scholarly journals Short-term variability of proton density fat fraction in pancreas and liver assessed by multi-echo chemical-shift encoding-based MRI at 3 T

2021 ◽  
Author(s):  
Juergen Machann ◽  
Maytee Hasenbalg ◽  
Julia Dienes ◽  
Robert Wagner ◽  
Arvid Koehn ◽  
...  
Keyword(s):  
Chemical Shift ◽  
Control Group ◽  
Proton Density ◽  
High Fat ◽  
Medium Term ◽  
Short Term ◽  
Proton Density Fat Fraction ◽  
Fat Fraction ◽  
High Caloric Diet ◽  
Fat Meal

BACKGROUND Quantification of pancreatic fat (PF) and intrahepatic lipids (IHL) is of increasing interest in cross-sectional epidemiological and interventional studies in subjects at risk for metabolic diseases. Up to now, short- and medium-term variations as well as their dependence on actual nutritional status are almost unknown. PURPOSE or HYPOTHESIS To assess short-term intraday variations of PF/IHL after a high-fat meal as well as medium-term changes after 5 days of high-caloric diet with a 1500 kcal surplus on individual daily energy requirement. STUDY TYPE Prospective cohort study. SUBJECTS Twelve healthy subjects (6m/6f) for intraday variations, 15 healthy male subjects for medium-term high-caloric diet and 11 age- and BMI-matched controls. FIELDSTRENGTH/SEQUENCE 3 T whole-body imager (Magnetom Vida, Siemens Healthineers, Erlangen, Germany), assessment of proton density fat fraction by chemical-shift encoded MRI (multi-echo gradient echo sequence, qDixon). ASSESSMENT Manually drawn regions of interest in head, body and tail of pancreas as well as in liver by an experienced medical physicist carefully avoiding inclusion of surrounding visceral fat (pancreas) or blood-vessels (liver). STATISTICAL TESTS Repeated measurements Anova for variabilities of PF and IHL, linear correlation analyses for relation of PF, IHL and BMI. Significance level p < 0.05 for all. RESULTS (must have numerical data and statistical testing for each phrase) Non-significant changes in PF in both studies (2.5±0.9 vs. 2.5±1.0% after high-fat meal, 1.4±0.8 vs. 1.6±0.6% after high-caloric diet and 1.6±0.7 vs. 1.8±1.0% in the isocaloric control group), unchanged IHL after high-fat meal (2.5±0.9 vs. 2.4±1.0 %) and in the control group (1.1±0.6 vs. 1.2±1.1%), but significantly increased IHL after 5-day high-caloric diet (1.6±2.2% vs. 2.6±3.6%, p < 0.05). DATA CONCLUSION Daytime and nutritional status have no significant influence on ectopic fat depots in pancreas and liver and will therefore represent no major confounders in epidemiologic or clinical studies.

scholarly journals Temperature‐corrected proton density fat fraction estimation using chemical shift‐encoded MRI in phantoms

2021 ◽  
Vol 86 (1) ◽  
pp. 69-81 ◽  
Author(s):  
Ruvini Navaratna ◽  
Ruiyang Zhao ◽  
Timothy J. Colgan ◽  
Houchun Harry Hu ◽  
Mark Bydder ◽  
...  
Keyword(s):  
Chemical Shift ◽  
Proton Density ◽  
Proton Density Fat Fraction ◽  
Fat Fraction

scholarly journals Association of Thigh Muscle Strength with Texture Features Based on Proton Density Fat Fraction Maps Derived from Chemical Shift Encoding-Based Water–Fat MRI

Diagnostics ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 302
Author(s):  
Michael Dieckmeyer ◽  
Stephanie Inhuber ◽  
Sarah Schläger ◽  
Dominik Weidlich ◽  
Muthu R. K. Mookiah ◽  
...  
Keyword(s):  
Chemical Shift ◽  
Muscle Strength ◽  
Neuromuscular Disorders ◽  
Texture Features ◽  
Thigh Muscle ◽  
Proton Density ◽  
Proton Density Fat Fraction ◽  
Thigh Muscles ◽  
Fat Fraction ◽  
Flexion Strength

