Three-dimensional analysis of pancreatic fat by fat-water magnetic resonance imaging provides detailed characterization of pancreatic steatosis with improved reproducibility

Pancreatic volume, fat content and T1 relaxation time using magnetic resonance imaging in patients with prior gestational diabetes mellitus

PURPOSE

To compare the volume, fat content, and T1 relaxation time of the pancreas in participants with and without prior gestational diabetes mellitus (GDM).

METHODS

In this prospective case-control study, we enrolled 29 women with prior GDM, and divided them into three groups (normoglycemic, prediabetic, and diabetic) based on their glycaemic status in the postpartum period; and a group of 13 participants as controls who had normoglycemia during pregnancy. Participants underwent MR examination including an axial multi-echo DIXON-based sequence and an axial-oblique T1 mapping sequence. The average proton density fat fraction (PDFF) and T1 value of the pancreas were measured by drawing multiple circular regions of interest (ROIs). Average hepatic PDFF was similarly calculated. Pancreatic volume was computed by summating cleaned freehand ROIs outlining pancreatic parenchyma.

RESULTS

Women were evaluated at a mean age of 32.9 ± 4.0 years and with a mean BMI of 25.2 ± 2.9 kg/m2. The median (IQR) duration of follow-up after childbirth was 24 (34-44) months. In controls, the pancreatic PDFF, T1 value, and volume were 5.4 ± 2.3%, 850.6 ± 101.6 ms, and 69.3 ± 16.2 cm³, respectively, while in subjects with a history of GDM, these values were 4.7 ± 2.0%, 844.6 ± 91.8 ms, and 69.8 ± 16.6 cm³, respectively. No statistical differences were observed (all p > 0.05). Mean hepatic PDFF was significantly higher in the diabetic and prediabetic groups (12.2 ± 6.4% and 11.0 ± 7.6% respectively) than in the control and normoglycemic groups (7.9 ± 7.3 and 4.7 ± 1.6% respectively; p -0.01).

CONCLUSION

We did not find any significant changes in pancreatic volume, fat content, or fibrosis in women with prior GDM and with different glycaemic categories when evaluated in the early postpartum period, compared to the control group. These findings may be a consequence of the transient state of insulin resistance in GDM and the finite duration of the disease course in new-onset prediabetes and diabetes patients.

Fatty Pancreas: Its Potential as a Risk Factor for Pancreatic Cancer and Clinical Implications

With the increasing use of imaging modalities such as ultrasonography, computed tomography, and magnetic resonance imaging, incidental findings of pancreatic abnormalities, including pancreatic cysts and fatty pancreas (FP), have become more common. FP, also referred to as pancreatic steatosis, intra-pancreatic fat deposition, or fatty pancreas disease, is characterized by the accumulation of fat in the pancreas. Although FP has been associated with metabolic syndromes such as obesity and diabetes, its clinical significance remains unclear. Recent evidence suggests that FP may play a role in pancreatic carcinogenesis. Metabolic disorders, including obesity, insulin resistance, and diabetes, have been implicated in the development of FP. Additionally, FP has been linked to an increased risk of pancreatic ductal adenocarcinoma (PDAC), possibly due to chronic inflammation, lipotoxicity, and an altered pancreatic microenvironment. While early detection of PDAC remains challenging, surveillance strategies for high-risk individuals, such as those with pancreatic cysts, new-onset diabetes, or a genetic predisposition, may be crucial. In this context, FP may be incorporated into this surveillance of high-risk individuals. Some pharmacological interventions, including glucagon-like peptide-1 (GLP-1) receptor agonists and sodium-glucose cotransporter-2 (SGLT2) inhibitors, have shown potential in reducing pancreatic fat accumulation, although further studies are needed to confirm their efficacy.

Prevalence, clinical characteristics, and outcomes of fatty pancreas disease: an updated systematic review and meta-analysis

Fatty pancreas disease (FPD) is a condition characterized by diffuse excessive intrapancreatic fat deposition with relevant metabolic implications but often overlooked by healthcare professionals. Our study aims to provide a comprehensive overview of the prevalence, clinical characteristics, and outcomes of FPD. PubMed and Embase databases were searched from inception to 10 April 2024. Pairwise meta-analysis was performed using the DerSimonian-Laird method. Meta-analysis of proportions was conducted using the inverse-variance method with logit transformation. Between-study heterogeneity was examined, with subsequent subgroup and meta-regression analyses, and publication bias was assessed. Eighteen studies with 111 682 individuals were included in this meta-analysis. The overall prevalence of FPD was 21.11% [95% confidence interval (CI): 11.04-36.58]. Diagnostic method influenced FPD prevalence ( P  < 0.01), with pooled prevalences of 17.53% (95% CI: 16.20-18.95), 30.05% (95% CI: 24.14-36.70), and 21.23% (95% CI: 8.52-43.88) for MRI, computed tomography, and transabdominal ultrasound, respectively. Patients with FPD were more likely to be older, have higher BMI, male, and have metabolic dysfunction. They also had an increased risk of metabolic syndrome, endocrine-related outcomes (i.e. diabetes and glycemic progression), and exocrine-related outcomes (i.e. acute pancreatitis and pancreatic cancer) compared with those without FPD. This study summarizes the epidemiology of FPD and highlights its clinical and prognostic significance. Increased multidisciplinary collaboration is needed to improve understanding of the disease and raise awareness among healthcare professionals. This study was a priori registered in International Prospective Register of Systematic Reviews (PROSPERO) (CRD42024514116).

Gender-specific correlations between serum lipid profiles and intra-pancreatic fat deposition: a cross-sectional study

BACKGROUND

Intra-pancreatic fat deposition (IPFD) is linked to metabolic and pancreatic diseases. MRI, while precise, is not cost-effective for routine IPFD screening, highlighting the need for accessible biomarkers. This study aims to analyze the relationships among serum lipid profiles, lipoprotein ratios, and IPFD, with a focus on sex differences.

