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Diffusion Tensor Imaging: The use of diffusion Anisotropy data from diffusion magnetic resonance imaging results to construct images based on the direction of the faster diffusing molecules.

Using Diffusion Tensor Imaging in Traumatic Brain Injury

JoVE 10276

Source: Laboratories of Jonas T. Kaplan and Sarah I. Gimbel—University of Southern California

Traditional brain imaging techniques using MRI are very good at visualizing the gross structures of the brain. A structural brain image made with MRI provides high contrast of the borders between gray and white matter, and information about the size and shape of brain structures. However, these images do not detail the underlying structure and integrity of white matter networks in the brain, which consist of axon bundles that interconnect local and distant brain regions. Diffusion MRI uses pulse sequences that are sensitive to the diffusion of water molecules. By measuring the direction of diffusion, it is possible to make inferences about the structure of white matter networks in the brain. Water molecules within an axon are constrained in their movements by the cell membrane; instead of randomly moving in every direction with equal probability (isotropic movement), they are more likely to move in certain directions, in parallel with the axon (anisotropic movement; Figure 1). Therefore, measures of diffusion anisotropy are thought to reflect properties of the white matter such as fiber density, axon thickness, and degree of myelination. One common measure is fractional anisotropy


 Neuropsychology

Quantitative Magnetic Resonance Imaging of Skeletal Muscle Disease

1Institute of Imaging Science, Vanderbilt University, 2Department of Radiology and Radiological Sciences, Vanderbilt University, 3Department of Biomedical Engineering, Vanderbilt University, 4Department of Molecular Physiology and Biophysics, Vanderbilt University, 5Department of Physical Medicine and Rehabilitation, Vanderbilt University, 6Department of Physics and Astronomy, Vanderbilt University

JoVE 52352


 Medicine

Fiber Connections of the Supplementary Motor Area Revisited: Methodology of Fiber Dissection, DTI, and Three Dimensional Documentation

1Department of Neurosurgery, University of Minnesota, 2Department of Neurosurgery, Barrow Neurological Institute, St. Josephs Hospital and Medical Center, 3Department of Radiology, University of Alabama at Birmingham, 4Department of Radiology, University of Minnesota, 5Department of Neurosurgery, Tepecik Training and Research Hospital, 6Department of Neurosurgery, Cerrahpasa Medical School, University of Istanbul

JoVE 55681


 Neuroscience

An Investigation of the Effects of Sports-related Concussion in Youth Using Functional Magnetic Resonance Imaging and the Head Impact Telemetry System

1Graduate Department of Rehabilitation Science, University of Toronto, 2Occupational Science and Occupational Therapy, University of Toronto, 3Department of Psychology, University of Toronto, 4Bloorview Kids Rehab, 5Toronto Rehab, 6Cognitive Neurology, Sunnybrook Health Sciences Centre, 7Faculty of Medicine, University of Toronto

JoVE 2226


 Medicine

fMRI: Functional Magnetic Resonance Imaging

JoVE 5212

Functional magnetic resonance imaging (fMRI) is a non-invasive neuroimaging technique used to investigate human brain function and cognition in both healthy individuals and populations with abnormal brain states. Functional MRI utilizes a magnetic resonance signal to detect changes in blood flow that are coupled to neuronal activation when a specific task is performed. This is possible because hemoglobin within the blood has different magnetic properties depending on whether or not it is bound to oxygen. When a certain task is performed, there is an influx of oxygenated blood to brain regions responsible for that function, and this influx can then be detected with specific MRI scan parameters. This phenomenon is termed the blood oxygen level ependent (BOLD) effect, and can be used to create maps of brain activity. This video begins with a brief overview of how MRI and fMRI signal is obtained. Then, basic experimental design is reviewed, which involves first setting up a stimulus presentation that is specifically designed to test the function that will be mapped. Next, key steps involved in performing the fMRI scan are introduced, including subject safety and setting up at the scanner. Commonly used steps for data processing are then presented, including pre-processing and statistical analysis with the general linear


 Neuroscience

Normothermic Ex Situ Heart Perfusion in Working Mode: Assessment of Cardiac Function and Metabolism

1Department of Surgery, Faculty of Medicine, University of Alberta, 2Department of Physiology, Faculty of Medicine, University of Alberta, 3Department of Biomedical Engineering, Faculty of Medicine, University of Alberta, 4Canadian National Transplant Research Program

Video Coming Soon

JoVE 58430


 JoVE In-Press

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