Noninvasive in vivo quantitative assessment of fat content in human liver

Once-weekly semaglutide in people with HIV-associated lipohypertrophy: a randomised, double-blind, placebo-controlled phase 2b single-centre clinical trial

BACKGROUND

HIV-associated lipohypertrophy, which is characterised by an abnormal accumulation of abdominal visceral adipose tissue, remains problematic in people with HIV. Effective interventions are lacking, despite HIV-associated lipohypertrophy carrying a substantial risk of cardiometabolic comorbidity. The primary aim of this trial was to investigate effects of the GLP-1 receptor agonist, semaglutide, on adipose tissue in HIV-associated lipohypertrophy.

METHODS

This randomised, double-blind, placebo-controlled phase 2b clinical trial was conducted at a single US site. Key inclusion criteria included people with HIV aged 18 years or older with controlled HIV-1, a BMI of 25 kg/m2 or more, and lipohypertrophy but without type 1 or type 2 diabetes. Participants were randomly assigned 1:1 to receive 32 weeks of once-weekly subcutaneous semaglutide (8-week dose titration and 24 weeks at 1·0 mg) or placebo; all research personnel and participants remained masked to treatment assignment. Primary outcomes were changes at 32 weeks in adipose tissue quantity by body compartment. Analyses, including safety, were performed using intention-to-treat principles. This trial was registered ClinicalTrials.gov (NCT04019197) and is complete.

FINDINGS

Between June 10, 2019, and July 28, 2022, 108 participants were randomly assigned to receive semaglutide (n=54) or placebo (n=54). Eight (15%) in each group withdrew prematurely. Significant effects of semaglutide were seen over the 32-week study period in sex-adjusted multiplicative regression analyses for the primary outcome, abdominal visceral adipose tissue (β -30·82 cm2, 95% CI -50·13 to -11·51; % change -30·6%). Decreases were also seen in other key measures, including abdominal subcutaneous adipose tissue (β -42·01 cm2, 95% CI -75·49 to -8·52; % change -11·2%) and total body fat (natural logarithmic -0·21 kg, 95% CI -0·33 to -0·08; % change -18·9%). There were no statistically significant differences in possibly related or related adverse events (absolute risk difference 0·1111, 95% CI -0·0727 to 0·2869); however, one semaglutide-related grade 4 elevated lipase and two possibly related cases of cholelithiasis (grades 1 and 2) were observed.

INTERPRETATION

Semaglutide holds promise as an effective treatment for HIV-associated lipohypertrophy. The potential risk of serious adverse events deserves further scrutiny in large trials in people with HIV.

FUNDING

National Institutes of Health.

Metabolic-associated fatty liver voxel-based quantification on CT images using a contrast adapted automatic tool

BACKGROUND & AIMS

Metabolic-dysfunction associated fatty liver disease (MAFLD) is highly prevalent and can lead to liver complications and comorbidities, with non-invasive tests such as vibration-controlled transient elastography (VCTE) and invasive liver biopsies being used for diagnosis The aim of the present study was to develop a new fully automatized method for quantifying the percentage of fat in the liver based on a voxel analysis on computed tomography (CT) images to solve previously unconcluded diagnostic deficiencies either in contrast (CE) or non-contrast enhanced (NCE) assessments.

METHODS

Liver and spleen were segmented using nn-UNet on CE- and NCE-CT images. Radiodensity values were obtained for both organs for defining the key benchmarks for fatty liver assessment: liver mean, liver-to-spleen ratio, liver-spleen difference, and their average. VCTE was used for validation. A classification task method was developed for detection of suitable patients to fulfill maximum reproducibility across cohorts and highlight subjects with other potential radiodensity-related diseases.

RESULTS

Best accuracy was attained using the average of all proposed benchmarks being the liver-to-spleen ratio highly useful for CE and the liver-to-spleen difference for NCE. The proposed whole-organ automatic segmentation displayed superior potential when compared to the typically used manual region-of-interest drawing as it allows to accurately obtain the percent of fat in liver, among other improvements. Atypical patients were successfully stratified through a function based on biochemical data.

CONCLUSIONS

The developed method tackles the current drawbacks including biopsy invasiveness, and CT-related weaknesses such as lack of automaticity, dependency on contrast agent, no quantification of the percentage of fat in liver, and limited information on region-to-organ affectation. We propose this tool as an alternative for individualized MAFLD evaluation by an early detection of abnormal CT patterns based in radiodensity whilst abording detection of non-suitable patients to avoid unnecessary exposure to CT radiation. Furthermore, this work presents a surrogate aid for assessing fatty liver at a primary assessment of MAFLD using elastography data.

Are transmembrane 6 superfamily member 2 gene polymorphisms associated with steatohepatitis after pancreaticoduodenectomy?

Aim

After pancreaticoduodenectomy, 20-40% of patients develop steatotic liver disease (SLD), and steatohepatitis can be a problem. Although patatin-like phospholipase domain-containing 3 protein (PNPLA3) and transmembrane 6 superfamily member 2 (TM6SF2) polymorphisms are involved in SLD and steatohepatitis development, whether this is the case after pancreaticoduodenectomy is unclear.

Methods and Results

Forty-three patients with pancreatic cancer who underwent pancreaticoduodenectomy at our hospital between April 1, 2018, and March 31, 2021, were included. We extracted DNA from noncancerous areas of residual specimens after pancreaticoduodenectomy and determined PNPLA3 and TM6SF2 gene polymorphisms using real-time polymerase chain reaction. SLD was defined as a liver with an attenuation value of ≤40 HU or a liver-to-spleen ratio of ≤0.9 on computed tomography. We defined high hepatic fibrosis indexes (HFI) instead of steatohepatitis as a Fibrosis-4 index of ≥2.67 or nonalcoholic fatty liver disease fibrosis score of ≥0.675 in patients with SLD. The cumulative incidence of SLD (P = 0.299) and high HFI (P = 0.987) after pancreaticoduodenectomy were not significantly different between the PNPLA3 homozygous and minor allele groups. The incidences of high HFI at 1 year after pancreaticoduodenectomy were 16.8% and 27.0% in the TM6SF2 major homozygous and minor allele groups, respectively, with a significant difference in the cumulative incidence (P = 0.046).

Conclusion

The TM6SF2 minor allele may contribute to steatohepatitis development after pancreaticoduodenectomy.

Detection of moderate hepatic steatosis on contrast-enhanced dual-source dual-energy CT: Role and accuracy of virtual non-contrast CT

PURPOSE

To investigate diagnostic accuracy of virtual non contrast (VNC) images, based on dual-source dual-energy CT (dsDECT), for detection of at least moderate steatosis and to define a threshold value to make this diagnosis on VNC.

METHODS

This single-institution retrospective study included patients who had multi-phasic protocol dsDECT. Regions of interests were placed in different segments of the liver and spleen on true non-contrast (TNC), VNC, and portal-venous phase (PVP) images. At least moderate steatosis was defined as liver attenuation (LHU) < 40 HU on TNC. Diagnostic performance of VNC to detect steatosis was determined and the new threshold was tested in a validation cohort.

RESULTS

236 patients were included in training cohort. Mean liver attenuation values were 51.3 ± 10.8 HU and 58.1 ± 11.5 HU for TNC and VNC (p < 0.001), with a mean difference (VNC - TNC) of 6.8 ± 6.9 HU. Correlation between TNC and VNC was strong (r = 0.81, p < 0.001). The AUCs of LHU on VNC for detection of hepatic steatosis were 0.92 (95 % Cl: 0.86-0.98), 0.92 (95 % Cl: 0.87-0.97), 0.92 (95 % Cl: 0.86-0.99), 0.91 (95 % Cl: 0.84-0.97), and 0.87 (95 % Cl: 0.80-0.95) for entire liver, left lateral, left medial, right anterior, and right posterior segments, respectively. VNC had sensitivity/specificity of 100 % /42 % when using a threshold of 40 HU; they were 69 % and 95 %, respectively, when using optimized threshold of 46 HU. This threshold showed similar performance in validation cohort (n = 80).

