The Experts below are selected from a list of 36204 Experts worldwide ranked by ideXlab platform
Rickmer Braren - One of the best experts on this subject based on the ideXlab platform.
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Acceleration of chemical shift encoding based water fat mri for liver proton density fat fraction and t2 mapping using compressed sensing
PLOS ONE, 2019Co-Authors: Fabian Lohofer, Georgios Kaissis, Christina Mullerleisse, Daniela Franz, Christoph Katemann, A Hock, Johannes M Peeters, Ernst J Rummeny, Dimitrios C Karampinos, Rickmer BrarenAbstract:Objectives To evaluate proton density fat fraction (PDFF) and T2* measurements of the liver with combined parallel imaging (sensitivity encoding, SENSE) and compressed sensing (CS) accelerated chemical shift encoding-based water-fat separation. Methods Six-echo Dixon imaging was performed in the liver of 89 subjects. The first acquisition variant used Acceleration based on SENSE with a total Acceleration Factor equal to 2.64 (acquisition labeled as SENSE). The second acquisition variant used Acceleration based on a combination of CS with SENSE with a total Acceleration Factor equal to 4 (acquisition labeled as CS+SENSE). Acquisition times were compared between acquisitions and proton density fat fraction (PDFF) and T2*-values were measured and compared separately for each liver segment. Results Total scan duration was 14.5 sec for the SENSE accelerated image acquisition and 9.3 sec for the CS+SENSE accelerated image acquisition. PDFF and T2* values did not differ significantly between the two acquisitions (paired Mann-Whitney and paired t-test P>0.05 in all cases). CS+SENSE accelerated acquisition showed reduced motion artifacts (1.1%) compared to SENSE acquisition (12.3%). Conclusion CS+SENSE accelerates liver PDFF and T2*mapping while retaining the same quantitative values as an acquisition using only SENSE and reduces motion artifacts.
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Acceleration of chemical shift encoding based water fat mri for liver proton density fat fraction and t2 mapping using compressed sensing
medRxiv, 2019Co-Authors: Fabian Lohofer, Georgios Kaissis, Christina Mullerleisse, Daniela Franz, Christoph Katemann, A Hock, Johannes M Peeters, Ernst J Rummeny, Dimitrios C Karampinos, Rickmer BrarenAbstract:Abstract Objectives To evaluate proton density fat fraction (PDFF) and T2* measurements of the liver with combined parallel imaging (sensitivity encoding, SENSE) and compressed sensing (CS) accelerated chemical shift encoding-based water-fat separation. Methods Six-echo Dixon imaging was performed in the liver of 89 subjects. The first acquisition variant used Acceleration based on SENSE with a total Acceleration Factor equal to 2.64 (acquisition labeled as SENSE). The second acquisition variant used Acceleration based on a combination of CS with SENSE with a total Acceleration Factor equal to 4 (acquisition labeled as CS+SENSE). Acquisition times were compared between acquisitions and proton density fat fraction (PDFF) and T2*-values were measured and compared separately for each liver segment. Results Total scan duration was 14.5 sec for the SENSE accelerated image acquisition and 9.3 sec for the CS+SENSE accelerated image acquisition. PDFF and T2* values did not differ significantly between the two acquisitions (paired Mann-Whitney and paired t-test P>0.05 in all cases). CS+SENSE accelerated acquisition showed reduced motion artifacts (1.1%) compared to SENSE acquisition (12.3%). Conclusion CS+SENSE accelerates liver PDFF and T2*mapping while retaining the same quantitative values as an acquisition using only SENSE and reduces motion artifacts. Strengths of this study Compressed sensing allows accelerated imaging with reduction of motion artifacts without alteration of quantitative measurements Robust results in fat and iron quantification in a heterogeneous patient cohort Limitations of this study No histopathological validation of the MR findings was performed The study was not performed at different field strengths
José P. Marques - One of the best experts on this subject based on the ideXlab platform.
