Optimization of diffusion spectrum imaging and ball. 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. Frontiers diffusion spectrum imaging of corticospinal. To address this limitation, diffusion spectrum mri dsi and related methods were developed to image complex distributions of intravoxel fiber orientation. Twentythree inph patients and twentyone healthy controls hcs were involved in this study. Diffusion mri tissue structure is traced by 3d patterns oftdiffif water diffusion 1994. Tseng 4 1precision positioning and control lab, department of power mechanical engineering, national tsing hua university, hsinchu, taiwan, 2mgh martinos center for biomedical imaging, harvard medical school, charlestown, ma, united states, 3interdisciplinary.
Complex diffusion behavior in brain tissue may be studied with different approaches including diffusion spectrum imaging dsi 1, qball imaging qbi 2, and diffusion model fitting charmed 3. Tseng 4 1 precision positioning and control lab, department of power mechanical engineering, national tsing hua university, hsinchu, taiwan, 2 mgh martinos center. The purpose of this study was to measure the diffusion spectrum imaging dsi parameters of corticospinal tracts csts and evaluate diffusional changes in csts in patients with idiopathic normal pressure hydrocephalus inph by dsi. To characterize the qspace truncation and sampling on the spindisplacement probability density function pdf in diffusion spectrum imaging dsi. 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 weighted magnetic resonance imaging dwi or dwmri is the use of specific mri sequences as well as software that generates images from the resulting data that uses the diffusion of water molecules to generate contrast in mr images.
Reliability was evaluated both in terms of the presenceabsence of fiber connections across sessions and the correlation of fiber density values. Evaluation of fiber tracking from subsampled qspace data in. However, the optimal imaging parameters for dsi to discriminate crossing fibers have not been studied yet. In contrast to other approaches, dsi facilitates quanti. Mapping complex myoarchitecture in the bovine tongue with. Purpose to validate ex vivo diffusion relaxation correlation spectrum imaging drcsi in the characterization of microstructural tissue compartments in prostate specimens from men with pca by using registered wholemount digital histopathology wmhp as the reference standard. Imaging methodology communications accelerated diffusion spectrum imaging in the human brain using compressed sensing marion i. Pdf diffusion spectrum imaging tractography in complex. Optimization of diffusion spectrum imaging and ball imaging. Wendell krieg 1963 human white matter by dissection dsi. After dsi data acquisition, the diffusion probability density function pdf was obtained according to the. 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. 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.
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