Circulating triacylglycerols but not pancreatic fat associate with insulin secretion in healthy humans.
Nowotny Bettina,Kahl Sabine,Klüppelholz Birgit,Hoffmann Barbara,Giani Guido,Livingstone Roshan,Nowotny Peter J,Stamm Valerie,Herder Christian,Tura Andrea,Pacini Giovanni,Hwang Jong-Hee,Roden Michael
Metabolism: clinical and experimental
BACKGROUND:Loss of adequate insulin secretion for the prevailing insulin resistance is critical for the development of type 2 diabetes and has been suggested to result from circulating lipids (triacylglycerols [TG] or free fatty acids) and/or adipocytokines or from ectopic lipid storage in the pancreas. This study aimed to address whether circulating lipids, adipocytokines or pancreatic fat primarily associates with lower insulin secretion. SUBJECTS/METHODS:Nondiabetic persons (n=73), recruited from the general population, underwent clinical examinations, fasting blood drawing to measure TG and adipocytokines and oral glucose tolerance testing (OGTT) to assess basal and dynamic insulin secretion and sensitivity indices. Magnetic resonance imaging and H-magnetic resonance spectroscopy were used to measure body fat distribution and ectopic fat content in liver and pancreas. RESULTS:In age-, sex- and BMI-adjusted analyses, total and high-molecular-weight adiponectin were the strongest negative predictors of fasting beta-cell function (BCF; β=-0.403, p=0.0003 and β=-0.237, p=0.01, respectively) and adaptation index (AI; β=-0.210, p=0.006 and β=-0.133, p=0.02, respectively). Circulating TG, but not pancreatic fat content, related positively to BCF (β=0.375, p<0.0001) and AI (β=0.192, p=0.003). Similar results were obtained for the disposition index (DI). CONCLUSIONS:The association of serum lipids and adiponectin with beta-cell function may represent a compensatory response to adapt for lower insulin sensitivity in nondiabetic humans.
Predictors of ectopic fat accumulation in liver and pancreas in obese men and women.
Rossi Andrea P,Fantin Francesco,Zamboni Giulia A,Mazzali Gloria,Rinaldi Caterina A,Del Giglio Micol,Di Francesco Vincenzo,Barillari Marco,Pozzi Mucelli Roberto,Zamboni Mauro
Obesity (Silver Spring, Md.)
UNLABELLED:The aim of the present study was to determine the relationship between body fat distribution, adipocytokines, inflammatory markers, fat intake and ectopic fat content of liver and pancreas in obese men and women. A total of 12 lean subjects (mean age 47.25 ± 14.88 years and mean BMI 22.85 ± 2), 38 obese subjects (18 men and 20 women) with mean age 49.1 ± 13.0 years and mean BMI 34.96 ± 4.21 kg/m2 were studied. MEASUREMENTS:weight, height, BMI, waist circumference, as well as glucose, insulin, HOMA (homeostasis model assessment of insulin resistance), cholesterol, triglycerides, high-density lipoprotein cholesterol, high sensitivity C-reactive protein, daily energy intake, leptin, and adiponectin. Magnetic resonance was used to evaluate visceral, subcutaneous adipose tissue (SCAT) as well as liver and pancreas lipid content using in-phase and out-of-phase magnetic resonance imaging (MRI) sequence. Obese subjects had significantly higher weight, waist circumference, SCAT, deep SCAT, visceral adipose tissue (VAT), liver and pancreatic lipid content than lean subjects. Obese women had significantly lower VAT, liver and pancreas lipid content regardless of same BMI. In multiple regression analyses, the variance of liver lipid content explained by gender and VAT was 46%. When HOMA was added into a multiple regression, a small increase in the proportion of variance explained was observed. A 59.2% of the variance of pancreas lipid content was explained by gender and VAT. In conclusion, obese men show higher VAT and ectopic fat deposition in liver and pancreas than obese women despite same BMI. Independent of overall adiposity, insulin resistance, adiponectin and fat intake, VAT, measured with MRI, is the main predictor of ectopic fat deposition in both liver and pancreas.
Intra-pancreatic fat deposition as a modifier of the relationship between habitual dietary fat intake and insulin resistance.
Ko Juyeon,Skudder-Hill Loren,Tarrant Conor,Kimita Wandia,Bharmal Sakina H,Petrov Maxim S
Clinical nutrition (Edinburgh, Scotland)
BACKGROUND:Insulin resistance is a well-known derangement after an attack of pancreatitis but the role of dietary fat intake and intra-pancreatic fat deposition (IPFD) in it is unknown. We aimed to investigate the relationship of dietary fat intake with markers of insulin resistance in individuals after acute pancreatitis, taking into account IPFD. METHODS:This was a cross-sectional study. The EPIC-Norfolk food frequency questionnaire was used to determine the habitual intake of saturated, monounsaturated, polyunsaturated fatty acids. The studied markers of insulin resistance were fasting insulin, HOMA-IR, and METS-IR. 3 T magnetic resonance imaging was used to quantify IPFD. Linear regression analysis, with adjustment for possible confounders, was performed. RESULTS:A total of 111 individuals after acute pancreatitis (33 low IPFD, 40 moderate IPFD, and 38 high IPFD) were included. In the high IPFD group, intake of monounsaturated fatty acids was inversely associated with both fasting insulin, and HOMA-IR, and METS-IR in the unadjusted (β = -65.405, p < 0.001; β = -15.762, p < 0.001; β = -0.760, p = 0.041, respectively) and fully adjusted models (β = -155.620, p < 0.001; β = -34.656, p < 0.001, β = -2.008, p = 0.018, respectively). Intake of polyunsaturated or saturated fatty acids did not have a consistently significant pattern of associations with the three markers of insulin resistance. None of the above associations was significant in the low IPFD and moderate IPFD groups. CONCLUSIONS:Habitual dietary fat intake is associated with insulin resistance only in individuals after an attack of pancreatitis who have high IPFD. These indviduals may benefit from a calorically balanced diet that is rich in monounsaturated fatty acids.
MRI assessment of ectopic fat accumulation in pancreas, liver and skeletal muscle in patients with obesity, overweight and normal BMI in correlation with the presence of central obesity and metabolic syndrome.