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Optimizing the Acceleration and resolution of three-dimensional fat image navigators for high-resolution motion correction at 7T
Magnetic Resonance in Medicine, 2017Co-Authors: Daniel Gallichan, José P. MarquesAbstract:PURPOSE To investigate the effect of spatial resolution and parallel imaging Acceleration Factor on the quality of the motion estimates derived from image navigators with a three-dimensional (3D) gradient-recalled echo (GRE) acquisition with fat excitation (3D FatNavs) for neuroimaging at 7T. METHODS Six healthy subjects were scanned for 10 min, during which time repeated GRE volumes were acquired during small movements-alternating between fat and water excitations (WaterNavs)-allowing retrospective decimation of the data to simulate a variety of combinations of image resolution and Acceleration Factor. Bias and error in the motion estimates were then compared across navigator parameters. RESULTS The 2-mm, 4 × 4 accelerated data (TRvolume = 1.2 s) provided motion estimates that were almost indistinguishable from those from the full original acquisition (2 mm, 2 × 2, TRvolume = 5.2 s). For faster navigators, it was found that good accuracy and precision were achievable with TRvolume = 144 ms, using a lower spatial resolution (4 mm, 6 × 6 Acceleration) to avoid the bias observed at exceptionally high Acceleration Factors (8 × 8 or higher). Parameter estimates from WaterNavs and FatNavs showed close agreement with FatNavs, with better performance at exceptionally high Acceleration Factors. CONCLUSION Our data help to guide the parameter choice for 3D FatNavs when a compromise must be reached between the quality of the motion estimates and the available scan time. Magn Reson Med, 2016. © 2016 Wiley Periodicals, Inc.
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Optimizing the Acceleration and resolution of three-dimensional fat image navigators for high-resolution motion correction at 7T
Magnetic resonance in medicine, 2016Co-Authors: Daniel Gallichan, José P. MarquesAbstract:PURPOSE: To investigate the effect of spatial resolution and parallel imaging Acceleration Factor on the quality of the motion estimates derived from image navigators with a three-dimensional (3D) gradient-recalled echo (GRE) acquisition with fat excitation (3D FatNavs) for neuroimaging at 7T. METHODS: Six healthy subjects were scanned for 10 min, during which time repeated GRE volumes were acquired during small movements-alternating between fat and water excitations (WaterNavs)-allowing retrospective decimation of the data to simulate a variety of combinations of image resolution and Acceleration Factor. Bias and error in the motion estimates were then compared across navigator parameters. RESULTS: The 2-mm, 4 x 4 accelerated data (TRvolume = 1.2 s) provided motion estimates that were almost indistinguishable from those from the full original acquisition (2 mm, 2 x 2, TRvolume = 5.2 s). For faster navigators, it was found that good accuracy and precision were achievable with TRvolume = 144 ms, using a lower spatial resolution (4 mm, 6 x 6 Acceleration) to avoid the bias observed at exceptionally high Acceleration Factors (8 x 8 or higher). Parameter estimates from WaterNavs and FatNavs showed close agreement with FatNavs, with better performance at exceptionally high Acceleration Factors. CONCLUSION: Our data help to guide the parameter choice for 3D FatNavs when a compromise must be reached between the quality of the motion estimates and the available scan time.
Fabian Lohofer - One of the best experts on this subject based on the ideXlab platform.
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Acceleration of chemical shift encoding based water fat mri for liver proton density fat fraction and t2 mapping using compressed sensing
PLOS ONE, 2019Co-Authors: Fabian Lohofer, Georgios Kaissis, Christina Mullerleisse, Daniela Franz, Christoph Katemann, A Hock, Johannes M Peeters, Ernst J Rummeny, Dimitrios C Karampinos, Rickmer BrarenAbstract:Objectives To evaluate proton density fat fraction (PDFF) and T2* measurements of the liver with combined parallel imaging (sensitivity encoding, SENSE) and compressed sensing (CS) accelerated chemical shift encoding-based water-fat separation. Methods Six-echo Dixon imaging was performed in the liver of 89 subjects. The first acquisition variant used Acceleration based on SENSE with a total Acceleration Factor equal to 2.64 (acquisition labeled as SENSE). The second acquisition variant used Acceleration based on a combination of CS with SENSE with a total Acceleration Factor equal to 4 (acquisition labeled as CS+SENSE). Acquisition times were compared between acquisitions and proton density fat fraction (PDFF) and T2*-values were measured and compared separately for each liver segment. Results Total scan duration was 14.5 sec for the SENSE accelerated image acquisition and 9.3 sec for the CS+SENSE accelerated image acquisition. PDFF and T2* values did not differ significantly between the two acquisitions (paired Mann-Whitney and paired t-test P>0.05 in all cases). CS+SENSE accelerated acquisition showed reduced motion artifacts (1.1%) compared to SENSE acquisition (12.3%). Conclusion CS+SENSE accelerates liver PDFF and T2*mapping while retaining the same quantitative values as an acquisition using only SENSE and reduces motion artifacts.