CONCLUSIONS

Hepatic attenuation on VNC has promising performance for detection of at least moderate steatosis. Proposed threshold of 46 HU provides high specificity and moderate sensitivity to detect steatosis.

Analysis of non-alcoholic fatty liver disease during induction therapy for B-cell precursor acute lymphoblastic leukemia in children and adolescents

BACKGROUND

A prospective evaluation of non-alcoholic fatty liver disease (NAFLD) during induction therapy for acute lymphoblastic leukemia (ALL) has not been performed. Herein, we prospectively investigated the frequency, risk factors, and outcomes of NAFLD during induction therapy in children and adolescents with B-cell precursor ALL (BCP-ALL).

METHODS

This study enrolled 74 newly diagnosed BCP-ALL cases aged 1 year and older who were admitted to our department between January 2011 and December 2020. Median age was 6.6 years (1.3-17.5 years). Plain computed tomography (CT) of the upper abdomen was performed before induction therapy, and on days 15 and 29 after initiation of induction therapy. Patients with a liver/spleen CT ratio <0.9 were defined as having NAFLD.

RESULTS

The frequency of NAFLD was 73%. Patients with NAFLD had a higher rate of hypertriglyceridemia. There was no significant difference in 5-year overall survival and event-free survival (EFS) between patients with and without NAFLD. However, after restricting the target age to 10 years and older, 5-year EFS was significantly higher in patients with NAFLD than in those without (88.5 vs. 42.9%, respectively, P = 0.037). Similarly, 5-year cumulative incidence of relapse (CIR) was significantly lower in patients with NAFLD than in those without it (5-year CIR, 6.3 vs. 57.1%, respectively, P = 0.013).

CONCLUSION

Patients with NAFLD exhibit better outcomes including 5-year EFS and CIR. Further studies are necessary.

The Use of Noninvasive Scores in Predicting NAFLD Progression After Bariatric Surgery

BACKGROUND

Bariatric surgery has been postulated to impact liver function resulting in favorable effects on nonalcoholic fatty liver disease (NAFLD). We aimed to analyze the long-term impact of bariatric surgery on noninvasive scores predicting the progression of liver fibrosis in a bariatric population.

METHODS

We retrospectively reviewed the records of patients without pre-existing liver disease who underwent sleeve gastrectomy or Roux-en-Y gastric bypass (RYGB) at our center between 2010 and 2018. Four predictive scores for liver fibrosis (AST/ALT, APRI, Fib-4, and BARD) were calculated preoperatively, 6 months post-operatively, and annually up to 5 years. Correlations were analyzed with Pearson R. Subgroup and sensitivity analyses were performed to identify populations at increased risk.

RESULTS

A total of 2769 patients were included. The mean age was 40 years, and the majority was females (88.5%) and of Hispanic ethnicity (59.2%). There was a steady post-operative increase in the percentage of patients at increased risk of progression of liver fibrosis. The Fib-4 score showed the largest increase in the population at risk for liver fibrosis (11.3% preoperatively to 28.9% at 5 years). Patients with diabetes and those who underwent a sleeve gastrectomy continued to display a higher risk for liver fibrosis than did patients without diabetes and those who underwent RYGB, respectively.

CONCLUSION

There was an overall trend to increased liver fibrosis scores over the 5-year post-operative follow-up, but this increase remained lower than that reported in previous literature. Bariatric surgery offers NAFLD risk reduction in a high-risk population.

ACR Appropriateness Criteria® Abnormal Liver Function Tests

Liver function tests are commonly obtained in symptomatic and asymptomatic patients. Various overlapping lab patterns can be seen due to derangement of hepatocytes and bile ducts function. Imaging tests are pursued to identify underlying etiology and guide management based on the lab results. Liver function tests may reveal mild, moderate, or severe hepatocellular predominance and can be seen in alcoholic and nonalcoholic liver disease, acute hepatitis, and acute liver injury due to other causes. Cholestatic pattern with elevated alkaline phosphatase with or without elevated γ-glutamyl transpeptidase can be seen with various causes of obstructive biliopathy. Acute or subacute cholestasis with conjugated or unconjugated hyperbilirubinemia can be seen due to prehepatic, intrahepatic, or posthepatic causes. We discuss the initial and complementary imaging modalities to be used in clinical scenarios presenting with abnormal liver function tests. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

Factors contributing to nonalcoholic fatty liver disease (NAFLD) and fat deposition after pancreaticoduodenectomy: A retrospective analysis

Aim

Nonalcoholic fatty liver disease (NAFLD) can occur due to various reasons after pancreaticoduodenectomy (PD). This study examined the risk and perioperative determinants of NAFLD and fat deposition after PD.

Methods

A total of 101 patients who had undergone computed tomography 6 months after PD were included. We compared perioperative factors between patients who developed NAFLD and those who developed fatty deposits after PD.

Results

In the NAFLD group, pancreatic cancer was significantly more prevalent among patients who developed postoperative NAFLD (p = 0.024) and had a lower postoperative body mass index (BMI; p = 0.008). Multivariate analysis revealed that pancreatic carcinoma (hazard ratio [HR] 4.42, 95% confidence interval [CI] 1.118-17.442, p = 0.034) and lower postoperative BMI (HR 0.51, 95% CI 0.274-0.954, p = 0.0355) were risk factors for fatty liver. Pancreatic leakage (p = 0.024) and postoperative BMI (p = 0.002) were significantly lower in the fat deposition group than those in the NAFLD group. Multivariate analysis also revealed that a lower postoperative BMI was a risk factor for fat deposition (HR 0.56, 95% CI 0.523-0.982, p = 0.042). Moreover, multivariate analysis revealed that the fat deposition group had significantly lower pancreatic leakage than the NAFLD group (HR 7.944, 95% CI 1.993-63.562, p = 0.049).

Conclusion

The findings of this study suggest that postoperative BMI and pancreatic cancer are associated with a higher risk of NAFLD after PD, possibly because of pancreatic exocrine insufficiency and impaired fat absorption.

Gamma-glutamyltransferase predicts macrovesicular liver graft steatosis - an analysis of discarded liver allografts in Finland

OBJECTIVE

Liver-transplantation activity is limited by the shortage of grafts. Donor-liver macrovesicular steatosis predisposes to ischemia-reperfusion injury and is associated with reduced graft survival. The increasing prevalence of fatty-liver disease underlines the importance of identifying macrovesicular steatosis in potential donor livers. We analyzed liver grafts discarded for transplantation, and particularly the role of gamma-glutamyltransferase (GGT) in predicting graft steatosis.

METHODS

One-hundred sixty rejected cadaveric-donor liver grafts were studied. Donor selection was based on clinical data, and macroscopic graft inspection. Discarded grafts were biopsied at procurement of non-liver organs.

RESULTS

The most common reasons for discarding the graft were abnormal liver tests, ultrasound-verified steatosis and history of harmful alcohol use. GGT correlated moderately with macrovesicular steatosis (r = 0.52, p < 0.001), but poorly with microvesicular steatosis (r = 0.36, p < 0.001). Increased correlation between GGT and macrovesicular steatosis was observed among alcohol abusers (r = 0.67, p < 0.001). Area under the curve (AUC) of GGT for predicting >30% macrovesicular steatosis was 0.79 (95% CI 0.71-0.88), and for >60% steatosis, 0.79 (95% CI 0.68-0.90). The optimal GGT-cut off for detecting >30% and >60% macrovesicular steatosis were, respectively, 66 U/L (sensitivity 76% and specificity 68%) and 142 U/L (sensitivity 66% and specificity 83%). Among alcohol users, a GGT value >90 U/L showed 100% sensitivity for >60% macrovesicular steatosis. AUC for GGT in predicting fibrosis Stages 2-4 was 0.82 (95% CI 0.71-0.92, p < 0.001, optimal cut off 68, sensitivity 92%, specificity 61%).