Pieńkowska Joanna,Brzeska Beata,Kaszubowski Mariusz,Kozak Oliwia,Jankowska Anna,Szurowska Edyta
Diabetes, metabolic syndrome and obesity : targets and therapy
Obesity, defined as a body mass index (BMI) exceeding 30 kg/m, is a serious health problem, which can be called an epidemic on a global scale and is one of the most important causes of preventable death. The aim of this study was to assess ectopic fat accumulation in pancreas, liver and skeletal muscle in patients with obesity, overweight and normal BMI in correlation with metabolic syndrome (MetS). The study included 267 consecutive patients who underwent a standard clinical assessment with BMI calculation. Ectopic fat accumulation in pancreas, liver, and skeletal muscle was evaluated by magnetic resonance imaging (MRI) using fat-water separated Dixon imaging. MetS was defined according to the criteria modified by the National Cholesterol Education Program Adult Treatment Panel III Guidelines. Central obesity was defined using gender and ethnic-specific values for waist circumference. There was a statistically significant correlation between the degree of steatosis of the assessed organs and BMI value as well as waist circumference ratio, that determined the degree of central obesity. It was found that the most rapid relative fat accumulation was in muscle, then in pancreas and then in liver. Higher steatosis of pancreas, liver, and muscle was demonstrated depending on the number of the satisfied MetS criteria. Knowing that pancreatic fatty disease is a risk factor for MetS, it seems that assessment and monitoring of ectopic fat accumulation may have important clinical implications and may be used in the prediction of metabolic risk and its early prevention.
MRI chemical shift imaging of the fat content of the pancreas and liver of patients with type 2 diabetes mellitus.
Chai Jun,Liu Peng,Jin Erhu,Su Tianhao,Zhang Jie,Shi Kaining,Hong X U,Yin Jie,Yu Hengchi
Experimental and therapeutic medicine
The present study aimed to investigate the association between the content and distribution of fat in the pancreas and liver in patients with type 2 diabetes mellitus (T2DM). A total of 70 patients newly diagnosed with T2DM (T2DM group) and 30 healthy volunteers (normal control group) were enrolled in the present study. Dual-echo magnetic resonance (MR) chemical shift imaging was used to measure the fat content of the liver and the head, body and tail regions of the pancreas. In addition, the distribution of fat in the various regions of the pancreas, as well as the average fat content of the pancreas versus the liver, were compared. The fat content of the pancreatic head, body and tail regions of the T2DM group were 5.59±4.70, 4.80±3.75 and 4.89±3.86%, respectively. The fat content of these regions in the normal control group were 3.89±2.47, 3.30±2.11 and 3.23±2.23%, respectively. The average fat content of the pancreas was 5.19±3.75% for the T2DM group and 3.47±2.00% for the normal control group. The average fat content of the liver was 9.87±3.19% for the T2DM group and 7.24±2.38% for the normal control group. Therefore, the results from MR chemical shift imaging suggested that there were no significant differences in the distribution of fat between the pancreas of patients newly diagnosed with T2DM and that from the healthy population; however, the average fat content in the pancreas of the T2DM group was significantly higher (F=3.597; P<0.05), as compared with the normal control group. In addition, there was no correlation between the fat contents in the pancreas and liver in patients newly diagnosed with T2DM and the healthy population.
The Relationship between Abdominal Fat Phenotypes and Insulin Resistance in Non-Obese Individuals after Acute Pancreatitis.
Ko Juyeon,Skudder-Hill Loren,Cho Jaelim,Bharmal Sakina H,Petrov Maxim S
Both type 2 prediabetes/diabetes (T2DM) and new-onset prediabetes/diabetes after acute pancreatitis (NODAP) are characterized by impaired tissue sensitivity to insulin action. Although the outcomes of NODAP and T2DM are different, it is unknown whether drivers of insulin resistance are different in the two types of diabetes. This study aimed to investigate the associations between abdominal fat phenotypes and indices of insulin sensitivity in non-obese individuals with NODAP, T2DM, and healthy controls. Indices of insulin sensitivity (homeostasis model assessment of insulin sensitivity (HOMA-IS), Raynaud index, triglyceride and glucose (TyG) index, Matsuda index) were calculated in fasting and postprandial states. Fat phenotypes (intra-pancreatic fat, intra-hepatic fat, skeletal muscle fat, visceral fat, and subcutaneous fat) were determined using magnetic resonance imaging and spectroscopy. Linear regression and relative importance analyses were conducted. Age, sex, and glycated hemoglobin A1c were adjusted for. A total of 78 non-obese individuals (26 NODAP, 20 T2DM, and 32 healthy controls) were included. Intra-pancreatic fat was significantly associated with all the indices of insulin sensitivity in the NODAP group, consistently in both the unadjusted and adjusted models. Intra-pancreatic fat was not significantly associated with any index of insulin sensitivity in the T2DM and healthy controls groups. The variance in HOMA-IS was explained the most by intra-pancreatic fat (R = 29%) in the NODAP group and by visceral fat (R = 21%) in the T2DM group. The variance in the Raynaud index was explained the most by intra-pancreatic fat (R = 18%) in the NODAP group and by visceral fat (R = 15%) in the T2DM group. The variance in the TyG index was explained the most by visceral fat in both the NODAP group (R = 49%) and in the T2DM group (R = 25%). The variance in the Matsuda index was explained the most by intra-pancreatic fat (R = 48%) in the NODAP group and by visceral fat (R = 38%) in the T2DM group. The differing association between intra-pancreatic fat and insulin resistance can be used to differentiate NODAP from T2DM. Insulin resistance in NODAP appears to be predominantly driven by increased intra-pancreatic fat deposition.
Pancreatic Steatosis Is Associated With Impaired Exocrine Pancreatic Function.
Kromrey Marie-Luise,Friedrich Nele,Hoffmann Ralf-Thorsten,Bülow Robin,Völzke Henry,Weiss Frank U,Lerch Markus M,Motosugi Utaroh,Kühn Jens-Peter
OBJECTIVES:The aim of this study was to investigate if pancreatic steatosis measured by proton density fat fraction (PDFF) is associated with exocrine pancreatic function defined by fecal elastase concentrations. MATERIALS AND METHODS:A total of 1458 volunteers (777 women; age range, 21-88 years) underwent magnetic resonance imaging of the pancreas, and organ fat content was quantified by using confounder corrected PDFF. Exocrine pancreatic function was categorized by fecal elastase levels using defined cutoffs: greater than 200 μg/g normal function (n = 1319) and 200 μg/g or less impaired function (n = 139). Statistical analysis to correlate pancreatic fat content with fecal elastase included linear regression, and analyses were adjusted for known confounders for pancreatic steatosis, such as age, sex, and body mass index. RESULTS:Overall mean (±standard deviation) of pancreatic fat content was 7.50% ± 3.78%. Pancreatic fat content was significantly higher in subjects with impaired pancreatic exocrine function (9.36% ± 4.95%) compared with subjects with normal function (7.30% ± 3.59%; P < 0.01). Linear regression analyses showed an inverse correlation between pancreatic fat and fecal elastase levels over the whole study population (beta, -7.19 [standard error, 1.39]; P < 0.01) as well as in the subgroup of subjects with normal function (-4.26 [1.32]; P < 0.01). Among subjects with impaired pancreatic exocrine function, a trend toward an inverse relation was detected (-1.28 [0.84]; P < 0.13). CONCLUSIONS:An inverse correlation between PDFF of the pancreas and fecal elastase suggests an association between pancreatic steatosis and impaired pancreatic exocrine function.
