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Intraoperative Infrared Optical Imaging in Neurosurgery
Published in Yu Chen, Babak Kateb, Neurophotonics and Brain Mapping, 2017
Michael E. Wolf, Richard P. Menger, Osama Ahmed, Shahdad Sherkat, Babak Kateb
The main and obvious limitation of NIRS was the lack of spatial data. It did not take long for investigators to overcome this limitation by combining multiple NIRS measurements consisting of multiple clusters of sources and detectors to pinpoint and localize brain emanating signals to form useful images of the brain (Maki et al. 1995). In the realm of noninvasive imaging, NIRS technology essentially served as the seed that sprouted into a tree of possibilities. The discovery of NIRS has led to imaging and tomography techniques such as diffuse optical tomography (DOT) and optical coherence tomography (OCT). DOT functions by extrapolating NIRS data with multiple measurement points to create three-dimensional computed tomographic images of the brain (Hielscher et al. 2002). OCT, on the other hand, is an interferometry technique that employs NIR light to scan cross-sectional images at various depths to create two- or three-dimensional images (Fujimoto et al. 2000). These technologies have shown to be a valuable method for noninvasive neuroscience discovery and medical applications, and their uses range from cognitive brain mapping to disease detection.
Magnetic Resonance Imaging
Published in Kayvan Najarian, Robert Splinter, Biomedical Signal and Image Processing, 2016
Kayvan Najarian, Robert Splinter
The fMRI is in principle the best tool available to perform brain mapping This technology allows observing the brain while a certain task is performed The parts of the brain that are activated in the collected MR images are then associated to the performed task Since any function in all cells including neurons is associated with the consumption of the oxygen contained in blood, the monitoring of the functional activities of the neurons is in principle equivalent to the detection of oxygen consumption. In the early 1990s, it was discovered that the oxygenation level of blood will act as a contrast agent in MRI This discovery forms the basis of fMRI as it is used in present day.
The effects of Alzheimer's disease related striatal pathologic changes on the fractional amplitude of low-frequency fluctuations
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2020
Resting-state functional Magnetic Resonance Imaging (rs-fMRI), a non-invasive functional imaging technique, has been used extensively in brain mapping for evaluating the regional interactions which occur in a resting state when a task is not being performed. fMRI is used to measure spontaneous brain activities in vivo and is most commonly performed using blood oxygenation level dependent (BOLD) contrast to study the local changes in deoxyhemoglobin concentration in the brain. Under normal and pathological conditions such as AD which is a progressive neurodegenerative disorder, it helps to detect the intrinsic brain functional architecture (Agosta et al. 2012; Liu et al. 2014; Lindquist and Wager 2016; Ren et al. 2016; Yang et al. 2018).