Pancreatic Fat Content Detected by Computed Tomography and Its Significant Relationship With Intraductal Papillary Mucinous Neoplasm

Intrapancreatic fat deposition and nutritional treatment: the role of various dietary approaches

Ectopic fat accumulation in various organs and tissues, such as the liver, muscle, kidney, heart, and pancreas, is related to impaired capacity of adipose tissue to accumulate triglycerides, as a consequence of overnutrition and an unhealthy lifestyle. Ectopic fat promotes organ dysfunction and is a key factor in the development and progression of cardiometabolic diseases. Interest in intrapancreatic fat deposition (IPFD) has developed in the last few years, particularly in relation to improvement in methodological techniques for detection of fat in the pancreas, and to growing evidence for the role that IPFD might have in glucose metabolism disorders and cardiometabolic disease. Body weight reduction represents the main option for reducing fat, and the evidence consistently shows that hypocaloric diets are effective in reducing IPFD. Changes in diet composition, independently of changes in energy intake, might offer a more feasible and safe alternative treatment to energy restriction. This current narrative review focused particularly on the possible beneficial role of the diet and its nutrient content, in hypocaloric and isocaloric conditions, in reducing IPFD in individuals with high cardiometabolic risk, highlighting the possible effects of differences in calorie quantity and calorie quality. This review also describes plausible mechanisms by which the various dietary approaches could modulate IPFD.

Risk factors for fatty pancreas and effects of fatty infiltration on pancreatic cancer

Objective: This study clarified the risk factors and pathophysiology of pancreatic cancer by examining the factors associated with fatty pancreas. Methods: The degree of fatty pancreas, background factors, and incidence of pancreatic cancer were examined among nonalcoholic fatty liver disease (NAFLD) patients (n = 281) and intraductal papillary mucinous neoplasm (IPMN) patients with a family history of pancreatic cancer (n = 38). The presence of fatty pancreas was confirmed by the pancreatic CT value/splenic CT value ratio (P/S ratio). Immunohistochemical staining was performed on 10 cases with fatty pancreas, confirmed via postoperative pathology. Results: Fatty pancreas occurred in 126 patients (44.8%) in the NAFLD group who were older (p = 0.0002) and more likely to have hypertension (p < 0.0001). The IPMN group had 18 patients (47.4%) with fatty pancreas, included more men than women (p = 0.0056), and was more likely to have patients with hypertension (p = 0.0010). On histological examination, a significant infiltration of adipocytes into the acini from the pancreatic interstitium induced atrophy of the pancreatic parenchyma, and both M1 and M2 macrophages were detected in the area where adipocytes invaded the pancreatic parenchyma. Accumulation of p62 and increased positive staining of NQO1 molecules related to autophagy dysfunction were detected in pancreatic acinar cells in the fatty area, acinar-ductal metaplasia, and pancreatic cancer cells. The rate of p62-positive cell area and that of NQO1-positive cell area were significantly higher in the fatty pancreatic region than those in the control lesion (pancreatic region with few adipocyte infiltration). Furthermore, the rate of p62-positive cell area or that of NQO1-positive cell area showed strong positive correlations with the rate of fatty pancreatic lesion. These results suggest that adipocyte invasion into the pancreatic parenthyme induced macrophage infiltration and autophagy substrate p62 accumulation. High levels of NQO1 expression in the fatty area may be dependent on p62 accumulation. Conclusion: Hypertension was a significant risk factor for fatty pancreas in patients with NAFLD and IPMN. In fatty pancreas, fatty infiltration into the pancreatic parenchyme might induce autophagy dysfunction, resulting in activation of antioxidant proteins NQO1. Thus, patients with fatty pancreas require careful follow-up.

Value of 3-T MR imaging in intraductal papillary mucinous neoplasm with a concomitant invasive carcinoma

OBJECTIVES

To examine the value of 3-T MRI for evaluating the difference between the pancreatic parenchyma of intraductal papillary mucinous neoplasm with a concomitant invasive carcinoma (IPMN-IC) and the pancreatic parenchyma of patients without an IPMN-IC.