Noninvasive fat quantification of the liver and pancreas may provide potential biomarkers of impaired glucose tolerance and type 2 diabetes.
Dong Zhi,Luo Yanji,Cai Huasong,Zhang Zhongwei,Peng Zhenpeng,Jiang Mengjie,Li Yanbing,Li Chang,Li Zi-Ping,Feng Shi-Ting
The aim of the study is to investigate if the fat content of the liver and pancreas may indicate impaired glucose tolerance (IGT) or type 2 diabetes mellitus (T2DM). A total of 83 subjects (34 men; aged 46.5 ± 13.5 years) were characterized as T2DM, IGT, or normal glucose tolerant (NGT). NGT individuals were stratified as <40 or ≥40 years. Standard laboratory tests were conducted for insulin resistance and β-cell dysfunction. The magnetic resonance imaging Dixon technique was used to determine fat distribution in the liver and pancreas. Correlations among liver and pancreatic fat volume fractions (LFVFs and PFVFs, respectively) and laboratory parameters were analyzed. Among the groups, fat distribution was consistent throughout sections of the liver and pancreas, and LFVFs closely correlated with PFVFs. LFVFs correlated more closely than PFVFs with insulin resistance and β-cell function. Both the LFVFs and PFVFs were the highest in the T2DM patients, less in the IGT, and least in the NGT; all differences were significant. The PFVFs of the NGT subjects ≥40 years were significantly higher than that of those <40 years. The fat content of the liver and pancreas, particularly the liver, may be a biomarker for IGT and T2DM.
Pancreatic fat content by magnetic resonance imaging in subjects with prediabetes, diabetes, and controls from a general population without cardiovascular disease.
Heber Sophia D,Hetterich Holger,Lorbeer Roberto,Bayerl Christian,Machann Jürgen,Auweter Sigrid,Storz Corinna,Schlett Christopher L,Nikolaou Konstantin,Reiser Maximilian,Peters Annette,Bamberg Fabian
BACKGROUND/OBJECTIVE:Despite the relevance of pancreatic fat content in the development of metabolic diseases, its association with impaired glucose metabolism, diabetes, and other adipose tissue compartments remains unclear. Thus, we determined differences in pancreatic fat content by magnetic resonance imaging (MRI) between subjects with prediabetes, diabetes, and normal controls in a cohort from the general population. METHODS:Subjects without history of cardiovascular disease with established diabetes or prediabetes as well as normal controls were included and underwent whole-body MRI on a 3T scanner. Pancreatic fat content was quantified by measuring the proton-density fat fraction (PDFFpanc) using a 3D multi-echo GRE sequence (increment: 1.23 ms, 6 echoes) by placing ROIs in the pancreatic head, body, and tail by independent readers. In addition, hepatic fat content as well as abdominal subcutaneous and visceral adipose tissue (SAT and VAT) were measured by multi-echo GRE and 3D 2-point volume-interpolated DIXON MRI, respectively. Univariate and multivariate analyses were employed to determine associations. RESULTS:A total of 385 subjects were included in the analysis (median age: 57 years, 58.2% males), of them 53 were classified as subjects with diabetes, 95 as prediabetes, and 237 as controls (13.8%, 24.7%, and 61.6%; respectively). The median PDFFpanc was 5.2% [IQR 3.3-9.4], and significantly higher in subjects with prediabetes and diabetes as compared to controls (PDFFpanc: 6.2% [IQR: 3.5-12] vs. 8.6% [IQR: 4.3-17.5] vs. 4.9% [3.1-7.4], p<0.001, respectively). After adjusting for age, gender and BMI the association was attenuated (all p>0.12). While in univariate analysis BMI, PDFFhepatic, SAT and VAT were associated with PDFFpanc (all p<0.05), only VAT predicted PDFFpanc independently (β: 0.02, 95%-confidence interval: 0.01-0.04, p<0.001). CONCLUSION:While pancreatic fat content differs significantly between subjects with prediabetes, diabetes and controls, this association may be confounded by age, gender, and the amount of VAT in this cross-sectional study.
Comprehensive analysis of body composition and insulin traits associated with intra-pancreatic fat deposition in healthy individuals and people with new-onset prediabetes/diabetes after acute pancreatitis.
Singh Ruma G,Nguyen Ngoc N,DeSouza Steve V,Pendharkar Sayali A,Petrov Maxim S
Diabetes, obesity & metabolism
Current knowledge of biomarkers of intra-pancreatic fat deposition (IFD) is limited. We aimed to analyse comprehensively body composition and insulin traits as biomarkers of IFD in healthy normoglycaemic individuals as well as in individuals with new-onset prediabetes or diabetes after acute pancreatitis (NODAP). A total of 29 healthy individuals and 34 individuals with NODAP took part in this cross-sectional study. The studied biomarkers belonged to the following domains: body composition (anthropometric and MRI-derived variables); indices of insulin secretion; indices of insulin sensitivity; incretins and related peptides; and pancreatitis-related factors. All MRI-derived variables (including IFD) were measured using ImageJ software. Univariate and step-wise regression analyses were conducted to determine variables that best explained variance in IFD. Visceral fat volume and oxyntomodulin were the best biomarkers of IFD in normoglycaemic healthy individuals, contributing to 64% variance. The Raynaud index was the best biomarker of IFD in individuals with NODAP, contributing to 20% variance. Longitudinal studies are warranted to investigate the cause and effect relationship between oxyntomodulin and IFD in healthy individuals, as well as insulin sensitivity and IFD in individuals with NODAP.
Pancreatic iron and fat assessment by MRI-R2* in patients with iron overload diseases.