METHODS

Data from adults at the Affiliated Hospital of Guizhou Medical University between 2018 and 2019 were analyzed. The subjects underwent routine Siemens 64-slice spiral CT scans, and IPFD was quantified via a quantitative computed tomography post-processing station. Lipid panel components were analyzed in the fasted state. Linear regression models stratified by gender were applied to evaluate these associations.

RESULTS

The study included 1,046 participants after exclusions, with significant sex differences found in the correlations between serum lipids, lipoprotein ratios, and IPFD. In females, remnant cholesterol was strongly associated with total IPFD (R2 = 0.155, P < 0.001), and similarly strong correlations existed with fat deposition in the pancreatic head (R2 = 0.124, P = 0.003), body (R2 = 0.102, P = 0.001), and tail (R2 = 0.146, P = 0.005). Total cholesterol was also positively correlated with IPFD in females, particularly with the total IPFD (R2 = 0.145, P = 0.002) and IPFD in the pancreatic head (R2 = 0.177, P = 0.003) and body (R2 = 0.100, P = 0.001). In males, triglycerides were notably correlated with IPFD in the tail (R2 = 0.200, P = 0.045), but not in other regions. Similarly, total cholesterol was correlated with IPFD in the tail (R2 = 0.197, P = 0.041). Additionally, in males, the triglyceride/high-density lipoprotein cholesterol ratio showed a positive association with tail fat deposition (R2 = 0.200, P = 0.033).

CONCLUSION

Significant differences between genders were evident in the correlations of serum lipids and lipoprotein ratios with IPFD. In women, remnant cholesterol was strongly correlated with IPFD, suggesting its potential as a biomarker.

Non-invasive diagnosis of pancreatic steatosis with ultrasound images using deep learning network

Objective

This study aimed to verify whether pancreatic steatosis (PS) is an independent risk factor for type 2 diabetes mellitus (T2DM). We also developed and validated a deep learning model for the diagnosis of PS using ultrasonography (US) images based on histological classifications.

Methods

In this retrospective study, we analysed data from 139 patients who underwent US imaging of the pancreas followed by pancreatic resection at our medical institution. Logistic regression analysis was employed to ascertain the independent predictors of T2DM. The diagnostic efficacy of the deep learning model for PS was assessed using receiver operating characteristic curve analysis and compared with traditional visual assessment methodology in US imaging.

Results

The incidence rate of PS in the study cohort was 64.7 %. Logistic regression analysis revealed that age (P = 0.003) and the presence of PS (P = 0.048) were independent factors associated with T2DM. The deep learning model demonstrated robust diagnostic capabilities for PS, with areas under the curve of 0.901 and 0.837, sensitivities of 0.895 and 0.920, specificities of 0.700 and 0.765, accuracies of 0.814 and 0.857, and F1-scores of 0.850 and 0.885 for the training and validation cohorts, respectively. These metrics significantly outperformed those of conventional US imaging (P < 0.001 and P = 0.045, respectively).

Conclusion

The deep learning model significantly enhanced the diagnostic accuracy of conventional ultrasound for PS detection. Its high sensitivity could facilitate widespread screening for PS in large populations, aiding in the early identification of individuals at an elevated risk for T2DM in routine clinical practice.

Non-alcoholic fatty pancreas disease: an updated review

Ectopic accumulation of fat can cause a variety of metabolic diseases, and the emerging non-alcoholic fatty pancreas disease (NAFPD) is increasingly being recognized by clinicians as a cause for concern. NAFPD is a disease caused by abnormal accumulation of adipose tissue in the pancreas, which is related to obesity. The main feature of NAFPD is death of acinar cells, which are then replaced by adipose cells. However, the underlying molecular mechanisms have not been fully explored. Obesity, aging, and metabolic syndrome are independent risk factors for the occurrence and development of NAFPD. Studies have shown that NAFPD leads to insulin resistance and pancreatic dysfunction, increases the risk of diabetes mellitus, worsens the severity of pancreatitis, and is significantly correlated with pancreatic cancer and postoperative pancreatic fistula. There is no standard treatment for NAFPD; exercise, a balanced diet, and lifestyle can help reduce pancreatic fat; however, other treatment modalities such as drugs and bariatric surgery are still being explored. The specific pathological mechanism of NAFPD remains unclear, and its potential association with various clinical diseases requires further study. This review summarizes the etiology, diagnosis, clinical consequences, and potential therapeutic strategies of NAFPD.

Development and Validation of Four Different Methods to Improve MRI-CEST Tumor pH Mapping in Presence of Fat

CEST-MRI is an emerging imaging technique suitable for various in vivo applications, including the quantification of tumor acidosis. Traditionally, CEST contrast is calculated by asymmetry analysis, but the presence of fat signals leads to wrong contrast quantification and hence to inaccurate pH measurements. In this study, we investigated four post-processing approaches to overcome fat signal influences and enable correct CEST contrast calculations and tumor pH measurements using iopamidol. The proposed methods involve replacing the Z-spectrum region affected by fat peaks by (i) using a linear interpolation of the fat frequencies, (ii) applying water pool Lorentzian fitting, (iii) considering only the positive part of the Z-spectrum, or (iv) calculating a correction factor for the ratiometric value. In vitro and in vivo studies demonstrated the possibility of using these approaches to calculate CEST contrast and then to measure tumor pH, even in the presence of moderate to high fat fraction values. However, only the method based on the water pool Lorentzian fitting produced highly accurate results in terms of pH measurement in tumor-bearing mice with low and high fat contents.

