Diffusion tensor imaging dti fiber tracking imagilys. Dti is based on the principle that water will diffuse more readily along the principal axis of an axon than perpendicular to it. Jones and alexander leemans abstract diffusion tensor mri dtmri is the only noninvasive method for characterising the microstructural organization of tissue in vivo. Diffusion weighted and diffusion tensor imaging in aging diffusion based imaging strategies is sensitive to more subtle agerelated changes in white matter integrity, and these methods may enable the differentiation of normal adult aging from mild cognitive impairment and alzheimer dementia.
Diffusion tensor imaging dti is used to investigate the microstructural features of white matter, and has recently been applied to the study of aging and dementia. Functional mri of the brain software library neuroimaging package allows voxelbased analysis vba of multisubject diffusion data, which is aimed at improving the objectivi. We sought to assess diffusion changes that are inherently related to brain structure during aging. The mri physics is based on the diffusion of water along the main direction of a nerve axon. Dti provides a unique noninvasive probe into the microstructure of brain tissue, facilitating many applications in medical research such as the characterization of brain lesions using voxelbased metrics and modern fi ber tractography. Assessment of reduced field of view in diffusion tensor imaging of the lumbar nerve roots at 3 t. Diffusion tensor imaging dti 1, 2, through the derived parameters such as fractional anisotropy fa, can directly assess the white matter fiber tracts which possibly degenerate with alzheimers disease and mild cognitive impairment 3 and probably to some degree with normal aging. Neuroimaging results in humans and animal models zhou, stratification of pseudoprogression and true progression of glioblastoma multiform based on longitudinal diffusion tensor imaging without. White matter correlates of cognitive domains in normal aging with diffusion tensor imaging the harvard community has made this article openly available. White matter atrophy and lesion formation explain the loss of structural integrity of white matter in aging. White matter correlates of cognitive domains in normal aging. Diffusion tensor imaging dti has been shown to be a reliable method for evaluation of white matter integrity and can detect abnormalities in the white matter that appear normal on conventional mri. The introduction of the diffusion tensor model enabled the indirect measurement of the degree of anisotropy and structural orientation that characterizes diffusion tensor imaging dti basser et al.
Diffusion tensor imaging definition of diffusion tensor. Diffusion tensor imaging of the normal pediatric spinal cord using an inner field of view echoplanar imaging sequence. Mr scans were obtained from 11 healthy volunteers and 27 patients ages 26. While dwi refers to the contrast of the acquired images, dti is a specific type of modeling of the dwi datasets. One of its uses is to identify the linkages and structures of white matter tracts in the brain. Even without disease, agerelated decline occurs in both cognition and wm integrity. We used quantitative diffusion mr imaging to investigate the microstructural changes that occur in white matter during normal aging in order to identify regional changes in anisotropy and to quantify global microstructural changes by use of wholebrain diffusion histograms. Diffusion tensor imaging dti measures diffusion of molecular water, which can be used to calculate indices of white matter integrity. Diffusion based imaging strategies is sensitive to more subtle agerelated changes in white matter integrity, and these methods may enable the differentiation of normal adult aging from mild cognitive impairment and alzheimer dementia. Quantifying changes in the human brain that occur as part of normal aging may help in the diagnosis of diseases that affect the elderly and that cause structural changes in the brain. Phillip patton, committee chair steen madsen, committee. Diffusion tensor imaging dti is an mri technique that uses anisotropic diffusion to estimate the axonal white matter organization of the brain.
May 03, 2020 the science behind diffusion tensor imaging is very complex, but put in the simplest of terms, this type of medical imaging involves agitating molecules with electromagnetic radiation and recording the release of that energy. Corpus callosal microstructural integrity influences. Clinical applications of diffusion tensor imaging dong. Brain injury when a routine brain mri shows no abnormality.
Anisotropic diffusion may be decribed in terms of an ellipsoid tensor. Full diffusion tensor mr imaging was performed in 20 healthy volunteers, 20. Disconnection of brain network may contribute to normal cognitive decline with age. Background and purposeamyloid imaging, gray matter gm morphometry and diffusion tensor imaging dti have all been used as predictive biomarkers in dementia. Frontiers a hitchhikers guide to diffusion tensor imaging. Conclusion advanced imaging tools using dti and dtt are making a significant impact in the clinical imaging of patients with neurological disease. Accelerated changes in white matter microstructure during aging. Whereas conventional magnetic resonance imaging cmri provides methods to map the anatomy or tissue volume, diffusionweighted imaging dwi of random translational water molecules offers quantitative anisotropy and orientation information that has been utilized to map the integrity or architecture of the soft tissue in the central nervous system 16.
