Stefan Ruschke1, Hermine Kienberger2, Thomas Baum1, Hendrik Kooijman3, Marcus Settles1, Axel Haase4, Michael Rychlik2,5, Ernst J Rummeny1, Dimitrios C Karampinos1. 1. Department of Diagnostic and Interventional Radiology, Technische Universität München, Munich, Germany. 2. Bioanalytik Weihenstephan, Research Center for Nutrition and Food Sciences, Technische Universität München, Freising, Germany. 3. Philips Healthcare, Hamburg, Germany. 4. Zentralinstitut für, Medizintechnik, Technische Universität München, Garching, Germany. 5. Chair of Analytical Food Chemistry, Technische Universität München, Freising, Germany.
Abstract
PURPOSE: To propose and optimize diffusion-weighted stimulated echo acquisition mode (DW-STEAM) for measuring fat unsaturation in the presence of a strong water signal by suppressing the water signal based on a shorter T2 and higher diffusivity of water relative to fat. METHODS: A parameter study for point-resolved spectroscopy (PRESS) and STEAM using oil phantoms was performed and correlated with gas chromatography (GC). Simulations of muscle tissue signal behavior using DW-STEAM and long-echo time (TE) PRESS and a parameter optimization for DW-STEAM were conducted. DW-STEAM and long-TE PRESS were applied in the gastrocnemius muscles of nine healthy subjects. RESULTS: STEAM with TE and mixing time (TM) up to 45 ms exhibited R(2) correlations above 0.98 with GC and little T2 -weighting and J-modulation for the quantified olefinic/methylene peak ratio. The optimal parameters for muscle tissue using DW-STEAM were b-value = 1800 s/mm(2), TE = 33 ms, TM = 30 ms, and repetition time = 2300 ms. In vivo measured mean olefinic signal-to-noise ratios were 72 and 40, mean apparent olefinic water fractions were 0.19 and 0.11 for DW-STEAM and long-TE PRESS, respectively. CONCLUSION: Optimized DW-STEAM MR spectroscopy is superior to long-TE PRESS for measuring fat unsaturation, if a strong water peak prevents the olefinic fat signal's quantification at shorter TEs and water's tissue specific ADC is substantially higher than fat.
PURPOSE: To propose and optimize diffusion-weighted stimulated echo acquisition mode (DW-STEAM) for measuring fat unsaturation in the presence of a strong water signal by suppressing the water signal based on a shorter T2 and higher diffusivity of water relative to fat. METHODS: A parameter study for point-resolved spectroscopy (PRESS) and STEAM using oil phantoms was performed and correlated with gas chromatography (GC). Simulations of muscle tissue signal behavior using DW-STEAM and long-echo time (TE) PRESS and a parameter optimization for DW-STEAM were conducted. DW-STEAM and long-TE PRESS were applied in the gastrocnemius muscles of nine healthy subjects. RESULTS: STEAM with TE and mixing time (TM) up to 45 ms exhibited R(2) correlations above 0.98 with GC and little T2 -weighting and J-modulation for the quantified olefinic/methylene peak ratio. The optimal parameters for muscle tissue using DW-STEAM were b-value = 1800 s/mm(2), TE = 33 ms, TM = 30 ms, and repetition time = 2300 ms. In vivo measured mean olefinic signal-to-noise ratios were 72 and 40, mean apparent olefinic water fractions were 0.19 and 0.11 for DW-STEAM and long-TE PRESS, respectively. CONCLUSION: Optimized DW-STEAM MR spectroscopy is superior to long-TE PRESS for measuring fat unsaturation, if a strong water peak prevents the olefinic fat signal's quantification at shorter TEs and water's tissue specific ADC is substantially higher than fat.
Authors: Christian Cordes; Thomas Baum; Michael Dieckmeyer; Stefan Ruschke; Maximilian N Diefenbach; Hans Hauner; Jan S Kirschke; Dimitrios C Karampinos Journal: Front Endocrinol (Lausanne) Date: 2016-06-27 Impact factor: 5.555
Authors: Dimitrios C Karampinos; Stefan Ruschke; Michael Dieckmeyer; Maximilian Diefenbach; Daniela Franz; Alexandra S Gersing; Roland Krug; Thomas Baum Journal: J Magn Reson Imaging Date: 2017-06-01 Impact factor: 4.813
Authors: Dominik Weidlich; Julius Honecker; Oliver Gmach; Mingming Wu; Rainer Burgkart; Stefan Ruschke; Daniela Franz; Bjoern H Menze; Thomas Skurk; Hans Hauner; Ulrich Kulozik; Dimitrios C Karampinos Journal: Magn Reson Med Date: 2019-01-16 Impact factor: 4.668