CONCLUSIONS

Abnormal liver values, steatosis and harmful alcohol use were the main reasons for discarding liver-graft offers in Finland. GGT proved useful in predicting moderate and severe liver graft macrovesicular steatosis.

Xanthine oxidoreductase activity is correlated with hepatic steatosis

The enzyme xanthine oxidoreductase (XOR) catalyzes the synthesis of uric acid (UA) from hypoxanthine and xanthine, which are products of purine metabolism starting from ribose-5-phosphate. Several studies suggested a relationship between hyperuricemia and hepatic steatosis; however, few previous studies have directly examined the relationship between XOR activity and hepatic steatosis. A total of 223 subjects with one or more cardiovascular risk factors were enrolled. The liver-to-spleen (L/S) ratio on computed tomography and the hepatic steatosis index (HSI) were used to assess hepatic steatosis. We used a newly developed highly sensitive assay based on [¹³C₂, ¹⁵N₂] xanthine and liquid chromatography/triple quadrupole mass spectrometry to measure plasma XOR activity. Subjects with the L/S ratio of < 1.1 and the HSI of < 36 had increased XOR activity and serum UA levels. Independent of insulin resistance and serum UA levels, multivariate logistic regression analysis revealed that plasma XOR activity was associated with the risk of hepatic steatosis as assessed by the L/S ratio and HSI. According to the findings of this study, plasma XOR activity is associated with hepatic steatosis independent of insulin resistance and serum UA levels.

Label-free metabolic imaging of non-alcoholic-fatty-liver-disease (NAFLD) liver by volumetric dynamic optical coherence tomography

Label-free metabolic imaging of non-alcoholic fatty liver disease (NAFLD) mouse liver is demonstrated ex vivo by dynamic optical coherence tomography (OCT). The NAFLD mouse is a methionine choline-deficient (MCD)-diet model, and two mice fed the MCD diet for 1 and 2 weeks are involved in addition to a normal-diet mouse. The dynamic OCT is based on repeating raster scan and logarithmic intensity variance (LIV) analysis that enables volumetric metabolic imaging with a standard-speed (50,000 A-lines/s) OCT system. Metabolic domains associated with lipid droplet accumulation and inflammation are clearly visualized three-dimensionally. Particularly, the normal-diet liver exhibits highly metabolic vessel-like structures of peri-vascular hepatic zones. The 1-week MCD-diet liver shows ring-shaped highly metabolic structures formed with lipid droplets. The 2-week MCD-diet liver exhibits fragmented vessel-like structures associated with inflammation. These results imply that volumetric LIV imaging is useful for visualizing and assessing NAFLD abnormalities.

68Ga-DOTATATE PET/CT: The Optimum Standardized Uptake Value (SUV) Internal Reference

RATIONALE AND OBJECTIVES

Standardized Uptake Value (SUV) is an important semiquantitative measurement used in the clinical and research domains to assess radiopharmaceutical concentration in tumors versus normal organs, but is susceptible to many factors beyond the tumor biological environment. So, the aim of this study is to identify the optimum internal reference among organs with physiological uptake in ⁶⁸Ga-DOTATATE PET/CT (DOTA PET/CT) scans.

MATERIALS AND METHODS

This HIPAA-compliant, IRB-approved study with waiver of consent included retrospective imaging review of 180 consecutive patients with neuroendocrine tumors presenting for DOTA PET/CT image acquisition: Ga-⁶⁸ DOTATATE dose was reported as (0.054 mCi/Kg) scans between September 2018 and May 2019. Mean value of body weight normalized SUV (SUV_bw) and lean body mass normalized SUV (SUL) of liver and spleen were measured. Information about the patients and scan characteristics were collected. The paired Grambsch test was used to compare variance among the measured SUVs. Spearman's rank correlation coefficient was used to assess correlation between SUVs and potential patient- and scan-specific confounding factors.

RESULTS

Variance of SUL was significantly lower than variance of SUV_bw in both liver and spleen (p-value < 0.0001). Variances of liver SUV_bw and SUL were significantly lower than the corresponding spleen SUVs. Liver SUL showed the lowest variance (3.69% ± 1.25%) among all measured SUVs.

CONCLUSION

SUL is a more reproducible, less variable, and therefore more reliable quantitative measure in DOTA PET/CT scans, compared SUV_bw. Among the available organs with physiological uptake, liver SUL is the optimum internal reference given the liver's larger size and uniform SUL values resulting in lower variability and better reproducibility.

Imaging of the chemotherapy-induced hepatic damage: Yellow liver, blue liver, and pseudocirrhosis

The liver is the major drug-metabolizing and drug-detoxifying organ. Many drugs can cause liver damage through various mechanisms; however, the liver response to injury includes a relatively narrow spectrum of alterations that, regardless of the cause, are represented by phlogosis, oxidative stress and necrosis. The combination of these alterations mainly results in three radiological findings: vascular alterations, structural changes and metabolic function reduction. Chemotherapy has changed in recent decades in terms of the drugs, protocols and duration, allowing patients a longer life expectancy. As a consequence, we are currently observing an increase in chemotherapy-associated liver injury patterns once considered unusual. Recognizing this form of damage in an early stage is crucial for reconsidering the therapy regimen and thus avoiding severe complications. In this frontier article, we analyze the role of imaging in detecting some of these pathological patterns, such as pseudocirrhosis, “yellow liver” due to chemotherapy-associated steatosis-steatohepatitis, and “blue liver”, including sinusoidal obstruction syndrome, veno-occlusive disease and peliosis.

Quantitative Assessment of Fatty Liver using Ultrasound with Normalized Local Variance Technique

PURPOSE

 To assess the diagnostic performance of the normalized local variance (NLV) ultrasound technique in the detection of the fatty liver using histopathology as a reference standard.

MATERIALS AND METHODS

 We prospectively enrolled 194 consecutive patients with clinical suspicion of diffuse liver disease or history of liver transplantation. Conventional grayscale ultrasound and NLV examinations were performed and immediately followed by liver biopsies. The degrees of fatty liver, necroinflammatory activity, and fibrosis stage were evaluated by histopathological assessment. The diagnostic performance of the NLV values in detecting each grade of fatty liver was determined using receiver operating characteristics analyses, and multivariate linear regression analyses were performed to identify variables significantly associated with the NLV values.

RESULTS

 The number of patients in each degree of fatty liver and hepatic fibrosis was 118/37/26/13 and 81/68/24/6/14 for none/mild/moderate/severe steatosis and F0 / F1/F2 / F3/F4 fibrosis on histopathological examinations, respectively. The area under the receiver operating characteristics curve and optimal cut-off NLV value for detecting fatty liver of varying degrees were 0.911 and 1.095 for ≥ S1, 0.974 and 1.055 for ≥ S2, and 0.954 and 1.025 for ≥ S3, respectively. Multivariate analyses revealed that not fibrosis or inflammation but rather the degree of steatosis was associated with the NLV value.

CONCLUSION

 The NLV value demonstrated excellent diagnostic performance for detecting varying degrees of fatty liver, and the degree of steatosis on histopathological examinations was the only significant factor affecting the NLV value.

Estimated functional remnant pancreatic volume predicts nonalcoholic fatty liver disease after pancreaticoduodenectomy: use of computed tomography attenuation value of the pancreas

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is a late complication of pancreaticoduodenectomy (PD). However, this complication is difficult to predict preoperatively. This study aimed to assess the association between NAFLD and preoperative computed tomography (CT) findings.

METHODS

Medical records of 112 patients who had undergone PD and had CT scans preoperatively and 6 months postoperatively were retrospectively reviewed. We evaluated several CT findings, including the CT attenuation value of the remnant pancreas, remnant pancreatic volume (RPV), and the estimated functional remnant pancreatic volume (eFRPV) on preoperative CT. The variables, including the CT findings and histopathological findings, were compared between the patients with and without NAFLD after PD.