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Acceleration of chemical shift encoding based water fat mri for liver proton density fat fraction and t2 mapping using compressed sensing
medRxiv, 2019Co-Authors: Fabian Lohofer, Georgios Kaissis, Christina Mullerleisse, Daniela Franz, Christoph Katemann, A Hock, Johannes M Peeters, Ernst J Rummeny, Dimitrios C Karampinos, Rickmer BrarenAbstract:Abstract Objectives To evaluate proton density fat fraction (PDFF) and T2* measurements of the liver with combined parallel imaging (sensitivity encoding, SENSE) and compressed sensing (CS) accelerated chemical shift encoding-based water-fat separation. Methods Six-echo Dixon imaging was performed in the liver of 89 subjects. The first acquisition variant used Acceleration based on SENSE with a total Acceleration Factor equal to 2.64 (acquisition labeled as SENSE). The second acquisition variant used Acceleration based on a combination of CS with SENSE with a total Acceleration Factor equal to 4 (acquisition labeled as CS+SENSE). Acquisition times were compared between acquisitions and proton density fat fraction (PDFF) and T2*-values were measured and compared separately for each liver segment. Results Total scan duration was 14.5 sec for the SENSE accelerated image acquisition and 9.3 sec for the CS+SENSE accelerated image acquisition. PDFF and T2* values did not differ significantly between the two acquisitions (paired Mann-Whitney and paired t-test P>0.05 in all cases). CS+SENSE accelerated acquisition showed reduced motion artifacts (1.1%) compared to SENSE acquisition (12.3%). Conclusion CS+SENSE accelerates liver PDFF and T2*mapping while retaining the same quantitative values as an acquisition using only SENSE and reduces motion artifacts. Strengths of this study Compressed sensing allows accelerated imaging with reduction of motion artifacts without alteration of quantitative measurements Robust results in fat and iron quantification in a heterogeneous patient cohort Limitations of this study No histopathological validation of the MR findings was performed The study was not performed at different field strengths
Daniel Gallichan - One of the best experts on this subject based on the ideXlab platform.
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Optimizing the Acceleration and resolution of three-dimensional fat image navigators for high-resolution motion correction at 7T
Magnetic Resonance in Medicine, 2017Co-Authors: Daniel Gallichan, José P. MarquesAbstract:PURPOSE To investigate the effect of spatial resolution and parallel imaging Acceleration Factor on the quality of the motion estimates derived from image navigators with a three-dimensional (3D) gradient-recalled echo (GRE) acquisition with fat excitation (3D FatNavs) for neuroimaging at 7T. METHODS Six healthy subjects were scanned for 10 min, during which time repeated GRE volumes were acquired during small movements-alternating between fat and water excitations (WaterNavs)-allowing retrospective decimation of the data to simulate a variety of combinations of image resolution and Acceleration Factor. Bias and error in the motion estimates were then compared across navigator parameters. RESULTS The 2-mm, 4 × 4 accelerated data (TRvolume = 1.2 s) provided motion estimates that were almost indistinguishable from those from the full original acquisition (2 mm, 2 × 2, TRvolume = 5.2 s). For faster navigators, it was found that good accuracy and precision were achievable with TRvolume = 144 ms, using a lower spatial resolution (4 mm, 6 × 6 Acceleration) to avoid the bias observed at exceptionally high Acceleration Factors (8 × 8 or higher). Parameter estimates from WaterNavs and FatNavs showed close agreement with FatNavs, with better performance at exceptionally high Acceleration Factors. CONCLUSION Our data help to guide the parameter choice for 3D FatNavs when a compromise must be reached between the quality of the motion estimates and the available scan time. Magn Reson Med, 2016. © 2016 Wiley Periodicals, Inc.
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Optimizing the Acceleration and resolution of three-dimensional fat image navigators for high-resolution motion correction at 7T
Magnetic resonance in medicine, 2016Co-Authors: Daniel Gallichan, José P. MarquesAbstract:PURPOSE: To investigate the effect of spatial resolution and parallel imaging Acceleration Factor on the quality of the motion estimates derived from image navigators with a three-dimensional (3D) gradient-recalled echo (GRE) acquisition with fat excitation (3D FatNavs) for neuroimaging at 7T. METHODS: Six healthy subjects were scanned for 10 min, during which time repeated GRE volumes were acquired during small movements-alternating between fat and water excitations (WaterNavs)-allowing retrospective decimation of the data to simulate a variety of combinations of image resolution and Acceleration Factor. Bias and error in the motion estimates were then compared across navigator parameters. RESULTS: The 2-mm, 4 x 4 accelerated data (TRvolume = 1.2 s) provided motion estimates that were almost indistinguishable from those from the full original acquisition (2 mm, 2 x 2, TRvolume = 5.2 s). For faster navigators, it was found that good accuracy and precision were achievable with TRvolume = 144 ms, using a lower spatial resolution (4 mm, 6 x 6 Acceleration) to avoid the bias observed at exceptionally high Acceleration Factors (8 x 8 or higher). Parameter estimates from WaterNavs and FatNavs showed close agreement with FatNavs, with better performance at exceptionally high Acceleration Factors. CONCLUSION: Our data help to guide the parameter choice for 3D FatNavs when a compromise must be reached between the quality of the motion estimates and the available scan time.