Track white matter bundles with the diffusion tensor imaging dti and the constrained spherical deconvolution csd algorithms. Based on the hypothesis that a diffusion kurtosis imaging dki theory is a valuable method for pd diagnosis based on the nongaussian diffusion of water in biologic systems, the purpose of this study is to develop an image processing scheme software based on imagej for the facilitating the application of dki to assist pd diagnosis. Diffusion weighted imaging and diffusion tensor imaging on followup. Full diffusion tensor mr imaging was performed in 20 healthy volunteers, 20 to 91 years.
Quantitative apparent diffusion coefficients and fractional anisotropy have emerged from being primarily research tools to methods enabling valuable clinical applications. Our objective was to define the imaging profile of healthy elderly controls as a function of their cognitive trajectories and explore whether amyloid burden and white matter wm microstructure changes are associated with subtle. Diffusion tensor imaging and fiber tractography of human brain pathways the brain 5 slides mr diffusion weighted imaging 20 slides the diffusion surface 30 slides the surface shape statistical analysis visualization. This software package is developed for processing diffusion tensor imaging dti data, under the auspice of national institute of biomedical imaging and bioengineering nibib and a grant from shanghai commission of science and technology. Diffusion tensor imaging dti comprises a group of techniques where calculated eigenvalues. The limbic system primarily responsible for our emotional life and memories is known to undergo degradation with aging and diffusion tensor imaging dti is capable of revealing the white matter integrity.
Diffusion tensor imaging dti questions and answers in mri. Mr spectroscopy, functional mri, and diffusiontensor imaging. Diffusion tensor imaging dti is a sophisticated mribased neuroimaging technique that enables in vivo quantification of differences in molecular diffusion at the cellular level. The aim of this study is to investigate agerelated changes of quantitative diffusivity parameters and fiber characteristics on limbic system in healthy volunteers. Diffusion tensor imaging, white matter lesions, the corpus. Dec 23, 2003 diffusion tensor imaging characterizes this directional nature of water motion and thereby provides structural information that cannot be obtained by standard anatomic imaging. Research article, report by the scientific world journal. Correlation with processing speed in aging stephen correia 1, stephanie y. Diffusiontensor imaging dti is a noninvasive medical imaging tool used to investigate the. Department of health physics and diagnostic sciences. Article clinical impact of diffusion tensor imaging. Diffusion tensor imaging and fiber tractography of human. It is well established that human brain white matter structure changes with aging, but the timescale and spatial distribution of this change remain uncertain.
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. Sullivanfrontal circuitry degradation marks healthy adult aging. Current clinical applications of diffusiontensor imaging. Generating parametric maps that help to visualise different aspects of. Diffusionweighted 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. Article applications of diffusion tensor imaging and. When an injury occurs, the diffusion flow is disrupted at that location and dti sees the disruption. Diffusion tensor imaging in the study of aging and age. An important distinction between diffusion tensor imaging and other imaging modality like t1 anatomicals or fmri scans, is that dti allows for a more sophisticated normalization. Diffusiontensor imaging dti is a noninvasive magnetic resonance mr imaging technique that enables measurement of diffusion of water and can be used to quantify subtle.
Regional and global changes in cerebral diffusion with. Amyloid load, hippocampal volume loss, and diffusion. What is the best program for analyzing diffusion tensor imaging data. Fiber tractography ft is a 3d reconstruction technique to assess neural tracts using data collected by diffusion tensor imaging. Magnetic resonance diffusion tensor imaging dti is a noninvasive in vivo method for characterizing the integrity of anatomical connections and white matter circuitry and provides a quantitative assessment of the brains white matter microstructure. Neuroimaging software is used to study the structure and function of the brain. Diffusion tensor imaging dti studies are increasingly popular among clinicians and researchers as they provide unique insights into brain network connectivity. White matter correlates of cognitive domains in normal. Yogesh rathi, ofer pasternak, peter savadjiev, oleg v michailovich, sylvain bouix, marek kubicki, carlfredrik westin, nikos makris, and martha e shenton. Agerelated decline in wm integrity interrupts communication among brain networks. Depending on the acquisition protocol, the dwi data may undergo modelbased single or multiple diffusion tensor imaging dti or modelfree analysis to obtain scalar and vector metrics that can be used to map the tissue connectivity 11. In terms of 1 efficiency 2 ability to perform roi analysis for dti parameters eigen values, fi, cl, et. Whereas conventional magnetic resonance imaging cmri provides methods to map the anatomy or tissue volume, diffusion weighted imaging dwi of random translational water molecules offers quantitative anisotropy and orientation information that has been utilized to map the integrity or architecture of the soft tissue in the central nervous system 16.