RESULTS

The NAFLD group included 21 patients (18.8%). The CT attenuation value of the remnant pancreas was correlated with the pancreatic acinar cell density (r = 0.537), and was lower in the NAFLD group than in the non-NAFLD group (p = 0.007). The eFRPV was lower in the NAFLD group than in the non-NAFLD group (p = 0.002). An eFRPV ≤47 mL·HU was an independent predictive factor for NAFLD (p = 0.007; odds ratio: 6.73; 95% confidence interval: 1.70-26.70).

CONCLUSION

The eFRPV can be used to preoperatively predict NAFLD after PD.

Multiparametric in vivo ultrasound shear wave viscoelastography on farm-raised fatty duck livers: human radiology imaging applied to food sciences

Nine mulard ducks that were being raised for foie gras (steatosis) production went through in vivo shear wave (SW) elastography imaging of their liver during the force-feeding period to investigate changes in liver tissue characteristics. A total of 4 imaging sessions at an interval of 3 to 4 d were conducted at the farm on each animal. Three ducks were sacrificed at the second, third, and fourth imaging sessions for histopathology analysis of all animals at these time points. Six SW elastography parameters were evaluated: SW speed, SW attenuation, SW dispersion, Young's modulus, viscosity, and shear modulus. Shear waves of different frequencies propagate with different phase velocities. Thus, SW speed and other dependent parameters such as Young's modulus, viscosity, and shear modulus were computed at 2 frequencies: 75 and 202 Hz. Each parameter depicted a statistically significant trend along the force-feeding process (P-values between 0.001 and 0.0001). The fat fraction of the liver increased over the 12-day period of feeding. All parameters increased monotonically over time at 75 Hz, whereas modal relations were seen at 202 Hz. Shear wave dispersion measured between 75 and 202 Hz depicted a plateau from day 5. Based on this validation, proposed imaging methods are aimed to be used in the future on naturally fed ducks and geese.

A Model to Predict Significant Macrosteatosis in Hepatic Grafts

BACKGROUND AND AIMS

Assessing the risk of significant macrosteatosis in donors is crucial before considering hepatic graft procurement. We aimed to build a model to predict significant macrosteatosis based on noninvasive methods.

METHODS

From January 2012 to December 2018, liver attenuation indices and liver-to-spleen (L/S) ratio were measured in 639 brain-dead donors by local radiologists. Quantity and quality of steatosis were evaluated by an expert pathologist, blinded for attenuation indices measurement.

RESULTS

Macrosteatosis ≥ 30% was found in 33 donors (5.2%). Body weight, body mass index (BMI), abdominal perimeters, history of alcohol abuse, L/S ratio, and liver parenchyma attenuation were associated with macrosteatosis ≥ 30%. The L/S ratio, BMI, and a history of alcohol abuse remained independent predictors in multivariate analysis and were used to build a predictive model (C-index: 0.77). The optimal cutoff to predict macrosteatosis ≥ 60% was 0.85.

CONCLUSION

Our model, including L/S ratio, BMI, and history of alcohol, might be helpful to refine indication for liver biopsy before donation after brain death. External validation is required.

Childhood severe acute malnutrition is associated with metabolic changes in adulthood

BACKGROUND

Severe acute malnutrition (SAM) is a major contributor to global mortality in children under 5 years. Mortality has decreased; however, the long-term cardiometabolic consequences of SAM and its subtypes, severe wasting (SW) and edematous malnutrition (EM), are not well understood. We evaluated the metabolic profiles of adult SAM survivors using targeted metabolomic analyses.

METHODS

This cohort study of 122 adult SAM survivors (SW = 69, EM = 53) and 90 age-, sex-, and BMI-matched community participants (CPs) quantified serum metabolites using direct flow injection mass spectrometry combined with reverse-phase liquid chromatography. Univariate and sparse partial least square discriminant analyses (sPLS-DAs) assessed differences in metabolic profiles and identified the most discriminative metabolites.

RESULTS

Seventy-seven metabolite variables were significant in distinguishing between SAM survivors (28.4 ± 8.8 years, 24.0 ± 6.1 kg/m²) and CPs (28.4 ± 8.9 years, 23.3 ± 4.4 kg/m²) (mean ± SDs) in univariate and sPLS-DA models. Compared with CPs, SAM survivors had less liver fat; higher branched-chain amino acids (BCAAs), urea cycle metabolites, and kynurenine/tryptophan (KT) ratio (P < 0.001); and lower β-hydroxybutyric acid and acylcarnitine/free carnitine ratio (P < 0.001), which were both associated with hepatic steatosis (P < 0.001). SW and EM survivors had similar metabolic profiles as did stunted and nonstunted SAM survivors.

CONCLUSION

Adult SAM survivors have distinct metabolic profiles that suggest reduced β-oxidation and greater risk of type 2 diabetes (BCAAs, KT ratio, urea cycle metabolites) compared with CPs. This indicates that early childhood SAM exposure has long-term metabolic consequences that may worsen with age and require targeted clinical management.

FUNDING

Health Research Council of New Zealand, Caribbean Public Health Agency, Centre for Global Child Health at the Hospital for Sick Children. DST is an Academic Fellow and a Restracomp Fellow at the Centre for Global Child Health. GBG is a postdoctoral fellow of the Research Foundation Flanders.

Pancreatic GLP-1r binding potential is reduced in insulin-resistant pigs

INTRODUCTION

The insulinotropic capacity of exogenous glucagon like peptide-1 (GLP-1) is reduced in type 2 diabetes and the insulin-resistant obese. We have tested the hypothesis that this response is the consequence of a reduced pancreatic GLP-1 receptor (GLP-1r) density in insulin-resistant obese animals.

RESEARCH DESIGN AND METHODS

GLP-1r density was measured in lean and insulin-resistant adult miniature pigs after the administration of a ⁶⁸Ga-labeled GLP-1r agonist. The effect of hyperinsulinemia on GLP-1r was assessed using sequential positron emission tomography (PET), both in the fasted state and during a clamp. The impact of tissue perfusion, which could account for changes in GLP-1r agonist uptake, was also investigated using ⁶⁸Ga-DOTA imaging.

RESULTS

GLP-1r binding potential in the obese pancreas was reduced by 75% compared with lean animals. Similar reductions were evident for fat tissue, but not for the duodenum. In the lean group, induced hyperinsulinemia reduced pancreatic GLP-1r density to a level comparable with that of the obese group. The reduction in blood to tissue transfer of the GLP-1r ligand paralleled that of tissue perfusion estimated using ⁶⁸Ga-DOTA.

CONCLUSIONS

These observations establish that a reduction in abdominal tissue perfusion and a lower GLP-1r density account for the diminished insulinotropic effect of GLP-1 agonists in type 2 diabetes.

Quantification of pancreas fat on dual-energy computed tomography: comparison with six-point Dixon magnetic resonance imaging

OBJECTIVES

Although it is important to quantify the degree of fatty degeneration of the pancreas, it is difficult to make such a quantification using conventional computed tomography (CT). The present study evaluated the feasibility of pancreatic fat quantification by dual-energy CT (DECT) compared with T2*-corrected six-point Dixon magnetic resonance imaging (MRI).

MATERIALS AND METHODS

Twenty-eight patients who underwent both DECT (100 and 150 kVp) and Dixon MRI without the use of contrast agents were analyzed. The region of interest (ROI) was placed at the head and body/tail of the pancreas on fat volume fraction (FVF) maps generated using the multi-material decomposition (MMD) algorithm on DECT. The FVF (%) of pancreatic parenchyma measured by DECT (CT-FVF) was compared with that measured on FVF maps calculated using Dixon MRI (MR-FVF) using the Spearman rank correlation coefficient.