A Hock - One of the best experts on this subject based on the ideXlab platform.
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Acceleration of chemical shift encoding based water fat mri for liver proton density fat fraction and t2 mapping using compressed sensing
PLOS ONE, 2019Co-Authors: Fabian Lohofer, Georgios Kaissis, Christina Mullerleisse, Daniela Franz, Christoph Katemann, A Hock, Johannes M Peeters, Ernst J Rummeny, Dimitrios C Karampinos, Rickmer BrarenAbstract:Objectives To evaluate proton density fat fraction (PDFF) and T2* measurements of the liver with combined parallel imaging (sensitivity encoding, SENSE) and compressed sensing (CS) accelerated chemical shift encoding-based water-fat separation. Methods Six-echo Dixon imaging was performed in the liver of 89 subjects. The first acquisition variant used Acceleration based on SENSE with a total Acceleration Factor equal to 2.64 (acquisition labeled as SENSE). The second acquisition variant used Acceleration based on a combination of CS with SENSE with a total Acceleration Factor equal to 4 (acquisition labeled as CS+SENSE). Acquisition times were compared between acquisitions and proton density fat fraction (PDFF) and T2*-values were measured and compared separately for each liver segment. Results Total scan duration was 14.5 sec for the SENSE accelerated image acquisition and 9.3 sec for the CS+SENSE accelerated image acquisition. PDFF and T2* values did not differ significantly between the two acquisitions (paired Mann-Whitney and paired t-test P>0.05 in all cases). CS+SENSE accelerated acquisition showed reduced motion artifacts (1.1%) compared to SENSE acquisition (12.3%). Conclusion CS+SENSE accelerates liver PDFF and T2*mapping while retaining the same quantitative values as an acquisition using only SENSE and reduces motion artifacts.
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Acceleration of chemical shift encoding based water fat mri for liver proton density fat fraction and t2 mapping using compressed sensing
medRxiv, 2019Co-Authors: Fabian Lohofer, Georgios Kaissis, Christina Mullerleisse, Daniela Franz, Christoph Katemann, A Hock, Johannes M Peeters, Ernst J Rummeny, Dimitrios C Karampinos, Rickmer BrarenAbstract:Abstract Objectives To evaluate proton density fat fraction (PDFF) and T2* measurements of the liver with combined parallel imaging (sensitivity encoding, SENSE) and compressed sensing (CS) accelerated chemical shift encoding-based water-fat separation. Methods Six-echo Dixon imaging was performed in the liver of 89 subjects. The first acquisition variant used Acceleration based on SENSE with a total Acceleration Factor equal to 2.64 (acquisition labeled as SENSE). The second acquisition variant used Acceleration based on a combination of CS with SENSE with a total Acceleration Factor equal to 4 (acquisition labeled as CS+SENSE). Acquisition times were compared between acquisitions and proton density fat fraction (PDFF) and T2*-values were measured and compared separately for each liver segment. Results Total scan duration was 14.5 sec for the SENSE accelerated image acquisition and 9.3 sec for the CS+SENSE accelerated image acquisition. PDFF and T2* values did not differ significantly between the two acquisitions (paired Mann-Whitney and paired t-test P>0.05 in all cases). CS+SENSE accelerated acquisition showed reduced motion artifacts (1.1%) compared to SENSE acquisition (12.3%). Conclusion CS+SENSE accelerates liver PDFF and T2*mapping while retaining the same quantitative values as an acquisition using only SENSE and reduces motion artifacts. Strengths of this study Compressed sensing allows accelerated imaging with reduction of motion artifacts without alteration of quantitative measurements Robust results in fat and iron quantification in a heterogeneous patient cohort Limitations of this study No histopathological validation of the MR findings was performed The study was not performed at different field strengths