It allows the mapping of the diffusion process of molecules, mainly water, in biological tissues, in vivo and noninvasively. Diffusion kurtosis imaging for diagnosis of parkinsons. Regional and global changes in cerebral diffusion with normal. Nov 12, 2014 it is well established that human brain white matter structure changes with aging, but the timescale and spatial distribution of this change remain uncertain. Diffusion tensor imaging is a cutting edge imaging technique that provides quantitive information with which to visualize and study connectivity and continuity of neural pathways in the central and peripheral nervous system in vivo. Diffusion tensor imaging investigations in alzheimers.
Diffusion tensor imaging in musculoskeletal disorders. If we apply diffusion gradients in at least 6 noncollinear directions, it is possible to calculate, for each pixel, a diffusion tensor i. Diffusion tensor imaging dti has been widely used to investigate microstructural deterioration associated with aging, including axonal disintegration and neuron cell loss in white matter wm. Dti can often reveal the actual injury that is invisible on standard mri. The number of publications in a pubmed search with any reference to diffusion tensor imaging yaxis, diffusion tensor imaging and aging or alzheimers disease symbol scalingcoloring. Brain adaptations in normal aging evaluated with diffusion. Dti an imaging technique in magnetic resonance imaging to identify the unique directional movement of molecules, esp. Amyloid load, hippocampal volume loss, and diffusion tensor. The diffusion tensor may be used to characterize the magnitude, the degree of anisotropy, and the orientation of directional diffusion. There was a rapid expansion in the number of publications referencing diffusion tensor imaging in the years after 2000, with a substantial. A diffusion tensor imaging software comparison and between.
Diffusion tensor imaging is a critical adjunct to bold imaging in the routine assessment of patients who are being considered for neurological surgery. Diffusion tensor imaging of the brain springerlink. What is the best program for analyzing diffusion tensor. How are my symptoms and my injury matched to the findings. Sullivan, department of psychiatry and behavioral sciences mc 5723, stanford university school of medicine, 401 quarry road, stanford, ca 943055723, usa. To see an nih blueprint for neuroscience research funded clearinghouse of many of these software applications, as well as hardware, etc. It has been recognized that both gray matter loss and white matter deterioration play an important role in brain aging and cognitive decline, and a vascular etiologic pathway has often been hypothesized. Where t1 and fmri scans are normalized based on intensity scales, diffusion tensor images instead offer the ability to register tensors, that have both length and. The neurography institute is the worlds leading expert source for diffusion tensor imaging. Dti uses mri technology to analyze the movement of water molecules in the white matter of the brain. Biological sciences environmental issues aging health aspects aging biology brain diagnostic imaging methods. Frontal executive function in vascular cognitive impairment stephen salloway, md stephen correia, phd paul malloy, phd william heindel, phd david laidlaw, phd goal to develop diffusion tensor imaging as an imaging biomarker of white matter integrity in aging and dementia research focus frontal systems disruption. However, in order to optimize the use of dti, several technical and methodological aspects must be factored in.