RESULTS

The median CT-FVF (%) values of the head and body/tail of the pancreas on DECT were 14.2% (range 0.1-81.2%) and 9.4% (range 0-40.8%), respectively. The median MR-FVF (%) values of the head and body/tail of the pancreas on Dixon MRI were 12.2% (range 1.2-80.9%) and 8.1% (range 0.3-43.7%), respectively. CT-FVF (%) measured by DECT showed a significant correlation with the MR-FVF (%) measured by Dixon MRI in the head of the pancreas (ρ = 0.631, P < 0.001) as well as the body/tail of the pancreas (ρ = 0.526, P = 0.004).

CONCLUSION

DECT may be useful for quantifying the degree of fatty degeneration of the pancreas.

Advances in Imaging of Diffuse Parenchymal Liver Disease

There are >1.5 billion people with chronic liver disease worldwide, causing liver diseases to be a significant global health issue. Diffuse parenchymal liver diseases, including hepatic steatosis, fibrosis, metabolic diseases, and hepatitis cause chronic liver injury and may progress to fibrosis and eventually hepatocellular carcinoma. As early diagnosis and treatment of these diseases impact the progression and outcome, the need for assessment of the liver parenchyma has increased. While the current gold standard for evaluation of the hepatic parenchymal tissue, biopsy has disadvantages and limitations. Consequently, noninvasive methods have been developed based on serum biomarkers and imaging techniques. Conventional imaging modalities such as ultrasound, computed tomography scan, and magnetic resonance imaging provide noninvasive options for assessment of liver tissue. However, several recent advances in liver imaging techniques have been introduced. This review article focuses on the current status of imaging methods for diffuse parenchymal liver diseases assessment including their diagnostic accuracy, advantages and disadvantages, and comparison between different techniques.

Multi-energy computed tomography and material quantification: Current barriers and opportunities for advancement

Computed tomography (CT) technology has rapidly evolved since its introduction in the 1970s. It is a highly important diagnostic tool for clinicians as demonstrated by the significant increase in utilization over several decades. However, much of the effort to develop and advance CT applications has been focused on improving visual sensitivity and reducing radiation dose. In comparison to these areas, improvements in quantitative CT have lagged behind. While this could be a consequence of the technological limitations of conventional CT, advanced dual-energy CT (DECT) and photon-counting detector CT (PCD-CT) offer new opportunities for quantitation. Routine use of DECT is becoming more widely available and PCD-CT is rapidly developing. This review covers efforts to address an unmet need for improved quantitative imaging to better characterize disease, identify biomarkers, and evaluate therapeutic response, with an emphasis on multi-energy CT applications. The review will primarily discuss applications that have utilized quantitative metrics using both conventional and DECT, such as bone mineral density measurement, evaluation of renal lesions, and diagnosis of fatty liver disease. Other topics that will be discussed include efforts to improve quantitative CT volumetry and radiomics. Finally, we will address the use of quantitative CT to enhance image-guided techniques for surgery, radiotherapy and interventions and provide unique opportunities for development of new contrast agents.

Risk factors for histological progression of non-alcoholic steatohepatitis analyzed from repeated biopsy cases

BACKGROUND AND AIM

The most important prognostic factor for non-alcoholic steatohepatitis (NASH) is liver fibrosis. The aim of this study is to examine clinical parameters involved in pathological progression in NASH patients who underwent repeated liver biopsy and to analyze the response to treatment with respect to NASH-related single nucleotide polymorphisms (SNPs). We performed longitudinal analysis of genetic and clinical factors associated with progression of NASH.

METHODS

Eighty NASH patients who had undergone serial liver biopsies were enrolled in this retrospective cohort study. Histological exacerbation was determined based on non-alcoholic fatty liver disease activity score (NAS) and liver fibrosis.

RESULTS

About 22.5% had progression of fibrosis, 22.5% had improvement of fibrosis, and 55.0% had no change. NAS increased in 12.5%, decreased in 61.3%, and remained stable in the remaining 26.3%. We examined factors associated with histological progression versus non-progression. Poor response of alanine aminotransferase (ALT) levels, increase in HbA1c levels, and presence of the tumor necrosis factor risk allele in the rs1799964 SNP were identified as independent risk factors contributing to histological progression in NASH patients. In addition, we found that the histological progression rate varies with ALT response, HbA1c levels, and rs1799964 genotype.

CONCLUSIONS

In this study, we clarified the serum ALT level and the clinical significance of HbA1c to evaluate the progression of fibrosis in Japanese NASH patients. Furthermore, the tumor necrosis factor SNP was more likely to be involved in the response than PNPLA3 SNP. By simultaneously evaluating three factors, it is possible to estimate the risk of histological progression more accurately.

Quantitative Evaluation of Hepatic Steatosis Using Normalized Local Variance in a Rat Model: Comparison with Histopathology as the Reference Standard

Objective

To evaluate the diagnostic performance of the normalized local variance (NLV) ultrasound technique in the assessment of hepatic steatosis, and to identify the factors that influence the NLV value using histopathological examination as the reference standard.

Materials and Methods

Forty male Sprague-Dawley rats were fed a methionine-choline-deficient diet for variable periods (0, 2, 4, 6, 8, 10, or 12 days or 2, 3, or 4 weeks; four rats per group). At the end of each diet duration, magnetic resonance spectroscopy (MRS) and NLV examination were performed. Thereafter, the rats were sacrificed and their livers were histopathologically evaluated. Receiver operating characteristic (ROC) curve analysis was performed to assess the diagnostic capability of the NLV value in the detection of varying degrees of hepatic steatosis. Univariate and multivariate linear regressions were used to determine the factors associated with the NLV value.

Results

The areas under the ROC curve for the detection of mild, moderate, and severe hepatic steatosis were 0.953, 0.896, and 0.735, respectively. The NLV value showed comparable diagnostic performance to that of MRS in the detection of ≥ mild or ≥ moderate hepatic steatosis. Multivariate linear regression analysis revealed that the degree of hepatic steatosis was the only significant factor affecting the NLV value (p < 0.001).

Conclusion

The NLV value of ultrasound demonstrated satisfactory diagnostic performance in the assessment of varying degrees of hepatic steatosis. The degree of hepatic steatosis was the only significant factor that affected the NLV value.

In vivo Ultrafast Quantitative Ultrasound and Shear Wave Elastography Imaging on Farm-Raised Duck Livers during Force Feeding

Shear wave elastography (speed and dispersion), local attenuation coefficient slope and homodyned-K parametric imaging were used for liver steatosis grading. These ultrasound biomarkers rely on physical interactions between shear and compression waves with tissues at both macroscopic and microscopic scales. These techniques were applied in a context not yet studied with ultrasound imaging, that is, monitoring steatosis of force-fed duck livers from pre-force-fed to foie gras stages. Each estimated feature presented a statistically significant trend along the feeding process (p values <10^-3). However, whereas a monotonic increase in the shear wave speed was observed along the process, most quantitative ultrasound features exhibited an absolute maximum value halfway through the process. As the liver fat fraction in foie gras is much higher than that seen clinically, we hypothesized that a change in the ultrasound scattering regime is encountered for high-fat fractions, and consequently, care has to be taken when applying ultrasound biomarkers to grading of severe states of steatosis.

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.

Quantification of liver fat content with ultrasonographic attenuation measurement function: Correlation with unenhanced multidimensional computerized tomography

PURPOSE

To evaluate the efficacy of attenuation measurement function (ATT), a newly developed quantitative ultrasonography(US) method based on measurement of the attenuation coefficient, using unenhanced computerized tomography(CT) attenuation values as a reference standard, for the detection and measurement of hepatosteatosis.

MATERIAL AND METHODS

A total of 98 patients were analyzed. The diagnostic ability of ATT was evaluated using receiver operating characteristic (ROC) curve analysis, and the correlation between liver attenuation index (LAI), the liver-to-spleen attenuation ratio (CT^L/S), liver attenuation value (CT^L), and ATT was determined.