Intrapancreatic fat deposition is unrelated to liver steatosis in metabolic dysfunction-associated steatotic liver disease

Background & Aims

Individuals with obesity may develop intrapancreatic fat deposition (IPFD) and fatty pancreas disease (FPD). Whether this causes inflammation and fibrosis and leads to pancreatic dysfunction is less established than for liver damage in metabolic dysfunction-associated steatotic liver disease (MASLD). Moreover, the interrelations of FPD and MASLD are poorly understood. Therefore, we aimed to assess IPFD and fibro-inflammation in relation to pancreatic function and liver disease severity in individuals with MASLD.

Methods

Seventy-six participants from the Amsterdam MASLD-MASH cohort (ANCHOR) study underwent liver biopsy and multiparametric MRI of the liver and pancreas, consisting of proton-density fat fraction sequences, T1 mapping and intravoxel incoherent motion diffusion-weighted imaging (IVIM-DWI).

Results

The prevalence of FPD was 37.3%. There was a clear correlation between pancreatic T1 relaxation time, which indicates fibro-inflammation, and parameters of glycemic dysregulation, namely HbA1c (R = 0.59; p <0.001), fasting glucose (R = 0.51; p <0.001) and the presence of type 2 diabetes (mean 802.0 ms vs. 733.6 ms; p <0.05). In contrast, there was no relation between IPFD and hepatic fat content (R = 0.03; p = 0.80). Pancreatic IVIM diffusion (IVIM-D) was lower in advanced liver fibrosis (p <0.05) and pancreatic perfusion (IVIM-f), reflecting vessel density, inversely correlated to histological MASLD activity (p <0.05).

Conclusions

Consistent relations exist between pancreatic fibro-inflammation on MRI and endocrine function in individuals with MASLD. However, despite shared dysmetabolic drivers, our study suggests IPFD is a separate pathophysiological process from MASLD.

Impact and implications

Metabolic dysfunction-associated steatotic liver disease (MASLD) is the most common chronic liver disease worldwide and 68% of people with type 2 diabetes have MASLD. However, fat infiltration and inflammation in the pancreas are understudied in individuals with MASLD. In this cross-sectional MRI study, we found no relationship between fat accumulation in the pancreas and liver in a cohort of patients with MASLD. However, our results show that inflammatory and fibrotic processes in the pancreas may be interrelated to features of type 2 diabetes and to the severity of liver disease in patients with MASLD. Overall, the results suggest that pancreatic endocrine dysfunction in individuals with MASLD may be more related to glucotoxicity than to lipotoxicity.

Clinical trial number

NTR7191 (Dutch Trial Register).

Pancreatic steatosis and metabolic pancreatic disease: a new entity?

Overweight and obesity are some of the most important health challenges. Many diseases are related to these metabolic disorders, and, among them, the pancreatic fat accumulation, also called "pancreatic steatosis" or "nonalcoholic fatty pancreas", seems to have an emerging role in different conditions. There are different method to evaluate the fat content in the pancreas, such as histology, different imaging techniques and endoscopic ultrasound, but there is no gold standard for the correct diagnosis and for the identification of "inter/intralobular" and "intra-acinar" pancreatic fat. However, the fat storage in the pancreas is linked to chronic inflammation and to several conditions, such as acute and chronic pancreatitis, type 2 diabetes mellitus and pancreatic cancer. In addition, pancreatic fat accumulation has also been demonstrated to play a role in surgical outcome after pancreatectomy, in particular for the development of postoperative pancreatic fistula. Different possible therapeutic approaches have been proposed, but there is still a lack of evidence. The aim of this review is to report the current evidence about the relationship between the obesity, the pancreatic fat accumulation and its potential role in pancreatic diseases.

Artificial intelligence assisted whole organ pancreatic fat estimation on magnetic resonance imaging and correlation with pancreas attenuation on computed tomography

BACKGROUND

Fatty pancreas is associated with inflammatory and neoplastic pancreatic diseases. Magnetic resonance imaging (MRI) is the diagnostic modality of choice for measuring pancreatic fat. Measurements typically use regions of interest limited by sampling and variability. We have previously described an artificial intelligence (AI)-aided approach for whole pancreas fat estimation on computed tomography (CT). In this study, we aimed to assess the correlation between whole pancreas MRI proton-density fat fraction (MR-PDFF) and CT attenuation.

METHODS

We identified patients without pancreatic disease who underwent both MRI and CT between January 1, 2015 and June 1, 2020. 158 paired MRI and CT scans were available for pancreas segmentation using an iteratively trained convolutional neural network (CNN) with manual correction. Boxplots were generated to visualize slice-by-slice variability in 2D-axial slice MR-PDFF. Correlation between whole pancreas MR-PDFF and age, BMI, hepatic fat and pancreas CT-Hounsfield Unit (CT-HU) was assessed.

RESULTS

Mean pancreatic MR-PDFF showed a strong inverse correlation (Spearman -0.755) with mean CT-HU. MR-PDFF was higher in males (25.22 vs 20.87; p = 0.0015) and in subjects with diabetes mellitus (25.95 vs 22.17; p = 0.0324), and was positively correlated with age and BMI. The pancreatic 2D-axial slice-to-slice MR-PDFF variability increased with increasing mean whole pancreas MR-PDFF (Spearman 0.51; p < 0.0001).

CONCLUSION

Our study demonstrates a strong inverse correlation between whole pancreas MR-PDFF and CT-HU, indicating that both imaging modalities can be used to assess pancreatic fat. 2D-axial pancreas MR-PDFF is variable across slices, underscoring the need for AI-aided whole-organ measurements for objective and reproducible estimation of pancreatic fat.

Associations Between Hepatic and Pancreatic Steatosis with Lumbar Spinal Bone Marrow Fat: A Single-Center Magnetic Resonance Imaging Study

BACKGROUND

To evaluate the associations between hepatic, pancreatic steatosis, and lumbar spinal bone marrow fat determined by magnetic resonance imaging-proton density fat fraction in patients with no known or suspected liver disease.