METHODS

A total of 132 patients underwent abdominal 3-T MRI. Of the normal pancreatic parenchymal measurements, the pancreas-to-muscle signal intensity ratio in in-phase imaging (SIR-I), SIR in opposed-phase imaging (SIR-O), SIR in T2-weighted imaging (SIR-T2), ADC (×10^-3 mm²/s) in DWI, and proton density fat fraction (PDFF [%]) in multi-echo 3D DIXON were calculated. The patients were divided into three groups (normal pancreas group: n = 60, intraductal papillary mucinous neoplasm (IPMN) group: n = 60, IPMN-IC group: n = 12).

RESULTS

No significant differences were observed among the three groups in age, sex, body mass index, prevalence of diabetes mellitus, and hemoglobin A1c (p = 0.141 to p = 0.657). In comparisons among the three groups, the PDFF showed a significant difference (p < 0.001), and there were no significant differences among the three groups in SIR-I, SIR-O, SIR-T2, and ADC (p = 0.153 to p = 0.684). The PDFF of the pancreas was significantly higher in the IPMN-IC group than in the normal pancreas group or the IPMN group (p < 0.001 and p < 0.001, respectively), with no significant difference between the normal pancreas group and the IPMN group (p = 0.916).

CONCLUSIONS

These observations suggest that the PDFF of the pancreas is associated with the presence of IPMN-IC.

KEY POINTS

• The cause and risk factors of IPMN with a concomitant invasive carcinoma have not yet been clarified. • The PDFF of the pancreas was significantly higher in the IPMN-IC group than in the normal pancreas group or the IPMN group. • Pancreatic PDFF may be a potential biomarker for the development of IPMN with a concomitant invasive carcinoma.

Pancreatic CT density is an optimal imaging biomarker for earlier detection of malignancy in the pancreas with intraductal papillary mucinous neoplasm

BACKGROUND

Intraductal papillary mucinous neoplasms (IPMNs) are typically detected as incidental findings by computed tomography (CT); however, the conventional surveillance is not valid for the early detection of concomitant pancreatic cancer. The pancreas of IPMN is often accompanied by fatty infiltration in the parenchyma, and pancreatic fatty infiltration could be evaluated by pancreatic CT density (pancreatic index, PI). We aimed to investigate whether PI could be an imaging biomarker for the early prediction of malignancies in the pancreas with IPMN.

METHODS

Two different cohorts were investigated. (Investigation cohort): A total of 1137 patients with initially low-risk IPMN were compensated by initial IPMN findings, and 2 groups (malignancy/possible benign, 50 cases each) were investigated for yearly changes in PI and for the cutoff value of PI indicating the development of malignancies. (Validation cohort): To validate the cutoff value, 256 patients radiologically suspected of having IPMNs were investigated.

RESULTS

(Investigation-cohort): The malignancy group showed a gradual decrease in PI every year, and PI significantly differed among the 2 groups 1 year prior to the last investigation. The cutoff value of PI was set at 0.65. (Validation-cohort): A total of 55% of the patients with a PI below the cutoff value had malignancy in the pancreas, including concomitant pancreatic cancer, and the cutoff value was the most significant risk factors for the development of malignancies in the pancreas compared to the conventional risk factors for IPMN.

CONCLUSIONS

Decreasing PI would be an optimal imaging biomarker for earlier detection of malignancies in the pancreas with IPMN.

Uniting epidemiology and experimental models: pancreatic steatosis and pancreatic cancer

Research from epidemiologic studies and experimental animal models provide insights into the role of pancreatic steatosis in the development of pancreatic cancer. Epidemiologic data demonstrate that pancreatic steatosis is widely prevalent and significantly associated with both development and progression of pancreatic cancer. By focusing on current experimental models, this review elucidates potential cellular mechanisms underlying not only the pathophysiology of pancreatic steatosis itself, but also the pathogenesis behind pancreatic steatosis's role in changing the tumour microenvironment and accelerating the development of pancreatic cancer. This review further explores the impact of bariatric surgery on pancreatic steatosis and pancreatic cancer. Synthesizing knowledge from both epidemiologic studies and experimental animal models, this review identifies gaps in current knowledge regarding pancreatic steatosis and its role in carcinogenesis and proposes future research directions to elucidate the possible mechanisms underlying other obesity-associated cancers.