Pfeifer Charlotte D,Schoennagel Bjoern P,Grosse Regine,Wang Zhiyue J,Graessner Joachim,Nielsen Peter,Adam Gerhard,Fischer Roland,Yamamura Jin
Journal of magnetic resonance imaging : JMRI
BACKGROUND:To determine the pancreatic iron (R2*) and fat content (FC) in comparison to hepatic and cardiac R2* in patients with iron overload disorders like β-thalassemia major (TM), Diamond-Blackfan anemia (DBA) or hereditary hemochromatosis. METHODS:R2* rates were assessed in the liver, heart and pancreas of 42 patients with TM, 29 subjects with other iron overload diseases, and 10 controls using an ECG-gated breathhold sequence (12 echo time [TE] = 1.3-25.7 ms, readout repetition time [TR] = 244 ms). Pancreatic R2* and FC were assessed from TE dependent region of interest based signal intensities performing water-fat chemical shift relaxometry and were compared with laboratory parameters (glucose, HbA1c, amylase and lipase). RESULTS:A pancreatic iron gradient from tail (R2* = 122 s(-1) ) to head (R2* = 114 s(-1) , P < 10(-4) ) was found. The close association between cardiac and pancreatic R2* was also confirmed in patients with TM and other iron overload diseases (rs = 0.64, P < 10(-4) ). Receiver operator characteristic analysis (area: 0.89, P < 10(-4) ) identified patients with elevated cardiac iron at a pancreatic R2* cut-off level of 131s(-1) (sensitivity = specificity at 81%). Highest pancreatic R2* (211s(-1) ) and FC (36%) were found in the tail region of diabetic patients with TM. CONCLUSION:Pancreatic tail showed highest R2* rates and fat contents, especially in patients with thalassemia. Besides iron accumulation fatty degeneration might be an additional risk factor for the development of diabetes in β-thalassemia major, but this hypothesis needs further studies in prediabetic patients.
Pancreatic fat content is associated with β-cell function and insulin resistance in Chinese type 2 diabetes subjects.
Lu Ting,Wang Yao,Dou Ting,Xue Bizhen,Tan Yuanyuan,Yang Jiao
The pathogenesis of type 2 diabetes mellitus (T2DM) is characterized by insulin resistance and β-cell dysfunction. Earlier studies reported that increased levels of pancreatic fat may lead to the development of β-cell dysfunction and insulin resistance. The present study aimed to demonstrate the relationship between pancreatic fat content (PFC) and insulin secretion and insulin resistance in Chinese subjects with T2DM. Seventy-eight T2DM subjects and 35 non-diabetic volunteers were recruited in this study. All subjects were subjected to an oral glucose tolerance test (OGTT). We also measured PFC and liver fat content (LFC) by three-point Dixon method (3p-Dixon), and we examined the relations between PFC and OGTT-derived parameters. T2DM subjects had higher PFC than non-diabetic subjects (p < 0.01). PFC was correlated with body mass index (BMI), liver fat content (LFC) and age in two groups, however, it was only positively associated with insulin secretion, insulin resistance, early- and late-phase insulin secretion in male T2DM subjects, but not in non-diabetic and female T2DM subjects. After adjusting for BMI, LFC and age, the association still existed (all p < 0.05). Furthermore, the relationship was more obvious in male T2DM subjects with a shorter course of disease. PFC was associated with β-cell dysfunction and insulin resistance in subjects with T2DM and was more obvious in male T2DM subjects with shorter duration of diabetes. Therefore, PFC might represent a potential risk factor for the development of T2DM.
Association of Pancreatic Steatosis With Chronic Pancreatitis, Obesity, and Type 2 Diabetes Mellitus.
Tirkes Temel,Jeon Christie Y,Li Liang,Joon Aron Y,Seltman Ted A,Sankar Meghana,Persohn Scott A,Territo Paul R
OBJECTIVE:The aim of this study was to determine the association of the pancreatic steatosis with obesity, chronic pancreatitis (CP), and type 2 diabetes mellitus. METHODS:Patients (n = 118) were retrospectively identified and categorized into no CP (n = 60), mild (n = 21), moderate (n = 27), and severe CP (n = 10) groups based on clinical history and magnetic resonance cholangiopancreatography using the Cambridge classification as the diagnostic standard. Visceral and subcutaneous compartments were manually segmented, and fat tissue was quantitatively measured on axial magnetic resonance imaging. RESULTS:Pancreatic fat fraction showed a direct correlation with fat within the visceral compartment (r = 0.54). Patients with CP showed higher visceral fat (P = 0.01) and pancreatic fat fraction (P < 0.001): mild, 24%; moderate, 23%; severe CP, 21%; no CP group, 15%. Patients with type 2 diabetes mellitus showed higher pancreatic steatosis (P = 0.03) and higher visceral (P = 0.007) and subcutaneous fat (P = 0.004). Interobserver variability of measuring fat by magnetic resonance imaging was excellent (r ≥ 0.90-0.99). CONCLUSIONS:Increased visceral adipose tissue has a moderate direct correlation with pancreatic fat fraction. Chronic pancreatitis is associated with higher pancreatic fat fraction and visceral fat. Type 2 diabetes mellitus is associated with higher pancreatic fat fraction and visceral and subcutaneous adiposity.
Quantification of pancreatic fat with dual-echo imaging at 3.0-T MR in clinical application: how do the corrections for T1 and T2* relaxation effect work and simplified correction strategy.
Yuan Fang,Song Bin,Huang Zixing,Xia Chunchao,Liu Xijiao
Acta radiologica (Stockholm, Sweden : 1987)
Background Dual-echo imaging is a routine clinical magnetic resonance (MR) sequence affected by T1 and T2* relaxation effect in fat quantification. The separate impacts of T1 and T2* relaxation effect in pancreatic fat quantification using dual-echo imaging at 3.0-T MR have not been reported in detail. Purpose To demonstrate the separate T1 and T2* relaxation effect on pancreatic fat quantification by dual-echo imaging at 3.0-T MR and the simplified correction strategy is discussed for convenient clinical application. Material and Methods Twenty-one non-alcoholic fatty liver disease (NAFLD) participants with high risk of pancreatic steatosis were included. Pancreatic fat fractions (FF) by dual-echo imaging with different corrections were compared to that of proton magnetic resonance spectroscopy (H-MRS). Correlation analysis and Bland-Altman analysis were applied. Results The FF by H-MRS was 5.9 ± 1.7%. Significant positive correlation (all P < 0.01) was found between FF by H-MRS and each dual-echo imaging, in which T1 and T2* correction showed the best correlation (r = 0.95, FF = 6.2 ± 1.7%) and no correction showed the worst correlation (r = 0.86, FF = 5.2 ± 2.0%), and the simplified T1 and T2* correction manifested as r = 0.93 and FF = 6.3 ± 1.8%. FF by T1 and T2* correction showed the best agreement, while T1 correction showed the worst agreement as compared to that of H-MRS. Conclusion T1 and T2* correction shows the best performance while no correction dual-echo imaging remains clinical available which may benefit from prior OP echo. Simplified correction using single T2* (32.6 ms) of water and fat is recommended for convenient clinical application in absence of obvious pancreatic iron overload.