METHODS

A total of 200 patients who were referred to our radiology department for upper abdominal magnetic resonance imaging between November 2015 and November 2017 were included in this study. All patients underwent a magnetic resonance imaging-proton density fat fraction on a 1.5-T magnetic resonance imaging system.

RESULTS

The mean liver, pancreas, and lumbar magnetic resonance imaging-proton density fat fraction were 7.52 ± 4.82%, 5.25 ± 5.44%, and 46.85 ± 10.38% in the study population. There were significant correlations between liver and pancreas (rs = 0.180, P = .036), liver and lumbar (rs = 0.317, P < .001), and pancreas and lumbar magnetic resonance imaging-proton density fat fraction (rs = 0.215, P = .012) in female patients. A weak correlation was observed between liver and lumbar magnetic resonance imaging-proton density fat fraction (rs = 0.174, P = .014) in the total population. The prevalence of hepatic and pancreatic steatosis was 42.5% and 29%, respectively. The prevalence of pancreatic steatosis (42.9% vs. 22.8%, P = .004) was higher in male patients compared to female patients. In subgroup analysis, in patients with hepatic steatosis, there were higher pancreas magnetic resonance imaging-proton density fat fraction (6.07 ± 6.42% vs. 4.66 ± 4.53%, P = .036) and lumbar magnetic resonance imaging-proton density fat fraction (48.81 ± 10.01% vs. 45.40 ± 10.46%, P =.029) compared to patients without hepatic steatosis. In patients with pancreatic steatosis, there were higher liver (9.07 ± 6.08 vs. 6.87 ± 4.06, P = .009) and lumbar magnetic resonance imaging-proton density fat fraction (49.31 ± 9.13% vs.45.83 ± 10.76%, P = .032) in comparison with patients without pancreatic steatosis.

CONCLUSION

Based on the results of the present study, fat accumulation in liver, pancreas, and lumbar vertebra have associations with more evident in females.

Using Free-Breathing MRI to Quantify Pancreatic Fat and Investigate Spatial Heterogeneity in Children

BACKGROUND

MRI acquisition for pediatric pancreatic fat quantification is limited by breath-holds (BH). Full segmentation (FS) or small region of interest (ROI) analysis methods may not account for pancreatic fat spatial heterogeneity, which may limit accuracy.

PURPOSE

To improve MRI acquisition and analysis for quantifying pancreatic proton-density fat fraction (pPDFF) in children by investigating free-breathing (FB)-MRI, characterizing pPDFF spatial heterogeneity, and relating pPDFF to clinical markers.

STUDY TYPE

Prospective.

POPULATION

A total of 34 children, including healthy (N = 16, 8 female) and overweight (N = 18, 5 female) subjects.

FIELD STRENGTH AND SEQUENCES

3 T; multiecho gradient-echo three-dimensional (3D) stack-of-stars FB-MRI, multiecho gradient-echo 3D Cartesian BH-MRI.

ASSESSMENT

A radiologist measured FS- and ROI-based pPDFF on FB-MRI and BH-MRI PDFF maps, with anatomical images as references. Regional pPDFF in the pancreatic head, body, and tail were measured on FB-MRI. FS-pPDFF, ROI-pPDFF, and regional pPDFF were compared, and related to clinical markers, including hemoglobin A1c.

STATISTICAL TESTS

T-test, Bland-Altman analysis, Lin's concordance correlation coefficient (CCC), one-way analysis of variance, and Spearman's rank correlation coefficient were used. P < 0.05 was considered significant.

RESULTS

FS-pPDFF and ROI-pPDFF from FB-MRI and BH-MRI had mean difference = 0.4%; CCC was 0.95 for FS-pPDFF and 0.62 for ROI-pPDFF. FS-pPDFF was higher than ROI-pPDFF (10.4% ± 6.4% vs. 4.2% ± 2.8%). Tail-pPDFF (11.6% ± 8.1%) was higher than body-pPDFF (8.9% ± 6.3%) and head-pPDFF (8.7% ± 5.2%). Head-pPDFF and body-pPDFF positively correlated with hemoglobin A1c.

DATA CONCLUSION

FB-MRI pPDFF is comparable to BH-MRI. Spatial heterogeneity affects pPDFF quantification. Regional measurements of pPDFF in the head and body were correlated with hemoglobin A1c, a marker of insulin sensitivity.

EVIDENCE LEVEL

2 TECHNICAL EFFICACY: Stage 2.

Automated Measurement of Pancreatic Fat Deposition on Dixon MRI Using nnU-Net

BACKGROUND

Pancreatic fat accumulation may cause or aggravate the process of acute pancreatitis, β-cell dysfunction, T2DM disease, and even be associated with pancreatic tumors. The pathophysiology of fatty pancreas remains overlooked and lacks effective imaging diagnostics.

PURPOSE

To automatically measure the distribution of pancreatic fat deposition on Dixon MRI in multicenter/population datasets using nnU-Net models.

STUDY TYPE

Retrospective.

POPULATION

A total of 176 obese/nonobese subjects (90 males, 86 females; mean age, 27.2 ± 19.7) were enrolled, including a training set (N = 132) and a testing set (N = 44).

FIELD STRENGTH/SEQUENCE

A 3 T and 1.5 T/gradient echo T₁ dual-echo Dixon.

ASSESSMENT

The segmentation results of four types of nnU-Net models were compared using dice similarity coefficient (DSC), positive predicted value (PPV), and sensitivity. The ground truth was the manual delineation by two radiologists according to in-phase (IP) and opposed-phase (OP) images.

STATISTICAL TESTS

The group difference of segmentation results of four models were assessed by the Kruskal-Wallis H test with Dunn-Bonferroni comparisons. The interobserver agreement of pancreatic fat fraction measurements across three observers and test-retest reliability of human and machine were assessed by intragroup correlation coefficient (ICC). P < 0.05 was considered statistically significant.