Purpose: Based on conventional and quantitative magnetic resonance imaging (MRI), texture analysis (TA) has shown encouraging results as a biomarker for tissue structure. Chemical shift encoding-based water–fat MRI (CSE-MRI)-derived proton density fat fraction (PDFF) of thigh muscles has been associated with musculoskeletal, metabolic, and neuromuscular disorders and was demonstrated to predict muscle strength. The purpose of this study was to investigate PDFF-based TA of thigh muscles as a predictor of thigh muscle strength in comparison to mean PDFF. Methods: 30 healthy subjects (age = 30 ± 6 years; 15 females) underwent CSE-MRI of the lumbar spine at 3T, using a six-echo 3D spoiled gradient echo sequence. Quadriceps (EXT) and ischiocrural (FLEX) muscles were segmented to extract mean PDFF and texture features. Muscle flexion and extension strength were measured with an isokinetic dynamometer. Results: Of the eleven extracted texture features, Variance(global) showed the highest significant correlation with extension strength (p < 0.001, R2adj = 0.712), and Correlation showed the highest significant correlation with flexion strength (p = 0.016, R2adj = 0.658). Multivariate linear regression models identified Variance(global) and sex, but not PDFF, as significant predictors of extension strength (R2adj = 0.709; p < 0.001), while mean PDFF, sex, and BMI, but none of the texture features, were identified as significant predictors of flexion strength (R2adj = 0.674; p < 0.001). Conclusions: Prediction of quadriceps muscle strength can be improved beyond mean PDFF by means of TA, indicating the capability to quantify muscular fat infiltration patterns.

scholarly journals Diurnal Variation of Proton Density Fat Fraction in the Liver Using Quantitative Chemical Shift Encoded MRI

2019 ◽  
Vol 51 (2) ◽  
pp. 407-414
Author(s):  
Timothy J. Colgan ◽  
Andrew J. Van Pay ◽  
Samir D. Sharma ◽  
Lu Mao ◽  
Scott B. Reeder
Keyword(s):  
Chemical Shift ◽  
Diurnal Variation ◽  
Proton Density ◽  
Proton Density Fat Fraction ◽  
Fat Fraction ◽  
Quantitative Chemical

scholarly journals Acceleration of chemical shift encoding-based water fat MRI for liver proton density fat fraction and T2* mapping using compressed sensing

2019 ◽  
Author(s):  
Fabian K. Lohöfer ◽  
Georgios A. Kaissis ◽  
Christina Müller-Leisse ◽  
Daniela Franz ◽  
Christoph Katemann ◽  
...  
Keyword(s):  
Chemical Shift ◽  
Compressed Sensing ◽  
T2 Mapping ◽  
Motion Artifacts ◽  
Acceleration Factor ◽  
Proton Density ◽  
List Type ◽  
Proton Density Fat Fraction ◽  
Fat Fraction ◽  
Total Acceleration

AbstractObjectivesTo 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.MethodsSix-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.ResultsTotal 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%).ConclusionCS+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 studyCompressed sensing allows accelerated imaging with reduction of motion artifacts without alteration of quantitative measurementsRobust results in fat and iron quantification in a heterogeneous patient cohortLimitations of this studyNo histopathological validation of the MR findings was performedThe study was not performed at different field strengths

scholarly journals Accuracy of common proton density fat fraction thresholds for magnitude- and complex-based chemical shift-encoded MRI for assessing hepatic steatosis in patients with obesity

2019 ◽  
Vol 45 (3) ◽  
pp. 661-671 ◽  
Author(s):  
Guilherme Moura Cunha ◽  
Tydus T. Thai ◽  
Gavin Hamilton ◽  
Yesenia Covarrubias ◽  
Alexandra Schlein ◽  
...  
Keyword(s):  
Chemical Shift ◽  
Hepatic Steatosis ◽  
Proton Density ◽  
Proton Density Fat Fraction ◽  
Fat Fraction

scholarly journals Texture Features of Proton Density Fat Fraction Maps from Chemical Shift Encoding-Based MRI Predict Paraspinal Muscle Strength

Diagnostics ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 239
Author(s):  
Michael Dieckmeyer ◽  
Stephanie Inhuber ◽  
Sarah Schlaeger ◽  
Dominik Weidlich ◽  
Muthu Rama Krishnan Mookiah ◽  
...  
Keyword(s):  
Chemical Shift ◽  
Muscle Strength ◽  
Texture Features ◽  
Paraspinal Muscle ◽  
Tissue Structure ◽  
Proton Density ◽  
Paraspinal Muscles ◽  
Proton Density Fat Fraction ◽  
Fat Fraction ◽  
Flexion Strength