Associations between intra-pancreatic fat deposition and circulating levels of cytokines.
Singh Ruma G,Nguyen Ngoc Nhu,Cervantes Aya,Alarcon Ramos Gisselle C,Cho Jaelim,Petrov Maxim S
While a plethora of studies have been conducted to investigate the associations between pro-inflammatory cytokines and obesity, the inter-relationship between pro-inflammatory cytokines and intra-pancreatic fat deposition (IPFD) has been poorly investigated. In the present study, circulating levels of C-C motif chemokine ligand 2 (CCL2), interleukin-6 (IL-6), leptin, and tumor necrosis factor-alpha (TNFα) were measured in 90 individuals after acute pancreatitis (AP) as well as 21 healthy non-obese individuals. Magnetic resonance imaging was used to quantify IPFD and visceral-to-subcutaneous fat volume ratio by two independent raters. Linear regression analyses were performed to investigate the associations between IPFD and each cytokine, adjusting for demographic, metabolic, and pancreatitis-related factors, as well as abdominal fat distribution. In healthy non-obese individuals, IPFD was not significantly associated with any of the studied cytokines in both the unadjusted and adjusted models. In individuals after AP, IPFD was significantly associated with leptin in the models adjusted for age and sex (β = 0.063 [95% confidence interval: 0.007, 0.119], P = 0.026); age, sex, visceral-to-subcutaneous fat volume ratio, glycated hemoglobin, and pancreatitis-related factors (β = 0.056 [95% confidence interval: 0.000, 0.111], P = 0.049). Also, IPFD was significantly associated with TNFα in the unadjusted model (β = 0.102 [95% confidence interval: 0.002, 0.202], P = 0.045) and the model adjusted for age, sex, visceral-to-subcutaneous fat volume ratio, glycated hemoglobin, and pancreatitis-related factors (β = 0.128 [95% confidence interval: 0.034, 0.223], P = 0.008). The associations between IPFD and IL-6, CCL2 were not statistically significant, in both the unadjusted and adjusted models. These findings indicate that leptin and TNFα are associated with IPFD independent of abdominal fat distribution and other covariates in individuals after AP. The role of IPFD in low-grade inflammation warrants further investigations.
Pancreatic Fat Is Associated With Metabolic Syndrome and Visceral Fat but Not Beta-Cell Function or Body Mass Index in Pediatric Obesity.
Staaf Johan,Labmayr Viktor,Paulmichl Katharina,Manell Hannes,Cen Jing,Ciba Iris,Dahlbom Marie,Roomp Kirsten,Anderwald Christian-Heinz,Meissnitzer Matthias,Schneider Reinhard,Forslund Anders,Widhalm Kurt,Bergquist Jonas,Ahlström Håkan,Bergsten Peter,Weghuber Daniel,Kullberg Joel
OBJECTIVE:Adolescents with obesity have increased risk of type 2 diabetes and metabolic syndrome (MetS). Pancreatic fat has been related to these conditions; however, little is known about associations in pediatric obesity. The present study was designed to explore these associations further. METHODS:We examined 116 subjects, 90 with obesity. Anthropometry, MetS, blood samples, and oral glucose tolerance tests were assessed using standard techniques. Pancreatic fat fraction (PFF) and other fat depots were quantified using magnetic resonance imaging. RESULTS:The PFF was elevated in subjects with obesity. No association between PFF and body mass index-standard deviation score (BMI-SDS) was found in the obesity subcohort. Pancreatic fat fraction correlated to Insulin Secretion Sensitivity Index-2 and Homeostatic Model Assessment of Insulin Resistance in simple regression; however, when using adjusted regression and correcting for BMI-SDS and other fat compartments, PFF correlated only to visceral adipose tissue and fasting glucose. Highest levels of PFF were found in subjects with obesity and MetS. CONCLUSIONS:In adolescents with obesity, PFF is elevated and associated to MetS, fasting glucose, and visceral adipose tissue but not to beta-cell function, glucose tolerance, or BMI-SDS. This study demonstrates that conclusions regarding PFF and its associations depend on the body mass features of the cohort.
Estimation of pancreatic R2* for iron overload assessment in the presence of fat: a comparison of different approaches.
Santarelli Maria Filomena,Meloni Antonella,De Marchi Daniele,Pistoia Laura,Quarta Antonella,Spasiano Anna,Landini Luigi,Pepe Alessia,Positano Vincenzo
Magma (New York, N.Y.)
OBJECTIVES:To propose a method for estimating pancreatic relaxation rate, R2*, from conventional multi-echo MRI, based on the nonlinear fitting of the acquired magnitude signal decay to MR signal models that take into account both the signal oscillations induced by fat and the different R2* values of pancreatic parenchyma and fat. MATERIALS AND METHODS:Single-peak fat (SPF) and multi-peak fat (MPF) models were introduced. Single-R2* and dual-R2* assumptions were considered as well. Analyses were conducted on simulated data and 20 thalassemia major patients. RESULTS:Simulations revealed the ability of the MPF model to correctly estimate the R2* value in a large range of fat fractions and R2* values. From the comparison between the results obtained with a single R2* value for water and fat and the dual-R2* approach, the latter is more accurate in both water R2* and fat fraction estimation. In patient's data analysis, a strong concordance was found between SPF and MPF estimated data with measurements done with manual signal correction and from fat-saturated images. The MPF method showed better reproducibility. CONCLUSION:The MPF dual-R2* approach improves reproducibility and reduces image analysis time in the assessment of pancreatic R2* value in patients with iron overload.
Pilot study on longitudinal change in pancreatic proton density fat fraction during a weight-loss surgery program in adults with obesity.