Fatty Pancreas-Centered Metabolic Basis of Pancreatic Adenocarcinoma: From Obesity, Diabetes and Pancreatitis to Oncogenesis

Pancreatic ductal adenocarcinoma (PDAC) is one of the deadliest types of cancer, and it is currently the third most common cause of cancer death in the U.S.A. Progress in the fight against PDAC has been hampered by an inability to detect it early in the overwhelming majority of patients, and also by the reduced oxygen levels and nutrient perfusion caused by new matrix formation through the activation of stromal cells in the context of desmoplasia. One harbinger of PDAC is excess intrapancreatic fat deposition, namely, fatty pancreas, which specifically affects the tumor macro- and microenvironment in the organ. Over half of PDAC patients have diabetes mellitus (DM) at the time of diagnosis, and fatty pancreas is associated with subsequent DM development. Moreover, there is a strong association between fatty pancreas and fatty liver through obesity, and a higher intrapancreatic fat percentage has been noted in acute pancreatitis patients with DM than in those without DM. All these findings suggest that the link between fatty pancreas and PDAC might occur through metabolic alterations, either DM-related or non-DM-related. Based on clinical, in vivo and in vitro evidence, the current review highlights the etiologies of fatty pancreas (including fatty infiltration and replacement) and the fatty pancreas-associated metabolic alterations involved in oncogenesis to provide crucial targets to prevent, detect, and/or effectively treat PDAC.

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.

Impact of qualitative endoscopic ultrasonography on fatty pancreas at a referral medical center

Background

Taking advantage of the current advances in diagnostic imaging modalities, including endoscopic ultrasonography (EUS), and due to the increased attention to ectopic fat accumulation in the pancreas following the rising trend of metabolic syndrome, we qualitatively assessed the clinical implication of pancreatic steatosis by EUS in this study.

Methods

The study included 243 patients that were divided into four groups. The correlation between the average echogenicity of the pancreas and that of the control organs and the key clinical data of all study patients were collectively analyzed. The cut‐off point of the pancreas‐control (PC) ratio in EUS and liver‐control (LC) ratio on abdominal ultrasound were determined from the population distribution and the obtained median values.

Results

With the cut‐off point of 1.30 for the PC ratio and 1.20 for the LC ratio, sex, the Brinkman index, habitual alcohol drinkers, and fatty pancreas were significant factors. The associations between each relevant factor in fatty pancreas, metabolic syndrome in the fatty liver group, and age in the pancreatic cancer group were all significant in the analysis. In addition, we investigated whether the PC ratio differed according to age and staging in pancreatic cancer patients. Interestingly, the PC ratio was lower in the advanced stage group than in the early‐stage group.

Conclusion

Our results suggest that, irrespective of the degree, ectopic fat infiltration in the pancreas could be a specific clinical phenotype of serious pancreatic diseases, including pancreatic cancer, especially in high‐risk patients.

Magnetic resonance imaging-derived fat fraction predicts risk of malignancy in intraductal papillary mucinous neoplasm

PURPOSE

Assess the relationship between MRI-derived pancreatic fat fraction and risk of malignancy in intraductal papillary mucinous neoplasm (IPMN).

METHODS

MRIs of patients with IPMN who underwent pancreaticoduodenectomy were analyzed. IPMN with low-grade dysplasia (n = 29) were categorized as low-risk while IPMN at high risk of malignancy consisted of those with high-grade dysplasia/invasive carcinoma (n = 33). Pancreatic fat-fraction (FFmean) was measured using the 2-point Dixon-method. Images were evaluated for the high-risk stigmata and worrisome features according to the revised 2017 Fukuoka consensus criteria. Data on serum CA19-9, Diabetes Mellitus (DM) status, body mass index (BMI), and histological chronic pancreatitis were obtained.

RESULTS

A significant difference in FFmean was found between the high-risk IPMN (11.45%) and low-risk IPMN (9.95%) groups (p = 0.027). Serum CA19-9 level (p = 0.021), presence of cyst wall enhancement (p = 0.029), and solid mass (p = 0.008) were significantly associated with high-risk IPMN. There was a significant correlation between FFmean and mural nodule size (r = 0.36, p ˂ 0.01), type 2 DM (r = 0.34, p ˂ 0.01), age (r = 0.31, p ˂ 0.05), serum CA 19-9 (r = 0.30, p ˂ 0.05), cyst diameter (r = 0.30, p ˂ 0.05), and main pancreatic duct diameter (r = 0.26, p ˂ 0.05). Regression analysis revealed FFmean (OR 1.103, p = 0.035) as an independent predictive variable of high-risk IPMN.