RESULTS

The three-dimensional (3D) dual-contrast model had significantly improved performance than 2D dual-contrast (DSC/sensitivity) and 3D one-contrast (IP) models (DSC/PPV/sensitivity) and had less errors than 3D one-contrast (OP) model according to higher DSC and PPV (not significant), with a mean DSC of 0.9158, PPV of 0.9105 and sensitivity of 0.9232 in the testing set. The test-retest ICC of this model was above 0.900 in all pancreatic regions, exceeded human.

DATA CONCLUSION

3D Dual-contrast nnU-Net aided segmentation of pancreas on Dixon images appears to be adaptable to multicenter/population datasets. It fully automates the assessment of pancreatic fat distribution and has high reliability.

EVIDENCE LEVEL

3 TECHNICAL EFFICACY: Stage 3.

Quantitative Assessment of Pancreatic Fat by Quantitative CT in Type 2 Diabetes Mellitus

Objective

To characterize the pancreatic fat deposition (PFD) in patients with type 2 diabetes mellitus (T2DM) by quantitative computed tomography (QCT) and investigate the relationship between PFD and clinical metabolic parameters and islet function.

Materials and Methods

A total of 150 patients with T2DM and 93 age-matched healthy subjects underwent QCT to quantify PFD were included. PFD and various biochemical parameters were correlated by statistical methods and multiple stepwise linear regression modeling.

Results

PFD measured by QCT in the T2DM group was statistically higher than that in the healthy control group, and the pancreatic CT value was statistically lower than that in the control group. The QCT measured PFD was negatively correlated with the pancreatic CT values (P < 0.001), and positively correlated with triglyceride (TG), high-density lipoprotein cholesterol (HDL-C), visceral fat area (VAT) and insulin resistance index (HOMA-IR) (P < 0.05) in the T2DM patients. Multiple stepwise linear regression analysis identified PFD as the dependent variable factor for T2DM.

Conclusion

This study suggests QCT as a reliable technique in measuring PFD in T2DM. High PFD is positively correlated with the degree of insulin resistance and may play an important role in islet cell dysfunction in T2DM.

Use of Magnetic Resonance Imaging to Quantify Fat and Steatosis in the Pancreas in Patients after Bariatric Surgery: a Retrospective Study

INTRODUCTION

Pancreatic steatosis (PS) has both metabolic consequences and local effects on the pancreas itself. Magnetic resonance imaging (MRI) is the most reliable non-invasive method for diagnosing PS. We investigated the impact of metabolic syndrome (MS) on the presence of PS, differences in individuals with and without PS, and the metabolic effects of bariatric procedures.

METHODS

Changes in anthropometric and basic biochemistry values and MS occurrence were evaluated in 34 patients with obesity who underwent a bariatric procedure. After the procedure, patients underwent MRI with manual 3D segmentation mask creation to determine the pancreatic fat content (PFC). We compared the differences in the PFC and the presence of PS in individuals with and without MS and compared patients with and without PS.

RESULTS

We found no significant difference in the PFC between the groups with and without MS or in the occurrence of PS. There were significant differences in patients with and without PS, especially in body mass index (BMI), fat mass, visceral adipose tissue (VAT), select adipocytokines, and lipid spectrum with no difference in glycemia levels. Significant metabolic effects of bariatric procedures were observed.

CONCLUSIONS

Bariatric procedures can be considered effective in the treatment of obesity, MS, and some of its components. Measuring PFC using MRI did not show any difference in relation to MS, but patients who lost weight to BMI < 30 did not suffer from PS and had lower overall fat mass and VAT. Glycemia levels did not have an impact on the presence of PS.

Clinical Significance of Pancreatic Fat in Children: A Single-Center Experience

OBJECTIVES

Recently, interest in pancreatic fat has increased, and fatty pancreas is considered to be related to nonalcoholic fatty liver disease (NAFLD) and metabolic syndrome. We aimed to evaluate the prevalence of echogenic pancreas in children and its related factors.

METHODS

We retrospectively analyzed the data of patients aged 5 to 18 years who had undergone abdominal sonography between January 2020 and December 2020. Patients with chronic or pancreatic diseases were excluded.

RESULTS

Of 102 patients, 27 (26.5%) had echogenic pancreas and 55 (53.9%) had NAFLD. Among the 55 patients with NAFLD, 18 (32.7%) had an echogenic pancreas. Patients with echogenic pancreas had significantly higher fasting glucose, low-density lipoprotein cholesterol, and triglyceride levels than those without echogenic pancreas. The proportion of NAFLD and obesity was higher in the echogenic group; however, only the proportion of obese subjects showed a significant difference. In multivariate analysis, family history of diabetes mellitus (DM) and/or dyslipidemia and presence of DM and/or dyslipidemia were factors related to the presence of echogenic pancreas.

CONCLUSIONS

Echogenic pancreas is relatively common in children. Echogenic pancreas, typically observed in patients with a family history of DM and/or dyslipidemia, was strongly associated with metabolic syndrome, even in the absence of fatty liver.

Combined effect of pancreatic lipid content and gene variants (TCF7L2, WFS1 and 11BHSD1) on B-cell function in Middle Aged Women in a Post Hoc Analysis

BACKGROUND

TCF7L2 rs7903146 and PNPLA3 rs738409 gene variants confer the strongest risk for type 2 diabetes mellitus (T2DM) and non-alcoholic fatty liver disease (NAFLD), respectively. Pancreatic triacylglycerol content (PTGC) was reported to have a role in T2DM development. We aimed to assess the correlation between PTGC and hepatic triacylglycerol content (HTGC) stratified by PNPLA3 rs738409 genotype and subsequently interactions between PTGC and gene variants associated with β-cell dysfunction (TCF7L2, WFS1) and visceral adiposity (11ΒHSD1) on β-cell function were also tested.

