Traditional Posters: Miscellaneous
Yüklə 355,76 Kb.
|
| Andrew Borgert1,2, Kelvin O. Lim1,2, Pierre-Gilles Henry1,3
1Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, United States; 2Department of Psychiatry, University of Minnesota, Minneapolis, MN, United States; 3Department of Radiology, University of Minnesota, Minneapolis, MN, United States Spectral fitting methods such as commercial metabolomics software (eg, Chenomx) or capabilities built into NMR system software (eg, Varian or Bruker) require significant user input and are generally not amenable to automation, making them time-consuming, cumbersome, and prone to user error. To address these issues, we have adapted the LCModel software package for use with high resolution in vitro NMR data, allowing for automated and consistent analysis of such data. This adaptation utilizes a simulated basis set, with basis spectra generated for the majority of individual protons within each metabolite, as opposed to the metabolite as a whole. 907. Simulating Human Brain Glutamate FMRS at 7.0 T to Determine Minimum SNR Requirements Reggie Taylor1,2, Jean Théberge1,2, Peter Williamson, 1,3 1Medical Biophysics, University of Western Ontario, London, ON, Canada; 2Lawson Health Research Institute, London, ON, Canada; 3Department of Psychiatry, University of Western Ontario, London, ON, Canada Human brain glutamate fMRS has the potential to provide dynamic information regarding normal and abnormal glutamate metabolism. With ultra-high field magnets (≤7T) increased spectral dispersion and SNR should result in more precise fMRS but how much SNR is required is not known. Using simulations of an in vivo spectrum acquired with a STEAM sequence (TE/TM 6/32ms) at 7T minimum numbers of spectra required to detect a 3% concentration change in glutamate between rest and activation were determined for various SNRs. A minimum SNR of 212 was needed to detect the 3% change when comparing only one spectrum from each state. 908. Ultrafast 2D High-Resolution COSY Spectra in Inhomogeneous Fields Congbo Cai1, Fenglian Gao1, Shuhui Cai1, Zhong Chen1 1Departments of Physics and Communication Engineering, Fujian Key Laboratory of Plasma and Magnetic Resonance, Xiamen University, Xiamen, Fujian, China High-resolution COSY spectra can provide more information than 1D spectra. Recently, our group proposed a method to achieve high-resolution COSY spectra under inhomogeneous fields based on the intermolecular multiple-quantum coherences (iMQCs). However, 3D acquisition is necessary for a 2D COSY spectrum, which makes the experiment rather time-consuming. In this study, we introduced Hadamard technique to speed up the acquisition greatly. A high-resolution iMQC COSY spectrum can then be obtained in less than 10 minutes under inhomogeneous fields. Such a technique would widen the application field of iMQC methods. 909. Handling Arbitrary Unknown Line-Shape Without Introducing Extra Parameters. Emil Popa1, Enrico Capobianco2, Jan Willem van der Veen3, Ronald de Beer4, Dirk van Ormondt5, Danielle Graveron-Demilly1 1Université Lyon 1, Villeurbanne, France; 2CRS4 Bioinformatics Laboratory, Pula (Cagliari), Italy; 3NIH, NIMH, Bethesda, United States; 4Delft University of Technology; 5Applied Physics, Delft University of Technology, Delft, Zuid Holland, Netherlands This work concerns a new way of dealing with in vivo spectral lineshapes for the case that a reference line is not available. It is based on dual-criterion non-linear least-squares fitting. All data-points are used simultaneously, in conjunction with the general a priori knowledge that a lineshape can be confined to a certain frequency region. The experimental lineshape at hand can be arbitrary, including asymmetric shapes. Modelling with analytical mathematical functions like splines, wavelets, or decaying sinusoids is circumvented. As a result, setting of hyper-parameters by a user is avoided. This favours automation. 910. Precision and Robustness of Deep Brain Temperature Estimation Using Localised Proton Magnetic Resonance Spectroscopy in Normothermic and Hypothermic Newborn Infants Alan Bainbridge1, Giles Kendall2, Enrico DeVita3, Cornelia Hagmann2, Andrew Kapetanakis2, Ernest Cady1, Nicola Robertson2 1Medical Physics and Bioengineering, UCL Hospitals NHS Foundation Trust, London, United Kingdom; 2Academic Neonatology, EGA UCL Institute for Women’s Health, University College London, London, United Kingdom; 3UCL Hospitals NHS Foundation Trust, Medical Physics and Bioengineering, London, United Kingdom Therapeutic cerebral hypothermia is an effective and safe treatment for perinatal asphyxial encephalopathy. Precise knowledge of regional brain temperature is needed in order to optimise therapeutic hypothermia. Proton MRS can be used to estimates regional brain temperature. Reliable absolute temperature measurement depends on good calibration data and robust clinical spectrum acquisition. Serial acquisition of subspectra allows both removal of motion-corrupted data and frequency correction of the remaining subspectra to remove effects of static magnetic field decay. The magnetic field decay correction significantly reduced fitted peak linewidths and increased the precision of the measurement. 911. Metabolite Nulling to Measure the Macromolecule Baseline for Quantitative 1H Magnetic Resonance Spectroscopy at 7 Tesla Jacob Penner1,2, Andrew Curtis1,2, Martyn Klassen1, Joseph Gati1, Matthew Smith3, Michael J. Borrie3,4, Robert Bartha1,2 1Centre for Functional and Metabolic Mapping, Robarts Research Institute, London, ON, Canada; 2Medical Biophysics, University of Western Ontario, London, ON, Canada; 3Division of Aging, Rehabilitation, and Geriatric Care, Lawson Health Research Institute, London, ON, Canada; 4Department of Medicine, University of Western Ontario, London, ON, Canada The purpose of this study was to determine the optimal inversion time to null metabolite signals allowing accurate measurement of the macromolecule baseline for quantitative 1H MR spectroscopy at 7T. Spectra were acquired within a phantom using single-voxel localization by adiabatic selective refocusing (LASER). The TI values that would result in complete suppression of NAA and Cr were found to be 0.47 seconds and 1.27 seconds, respectively. Furthermore, T1 values were found to be 1.28 seconds for NAA and 2.45 seconds for Cr. Future work will extend this method to determine the optimal TI values for in-vivo metabolite suppression. 912. Decoupled Proton NMR Spectroscopy in Modest to Severe Inhomogeneous Fields Via Distant Dipolar Interactions Yüklə 355,76 Kb. Dostları ilə paylaş:
|