CONCLUSION

FFmean is significantly associated with high-risk IPMN and an independent predictor of IPMN malignant risk. FFmean may have clinical utility as a biomarker to complement the current IPMN treatment algorithm and improve clinical decision making regarding the need for surgical resection or surveillance.

Post-pancreatitis diabetes mellitus and excess intra-pancreatic fat deposition as harbingers of pancreatic cancer

Progress in the fight against pancreatic cancer has been hampered by many factors. One of them is the inability to detect the disease early in overwhelming majority of patients. The present paper outlines a novel way in which progress could be accelerated. This includes a focus on two harbingers—post-pancreatitis diabetes mellitus and excess intra-pancreatic fat deposition—that converge at affecting the tumor macroenvironment and microenvironment specifically in the pancreas, not other organs. The two entities have the potential to be incorporated into future screening strategies with a view to early detecting of pancreatic cancer.

Computed Tomography-Estimated Pancreatic Steatosis is Associated with Carotid Plaque in Type 2 Diabetes Mellitus Patients: A Cross-Sectional Study from China

OBJECTIVE

To explore potential effects of pancreatic fat content measured by computed  tomography (CT) on carotid plaque in patients with type 2 diabetes mellitus (T2DM).

METHODS

T2DM patients who underwent an un-enhanced CT scan of the upper abdomen and ultrasound of the carotid artery were enrolled. The patients were divided into a non-plaque group and a plaque group (including hypoechoic plaque subgroup and non-hypoechoic plaque subgroup). The CT attenuation of pancreas and spleen were measured. Pancreas-to-spleen attenuation ratio (P/S) and the difference between pancreatic and splenic attenuation (P-S) were calculated. The cutoff values of P/S and P-S were obtained using receiver operating characteristic curves. Logistic regression models were used to evaluate association of P/S or P-S with carotid plaque or hypoechoic plaque.

RESULTS

337 patients were enrolled, including 101 cases in the non-plaque group, 146 cases in the hypoechoic plaque subgroup, and 90 cases in the non-hypoechoic plaque subgroup. P/S and P-S in hypoechoic plaque group were lower than those in non-plaque group, with a cutoff value of P/S and P-S as 0.72 and -13.33, respectively. After adjusting for risk factors, P/S and P-S correlated with carotid plaque [for low P/S: OR (95% CI): 3.15 (1.47-6.73), P = 0.0031; for low P-S: OR (95% CI): 2.84 (1.42-5.66), P = 0.0031] as well as carotid hypoechoic plaque [for low P/S: OR (95% CI): 1.82 (1.07-3.08), P = 0.0259; for low P-S: OR (95% CI): 1.82 (1.09-3.02), P = 0.021].

CONCLUSION

T2DM patients with hypoechoic carotid plaque have higher pancreatic fat content than those without. Pancreatic steatosis correlates with carotid plaque and hypoechoic plaque in T2DM patients.

LDL, HDL and endocrine-related cancer: From pathogenic mechanisms to therapies

Cholesterol is essential for a variety of functions in endocrine-related cells, including hormone and steroid production. We have reviewed the progress to date in research on the role of the main cholesterol-containing lipoproteins; low-density lipoprotein (LDL) and high-density lipoprotein (HDL), and their impact on intracellular cholesterol homeostasis and carcinogenic pathways in endocrine-related cancers. Neither LDL-cholesterol (LDL-C) nor HDL-cholesterol (HDL-C) was consistently associated with endocrine-related cancer risk. However, preclinical studies showed that LDL receptor plays a critical role in endocrine-related tumor cells, mainly by enhancing circulating LDL-C uptake and modulating tumorigenic signaling pathways. Although scavenger receptor type BI-mediated uptake of HDL could enhance cell proliferation in breast, prostate, and ovarian cancer, these effects may be counteracted by the antioxidant and anti-inflammatory properties of HDL. Moreover, 27-hydroxycholesterol a metabolite of cholesterol promotes tumorigenic processes in breast and epithelial thyroid cancer. Furthermore, statins have been reported to reduce the incidence of breast, prostate, pancreatic, and ovarian cancer in large clinical trials, in part because of their ability to lower cholesterol synthesis. Overall, cholesterol homeostasis deregulation in endocrine-related cancers offers new therapeutic opportunities, but more mechanistic studies are needed to translate the preclinical findings into clinical therapies.