Covarrubias Yesenia,Fowler Kathryn J,Mamidipalli Adrija,Hamilton Gavin,Wolfson Tanya,Leinhard Olof Dahlqvist,Jacobsen Garth,Horgan Santiago,Schwimmer Jeffrey B,Reeder Scott B,Sirlin Claude B
Journal of magnetic resonance imaging : JMRI
BACKGROUND:Quantitative-chemical-shift-encoded (CSE)-MRI methods have been applied to the liver. The feasibility and potential utility CSE-MRI in monitoring changes in pancreatic proton density fat fraction (PDFF) have not yet been demonstrated. PURPOSE:To use quantitative CSE-MRI to estimate pancreatic fat changes during a weight-loss program in adults with severe obesity and nonalcoholic fatty liver disease (NAFLD). To explore the relationship of reduction in pancreatic PDFF with reductions in anthropometric indices. STUDY TYPE:Prospective/longitudinal. POPULATION:Nine adults with severe obesity and NAFLD enrolled in a weight-loss program. FIELD STRENGTH/SEQUENCE:CSE-MRI fat quantification techniques and multistation-volumetric fat/water separation techniques were performed at 3 T. ASSESSMENT:PDFF values were recorded from parametric maps colocalized across timepoints. STATISTICAL TESTS:Rates of change of log-transformed variables across time were determined (linear-regression), and their significance assessed compared with no change (Wilcoxon test). Rates of change were correlated pairwise (Spearman's correlation). RESULTS:Mean pancreatic PDFF decreased by 5.7% (range 0.7-17.7%) from 14.3 to 8.6%, hepatic PDFF by 11.4% (2.6-22.0%) from 14.8 to 3.4%, weight by 30.9 kg (17.3-64.2 kg) from 119.0 to 88.1 kg, body mass index by 11.0 kg/m (6.3-19.1 kg/m ) from 44.1 to 32.9 kg/m , waist circumference (WC) by 25.2 cm (4.0-41.0 cm) from 133.1 to 107.9 cm, HC by 23.5 cm (4.5-47.0 cm) from 135.8 to 112.3 cm, visceral adipose tissue (VAT) by 2.9 L (1.7-5.7 L) from 7.1 to 4.2 L, subcutaneous adipose tissue (SCAT) by 4.0 L (2.9-7.4 L) from 15.0 to 11.0 L. Log-transformed rate of change for pancreatic PDFF was moderately correlated with log-transformed rates for hepatic PDFF, VAT, SCAT, and WC (ρ = 0.5, 0.47, 0.45, and 0.48, respectively), although not statistically significant. DATA CONCLUSION:Changes in pancreatic PDFF can be estimated by quantitative CSE-MRI in adults undergoing a weight-loss surgery program. Pancreatic and hepatic PDFF and anthropometric indices decreased significantly. LEVEL OF EVIDENCE:2 Technical Efficacy Stage: 1 J. Magn. Reson. Imaging 2019;50:1092-1102.
Noninvasive assessment of abdominal adipose tissues and quantification of hepatic and pancreatic fat fractions in type 2 diabetes mellitus.
Sarma Manoj Kumar,Saucedo Andres,Darwin Christine Hema,Felker Ely Richard,Umachandran Kavya,Kohanghadosh Daniel,Xu Edward,Raman Steve,Thomas Michael Albert
Magnetic resonance imaging
The purpose of this study was to evaluate adipose tissue distributions and hepatic and pancreatic fat contents using a 6-point Dixon MRI technique in type 2 diabetes mellitus (T2DM), and to assess associations between fat distributions and biochemical markers of insulin resistance. Intra-abdominal MRI was investigated in 14 T2DM patients, 13 age- and sex-matched healthy controls (HC) and 11 young HC using a 3 T Prisma MRI scanner. All T2DM subjects completed a fasting comprehensive metabolic panel, and demographic measurements were taken according to standardized methodologies. We observed excellent correlation (R = 0.94) between hepatic fat fraction quantified using 6-point Dixon MRI and gold standard MRS, establishing the accuracy and reliability of the Dixon technique. Significantly increased visceral adipose tissue (VAT) volumes were found in T2DM patients compared to age-matched HC (1569.81 ± 670.62 cm vs. 1106.60 ± 566.85 cm, p = .04). We also observed a trend of increasing subcutaneous adipose tissues (SAT), and total abdominal fat (TAT) volumes in T2DM compared to age-matched HC. Hepatic fat fraction percentage (HFF%) was 44.6% higher in T2DM compared to age-matched HC and 64.4% higher compared to young HC. Pancreatic fat fractions in the head and body/tail were higher in T2DM patients compared to both healthy cohorts. We also observed correlations between fat contents of the liver and pancreas in T2DM patients, and association between biochemical markers of T2DM with HFF, indicating a risk for non-alcoholic fatty liver disease among T2DM. In summary, this study provides evidence of T2DM patients having increased liver and pancreatic fat, as well as increased adipose tissues.
Development of MR quantified pancreatic fat deposition as a cancer risk biomarker.
Coe Peter O,Williams Steve R,Morris David M,Parkin Ed,Harvie Michelle,Renehan Andrew G,O'Reilly Derek A
Pancreatology : official journal of the International Association of Pancreatology (IAP) ... [et al.]
BACKGROUND:Excess body adiposity is associated with increased risk of pancreatic cancer, and in animal models excess intra-pancreatic fat is a driver of pancreatic carcinogenesis. Within a programme to evaluate pancreatic fat and PC risk in humans, we assessed whether MR-quantified pancreatic fat fraction (PFF) was 'fit for purpose' as an imaging biomarker. METHODS:We determined PFF using MR spectroscopy (MRS) and MR chemical shift imaging (CS-MR), in two groups. In Group I, we determined accuracy of MR-derived PFF with histological digital fat quantification in 12 patients undergoing pancreatic resection. In a second study, we assessed reproducibility in 15 volunteers (Group IIa), and extended to 43 volunteers (Group IIa & IIb) to relate PFF with MR-derived hepatic fat fraction (HFF), body mass index (BMI), and waist circumference (WC) using linear regression models. We assessed intra- and inter-observer, and between imaging modality levels of agreement using Bland-Altman plots. RESULTS:In Group I patients, we found strong levels of agreement between MRS and CS-MR derived PFF and digitally quantified fat on histology (rho: 0.781 and 0.672 respectively). In Group IIa, there was poor reproducibility in initial assessments. We refined our protocols to account for 3D dimensionality of the pancreas, and found substantially improved intra-observer agreements. In Group II, HFF and WC were significantly correlated with PFF (p values < 0.05). INTERPRETATION:Both CS-MR and MRS (after accounting for pancreatic 3D dimensionality) were 'fit for purpose' to determine PFF and might add information on cancer prediction independent from measures of general body adiposity.
Fatty pancreas, insulin resistance, and β-cell function: a population study using fat-water magnetic resonance imaging.
