Sreenath P Kyathanahally1,2, Roland Kreis1. 1. Department of Clinical Research and Institute of Diagnostic, Interventional and Pediatric Radiology, University of Bern, Bern, Switzerland. 2. Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland.
Abstract
PURPOSE: To investigate whether an initial non-water-suppressed acquisition that provides information about the signal-to-noise ratio (SNR) and linewidth is enough to forecast the maximally achievable final spectral quality and thus inform the operator whether the foreseen number of averages and achieved field homogeneity is adequate. METHODS: A large range of spectra with varying SNR and linewidth was simulated and fitted with popular fitting programs to determine the dependence of fitting errors on linewidth and SNR. A tool to forecast variance based on a single acquisition was developed and its performance evaluated on simulated and in vivo data obtained at 3 Tesla from various brain regions and acquisition settings. RESULTS: A strong correlation to real uncertainties in estimated metabolite contents was found for the forecast values and the Cramer-Rao lower bounds obtained from the water-suppressed spectra. CONCLUSION: It appears to be possible to forecast the best-case errors associated with specific metabolites to be found in model fits of water-suppressed spectra based on a single water scan. Thus, nonspecialist operators will be able to judge ahead of time whether the planned acquisition can possibly be of sufficient quality to answer the targeted clinical question or whether it needs more averages or improved shimming. Magn Reson Med 78:441-451, 2017.
PURPOSE: To investigate whether an initial non-water-suppressed acquisition that provides information about the signal-to-noise ratio (SNR) and linewidth is enough to forecast the maximally achievable final spectral quality and thus inform the operator whether the foreseen number of averages and achieved field homogeneity is adequate. METHODS: A large range of spectra with varying SNR and linewidth was simulated and fitted with popular fitting programs to determine the dependence of fitting errors on linewidth and SNR. A tool to forecast variance based on a single acquisition was developed and its performance evaluated on simulated and in vivo data obtained at 3 Tesla from various brain regions and acquisition settings. RESULTS: A strong correlation to real uncertainties in estimated metabolite contents was found for the forecast values and the Cramer-Rao lower bounds obtained from the water-suppressed spectra. CONCLUSION: It appears to be possible to forecast the best-case errors associated with specific metabolites to be found in model fits of water-suppressed spectra based on a single water scan. Thus, nonspecialist operators will be able to judge ahead of time whether the planned acquisition can possibly be of sufficient quality to answer the targeted clinical question or whether it needs more averages or improved shimming. Magn Reson Med 78:441-451, 2017.
Authors: Martin Wilson; Ovidiu Andronesi; Peter B Barker; Robert Bartha; Alberto Bizzi; Patrick J Bolan; Kevin M Brindle; In-Young Choi; Cristina Cudalbu; Ulrike Dydak; Uzay E Emir; Ramon G Gonzalez; Stephan Gruber; Rolf Gruetter; Rakesh K Gupta; Arend Heerschap; Anke Henning; Hoby P Hetherington; Petra S Huppi; Ralph E Hurd; Kejal Kantarci; Risto A Kauppinen; Dennis W J Klomp; Roland Kreis; Marijn J Kruiskamp; Martin O Leach; Alexander P Lin; Peter R Luijten; Małgorzata Marjańska; Andrew A Maudsley; Dieter J Meyerhoff; Carolyn E Mountford; Paul G Mullins; James B Murdoch; Sarah J Nelson; Ralph Noeske; Gülin Öz; Julie W Pan; Andrew C Peet; Harish Poptani; Stefan Posse; Eva-Maria Ratai; Nouha Salibi; Tom W J Scheenen; Ian C P Smith; Brian J Soher; Ivan Tkáč; Daniel B Vigneron; Franklyn A Howe Journal: Magn Reson Med Date: 2019-03-28 Impact factor: 4.668
Authors: Roland Kreis; Vincent Boer; In-Young Choi; Cristina Cudalbu; Robin A de Graaf; Charles Gasparovic; Arend Heerschap; Martin Krššák; Bernard Lanz; Andrew A Maudsley; Martin Meyerspeer; Jamie Near; Gülin Öz; Stefan Posse; Johannes Slotboom; Melissa Terpstra; Ivan Tkáč; Martin Wilson; Wolfgang Bogner Journal: NMR Biomed Date: 2020-08-17 Impact factor: 4.044