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Rapid Imaging (rapid + imaging)
Selected AbstractsThe benefits of rapid 3D fMRIINTERNATIONAL JOURNAL OF IMAGING SYSTEMS AND TECHNOLOGY, Issue 1 2010Martin A. Lindquist Abstract Functional magnetic resonance imaging (fMRI) provides the ability to image blood dynamics through the entire brain with a high spatial resolution. However, the temporal resolution is much slower than the underlying neuronal activity one seeks to infer. Recent developments in rapid imaging allow 3D fMRI studies to be performed at a temporal resolution of 100 ms; a 10-fold increase compared to standard approaches. This increase in temporal resolution offers a number of potential benefits. First, it allows the focus of analysis to be shifted from changes in blood flow taking place 5,8 s after neuronal activity to more transient changes taking place immediately following activation. We argue that studying these changes provides valuable information about the relative timing of activation across different regions of the brain, which is crucial for inferring brain pathways. Second, rapid imaging allows for the efficient modeling of physiological artifacts without problems with aliasing; something that is difficult at standard resolutions. We illustrate how removal of these artifacts provides the increase in signal-to-noise ratio required for studying the subtle changes in oxygenation we are interested in. Finally, we show how high temporal resolution data provides the opportunity to focus the analysis on the rate of change in oxygenation rather than the level of oxygenation as is the current practice. The price of performing rapid imaging studies is a decrease in spatial resolution. However, we argue that the resolution is still comparable to the effective resolution used in most fMRI studies. We illustrate our approach using two fMRI data sets. © 2010 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 20, 14,22, 2010 [source] Hybrid Rayleigh, Raman and two-photon excited fluorescence spectral confocal microscopy of living cellsJOURNAL OF RAMAN SPECTROSCOPY, Issue 6 2010Vishnu Vardhan Pully Abstract A hybrid fluorescence,Raman confocal microscopy platform is presented, which integrates low-wavenumber-resolution Raman imaging, Rayleigh scatter imaging and two-photon fluorescence (TPE) spectral imaging, fast ,amplitude-only' TPE-fluorescence imaging and high-spectral-resolution Raman imaging. This multi-dimensional fluorescence,Raman microscopy platform enables rapid imaging along the fluorescence emission and/or Rayleigh scatter dimensions. It is shown that optical contrast in these images can be used to select an area of interest prior to subsequent investigation with high spatially and spectrally resolved Raman imaging. This new microscopy platform combines the strengths of Raman ,chemical' imaging with light scattering microscopy and fluorescence microscopy and provides new modes of correlative light microscopy. Simultaneous acquisition of TPE hyperspectral fluorescence imaging and Raman imaging illustrates spatial relationships of fluorophores, water, lipid and protein in cells. The fluorescence,Raman microscope is demonstrated in an application to living human bone marrow stromal stem cells. Copyright © 2009 John Wiley & Sons, Ltd. [source] Rapid AFM imaging of large soft samples in liquid with small forces,ASIAN JOURNAL OF CONTROL, Issue 2 2009Szuchi Tien Abstract This article addresses the reduction of the tip-sample force during rapid Atomic Force Microscope (AFM) imaging of large soft samples in liquid medium. Maintaining a small tip-sample force is critical to avoid sample damage, especially when imaging soft biological samples or polymers. The tip-sample force can be reduced if the AFM-probe can be positioned to follow the sample topography as it is scanned over the surface. However, precision positioning over the sample topography has been challenging when imaging relatively large areas in soft samples. A zoom-out/zoom-in iterative method is proposed to achieve the precision positioning needed to maintain small tip-sample forces during rapid AFM imaging. The method is used to demonstrate rapid imaging of soft hydrogel samples. Copyright © 2009 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society [source] Retinal vessel oximetry using sequential and 'snapshot' hyperspectral imagingACTA OPHTHALMOLOGICA, Issue 2009A MCNAUGHT Purpose Use of sequential, and 'snapshot' hyperspectral imagers to measure oxygen saturation in retinal vessels in normals, and examples of eye disease, eg glaucoma, and retinovascular diseases. Validation of estimated oximetry values using a model eye. Methods A sequential hyperspectral imager was constructed using a fundus camera with built-in liquid-crystal tuneable filter. Images of normals,and ocular disease are presented. A novel 'snapshot' hyperspectral imager is also described: this produces images in a single exposure. Validation of both devices using an artificial eye with capillary tubes containing human blood of known oxygen saturation, placed in front of an 'artificial retina' is described. The image analysis used to detect retinal vessels, and generate oximetric values is detailed. Results Both the sequential, and 'snapshot' retinal imagers produced accurate estimations of retinal vessel oxygen saturation, when compared with the model eye. Imaging of a small group of glaucoma eyes showed abnormally elevated venous oxygen saturation. In proliferative diabetic retinopathy, abnormally elevated venular saturation was found in areas of capillary loss on FFA. In vein occlusion, elevated venous saturation was found in eyes with ischaemic FFAs. Conclusion Both the sequential and 'snapshot' hyperspectral imagers deliver useful oximetric maps of the retina. The 'snapshot' device allows more rapid imaging. The elevated venular oxygen saturation seen in both glaucoma, and retinovascular disease, is perhaps evidence of reduced oxygen consumption in damaged inner retina in glaucoma, and/or vascular 'shunting' in retinovascular disease. [source] | ||||||||||