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Blood-oxygen-level-dependent imaging, or BOLD-contrast imaging, is a method used in functional magnetic resonance imaging (fMRI) to observe different areas of the brain or other organs, which are found to be active at any given time.
The primary form of fMRI uses the blood-oxygen-level dependent (BOLD) contrast, [4] discovered by Seiji Ogawa in 1990. This is a type of specialized brain and body scan used to map neural activity in the brain or spinal cord of humans or other animals by imaging the change in blood flow ( hemodynamic response ) related to energy use by brain ...
This image weighting is useful for detecting edema and inflammation, revealing white matter lesions, and assessing zonal anatomy in the prostate and uterus. The standard display of MRI images is to represent fluid characteristics in black and white images, where different tissues turn out as follows:
Susceptibility weighted imaging (SWI), originally called BOLD venographic imaging, is an MRI sequence that is exquisitely sensitive to venous blood, hemorrhage and iron storage. SWI uses a fully flow compensated, long echo, gradient recalled echo (GRE) pulse sequence to acquire images.
Functional MRI (fMRI) Blood-oxygen-level dependent imaging: BOLD: Changes in oxygen saturation-dependent magnetism of hemoglobin reflects tissue activity. [26] Localizing brain activity from performing an assigned task (e.g. talking, moving fingers) before surgery, also used in research of cognition. [27] Magnetic resonance angiography (MRA ...
The hemodynamic response is the basis for the BOLD (blood oxygen level dependent) contrast in fMRI. [5] The hemodynamic response occurs within seconds of the presented stimuli, but it is essential to space out the events in order to ensure that the response being measured is from the event that was presented and not from a prior event.
BOLD-contrast is a naturally occurring process in the body so fMRI is often preferred over imaging methods that require radioactive markers to produce similar imaging. [33] A concern in the use of fMRI is its use in individuals with medical implants or devices and metallic items in the body.
White matter is the tissue through which messages pass between different areas of grey matter within the central nervous system. The white matter is white because of the fatty substance (myelin) that surrounds the nerve fibers (axons). This myelin is found in almost all long nerve fibers, and acts as an electrical insulation.