Texture analysis (TA) has shown promise as a surrogate marker for tissue structure, based on conventional and quantitative MRI sequences. Chemical-shift-encoding-based MRI (CSE-MRI)-derived proton density fat fraction (PDFF) of paraspinal muscles has been associated with various medical conditions including lumbar back pain (LBP) and neuromuscular diseases (NMD). Its application has been shown to improve the prediction of paraspinal muscle strength beyond muscle volume. Since mean PDFF values do not fully reflect muscle tissue structure, the purpose of our study was to investigate PDFF-based TA of paraspinal muscles as a predictor of muscle strength, as compared to mean PDFF. We performed 3T-MRI of the lumbar spine in 26 healthy subjects (age = 30 ± 6 years; 15 females) using a six-echo 3D spoiled gradient echo sequence for chemical-shift-encoding-based water–fat separation. Erector spinae (ES) and psoas (PS) muscles were segmented bilaterally from level L2–L5 to extract mean PDFF and texture features. Muscle flexion and extension strength was measured with an isokinetic dynamometer. Out of the eleven texture features extracted for each muscle, Kurtosis(global) of ES showed the highest significant correlation (r = 0.59, p = 0.001) with extension strength and Variance(global) of PS showed the highest significant correlation (r = 0.63, p = 0.001) with flexion strength. Using multivariate linear regression models, Kurtosis(global) of ES and BMI were identified as significant predictors of extension strength (R2adj = 0.42; p < 0.001), and Variance(global) and Skewness(global) of PS were identified as significant predictors of flexion strength (R2adj = 0.59; p = 0.001), while mean PDFF was not identified as a significant predictor. TA of CSE-MRI-based PDFF maps improves the prediction of paraspinal muscle strength beyond mean PDFF, potentially reflecting the ability to quantify the pattern of muscular fat infiltration. In the future, this may help to improve the pathophysiological understanding, diagnosis, monitoring and treatment evaluation of diseases with paraspinal muscle involvement, e.g., NMD and LBP.

scholarly journals Feasibility of Hepatic Fat Quantification Using Proton Density Fat Fraction by Multi-Echo Chemical-Shift-Encoded MRI at 7T

2021 ◽  
Vol 9 ◽  
Author(s):  
Radim Kořínek ◽  
Lorenz Pfleger ◽  
Korbinian Eckstein ◽  
Hannes Beiglböck ◽  
Simon Daniel Robinson ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Chemical Shift ◽  
Phased Array ◽  
Liver Volume ◽  
Breath Hold ◽  
Proton Density ◽  
Gradient Echo ◽  
Alcoholic Fatty Liver ◽  
Proton Density Fat Fraction ◽  
Fat Fraction

Fat fraction quantification and assessment of its distribution in the hepatic tissue become more important with the growing epidemic of obesity, and the increasing prevalence of diabetes mellitus type 2 and non-alcoholic fatty liver disease. At 3Tesla, the multi-echo, chemical-shift-encoded magnetic resonance imaging (CSE-MRI)-based acquisition allows the measurement of proton density fat-fraction (PDFF) even in clinical protocols. Further improvements in SNR can be achieved by the use of phased array coils and increased static magnetic field. The purpose of the study is to evaluate the feasibility of PDFF imaging using a multi-echo CSE-MRI technique at ultra-high magnetic field (7Tesla). Thirteen volunteers (M/F) with a broad range of age, body mass index, and hepatic PDFF were measured at 3 and 7T by multi-gradient-echo MRI and single-voxel spectroscopy MRS. All measurements were performed in breath-hold (exhalation); the MRI protocols were optimized for a short measurement time, thus minimizing motion-related problems. 7T data were processed off-line using Matlab® (MRI:multi-gradient-echo) and jMRUI (MRS), respectively. For quantitative validation of the PDFF results, a similar protocol was performed at 3T, including on-line data processing provided by the system manufacturer, and correlation analyses between 7 and 3T data were performed off-line. The multi-echo CSE-MRI measurements at 7T with a phased-array coil configuration and an optimal post-processing yielded liver volume coverage ranging from 30 to 90% for high- and low-BMI subjects, respectively. PDFFs ranged between 1 and 20%. We found significant correlations between 7T MRI and -MRS measurements (R2 ≅ 0.97; p &lt; 0.005), and between MRI-PDFF at 7T and 3T fields (R2 ≅ 0.94; p &lt; 0.005) in the evaluated volumes. Based on the measurements and analyses performed, the multi-echo CSE-MRI method using a 32-channel coil at 7T showed its aptitude for MRI-based quantitation of PDFF in the investigated volumes. The results are the first step toward qMRI of the whole liver at 7T with further improvements in hardware.

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