Providing background on the tools, methods and software to effectively analyze dti data. This is followed by an overview of the additional information that can be derived from the. It implements a broad range of algorithms for denoising, registration, reconstruction, tracking, clustering, visualization, and statistical analysis of mri data. Diffusion toolkit is a set of commandline tools with a gui frontend that performs data reconstruction and fiber tracking on diffusion mr images. Diffusiontensor magnetic resonance mr imaging dti and fiber tractography ft are new methods that can demonstrate the orientation and integrity of white matter fibers in vivo, 1, 5. To demonstrate the utility of diffusion tensor imaging and tractography in two patients with brownsequard syndrome after penetrating cervical cord injury.
Interactive diffusion tensor tractography visualization for. There have been various existing software packages that can process diffusion tensor imaging dti data as well as perform fiber. Schebesch 1 christian doenitz 1 thomas finkenzeller 2 alexander brawanski 1 juergen schlaier 1. Components of the human connectome project diffusion. Fiber tractography based on diffusion tensor imaging compared. On deeper inspection we find that the conclusions drawn from the results of this. Diffusiontensor imaging dti is a noninvasive magnetic resonance mr technique that. If the water diffuses in a medium with barriers, the diffusion will be uneven, which is termed anisotropic diffusion. Fiber tractography results presented for each patient based on diffusion tensor imaging within iplan cranial column 1, slicer4 column 2, and medalyvis column 3 and based on highangularresolution diffusion imaging with compressed sensing within medalyvis column 4. Basically, it does the preparation work for trackvis.
Diffusion tensor imaging dti is an advanced mr technique that provides qualitative and quantitative information about the microarchitecture of white matter. Article applications of diffusion tensor imaging and. Diagnosis of conversion disorder using diffusion tensor. The corticospinal tracts depicted by diffusion tensor dt tractography in the coronal plane of a t2weighted magnetic resonance imaging mri scan are outlined in red. Dec 12, 20 diffusion tensor tractography is a noninvasive imaging technique that can track neuronal fibre pathways or tracts in a living human brain. Diffusion tensor imaging tractography tutorial and. Spatial normalization of diffusion mri dsi studioa. For a correct diagnosis of conversion disorder with motor weakness, the possibility of injury of the neural tracts for motor execution, especially the corticospinal tract cst, and the corticofugal tract cft from the secondary motor area for motor planning, should be ruled out 4,5,6,7. Measurement of fractional anisotorpy fa and apparent diffusion coefficient adc values along the corticospinal tract. Gqi has a length parameter termed diffusion sampling lengh ratio to specify the distance scale for restricted diffusion to be evaluated. Previous studies include an evaluation of axonal damage caused by a chronic infarct or motor neuron disease, 6, a direct. Diffusion tensor imaging is a magnet resonance imagingtechnique that allows for the noninvasive in vivo assessment and delineation of white matter tracts.
This image was used to determine the level yellow band of the hematoma white arrow. Diffusion mri metrics dsi studioa tractography software tool. For example, one can determine the location of the corticospinal tract or the thalamocortical tract with the help of dti tractography. It is a collective implementation of several diffusion mri methods, including diffusion tensor imaging dti, generalized qsampling imaging gqi, qspace. 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. Diffusionweighted imaging methods and diffusion tensors are. Feigl 1 wolfgang hiergeist 1 claudia fellner 2 karlmichael m. Stereotactic diffusion tensor imaging tractography for.
Magnetic resonance imaging diffusion tensor tractography. Diffusion tensor tractography dtt provides a threedimensional evaluation of the. Diffusion tensor imaging dti infers the trajectory and location of large white. Models beyond tensor dsi studioa tractography software tool. The aim of this study was to analyze the anatomic accuracy of visualized white matter fiber pathways using different, readily available dti tractography software. Dipy is a free and open source software project for computational neuroanatomy, focusing mainly on diffusion magnetic resonance imaging dmri analysis. Tractography or fiber tracking consists of threedimensional modeling of the preferential movement of water molecules in the form of fiber tracks from the tensor field information. Wedeen 1 martinos center for biomedical imaging, mgh, charlestown, ma, united states. Stereotaxic white matter atlas based on diffusion tensor imaging in an icbm template. Diffusiontensortractographybased diagnosis for injury.
There is a large number of variety of software for dti analysis. Toward standardized evaluation of diffusion tensor imaging tractography for neurosurgery sonia pujol. The aim of this study was to analyze the anatomic accuracy of visualized white matter fiber pathways. Conventional mri is commonly used for tumor localization and characterization. Diffusion tensor imaging tractography, or dti tractography, is an mri magnetic resonance imaging technique that measures the rate of water diffusion between cells to understand and create a map of the bodys internal structures. Diffusion tensor imaging dti and tractography request pdf. This image, visualized in our neuroimaging software suite, brainmagix, displays an overview of the brains main white matter bundles. In particular, dtt allows access to injury mechanisms of traumatic axonal injury tai following tbi, useful for detecting axonal injury lesions that are not detected by conventional brain mri t1weighted, t2weighted, fluid. We read with great interest the paper by said et al. The most frequently used method for fiber tractography based on diffusion tensor imaging dti is associated with restrictions in the resolution of crossing or kissing fibers and in the vicinity of tumor or edema. Surgical planning laboratory harvard medical school. It is the responsibility of the user of 3dslicer to comply with both the terms of the license and with the.