METHODS

PTGC and HTGC were assessed using MR in a post-hoc analysis of a genotype-based (PNPLA3 rs738409) recall study of 39 (lipid- and glucose lowering) drug-naïve women. Oral glucose tolerance test, HbA1c, insulin indices, anthropometric data were evaluated. The effect of minor allele carrying of TCF7L2 (rs7903146); WFS1 (rs1801214) and 11ΒHSD1 (rs4844880) variants in combination with PTGC was studied on surrogate markers of β-cell function. We used Spearman's rank-order, Mann-Whitney-U tests, and linear regression models.

RESULTS

PTGC and HTGC values were correlated after stratification by the rs738409 variant (only in CC genotype group R = 0.67, p = 10- 4). PTGC and HbA1c values correlated in the entire study population (R = 0.58, p = 10- 4). Insulin resistance, sensitivity and disposition indices were correlated with PTGC (HOMA2-IR: R = 0.42, p = 0.008; TyG: R = 0.38, p = 0.018; Matsuda: R= - 0.48, p = 0.002; DIbasal: R=-0.33, p = 0.039; ISSI-2: R=-0.35, p = 0.028). Surrogate markers of β-cell function (HOMA2-B, AUCinsulin/AUCglucose) correlated significantly with PTGC in subjects with the following genotypes rs7903146: CC R = 0.51, p = 0.022; rs18001214: CT + CC R = 0.55, p = 0.013; rs4844880: TA + AA R = 0.56, p = 0.016. The strongest interactions were found between PTGC and TCF7L2 rs7903146 effect on HOMA2-B (p = 0.001) and AUCinsulin/AUCglucose (p = 0.013).

CONCLUSIONS

The PNPLA3 rs738409 genotype has a major effect on the correlation between PTGC and HTGC. Furthermore we first report the combined effect of PTGC and individual risk gene variants of TCF7L2, WFS1 and 11ΒHSD1 on β-cell dysfunction. The correlation between pancreatic lipid accumulation and HbA1c also indicates an important role for the latter pathology.

Estimating Fatty Pancreas-A Preoperative Bedside Assessment by Bioelectric Impedance Analysis: Implications for Pancreatic Surgery

OBJECTIVE

The aim of the study was to evaluate whether fatty pancreas could be estimated by fat mass measurement by preoperative bioelectric impedance analysis. Preoperative computed tomography scan and pathologic evaluation were used as validation methods. Moreover, the 3 methodologies were tested for their ability in predicting postoperative pancreatic fistula.

METHODS

Seventy-five patients who underwent pancreatic resection were analyzed. Preoperative computed tomography attenuation in Hounsfield unit (CT-HU) was used to assess fatty pancreas. Bioelectric impedance analysis was performed the day before surgery and fat mass index (FMI) was calculated. Pancreatic steatosis was assessed by pathologists at the line of surgical transection. The ability of the methods in predicting postoperative pancreatic fistula was evaluated by the area under the receiver operating characteristics curves.

RESULTS

There was a strong correlation between CT-HU values and grade of pancreatic steatosis evaluated at histology ( r = -0.852, P < 0.001) and a moderate correlation between FMI and histologic pancreatic steatosis ( r = 0.612, P < 0.001) and between CT-HU value and FMI ( r = -0.659, P < 0.001) values. The area under the curve (95% confidence interval) was 0.942 (0.879-1) for histology, 0.924 (0.844-1) for CT-HU, and 0.884 (0.778-0.990) for FMI.

CONCLUSIONS

Bioelectric impedance analysis represents a valid alternative to assess pancreatic steatosis.

Intra-pancreatic fat deposition: bringing hidden fat to the fore

Development of advanced modalities for detection of fat within the pancreas has transformed understanding of the role of intra-pancreatic fat deposition (IPFD) in health and disease. There is now strong evidence for the presence of minimal (but not negligible) IPFD in healthy human pancreas. Diffuse excess IPFD, or fatty pancreas disease (FPD), is more frequent than type 2 diabetes mellitus (T2DM) (the most common disease of the endocrine pancreas) and acute pancreatitis (the most common disease of the exocrine pancreas) combined. FPD is not strictly a function of high BMI; it can result from the excess deposition of fat in the islets of Langerhans, acinar cells, inter-lobular stroma, acinar-to-adipocyte trans-differentiation or replacement of apoptotic acinar cells. This process leads to a wide array of diseases characterized by excess IPFD, including but not limited to acute pancreatitis, chronic pancreatitis, pancreatic cancer, T2DM, diabetes of the exocrine pancreas. There is ample evidence for FPD being potentially reversible. Weight loss-induced decrease of intra-pancreatic fat is tightly associated with remission of T2DM and its re-deposition with recurrence of the disease. Reversing FPD will open up opportunities for preventing or intercepting progression of major diseases of the exocrine pancreas in the future.

Pancreatic fat relates to fasting insulin and postprandial lipids but not polycystic ovary syndrome in adolescents with obesity

OBJECTIVE

Adolescents with polycystic ovary syndrome (PCOS) and obesity can have insulin resistance, dysglycemia, and hepatic steatosis. Excess pancreatic fat may disturb insulin secretion and relate to hepatic fat. Associations between pancreatic fat fraction (PFF) and metabolic measures in PCOS were unknown.

METHODS

This secondary analysis included 113 sedentary, nondiabetic adolescent girls (age = 15.4 [1.9] years), with or without PCOS and BMI ≥ 90th percentile. Participants underwent fasting labs, oral glucose tolerance tests, and magnetic resonance imaging for hepatic fat fraction (HFF) and PFF. Groups were categorized by PFF (above or below the median of 2.18%) and compared.