RESULTS

ATT is negatively correlated with LAI (r = -0.571, p < 0.001), CT^L/S (r = -0.532, p < 0.001), and mean CT^L (r = -0.50, p < 0.001). A significant difference was found between ATT values of patients with different grades of hepatosteatosis (p < 0.001). A significant difference was found between ATT values of patients with LAI < -10 and LAI > -10, CT^L < 40 and CT^L > 40, and CT^L/S < 1 and CT^L/S > 1 (p < 0.001). An ATT ≥ 0.665 showed a sensitivity of 100% and a specificity of 90% in diagnosing moderate-severe steatosis. The corresponding area under the ROC curve(AUROC) was 0.935. The intraclass correlation coefficient for the interobserver variability of ATT was 0.907 (95% CI, 0.85-0.95).

CONCLUSION

In conclusion, ATT values for evaluation of hepatosteatosis was closely correlated with the degree of hepatosteatosis and liver fat content. It can be used as a noninvasive method in the diagnosis and follow-up.

Comparison of computed tomography hepatic steatosis criteria for identification of abnormal liver function and clinical risk factors, in incidentally noted fatty liver

OBJECTIVES

Hounsfield Units (HU) to compare the various computed tomography (CT) criteria for diagnosing hepatic steatosis with laboratory liver function parameters, and clinical risk factors retrospectively, when hepatic steatosis was incidentally detected.

METHODS

Institutional review board-approved, Health Insurance Portability and Accountability Act-compliant, retrospective study in 200 randomly selected patients who had either nonenhanced CT (NECT) or contrast-enhanced CT (CECT) studies with reported hepatic steatosis. The participants were matched to age, gender, and ethnicity with 200 patients without hepatic steatosis. For NECT, four different criteria have been proposed in the literature to diagnose fatty liver: (1) liver HU less than 48 HU; (2) ratio of liver to spleen HU less than 0.8; (3) HU difference between liver and spleen less than -10; and (4) hepatic vessel HU ≥ liver HU. For CECT, difference between liver and spleen HU, in portal venous phase, ≤ -20 to -25 HU. Serum glucose, aspartate aminotransferase (AST), amino alanine transferase (ALT), total bilirubin were documented. Clinical history and clinical risk factors were documented from the electronic health records. Matched analyses and Wilcoxon signed rank sum test analysis were performed for matched variables.

RESULTS

Fatty liver by NECT criteria 1 and 3 has statistically significant correlation with elevated glucose levels (P = 0.02). Similarly, fatty liver by 1, 3, and 4 NECT criteria showed statistically significant associations with higher levels of ALT and AST. There were statistically significant higher prevalence of diabetes mellitus (P = 0.003) and alcohol consumption (P ≤ 0.0001) in cases when compared with the controls. There was marginal significance in CT Dose Index between cases and controls (95% confidence interval: 0.98, 1.00; odds ratio 0.99), reflecting that cases had slightly higher BMI compared to their matched controls, thereby requiring slightly higher mA/mAs for imaging.

CONCLUSION

Particular NECT criteria for fatty liver are best at identification of abnormal liver function and certain comorbidities, in the setting of incidental fatty liver detection, This creates the potential for benefits of early detection in clinical management.

Liver fat accumulation assessed by computed tomography is an independent risk factor for diabetes mellitus in a population-based study: SESSA (Shiga Epidemiological Study of Subclinical Atherosclerosis)

AIMS

Ectopic fat accumulation is related to insulin resistance and diabetes mellitus (DM). However, the effect of fatty liver on DM in non-obese individuals has not been clarified. We investigated whether liver fat accumulation assessed by computed tomography (CT) is associated with the incidence of DM.

METHODS

In a prospective population-based study, 640 Japanese men were followed up for 5 years. The liver to spleen (L/S) ratio of the CT attenuation value was used as the liver fat accumulation index. We calculated the odds ratio (OR) and 95% confidence interval (CI) for the DM incidence of per 1 standard deviation (SD) lower L/S and those of L/S < 1.0 compared with L/S ≥ 1.0, using logistic regression models.

RESULTS

Both per 1 SD lower L/S and L/S < 1.0 were significantly associated with a risk for DM incidence (1 SD lower L/S: OR = 1.57, 95%CI = 1.14-2.16; L/S < 1.0: OR = 2.27, 95%CI = 1.00-5.14). The relationship between L/S and incidence of DM was consistent in the obese and non-obese groups, with thresholds of BMI 25 kg/m², waist circumference 85 cm, or visceral adipose tissue 100 cm².

CONCLUSIONS

Liver fat accumulation assessed by CT was associated with the incidence of DM.

Torsion of Wandering Spleen: Importance of Splenic Density and Liver-to- Spleen Attenuation Ratio on CT

BACKGROUND

Wandering spleen (WS) is a rare clinical condition which may cause fatal complication like torsion with subsequent infarction. Determination of splenic parenchyma viability is very important in deciding whether splenopexy rather than splenectomy is an option. Contrast- enhanced computed tomography (CECT) is important for the diagnosis of WS and assessment of the viability of spleen.

DISCUSSION

We reviewed the CT studies of four cases with WS. We measured the mean splenic and liver density and calculated liver-to-spleen attenuation ratio (LSAR). We also assessed the CT findings for each patient. Mean splenic density was measured as 40.77 Hounsfield Unit (HU) in cases with infarction, 127.1 HU in case without infarction. LSAR was calculated as 2.55 in cases with infarction, 0.99 in case without infarction. We detected whirlpool sign, intraperitoneal free fluid, splenic arterial enhancement in all patient, parenchymal and splenic vein enhancement in one patient without infarction, fat rim sign in three patients with infarction, capsular rim sign in one patient with infarction.

CONCLUSION

CECT should be obtained for the diagnosis of WS and assessment of the viability of spleen. CECT could suggest the diagnosis of infarction of the spleen with following findings; absence of parenchymal enhancement, very low density of spleen (<45 HU), and LSAR which is greater than 2.

Noninvasive Imaging Modalities in Nonalcoholic Fatty Liver Disease: Where Do We Stand?

Nonalcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease worldwide. Liver biopsy is the gold standard for diagnosis and staging of fibrosis in patients with NAFLD; however, it is invasive, costly, and may be associated with morbidity and even mortality, so is not suitable for screening the large number of individuals who are at risk of, or have, NAFLD. Therefore, there has been tremendous focus on finding noninvasive diagnostic modalities, including imaging. New imaging modalities are emerging and may potentially replace biopsy. This review discusses the different noninvasive imaging modalities for the assessment of NAFLD.

Branched chain amino acids are associated with the heterogeneity of the area of lipid droplets in hepatocytes of patients with non-alcoholic fatty liver disease

AIM

Macrovesicular steatosis around the central vein (zone 3) is one of the pathological features of non-alcoholic fatty liver disease or steatohepatitis (NAFLD/NASH). The aim of this study is to elucidate precisely the association between the area of lipid droplets (LDs) and the plasma metabolic parameters in patients with NAFLD/NASH.

METHODS

Eighty patients with NAFLD/NASH diagnosed by needle biopsy were enrolled. The LDs around zone 3 were counted automatically by image processing software, the total area of LDs (TLDs), the maximum area of LDs (MAXLDs), the average area of LDs (AVELDs) and the heterogeneity by the coefficient of variation (CV [%]) were quantified. The correlations between these values and plasma metabolic parameters were analyzed. We evaluated the association between branched chain amino acids (BCAAs) and the heterogeneity of LDs in hepatocytes in vitro and in vivo.

RESULTS

The MAXLDs was significantly correlated with more metabolic parameters than AVELDs and TLDs. The level of BCAAs was independently associated with the CV among the metabolic parameters. In early stage NAFLD, aspartate and alanine aminotransferase were significantly higher in the high CV group than in the low CV group. The high concentration of BCAAs increased the CV of LDs in hepatocytes accompanied by the expression of phosphor-p70 S6 kinase and sterol regulatory element-binding protein 1 in vitro. A high BCAA diet induced high heterogeneity of LDs around zone 3 in ob/ob mice.

