Mri Machine
Mri Machine - Related Videos
08:20
MRI-guided dmPFC-rTMS as a Treatment for Treatment-resistant Major Depressive Disorder
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Cited by 31 •
2015
Here we outline the procedure for MRI-guided repetitive transcranial magnetic stimulation to the dorsomedial prefrontal cortex as an experimental treatment for major depressive disorder.
06:06
Optogenetic Functional MRI
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Cited by 15 •
2016
This protocol describes the steps and data analysis required to successfully perform optogenetic functional magnetic resonance imaging (ofMRI). ofMRI is a novel technique that combines high-field fMRI readout with optogenetic stimulation, allowing for cell type-specific mapping of functional neural circuits and their dynamics across the whole living brain.
06:58
Synthesis of an In vivo MRI-detectable Apoptosis Probe
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Cited by 3 •
2012
Early detection of apoptosis may identify at-risk cell populations in a variety of diseases. Here we demonstrate a method to link an early apoptosis-detection protein (Annexin V) to a MRI-detectable iron oxide nanoparticle (SPIO). This method may be extended to other proteins of interest to generate MRI-detectable molecular imaging probes.
10:26
A Multicenter MRI Protocol for the Evaluation and Quantification of Deep Vein Thrombosis
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Cited by 5 •
2015
The goal of this study is to use magnetic resonance venography with long-circulating gadolinium-based contrast agent and direct thrombus imaging for quantitative evaluation of DVT volume in a multicenter, clinical trial setting. Inter- and intra-observer variability assessments were conducted, and reproducibility of the protocol was determined.
09:02
AC Synchronous Machine Synchronization
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2023
Source: Ali Bazzi, Department of Electrical Engineering, University of Connecticut, Storrs, CT. Three-phase wound-rotor synchronous generators are the main source of electrical power worldwide. They require a prime mover and an exciter in order to generate power. The prime mover can be a turbine spun by fluid (gas or liquid), thus the sources of the fluid can be water running off a dam through a long nozzle, steam from water evaporated using burned coal, etc. Most power plants including coal,...
FAQs
Magnetic-field gradients vary the magnetic field across different locations in the brain. This variation changes the behavior of aligned hydrogen nuclei according to their position, allowing the system to encode spatial information in the detected signals. Without gradient-based encoding, the returning signals would not provide enough location-specific information to reconstruct distinct anatomical regions.
Radiofrequency pulses temporarily disturb the alignment of hydrogen nuclei created by the main magnetic field. As the nuclei return toward equilibrium, they produce detectable signals whose characteristics reflect the tissue being measured. The timing of this disturbance and recovery provides the signal information needed to distinguish internal brain structures during image formation.
Computational reconstruction processes the spatially encoded signals detected as nuclei return to equilibrium and converts them into an interpretable image. The reconstruction links signal patterns to their locations within the brain, producing detailed structural scans or other measurements. This computational step makes the raw detected response useful for examining anatomy and brain-related changes.
Structural MRI scans are used to examine the brain’s anatomy, whereas functional measurements assess changes associated with brain activity, including blood-oxygenation changes. The two approaches answer different questions: one emphasizes physical organization, while the other helps investigate responses during cognitive tasks. Together, they provide complementary information about brain structure and function.
A scan begins with the magnetic field aligning hydrogen nuclei in tissue. Radiofrequency pulses then disturb that alignment, and magnetic-field gradients encode where the resulting signals originate. As the nuclei return toward equilibrium, the system detects their signals and computational methods reconstruct the measurements into structural images or functional information.
Neuroscientists use MRI to investigate neural development, brain tumors, stroke, neurodegenerative disease, connectivity, and responses to cognitive tasks. Its ability to provide structural and functional information supports both research and clinical assessment. The same imaging system can therefore contribute to studying normal brain organization as well as disease-related changes.
MRI provides detailed information about internal brain anatomy while also supporting measurements related to function. It can be used to examine connectivity and task-related responses alongside structural changes, making it valuable across multiple neuroscience questions. MRI is also performed without ionizing radiation, which distinguishes it from imaging approaches that rely on that type of radiation.