A Systematic Review of Intra-pancreatic Fat Deposition and Pancreatic Carcinogenesis

BACKGROUND

Excess adiposity is considered causally related to pancreatic cancer. While most knowledge on the topic comes from studies on general and visceral adiposity, the role of intra-pancreatic fat deposition in pancreatic carcinogenesis just begins to be elucidated. The aim was to conduct a comprehensive systematic review of clinical studies on intra-pancreatic fat deposition in individuals with pancreatic cancer or pre-malignant lesions.

METHODS

A literature search was conducted independently by two reviewers using three electronic databases. Studies were included if they reported on intra-pancreatic fat deposition determined based on modern radiology or histology. Summary estimates were presented as pooled prevalence or relative risk and 95% confidence interval.

RESULTS

A total of 13 studies (encompassing 2178 individuals) were included. The pooled prevalence of intra-pancreatic fat deposition in individuals with pancreatic cancer or pre-malignant lesions was 52% (95% confidence interval, 38-66%). The presence of pancreatic cancer or pre-malignant lesions was associated with a significantly increased risk of intra-pancreatic fat deposition (relative risk 2.78 (95% confidence interval, 1.56-4.94, p < 0.001).

CONCLUSION

Individuals with pancreatic cancer or pre-malignant lesions are characterized by increased intra-pancreatic fat deposition. There are sound grounds for conceptually viewing intra-pancreatic fat deposition as a combination of fat accumulation in the pancreas (due to expansion of excess visceral fat) and fatty replacement of the pancreas (due to changes in cellular identity within the pancreas). Guidelines on reporting intra-pancreatic fat deposition need to be developed with a view to informing a comprehensive and standardized characterization of this clinical entity in future studies.

Pancreatic Fat Infiltration Is Associated with a Higher Risk of Pancreatic Ductal Adenocarcinoma

Background

Pancreatic ductal adenocarcinoma (PDAC) has a poor survival rate, partly due to delayed diagnosis. Identifying high-risk individuals could lead to early detection and improve survival. A number of risk factors such as alcohol consumption and metabolic syndrome are associated with fatty infiltration of the pancreas. Experimental models show that a fatty pancreas promotes tissue inflammation and fibrosis, which could promote PDAC.

Methods

We conducted a case-control study in a single-university tertiary hospital. Sixty-eight PDAC cases with recent non-contrast computed tomography (CT) and 235 controls were studied. The controls had no history of malignancy and underwent CT colonography for cancer screening in the same period. Pancreatic fat was estimated by calculating pancreatic (P) attenuation, corrected to splenic (S) attenuation, measured in three 1.0-cm² regions of the pancreas. The P.S100 value calculated was used to estimate fatty infiltration of the pancreas (FIP), with a lower P.S100 representing a higher FIP.

Results

The PDAC patients had a lower BMI and a higher rate of type 2 diabetes mellitus. The P.S100 was lower in cases than in controls (86.452 vs. 92.414, p = 4.016e-06), suggesting that FIP is higher with PDAC. The risk of developing PDAC steadily increased significantly for the quartiles with a higher FIP compared to the low FIP quartile. No correlation between BMI and FIP (r = -0.1031179; 95% confidence interval [CI] -0.22267106 to 0.01949092) was found. Adjusting for confounders (age, sex, BMI, and DM), the risk of developing PDAC according to the FIP was estimated to be 3.75 (95% CI 1.9234408-7.993337; p = 0.000171). FIP was stable before and after the diagnosis of PDAC in 9 cases with prior CT scans when no pancreatic tumor was identifiable.

Conclusion

Fatty pancreas is associated with an increased risk of pancreatic cancer. Once confirmed in larger-scale studies, these findings could help to identify at-risk individuals, particularly in high-risk groups such as chronic alcohol consumers.

Decreased CT-number in the pancreatic parenchyma is a reliable imaging biomarker of the presence of malignancies in patients with high-risk intraductal papillary mucinous neoplasm

BACKGROUND

Intraductal papillary mucinous neoplasm (IPMN) is a premalignant cystic neoplasm of the pancreas and is frequently detected in imaging investigations. A proportion of the patients with IPMN develop malignancies including high-grade dysplasia and invasive carcinoma. To predict the presence of malignancies in IPMN, constant imaging follow-up is usually required. Pancreatic steatosis (PS) has been recently identified as a facilitating factor for pancreatic cancer, and can be predicted through computed tomography (CT). We hypothesized that the CT-number of the pancreatic parenchyma could be a new reliable imaging biomarker for IPMN patients.