CONCLUSIONS

The levels of BCAAs were associated with the LD heterogeneity of hepatocytes around zone 3 in patients with NAFLD/NASH.

The association between liver fat and systemic calcified atherosclerosis

BACKGROUND

The association of nonalcoholic fatty liver disease (NAFLD) with systemic calcified atherosclerosis, other than the coronary arteries, has not been clearly elucidated. We investigated the association between NAFLD and calcification in eight different vascular beds.

METHODS

In a community-based cohort with computed tomography scans for carotid artery, coronary artery, thoracic aorta, abdominal aorta, iliac artery, renal artery, celiac trunk, and superior mesenteric artery, the association between NAFLD and arterial calcification was evaluated with adjustment for age, sex, hypertension, dyslipidemia, diabetes, obesity, current smoking status, and family history of heart disease in the first-degree relatives.

RESULTS

In age- and sex-adjusted models, NAFLD was significantly associated with calcification in the coronary artery, carotid artery, thoracic aorta, celiac trunk, and superior mesenteric artery vascular beds (P < .05). However, adjustment for the traditional chronic venous disease risk factors attenuated the associations, except in the case of the thoracic aorta (odds ratio [OR], 1.38; 95% confidence interval [CI], 1.09-1.78) and celiac trunk (OR, 2.05; 95% CI, 1.16-3.65). In addition, NAFLD was independently associated with multiarterial calcification (four or more [OR, 1.33; 95% CI, 1.01-1.74], five or more [OR, 1.46; 95% CI, 1.09-1.97], and six or more [OR, 1.58; 95% CI, 1.09-2.30] of eight evaluated arterial segments).

CONCLUSIONS

The association between NAFLD and arterial calcification is mainly mediated by conventional risk factors. The independent association between NAFLD and calcification in the thoracic aorta and celiac trunk as well as in a larger number of vascular beds needs confirmation in future prospective studies in diverse populations.

The "Skinny" on Assessment and Utilization of Steatotic Liver Grafts: A Systematic Review

The frequency at which steatotic deceased donor liver grafts are encountered will likely continue to increase. Utilization of liver grafts with moderate-to-severe steatosis for liver transplantation (LT) has been previously shown to be associated with increased rates of primary nonfunction and decreased recipient survival. In order to better inform clinical decision making and guide future research, critical evaluation of the literature on donor liver steatosis and posttransplantation outcome is needed. This literature review aims to provide the "skinny" on using deceased donor steatotic livers for LT.

Plasma fibroblast growth factor 21 levels increase with ectopic fat accumulation and its receptor levels are decreased in the visceral fat of patients with type 2 diabetes

BACKGROUND

Fibroblast growth factor 21 (FGF21) is a novel metabolic regulator that has beneficial effects on glucose and lipid metabolism. However, plasma FGF21 levels are paradoxically increased in type 2 diabetes mellitus (T2DM) and obesity, suggesting resistance to this ligand. FGF21 acts mainly on adipose tissue and ectopic fat accumulation is a typical feature in metabolic deterioration such as diabetes, metabolic syndrome, and cardiovascular disease.

OBJECTIVE

To investigate the relationship between FGF21 resistance and ectopic fat accumulation.

RESEARCH DESIGN AND METHODS

Subjects who underwent 64-slice multidetector CT (MDCT) were enrolled (n=190). Plasma FGF21 levels and MDCT data of ectopic fats at various sites were analyzed. Human visceral and subcutaneous fat tissues from abdominal and coronary artery bypass surgery were obtained. FGF21 receptor expression and postreceptor signaling in different fat deposits of both control and T2DM subjects were analyzed.

RESULTS

Plasma FGF21 levels were significantly associated with body mass index, triglyceride, homeostatic model assessment of insulin resistance, and Matsuda index. Plasma FGF21 levels were significantly higher in patients with T2DM than in the pre-diabetes and normal glucose tolerance groups. The ectopic fat phenotypes (visceral, epicardial, intrahepatic, and intramuscular fat) of T2DM were significantly higher than controls. Plasma FGF21 levels were elevated and exhibited a strong positive correlation with ectopic fat accumulation in T2DM. The expression of genes comprising the FGF21 signaling pathway was also lower in visceral fat than in subcutaneous fat in this disease.

CONCLUSIONS

Human FGF21 resistance in T2DM could result from increases in FGF21-resistant ectopic fat accumulation. Our study provides novel clinical evidence linking FGF21 resistance and T2DM pathogenesis.

Diabetes Mellitus, Nonalcoholic Fatty Liver Disease, and Conjugated Linoleic Acid (Omega 6): What Is the Link?

BACKGROUND AND OBJECTIVE

Type 2 DM and obesity are the coming epidemics and their association with NAFLD is well established; essential fatty acids are vital for body health yet the body cannot make them; 2 essential fatty acids are especially important: linoleic (omega-6) and alpha-linoleic (omega-3) acids; they can be considered as "bioactive lipids" and serve as functional foods.

METHODS

50 type 2 Egyptian diabetic patients controlled on oral hypoglycemic drugs together with 20 age- and sex-matched healthy participants were enrolled in the study; all were subjected to complete history taking, BMI, fasting plasma glucose, HOMA-IR, ALT, AST, GGT, urea and creatinine, total lipid profile, hepatitis markers including hepatitis B surface antigen and hepatitis C virus antibodies, conjugated linoleic fatty acid "CLA," and abdominal ultrasound for grading of NAFLD.

RESULTS

Our study in Egyptian diabetics with NAFLD revealed a low level of serum CLA compared to healthy control; such deficiency was more marked with advanced grades of NAFLD; lowest levels were observed in those with severe steatosis (NASH) with definite association between CLA and obesity.

CONCLUSION

Insulin resistance is the main link between NAFLD, diabetes, and obesity. Conjugated linoleic acid (CLA) has a role in fat deposition in the liver and in development and improvement of insulin resistance. Fatty food had a documented role in the pathogenesis of obesity and diabetes but it can also be the cure.

Quantitative Hepatic Fat Quantification in Non-alcoholic Fatty Liver Disease Using Ultrasound-Based Techniques: A Review of Literature and Their Diagnostic Performance

Non-alcoholic fatty liver disease is a condition that is characterized by the presence of >5% fat in the liver and affects more than one billion people worldwide. If adequate and early precautions are not taken, non-alcoholic fatty liver disease can progress to cirrhosis and death. The current reference standard for detecting hepatic steatosis is a liver biopsy. However, because of the potential morbidity associated with liver biopsies, non-invasive imaging biomarkers have been extensively investigated. Magnetic resonance imaging-based methods have proven accuracy in quantifying liver steatosis; however, these techniques are costly and have limited availability. Ultrasound-based quantitative imaging techniques are increasingly utilized because of their widespread availability, ease of use and relative cost-effectiveness. Several ultrasound-based liver fat quantification techniques have been investigated, including techniques that measure changes in the acoustic properties of the liver caused by the presence of fat. In this review, we focus on quantitative ultrasound approaches and their diagnostic performance in the realm of non-alcoholic fatty liver disease.

Identification of nonalcoholic fatty liver disease following pancreatectomy for noninvasive intraductal papillary mucinous neoplasm

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) following pancreatectomy is a potential cause of long term morbidity in patients undergoing pancreatic resection with curative intent. Prior studies have reported an incidence of NAFLD up to 30% following pancreatectomy but the investigated cohorts were typically a mix of benign and malignant disease. Here we examined the incidence of NAFLD in a homogenous cohort of patients following pancreatectomy for benign intraductal papillary mucinous neoplasm (IPMN).