Twentyfour healthy volunteers 12 men and 12 women, age 2029 years underwent dti for visualization with tractography and. Posts include stepbystep processing and tractography tutorials. Diffusion is the spread of molecules in a fluid due to constant thermal motion. First, a brief explanation of the basic physics of diffusionweighted imaging dwi and apparent diffusion coefficient adc mapping is provided. The aim of this study was to analyze the anatomic accuracy of visualized white matter fiber pathways using different, readily available dti. It uses special techniques of magnetic resonance imaging mri and computerbased diffusion mri. It is a collective implementation of several diffusion mri methods, including diffusion tensor imaging dti, generalized qsampling imaging gqi, qspace diffeomorphic reconstruction qsdr. Correlation of diffusion tensor tractography and intraoperative macrostimulation during deep brain stimulation for parkinson disease. Qualitative comparison of four different dti software in addition to substantial. This technique uses magnetic resonance imaging and. Although the software developed for this research is available for download, it is. This technique allows a new approach for the microarchitectural analysis of anisotropic structures such as nerves, white matter, and muscles. Diffusion based tractography enables the graphical reconstruction of the white matter pathways in the brain and spinal cord of living humans. Diffusion tensor tractography is a recently developed imaging modality that can demonstrate the anatomy of white matter tracts in vivo.
Nov 18, 2012 diffusion gives a comprehensive overview of available software, analyzing methods and research possibilities. First, a brief explanation of the basic physics of diffusion weighted imaging dwi and apparent diffusion coefficient adc mapping is provided. Fiber tractography based on diffusion tensor imaging. The results are presented in two and threedimensional images called tractograms.
Background diffusion tensor imaging dtibased tractography has become an integral part of preoperative diagnostic imaging in many neurosurgical centers, and other nonsurgical specialties depend increasingly on dti tractography as a diagnostic tool. When starting out in a new imaging field like diffusion tensor imaging it is easy to be overwhelmed by different processing steps and tools. Oct 31, 20 diffusion gives a comprehensive overview of available software, analyzing methods and research possibilities. One direct solution is to use the multiple tensor model to model the diffusion signal, allowing for accessing the diffusivity and fiber orientations for multiple fiber populations 1. All tensor derived measurements, including fa, ad, rd, are based on diffusivity, which by definition measures the rate of diffusion. Visualization of peripheral nerve degeneration and. Gliomas are the most common brain tumors that diffusely infiltrate the surrounding white matter wm tracts. Dti tutorial 3 fiber tractography diffusion imaging. Separating them will require complicated model fitting e.
The standard streamline tractography method as in basser et al. Diffusion tensor imaging dti fiber tracking imagilys. Diffusion tensor imaging dti is the most widely used method for. In such a case, the relative mobility of the molecules from the origin has a shape different from a sphere. Evaluation of anatomic accuracy of different fiber tracking software packages author links open overlay panel guenther c. Dti data may then be analyzed and presented as tractography for visualization of the tracts in 3 dimensions. Takes raw dicom image as well as niftianalyze image. Dti diffusion tensor imaging tractography uses diffusion tensor data and allows 3d visualization of specific white matter tracts. Diffusion tensor imaging dti enables in vivo reconstruction of white matter. Early in the development of dti based tractography, a number of researchers pointed out a flaw in the diffusion tensor model.
Kovanlikaya i, firat z, kovanlikaya a, ulug am, et al assessment of the corticospinal tract alterations before and after resection of brainstem lesions using diffusion tensor imaging dti and tractography at 3t. 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. At the same time, we are investing significant effort into optimizing data acquisition strategies and tractography algorithms to maximize accuracy and minimize errors in the diffusion tractography data. Diffusion tensor imaging dti tractographyloyola medicine. In dti, the scalar elements of this diffusion tensor matrix may be calculated on a voxelbyvoxel basis from data obtained by performing multiple dwi sequences, applying the diffusionweighted gradient along. The biggest drawback of using diffusivity is that nonerestricted and restricted diffusion are always mixed due to brownian motion. Diffusion tensor tractography dtt refers to the analysis and reconstruction of the data obtained by dti, by which the orientation of nerve fibers can be followed to trace specific neural pathways, such as that of the corticospinal tract in the brain or the spinal cord conturo et al. Diffusion tensor is known to be limited by its ability to describe restricted diffusion or multiple fiber population. Dti and its postprocessing tool fiber tractography ft have been increasingly used in the last decade to investigate the microstructural neuroarchitecture of brain malformations. The aim of this study was to demonstrate the feasibility of this technique and to address some of the technical limitations of previously reported techniques.