METHODS

Eighty-six patients undergoing pancreatectomy for IPMN were investigated. Using preoperative CT, the pancreatic index (PI) was calculated by dividing the CT-number of the pancreas by that of the spleen.

RESULTS

Malignancies were pathologically detected in 63 cases (73.3%). Patients were divided into two cohorts according to the presence of malignancies and were compared for various factors including the PI scores. The comparison of the two cohorts detected significant differences in two parameters (CA19-9 and PI score), and the PI score was the most sensitive biomarker to predict the presence of malignancies in patients showing high-risk stigmata of IPMN.

CONCLUSIONS

Pancreatic CT-number is an additional reliable imaging biomarker in distinguishing patients with IPMN having malignancies when investigating the patients showing high-risk stigmata.

Negative effect of fatty liver on visualization of pancreatic cystic lesions at screening transabdominal ultrasonography

RATIONALE, AIMS, AND OBJECTIVES

The aim of this observational study is to identify factors by which some pancreatic cystic lesions (PCLs) were undetectable at transabdominal ultrasonography (TAUS), using magnetic resonance imaging (MRI) as reference standard.

METHODS

The database for 781 consecutive subjects who underwent a health checkup including fat computed tomography and upper abdominal MRI as option was searched. The presence of fatty liver and fatty pancreas was diagnosed by TAUS, and atrophic pancreas was determined by reevaluating the image of the pancreas in the chest computed tomography for screening. Subjects with PCL detected and those undetected at TAUS were statistically compared in clinical characteristics.

RESULTS

The prevalence of PCL detected at MRI was 17.8% in the general population. Multivariate logistic regression analysis showed that fatty liver, body mass index, and the size of PCL were significantly associated with the factors influencing the visualization of PCL at TAUS (odds ratio [OR]: 0.337, 95% confidence interval [CI]: 0.154-0.734, P = 0.006; OR: 0.852, 95% CI: 0.737-0.985, P = 0.030; OR:1.120, 95% CI: 1.045-1.200, P = .001). Thirty-six PCLs (64.3%) in a total of 56 PCLs were undermeasured by TAUS. Additionally, nine (56%) out of 16 PCLs (≥ 15 mm) were undermeasured by 5 mm or more by TAUS, although a significantly higher detection rate was observed for PCLs (≥ 15 mm) in comparison with that for PCLs (< 15 mm) (80% vs 33.6%, P = .000).

CONCLUSIONS

It should be noted that coexisting fatty liver may lower the detection of PCL, and its size may be underestimated by TAUS.

Pancreatic fat content may increase the risk of imaging progression in low-risk branch duct intraductal papillary mucinous neoplasm

OBJECTIVE

To identify risk factors of imaging progression (increase in cyst size or main pancreatic duct size, or a new mural nodule) in low-risk branch duct intraductal papillary mucinous neoplasm (BD-IPMN), including obesity-related factors such as pancreatic fat content.

METHODS

Our hospital databases were searched for patients who had completed health checkup, including upper abdominal magnetic resonance imaging (MRI) over 48 months (August 2012 to July 2016). Individuals with BD-IPMN without worrisome features and high-risk stigmata who underwent surveillance with at least one follow-up MRI, irrespective of the follow-up period, were included. Pancreatic computed tomography attenuation indexes were defined as the difference between the pancreas and spleen attenuation (P - S) and the pancreas to spleen attenuation ratio (P/S).

RESULTS

Among 75 patients diagnosed as having low-risk BD-IPMN, during a median follow-up of 36 months, 11 (15%) had imaging progression in cyst size, including two with worrisome features. A multivariate logistic analysis showed that the initial cyst size and both indexes (P - S, or P/S) were significantly associated with imaging progression in IPMN, respectively (Model 1: odds ratio [OR] 1.188, 95% confidence interval [CI] 1.060-1.331, P = 0.003; OR 0.871, 95% CI 0.776-0.977, P = 0.019; Model 2: OR 1.186, 95% CI 1.064-1.322, P = 0.002; OR 0.002, 95% CI 0.000-0.970, P = 0.049).

CONCLUSIONS

Pancreatic fat content and initial cyst size were significantly associated with imaging progression in low-risk BD-IPMN. Revisions of international consensus Fukuoka guidelines might be customized based on initial cyst size and pancreatic fat content.