Regular diffusionweighted dw imaging produces images based on only the sum or average of the eigenvalues. Ultrahighresolution microstructural diffusion tensor. Microstructural measurements produced through diffusion imaging are particularly helpful in charting patterns of alterations in tissue integrity and changes in anatomical connectivity that result from both the typical aging process as well as the myriad of detrimental conditions that increase in incidence with advancing age and affect the nervous system. It is a noninvasive method, with unparalleled sensitivity to water movements within the architecture of the tissues that uses existing mri technology. Diffusion tensor imaging dti is a type of magnetic resonance imaging which uses the rate at which water diffuses between cells to gather information about the internal structures of the body. Diffusion tensor imaging when d1 is much greater than d2 and d3, diffusion is ellipsoid b when any two eigenvalues are large, and much larger than the third, diffusion is planar c anisotropy based on principle eigenvector, d1. In vivo magnetic resonance spectroscopy mrs, functional magnetic resonance imaging fmri, and diffusiontensor imaging dti have recently opened new possibilities for noninvasively assessing the metabolic, functional, and connectivity correlates of aging in research and clinical settings. Corpus callosal microstructural integrity influences interhemispheric processing. Diffusion tensor imaging and fiber tractography radiology. Diffusion weighted and diffusion tensor imaging in aging. The diffusion rate varies around barriers between different structures in the body, and this trait can be used to create a complex and detailed map of internal structures with the assistance of dti. Owing to the highly directional architecture of white matter wm, dti is providing important clues of the structure and geometric organization of this neural compartment. Quantify the atrophy of the brain and its structures fmri module.
Random motion of water molecules, also known as brownian motion, can be quantified and reflects intrinsic features of tissue microstructure in vivo. Diffusion changes in the aging human brain american journal. Doniger, ofer pasternak, ricardo tarrasch, and yaniv assaf. Dti diffusion tensor imaging is an imaging method that grew out of and is part of mri. Early dti studies of aging primarily focused on two global measures of integrity. Diffusion tensor imaging dti is a promising method for characterizing microstructural changes or differences with neuropathology and treatment. Diffusionweighted imaging dwi le bihan and breton, 1985. A hitchhikers guide to diffusion tensor imaging frontiers. This data is weighted with known information about the rates of diffusion between different types of tissue to create a.
Localize eloquent brain areas for neurosurgical planning. Mr scans were obtained from 11 healthy volunteers and 27 patients ages 26 to 86. Crosssectional diffusion tensor imaging dti studies indicate that, after a period of relative stability during adulthood, there is an accelerated decline in anisotropy and increase in diffusivity values during senescence. Brainmagix combines the most advanced neuroimaging techniques into a unified, vendorneutral, and clinicallyoriented software suite. Mar 12, 20 the introduction of the diffusion tensor model enabled the indirect measurement of the degree of anisotropy and structural orientation that characterizes diffusion tensor imaging dti basser et al. Diffusion tensor imaging dti the architecture of the axons in parallel bundles and their myelin shield facilitate the diffusion of the water molecules along their main direction. Nov 15, 2019 background and purposeamyloid imaging, gray matter gm morphometry and diffusion tensor imaging dti have all been used as predictive biomarkers in dementia. This image, visualized in our neuroimaging software suite, brainmagix, displays an overview of the brains main white matter bundles. Dti can see the direction of diffusion flow in any part of the brain and so can see the fibers. Accelerated changes in white matter microstructure during.
White matter indices are more sensitive to subtle changes than anatomical volumetric analyses examining atrophy in a variety of dementias. Diffusion tensor imaging dti is an mribased neuroimaging technique which makes it possible to estimate the location, orientation, and anisotropy of the brains white matter tracts. This software package is written in python with tkinter. Diffusionweighted imaging dwi is based on the measurement of thermal brownian motion of water molecules. In unconstrained water molecules in a pure liquid environment free of impediments or in a. Frontal executive function in vascular cognitive impairment stephen salloway, md stephen correia, phd paul malloy, phd william heindel, phd david laidlaw, phd goal to develop diffusiontensor imaging as an imaging biomarker of white matter integrity in aging and dementia research focus frontal systems disruption. Mr spectroscopy, functional mri, and diffusiontensor. A diffusion tensor imaging software comparison and between control subjects and subjects with known anatomical diagnosis. In vivo magnetic resonance spectroscopy mrs, functional magnetic resonance imaging fmri, and diffusion tensor imaging dti have recently opened new possibilities for noninvasively assessing the metabolic, functional, and connectivity correlates of aging in research and clinical settings. Diffusion changes in the aging human brain american. The procedure was invented approximately 20 years ago, and many areas of the country are just beginning to see dti available in their area. This data averaging can be done by the scanner software.
699 1153 346 736 642 1519 1589 731 519 571 1348 170 200 506 462 13 175 1212 1369 150 1403 609 69 375 671 452 1365 416 1017 53