Diffusionbased tractography enables the graphical reconstruction of the white matter pathways in the brain and spinal cord of living humans. It is a collective implementation of several diffusion mri methods, including diffusion tensor imaging dti, generalized qsampling imaging gqi, qspace diffeomorphic reconstruction qsdr, diffusion mri. Open source diffusion mri software for brain cancer. The authors report their method of integrating stereotactic diffusion tensor imaging dti tractography into conventional treatment planning for gamma knife radiosurgery gkrs.
Diffusion tensor tractography is a noninvasive imaging technique that can track neuronal fibre pathways or tracts in a living human brain. A tractography software dsi studio is a tractography software tool that maps brain connections and correlates findings with neuropsychological disorders. One direct solution is to use the multiple tensor model to model the diffusion signal, allowing for accessing the diffusivity and fiber orientations for. Diffusion tensor imaging and tractography of the sciatic. Tractography is performed using data from diffusion mri. Dsi studio is a tractography software tool for diffusion mri analysis. Diffusion tensor mr imaging and fiber tractography. Diffusion tensor tractography dtt can provide information about neural tracts not available by conventional magnetic resonance imaging mri 1,6,7. Nine pd, six morbid obesity, and five ocd patients were included with a mean age of 65. The technique can help neurosurgeons to localize important white matter tracts e. Diffusion tensor tractography in patients with cerebral tumors.
The aim was to clarify the normal fractional anisotropy fa and apparent diffusion coefficient adc values of the sciatic and femoral nerves at the level of the hip joint and to visualize the neural tracts with diffusion tensor imaging dti. Diffusion tensor imaging dti infers the trajectory and location of large white matter tracts by measuring the anisotropic diffusion of water. This technique has many potential clinical applications, including the investigation of stroke, multiple sclerosis, epilepsy, neurodegenerative diseases, and spinal cord disorders, and it enables hypotheses to be tested that could not. Functional mri data were realigned, motion corrected, and analyzed using spm2 wellcome department of cognitive neurology, london, uk. This technique has many potential clinical applications, including the investigation of stroke, multiple sclerosis, epilepsy, neurodegenerative diseases, and spinal cord disorders, and it enables hypotheses to be tested that could not previously be. This article outlined the dti protocol used at our institution, discussed the preferred locations of rois, addressed the optimal tractography parameters, and detailed the anatomy and function of the major white. The second half of the article focuses on technical considerations specific to diffusion tensor imaging dti and fiber tractography, including optimizing the bvalues, the number and orientations of diffusion weighted acquisitions, as well as the fiber tracking parameters. Tractography methods team id diffusion model fiber tracking algorithm roi team 1 single tensor deterministic precentral gyrus, postcentral gyrus, cerebral peduncles team 2 multicompartment diffusion direction imaging deterministic mesencephalon, internal capsule team 3 single tensor probabilistic somatosensory cortex, pons, temporal lobes. Diffusion tensor image tractography was reconstructed using brainlab elements software brainlab ag, munich, germany. The free water diffusion is termed isotropic diffusion. Tractography in neuroscience, tractography is a 3d modeling technique used to visually represent nerve tracts using data collected by diffusion mri. It allows the mapping of the diffusion process of molecules, mainly water, in biological tissues, in vivo and noninvasively.
Diffusion mri metrics dsi studioa tractography software. Dsi studio is a tractography software tool that maps brain connections and correlates findings with neuropsychological disorders. Interactive diffusion tensor tractography visualization. A software package for diffusion imaging data processing and tractography r.
Diffusion tensor imaging and fiber tractography in brain. Jan 01, 2014 background diffusion tensor imaging dtibased tractography has become an integral part of preoperative diagnostic imaging in many neurosurgical centers, and other nonsurgical specialties depend increasingly on dti tractography as a diagnostic tool. What is the best program for analyzing diffusion tensor. However, this does not give precise information about the wm infiltration surrounding the tumor.
Handles diffusion tensor imaging dti, diffusion spectrum imaging dsi, qball imaging and high angular resolution diffusion imaging hardi data. Diffusion gives a comprehensive overview of available software, analyzing methods and research possibilities. What is the best program for analyzing diffusion tensor imaging data. Camino is a free, opensource, objectoriented software package for analysis and reconstruction of diffusion mri data, tractography and connectivity mapping. Citeseerx document details isaac councill, lee giles, pradeep teregowda. An ellipsoid diffusion tensor water molecules move in physical brownian motion t time. Many disorders have been studied including cervical myelopathy, carpal.
Tractography based on highangularresolution diffusion imaging hardi is capable of overcoming this restriction. Wedeen 1martinos center for biomedical imaging, mgh, charlestown, ma, united states introduction. The tensor analysis assumes that there is a single ellipsoid in each imaging voxel as if all of the axons traveling through a voxel traveled in exactly the same direction. As a result, qa is quantifying the anisotropy of restricted diffusion and thus more robust against inflammation and edema. Dec 05, 2019 tractography in neuroscience, tractography is a 3d modeling technique used to visually represent nerve tracts using data collected by diffusion mri. A neurosurgery study has shown that qa is robust against peritumoral edema and contributes to more reliable. Diffusion tensor imaging and fiber tractography of human.
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