Wong Vincent Wai-Sun,Wong Grace Lai-Hung,Yeung David Ka-Wai,Abrigo Jill M,Kong Alice Pik-Shan,Chan Ruth Suk-Mei,Chim Angel Mei-Ling,Shen Jiayun,Ho Chung-Shun,Woo Jean,Chu Winnie Chiu-Wing,Chan Henry Lik-Yuen
The American journal of gastroenterology
OBJECTIVES:Nonalcoholic fatty liver disease is the most common chronic liver disease. Fatty pancreas has also been described but is difficult to assess. It is now possible to measure pancreatic and liver fat accurately with magnetic resonance imaging (MRI). We aimed to define the normal range of pancreatic fat and identify factors associated with fatty pancreas. In addition, the effect of fatty liver and fatty pancreas on insulin resistance (IR) and pancreatic β-cell function was studied. METHODS:Fat-water MRI and proton-magnetic resonance spectroscopy were performed on 685 healthy volunteers from the general population to measure pancreatic and liver fat, respectively. On the basis of fasting plasma glucose and insulin levels, the IR and β-cell function were assessed using the homeostasis model assessment (HOMA). RESULTS:Among subjects without significant alcohol consumption or any component of metabolic syndrome, 90% had pancreatic fat between 1.8 and 10.4%. Using the upper limit of normal of 10.4%, 110 (16.1%; 95% confidence interval 13.3-18.8%) subjects had fatty pancreas. On multivariable analysis, high serum ferritin, central obesity, and hypertriglyceridemia were independent factors associated with fatty pancreas. Subjects with both fatty pancreas and fatty liver had higher HOMA-IR than did those with either condition alone. Fatty pancreas was not associated with HOMA-β after adjusting for liver fat and body mass index. CONCLUSIONS:In all, 16.1% of this community cohort of adult Hong Kong Chinese volunteers had a fatty pancreas by our definition. Central obesity, hypertriglyceridemia, and hyperferritinemia are associated with fatty pancreas. Individuals with fatty pancreas have increased IR.
Three-dimensional analysis of pancreatic fat by fat-water magnetic resonance imaging provides detailed characterization of pancreatic steatosis with improved reproducibility.
Kato Shingo,Iwasaki Akito,Kurita Yusuke,Arimoto Jun,Yamamoto Toh,Hasegawa Sho,Sato Takamitsu,Imajo Kento,Hosono Kunihiro,Kobayashi Noritoshi,Yoneda Masato,Higurashi Takuma,Kubota Kensuke,Utsunomiya Daisuke,Nakajima Atsushi
BACKGROUND:Since pancreatic steatosis is reported as a possible risk factor for pancreatic cancer, the development of a non-invasive method to quantify pancreatic steatosis is needed. Proton density fat fraction (PDFF) measurement is a magnetic resonance imaging (MRI) based method for quantitatively assessing the steatosis of a region of interest (ROI). Although it is commonly used for quantification of hepatic steatosis, pancreatic PDFF can greatly vary depending on the ROI's location because of the patchy nature of pancreatic fat accumulation. In this study, we attempted to quantify pancreatic steatosis by fat-water MRI with improved reproducibility. METHODS:Using the MRI images of 159 patients with nonalcoholic fatty liver disease, we attempted to calculate the average PDFF of whole pancreas. We set ROIs covering the entire area of the pancreas appearing in every slice and calculated the average PDFF from all the voxels included in the pancreas. We named this average value as whole-pancreatic PDFF and evaluated the reproducibility of the measured values. In addition to whole-pancreatic PDFF, we measured the average PDFF of the pancreatic head (head-PDFF) and that of the pancreatic body plus tail separately and analyzed their correlation with the clinical characteristics of the patients. RESULTS:The mean inter-examiner coefficient of variation of the whole-pancreatic PDFF was 11.39%. The whole-pancreatic PDFF was correlated with age (p = 0.039), body mass index (p = 0.0093) and presence/absence of diabetes (p = 0.0055). The serum level of low-density lipoprotein cholesterol was inversely correlated with the head-PDFF. CONCLUSION:We developed a new measurement method of the pancreatic PDFF with greater reproducibility. Using this method, we characterized pancreatic steatosis in detail. This novel measurement method allows accurate estimation of the severity of pancreatic steatosis and is therefore useful for the detailed characterization of pancreatic steatosis.
Pancreas volume and fat fraction in children with Type 1 diabetes.
Regnell S E,Peterson P,Trinh L,Broberg P,Leander P,Lernmark Å,Månsson S,Elding Larsson H
Diabetic medicine : a journal of the British Diabetic Association
AIMS:People with Type 1 diabetes have smaller pancreases than healthy individuals. Several diseases causing pancreatic atrophy are associated with pancreatic steatosis, but pancreatic fat in Type 1 diabetes has not been measured. This cross-sectional study aimed to compare pancreas size and fat fraction in children with Type 1 diabetes and controls. METHODS:The volume and fat fraction of the pancreases of 22 children with Type 1 diabetes and 29 controls were determined using magnetic resonance imaging. RESULTS:Pancreas volume was 27% smaller in children with diabetes (median 34.9 cm(3) ) than in controls (47.8 cm(3) ; P < 0.001). Pancreas volume correlated positively with age in controls (P = 0.033), but not in children with diabetes (P = 0.649). Pancreas volume did not correlate with diabetes duration, but it did correlate positively with units of insulin/kg body weight/day (P = 0.048). A linear model of pancreas volume as influenced by age, body surface area and insulin units/kg body weight/day found that insulin dosage correlated with pancreas volume after controlling for both age and body surface area (P = 0.009). Pancreatic fat fraction was not significantly different between the two groups (1.34% vs. 1.57%; P = 0.891). CONCLUSIONS:Our findings do not indicate that pancreatic atrophy in Type 1 diabetes is associated with an increased pancreatic fat fraction, unlike some other diseases featuring reduced pancreatic volume. We speculate that our results may support the hypotheses that much of pancreatic atrophy in Type 1 diabetes occurs before the clinical onset of the disease and that exogenous insulin administration decelerates pancreatic atrophy after diabetes onset.
Effects of aging and menopause on pancreatic fat fraction in healthy women population: A strobe-compliant article.
Yang Wenjuan,Xie Yi,Song Bin,Xia Chunchao,Tang Chengwei,Li Jing
Pancreatic fat fraction has been shown to increase in many pathological situations. However, pancreatic fat fraction and its physiological changes in healthy women are still unclear. The aim of this study is to investigate the effect of aging and menopause on pancreatic fat fraction in healthy female population.This was a cross-sectional study. A phantom of fat-water mixtures was established. One hundred sixty-seven healthy women (20-70 years) were recruited. Fat fraction was quantified with double-echo chemical shift magnetic resonance imaging with T1 and T2* correction. The association between measured and actual fat fractions was determined with Pearson correlation. Linear regression analysis was used to establish the calibration curve. Fat fractions were analyzed via analysis of variance.A significant positive linear correlation was revealed between the measured and actual fat fractions on the phantom (r = 0.991, P < .001). There was no significant difference in fat fractions among caput, corpus, and cauda of the pancreas. Pancreatic fat fraction remained constant during the age of 20 to 40 years (4.41 ± 0.79%) but significantly increased during the ages of 41 to 50 and 51 to 70 years (7.49 ± 1.10% and 9.43 ± 1.51%, respectively, P < .001). Moreover, pancreatic fat fractions of the healthy women aged 41 to 70 years were still significantly higher than these in the groups aged 20 to 40 years when postmenopausal healthy women were removed (P < .001). For volunteers aged 46 to 49 years, pancreatic fat fraction of the postmenopausal women was significantly increased compared with that of their premenopausal counterparts (P < .001).We found that an even distribution of pancreatic fat in healthy women, aging and menopause as 2 independent risk factors for pancreatic steatosis, a fatty infiltration in the pancreas beginning in the fifth decade in women.