Circulating levels of lipocalin-2 are associated with fatty pancreas but not fatty liver

Lipocalin-2 (LCN-2), a peptide with diverse expression pattern, has been identified as a biomarker of various diseases as well as a factor contributing to inflammatory responses associated with excess adiposity and ensuing metabolic disorders. Although the inter-relationship between LCN-2 and excess adiposity is increasingly recognized, little is known about the inter-relationship between LCN-2 and ectopic fat deposition. The present study aimed to investigate the associations between LCN-2 and fatty pancreas as well as fatty liver. In addition, the associations between LCN-2 and pro-inflammatory cytokines were studied. Magnetic resonance imaging was used to quantify intra-pancreatic fat deposition and visceral-to-subcutaneous fat volume ratio whereas magnetic resonance spectroscopy was used to quantify liver fat deposition. Fasting venous blood was analyzed for LCN-2, C-C motif chemokine ligand 2, interleukin-6, leptin, tumor necrosis factor-α, glycated hemoglobin, glucose, and insulin. Binary logistic regression and linear regression analyses were conducted. Three statistical models were built to adjust for demographics, comorbidities, levels of glycated hemoglobin, insulin resistance, and abdominal fat distribution. A total of 79 individuals were studied, of whom 20 had fatty pancreas, 14 had fatty liver, and 4 had both. Lipocalin-2 was significantly associated with fatty pancreas in all the adjusted models (p = 0.014 in the most adjusted model) but was not significantly associated with fatty liver in any of the studied models. Lipocalin-2 was significantly associated with interleukin-6 and tumor necrosis factor-α, in both the unadjusted and adjusted models. Leptin and C-C motif chemokine ligand 2 were not significantly associated with LCN-2 in any of the studied models. These findings suggest that LCN-2 is a potential biomarker of fatty pancreas, independent of abdominal fat distribution, insulin resistance, and other covariates. The role of LCN-2 in intra-pancreatic fat deposition and related low-grade inflammation warrants further investigations.

Patient respiratory-triggered quantitative T2 mapping in the pancreas

Background

Long acquisition times and motion sensitivity limit T₂ mapping in the abdomen. Accelerated mapping at 3 T may allow for quantitative assessment of diffuse pancreatic disease in patients during free‐breathing.

Purpose

To test the feasibility of respiratory‐triggered quantitative T₂ analysis in the pancreas and correlate T₂‐values with age, body mass index, pancreatic location, main pancreatic duct dilatation, and underlying pathology.

Study Type

Retrospective single‐center pilot study.

Population

Eighty‐eight adults.

Field Strength/Sequence

Ten‐fold accelerated multiecho‐spin‐echo 3 T MRI sequence to quantify T₂ at 3 T.

Assessment

Two radiologists independently delineated three regions of interest inside the pancreatic head, body, and tail for each acquisition. Means and standard deviations for T₂ values in these regions were determined. T₂‐value variation with demographic data, intraparenchymal location, pancreatic duct dilation, and underlying pancreatic disease was assessed.

Statistical Tests

Interreader reliability was determined by calculating the interclass coefficient (ICCs). T₂ values were compared for different pancreatic locations by analysis of variance (ANOVA). Interpatient associations between T₂ values and demographical, clinical, and radiological data were calculated (ANOVA).

Results

The accelerated T₂ mapping sequence was successfully performed in all participants (mean acquisition time, 2:48 ± 0:43 min). Low T₂ value variability was observed across all patients (intersubject) (head: 60.2 ± 8.3 msec, body: 63.9 ± 11.5 msec, tail: 66.8 ± 16.4 msec). Interreader agreement was good (ICC, 0.82, 95% confidence interval: 0.77–0.86). T₂‐values differed significantly depending on age (P < 0.001), location (P < 0.001), main pancreatic duct dilatation (P < 0.001), and diffuse pancreatic disease (P < 0.03).

Data Conclusion

The feasibility of accelerated T₂ mapping at 3 T in moving abdominal organs was demonstrated in the pancreas, since T₂ values were stable and reproducible. In the pancreatic parenchyma, T₂‐values were significantly dependent on demographic and clinical parameters.

Level of Evidence: 4

Technical Efficacy: Stage 1

J. Magn. Reson. Imaging 2019;50:410–416.