RESULTS

Visceral fat and HFF were elevated in individuals with PCOS versus control individuals, but PFF was similar. PFF did not correlate with serum androgens. Higher and lower PFF groups had similar HFF, with no correlation between PFF and HFF, although hepatic steatosis was more common in those with higher PFF (≥5.0% HFF; 60% vs. 36%; p = 0.014). The higher PFF group had higher fasting insulin (p = 0.026), fasting insulin resistance (homeostatic model assessment of insulin resistance, p = 0.032; 1/fasting insulin, p = 0.028), free fatty acids (p = 0.034), and triglycerides (p = 0.004) compared with those with lower PFF. β-Cell function and insulin sensitivity were similar between groups.

CONCLUSIONS

Neither PCOS status nor androgens related to PFF. However, fasting insulin and postprandial lipids were worse with higher PFF.

Metabolic implications of pancreatic fat accumulation

Fat accumulation outside subcutaneous adipose tissue often has unfavourable effects on systemic metabolism. In addition to non-alcoholic fatty liver disease, which has received considerable attention, pancreatic fat has become an important area of research throughout the past 10 years. While a number of diagnostic approaches are available to quantify pancreatic fat, multi-echo Dixon MRI is currently the most developed method. Initial studies have shown associations between pancreatic fat and the metabolic syndrome, impaired glucose metabolism and type 2 diabetes mellitus. Pancreatic fat is linked to reduced insulin secretion, at least under specific circumstances such as prediabetes, low BMI and increased genetic risk of type 2 diabetes mellitus. This Review summarizes the possible causes and metabolic consequences of pancreatic fat accumulation. In addition, potential therapeutic approaches for addressing pancreatic fat accumulation are discussed.

Nonalcoholic Fatty Pancreas Disease: Role in Metabolic Syndrome, "Prediabetes," Diabetes and Atherosclerosis

Fat accumulation in the pancreas associated with obesity and the metabolic syndrome (MetS) has been defined as "non-alcoholic fatty pancreas disease" (NAFPD). The aim of this review is to describe the association of NAFPD with obesity, MetS, type 2 diabetes mellitus (T2DM) and atherosclerosis and also increase awareness regarding NAFPD. Various methods are used for the detection and quantification of pancreatic fat accumulation that may play a significant role in the differences that have been observed in the prevalence of NAFPD. Endoscopic ultrasound provides detailed images of the pancreas and its use is expected to increase in the future. Obesity and MetS have been recognized as NAFPD risk factors. NAFPD is strongly associated with non-alcoholic fatty liver disease (NAFLD) and it seems that the presence of both may be related with aggravation of NAFLD. A role of NAFPD in the development of "prediabetes" and T2DM has also been suggested by most human studies. Accumulation of fat in pancreatic tissue possibly initiates a vicious cycle of beta-cell deterioration and further pancreatic fat accumulation. Additionally, some evidence indicates a correlation between NAFPD and atherosclerotic markers (e.g., carotid intima-media thickness). Weight loss and bariatric surgery decreases pancreatic triglyceride content but pharmacologic treatments for NAFPD have not been evaluated in specifically designed studies. Hence, NAFPD is a marker of local fat accumulation possibly associated with beta-cell function impairment, carbohydrate metabolism disorders and atherosclerosis.

T1 relaxation times and MR elastography-derived stiffness: new potential imaging biomarkers for the assessment of chronic pancreatitis

PURPOSE

Non-invasive imaging methods to detect morphological changes of the pancreas in patients with mild chronic pancreatitis (CP) are needed. This study aimed to compare magnetic resonance imaging-based parameters, pancreatic volume, T1 mapping, magnetic resonance elastography (MRE), and proton density fat fraction between CP patients and controls, and determine the diagnostic performance for diagnosing different stages of CP.

METHODS

Nineteen patients with mild CP (Cambridge grade 2 or less or recurring acute pancreatitis; n = 19), 30 with moderate/severe CP (Cambridge grade 3 and 4), and 35 healthy controls underwent pancreatic magnetic resonance imaging to assess the above mentioned magnetic resonance imaging-based parameters. The diagnostic performance of each parameter for detecting any mild and moderate/severe CP was determined using receiver operating characteristic analysis.

RESULTS

Pancreatic volume, T1 relaxation times, MRE-derived stiffness, and proton density fat fraction differed significantly between patients with mild CP, moderate/severe CP, and healthy controls (all p < 0.05). T1 mapping and MRE showed a very high diagnostic performance for distinguishing the mild CP group from the control group (T1 mapping: receiver operating characteristic area under the curve (ROC-AUC): 0.94; sensitivity: 84%; specificity: 91%, MRE: ROC-AUC: 0.93; sensitivity: 89%; specificity: 94%). T1 mapping and MRE also had the highest performance for diagnosing the presence of any CP from the control group (ROC-AUCs of 0.98 and 0.97, respectively).

CONCLUSION

Quantitative assessments of T1 relaxation time and MRE-derived stiffness had high performance in detecting mild CP and could probably reflect the early fibrotic changes in CP.

Determining age and sex-specific distribution of pancreatic whole-gland CT attenuation using artificial intelligence aided image segmentation: Associations with body composition and pancreatic cancer risk

BACKGROUND & AIMS

Increased intrapancreatic fat is associated with pancreatic diseases; however, there are no established objective diagnostic criteria for fatty pancreas. On non-contrast computed tomography (CT), adipose tissue shows negative Hounsfield Unit (HU) attenuations (-150 to -30 HU). Using whole organ segmentation on non-contrast CT, we aimed to describe whole gland pancreatic attenuation and establish 5th and 10th percentile thresholds across a spectrum of age and sex. Subsequently, we aimed to evaluate the association between low pancreatic HU and risk of pancreatic ductal adenocarcinoma (PDAC).

METHODS

The whole pancreas was segmented in 19,456 images from 469 non-contrast CT scans. A convolutional neural network was trained to assist pancreas segmentation. Mean pancreatic HU, volume, and body composition metrics were calculated. The lower 5th and 10th percentile for mean pancreatic HU were identified, examining the association with age and sex. Pre-diagnostic CT scans from patients who later developed PDAC were compared to cancer-free controls.