Association of pancreatic fat content with type II diabetes mellitus.
Nadarajah C,Fananapazir G,Cui E,Gichoya J,Thayalan N,Asare-Sawiri M,Menias C O,Sandrasegaran K
AIM:To determine the association between regional fat content in the pancreas and the presence or absence of type II diabetes mellitus (T2DM), the value of regional pancreatic fat quantification in identifying patients at risk of T2DM, and whether pancreatic fat content is associated with glycaemic control in T2DM. MATERIALS AND METHODS:A retrospective survey of a radiology database identified 45 patients with T2DM, and 81 "at risk for T2DM" patients who developed diabetes, between 0.6 and 3.7 years after magnetic resonance imaging (MRI). A control group who did not develop diabetes during a 5-year follow-up and without known metabolic syndrome, liver, or pancreatic diseases were also identified. Fat content was measured by placing regions of interest (ROIs) on in-phase and out-of-phase chemical shift MRI images. Multiple clinical parameters including body mass index, cholesterol levels, blood pressure, glycated haemoglobin (HbA1c; in T2DM group) were collected. RESULTS:There was a significant difference between the T2DM and control groups for fat fraction in the pancreatic head (p=0.043), body (p=0.015), and tail (p=0.001), but not liver (p=0.107). On regression analysis, only the fat fraction within the pancreatic tail was significantly different between control group and "at risk" for T2DM group (p=0.007). A pancreatic tail fat content of >10% had a sensitivity of 45.5% and specificity of 81.3% for predicting development of T2DM within 4 years. Pancreatic fat content was not associated with glycaemic control. CONCLUSIONS:Increased fat in the pancreatic tail may identify patients at risk for T2DM.
The Plasma Metabolomic Profile is Differently Associated with Liver Fat, Visceral Adipose Tissue, and Pancreatic Fat.
Lind Lars,Salihovic Samira,Risérus Ulf,Kullberg Joel,Johansson Lars,Ahlström Håkan,Eriksson Jan W,Oscarsson Jan
The Journal of clinical endocrinology and metabolism
CONTEXT:Metabolic differences between ectopic fat depots may provide novel insights to obesity-related diseases. OBJECTIVE:To investigate the plasma metabolomic profiles in relation to visceral adipose tissue (VAT) volume and liver and pancreas fat percentages. DESIGN:Cross-sectional. SETTING:Multicenter at academic research laboratories. PATIENTS:Magnetic resonance imaging (MRI) was used to assess VAT volume, the percentage of fat in the liver and pancreas (proton density fat fraction [PDFF]) at baseline in 310 individuals with a body mass index ≥ 25 kg/m2 and with serum triglycerides ≥ 1.7 mmol/l and/or type 2 diabetes screened for inclusion in the 2 effect of omega-3 carboxylic acid on liver fat content studies. INTERVENTION:None. MAIN OUTCOME MEASURE:Metabolomic profiling with mass spectroscopy enabled the determination of 1063 plasma metabolites. RESULTS:Thirty metabolites were associated with VAT volume, 31 with liver PDFF, and 2 with pancreas PDFF when adjusting for age, sex, total body fat mass, and fasting glucose. Liver PDFF and VAT shared 4 metabolites, while the 2 metabolites related to pancreas PDFF were unique. The top metabolites associated with liver PDFF were palmitoyl-palmitoleoyl-GPC (16:0/16:1), dihydrosphingomyelin (d18:0/22:0), and betaine. The addition of these metabolites to the Liver Fat Score improved C-statistics significantly (from 0.776 to 0.861, P = 0.0004), regarding discrimination of liver steatosis. CONCLUSION:Liver PDFF and VAT adipose tissue shared several metabolic associations, while those were not shared with pancreatic PDFF, indicating partly distinct metabolic profiles associated with different ectopic fat depots. The addition of 3 metabolites to the Liver Fat Score improved the prediction of liver steatosis.
Correlation between incidental fat deposition in the liver and pancreas in asymptomatic individuals.
Aliyari Ghasabeh Mounes,Shaghaghi Mohammadreza,Khoshpouri Pegah,Pan Li,Pandy Ankur,Pandy Pallavi,Zhong Xiaodong,Kannengiesser Stephan,Kamel Ihab R
Abdominal radiology (New York)
PURPOSE:To explore the utility of two different fat quantification methods in the liver and pancreas and to test the accuracy of multi-echo Dixon as a single sequence in detecting early stage of fat deposition. METHODS:58 healthy potential liver donors underwent abdominal 3T MRI, prospectively. Single-voxel MR Spectroscopy (MRS), dual-echo Dixon, and multi-echo Dixon were performed. Two independent readers obtained proton density fat fraction (PDFF) of the liver and pancreas by placing ROIs on the 2 Dixon sequences. Correlation between the two PDFF measurements was assessed in the liver and pancreas. Values in the liver were also compared to those obtained by MRS. RESULTS:PDFF in the liver was 6.3 ± 4.2%, 5.5 ± 3.9%, and 5.1 ± 4.1% by MRS, dual-echo Dixon, and multi-echo Dixon, respectively. Dual-echo Dixon and multi-echo Dixon showed good correlation in PDFF quantification of the liver (r = 0.82, p < 0.0005). Multi-echo Dixon showed a good correlation (r = 0.72, p = 0.0005) between the fat measured in the liver and in the pancreas. To differentiate between normal (PDFF ≤ 6%) and mild fat deposition (PDFF: 6-33%) in the liver, analysis showed sensitivity, specificity, and accuracy of 74%, 81%, and 80% for dual-echo Dixon and 85%, 96%, and 89% for multi-echo Dixon, respectively. Mean PDFF in the pancreas was 7.2 ± 2.8% and 6.7 ± 3.3%, by dual-echo and multi-echo Dixon, respectively. Dual-echo Dixon and multi-echo Dixon showed good correlation in PDFF quantification of the pancreas (r = 0.58, p < 0.0005). CONCLUSION:Multi-echo Dixon in liver has high accuracy in distinguishing between subjects with normal liver fat and those with mildly elevated liver fat. Multi-echo Dixon can be used to screen for early fat deposition in the liver and pancreas.