RESULTS

Less than 5th percentile mean pancreatic HU was significantly associated with increase in BMI (OR 1.07; 1.03-1.11), visceral fat (OR 1.37; 1.15-1.64), total abdominal fat (OR 1.12; 1.03-1.22), and diabetes mellitus type 1 (OR 6.76; 1.68-27.28). Compared to controls, pre-diagnostic scans in PDAC cases had lower mean whole gland pancreatic HU (-0.2 vs 7.8, p = 0.026).

CONCLUSION

In this study, we report age and sex-specific distribution of pancreatic whole-gland CT attenuation. Compared to controls, mean whole gland pancreatic HU is significantly lower in the pre-diagnostic phase of PDAC.

Comparison of pancreatic fat content measured by different methods employing MR mDixon sequence

OBJECTIVE

To compare the reliability of different methods for measuring fat content of pancreas by MR modified Dixon(mDixon) Sequence and accurately evaluate pancreatic fat in as simple a way as possible.

METHODS

This is a retrospective study, 64 patients were included in this study who underwent abdominal MR scan that contained the mDixon sequence from June 2019 to May 2020(Included 7 patients with type 2 diabetes and 4 patients with impaired glucose tolerance (IGT), they were admitted to hospital through the obesity clinic set up by endocrine department, all of them were initially diagnosed and untreated). All of the 64 patients were scanned in 3.0T MR (Philips Ingenia II) due to their condition, 10-34 slice pancreas images were obtained, which were different from each other. Three different methods of measurement were employed by two observers using Philips Intellispace Portal software: (1) All images (whole-pancreas) measurement, the whole-pancreatic fat fraction (wPFF) was calculated by software. (2) Interval slices measurement, that is half-pancreatic slices fat fraction (hPFF) measured in the same way, fat fraction obtained by the interlayer assay was calculated. (3) As usual, the fat content of pancreatic head, body and tail fat was measured respectively, and in order to improve credibility, we also measured head、 body and tail in every layer, and its average value was taken. The elapsed time of the above different measurement methods was recorded. Intra-group correlation coefficient (ICC) was used to analyze the consistency of the measured data within and between observers. T-tests and Friedman tests were applied to compare the difference of measured values among groups.

RESULTS

No matter in normal person or diabetic or IGT, hPFF has shown good stability (ICChPFF = 0.988), and there was no significant difference compared with wPFF. But the average fat percentage composition of head, body and tail were significantly different from wPFF and hPFF (P < 0.01). At the same time, compared with normal person, pancreatic fat content in IGT and diabetic patients showed progressive significance(P<0.05).

CONCLUSION

The distribution of pancreatic fat is not uniform, the method of measuring half pancreas by interlayer data collection can reflect the fat content of the entire pancreas, this suggests that measuring 50% of the pancreas is sufficient, this method effectively saves time and effort without affecting the results, which may have a better clinical application prospect.

Genome-wide association study of pancreatic fat: The Multiethnic Cohort Adiposity Phenotype Study

Several studies have found associations between higher pancreatic fat content and adverse health outcomes, such as diabetes and the metabolic syndrome, but investigations into the genetic contributions to pancreatic fat are limited. This genome-wide association study, comprised of 804 participants with MRI-assessed pancreatic fat measurements, was conducted in the ethnically diverse Multiethnic Cohort-Adiposity Phenotype Study (MEC-APS). Two genetic variants reaching genome-wide significance, rs73449607 on chromosome 13q21.2 (Beta = -0.67, P = 4.50x10-8) and rs7996760 on chromosome 6q14 (Beta = -0.90, P = 4.91x10-8) were associated with percent pancreatic fat on the log scale. Rs73449607 was most common in the African American population (13%) and rs79967607 was most common in the European American population (6%). Rs73449607 was also associated with lower risk of type 2 diabetes (OR = 0.95, 95% CI = 0.89-1.00, P = 0.047) in the Population Architecture Genomics and Epidemiology (PAGE) Study and the DIAbetes Genetics Replication and Meta-analysis (DIAGRAM), which included substantial numbers of non-European ancestry participants (53,102 cases and 193,679 controls). Rs73449607 is located in an intergenic region between GSX1 and PLUTO, and rs79967607 is in intron 1 of EPM2A. PLUTO, a lncRNA, regulates transcription of an adjacent gene, PDX1, that controls beta-cell function in the mature pancreas, and EPM2A encodes the protein laforin, which plays a critical role in regulating glycogen production. If validated, these variants may suggest a genetic component for pancreatic fat and a common etiologic link between pancreatic fat and type 2 diabetes.

Use of Biomarkers and Imaging for Early Detection of Pancreatic Cancer

Pancreatic cancer remains one of the deadliest cancers worldwide, and it is typically diagnosed late, with a poor prognosis. Early detection is the most important underlying factor for improving the prognosis of pancreatic cancer patients. One of the most effective strategies for detecting cancers at an early stage is screening of the general population. However, because of the low incidence of pancreatic cancer in the general population, the stratification of subjects who need to undergo further examinations by invasive and expensive modalities is important. Therefore, minimally invasive modalities involving biomarkers and imaging techniques that would facilitate the early detection of pancreatic cancer are highly needed. Multiple types of new blood biomarkers have recently been developed, including unique post-translational modifications of circulating proteins, circulating exosomes, microRNAs, and circulating tumor DNA. We previously reported that circulating apolipoprotein A2 undergoes unique processing in the bloodstream of patients with pancreatic cancer and its precancerous lesions. Additionally, we recently demonstrated a new method for measuring pancreatic proton density in the fat fraction using a fat–water magnetic resonance imaging technique that reflects pancreatic steatosis. In this review, we describe recent developments in potential biomarkers and imaging modalities for the early detection and risk stratification of pancreatic cancer, and we discuss current strategies for implementing screening programs for pancreatic cancer.