METHODS

A retrospective review of patients who underwent pancreatic resection for IPMN from 2000 to 2016 was performed. Post pancreatectomy CT/MRI scans were obtained as standard surveillance. We investigated changes in the liver parenchymal density on post surgical imaging to estimate the frequency with which NAFLD occurred. Radiographic criteria for NAFLD included Hounsfield units less than 40 on CT or liver:spleen ratio <0.9 on CT or MRI. Fischer's exact test, Kruskal-Wallis test, and logistic regression were performed.

RESULTS

Our study cohort included 109 patients who underwent pancreatectomy for nonmalignant intraductal papillary mucinous neoplasm with no evidence of NAFLD preoperatively and at least 6 months follow-up. Mean follow-up was 52 months (range 8-130/months). The incidence of postoperative NAFLD was 17/109 (15.6%). Most cases occurred within 12 months of pancreatectomy. On multivariate analysis, proximal pancreatectomy (pancreaticoduodenectomy) and development of atrophy of the pancreas remnant were significant risk factors for development of hepatic steatosis (p < 0.05).

CONCLUSION

Patients undergoing pancreatectomy for benign disease have a significant risk of developing NAFLD but the frequency is lower than previously reported in cohorts that included individuals with malignant disease. Highest risk was observed in individuals who underwent pancreaticoduodenectomy or developed pancreatic atrophy. Further investigations to define the mechanisms that promote steatosis and interventions to prevent subsequent morbidity from NAFLD are warranted.

Dietary Patterns among Asian Indians Living in the United States Have Distinct Metabolomic Profiles That Are Associated with Cardiometabolic Risk

Background

Recent studies, primarily in non-Hispanic whites, suggest that dietary patterns have distinct metabolomic signatures that may influence disease risk. However, evidence in South Asians, a group with unique dietary patterns and a high prevalence of cardiometabolic risk, is lacking.

Objective

We investigated the metabolomic profiles associated with 2 distinct dietary patterns among a sample of Asian Indians living in the United States. We also examined the cross-sectional associations between metabolomic profiles and cardiometabolic risk markers.

Methods

We used cross-sectional data from 145 Asian Indians, aged 45-79 y, in the Metabolic Syndrome and Atherosclerosis in South Asians Living in America (MASALA) pilot study. Metabolomic profiles were measured from fasting serum samples. Usual diet was assessed by using a validated food-frequency questionnaire. We used principal components analysis to derive dietary and metabolomic patterns. We used adjusted general linear regression models to examine associations between dietary patterns, individual food groups, metabolite patterns, and cardiometabolic risk markers.

Results

We observed 2 major principal components or metabolite clusters, the first comprised primarily of medium- to long-chain acylcarnitines (metabolite pattern 1) and the second characterized by branched-chain amino acids, aromatic amino acids, and short-chain acylcarnitines (metabolite pattern 2). A "Western/nonvegetarian" pattern was significantly and positively associated with metabolite pattern 2 (all participants: β ± SE = 0.180 ± 0.090, P = 0.05; participants without type 2 diabetes: β ± SE = 0.323 ± 0.090, P = 0.0005). In all participants, higher scores on metabolite pattern 2 were adversely associated with measures of glycemia (fasting insulin: β ± SE = 2.91 ± 1.29, P = 0.03; 2-h insulin: β ± SE = 22.1 ± 10.3, P = 0.03; homeostasis model assessment of insulin resistance: β ± SE = 0.94 ± 0.42, P = 0.03), total adiponectin (β ± SE = -1.46 ± 0.47, P = 0.002), lipids (total cholesterol: β ± SE = 7.51 ± 3.45, P = 0.03; triglycerides: β ± SE = 14.4 ± 6.67, P = 0.03), and a radiographic measure of hepatic fat (liver-to-spleen attenuation ratio: β ± SE = -0.83 ± 0.42, P = 0.05).

Conclusions

Our findings suggest that a "Western/nonvegetarian" dietary pattern is associated with a metabolomic profile that is related to an adverse cardiometabolic profile in Asian Indians. Public health efforts to reduce cardiometabolic disease burden in this high-risk group should focus on consuming a healthy plant-based diet.

Vitamin D Levels, Body Composition, and Metabolic Factors in Asian Indians: Results from the Metabolic Syndrome and Atherosclerosis in South Asians Living in America Pilot Study

BACKGROUND/AIMS

Asian Indians have a high prevalence of vitamin D deficiency and metabolic syndrome. Vitamin D deficiency is associated with an increased risk of cardiovascular disease and diabetes.

METHODS

We performed a cross-sectional study of 150 Asian Indians (50% male) from the San Francisco Bay Area. We assessed the association between 25-OH vitamin D (25-OHD) levels and vitamin D deficiency with body composition (anthropometric and radiographic measures) and metabolic outcomes.

RESULTS

In both men and women, the presence of vitamin D deficiency was associated with higher systolic (p = 0.004) and diastolic (p = 0.01) blood pressure, and fasting glucose (p = 0.01). Only in women, vitamin D deficiency status was associated with higher body mass index (BMI), waist-to-hip ratio, visceral fat area, and hepatic fat content after adjusting for age, income, and physical activity level. In women, 25-OHD was also associated with fasting glucose after adjusting for age, income, and physical activity and further adjusting for BMI and waist circumference (β -2.1, 95% CI -0.86 to -0.01, p = 0.04). This association between vitamin D deficiency and metabolic parameters was not significant in men.

CONCLUSIONS

A lower level of 25-OHD and vitamin D deficiency were associated with higher levels of metabolic factors among Asian Indians. Our findings suggest that 25-OHD metabolism may differ by the distribution of adipose tissue and involve previously unexplored pathways accounting for the variability in the role of vitamin D in cardiovascular disease.

Involvement of Porphyromonas gingivalis in the progression of non-alcoholic fatty liver disease

BACKGROUND AND AIMS

The risk factors in the progression of nonalcoholic fatty liver disease (NAFLD) have not been fully clarified. Porphyromonas gingivalis (P.g) has been considered to be a confounding risk factor for systemic diseases. We aimed to evaluate the effect of P.g infection on risk of progression to NASH.

METHODS

(1) Serum IgG antibody titers against P.g fimbriae (fimA) in 200 biopsy-proven NAFLD patients were measured by ELISA and compared with histological findings. (2) C57BL/6J mice were fed a control diet (CD) or high-fat diet (HFD) with or without P.g-odontogenic infection and analyzed histologically. Mouse livers were analyzed using CE-TOFMS and LC-TOFMS.

RESULTS

(1) A significant correlation between fibrosis progression and antibody titers against P.g possessing fimA type 4 was identified (P = 0.0081). Multivariate analysis identified older age and type 4 P.g-positivity as risk factors for advanced fibrosis. (2) Fibrosis and steatosis were more severe in HFD P.g(+) mice compared with HFD P.g(-) mice. In metabolome analysis, fatty acid metabolism was significantly disrupted with HFD in P.g-infected mouse livers. Monounsaturated/saturated fatty acid ratios were significantly higher in the HFD P.g(+) group than in the HFD P.g(-) group (P < 0.05). Moreover, expression levels of SCD1 and ELOVL6 were significantly reduced.

CONCLUSIONS

These results suggest that P.g infection is an important risk factor for pathological progression in NAFLD. Increase in the monounsaturated/saturated fatty acid ratio may be an important change that facilitates progression of NAFLD.

Comparison of correlations between lipid profile and different computed tomography fatty liver criteria in the setting of incidentally noted fatty liver on computed tomography examinations

PURPOSE

The aim of this study was to compare the correlations between computed tomography (CT) criteria for hepatic steatosis and lipid profile values when hepatic steatosis is incidentally detected.

PARTICIPANTS AND METHODS

This is an institutional Review Board-approved, HIPPA-compliant, retrospective study of abdominal CT scans in 200 randomly selected patients who had either nonenhanced CT (NECT) or contrast-enhanced CT (CECT) studies with reported fatty liver. The participants were matched for age, sex, and ethnicity with 200 patients with nonfatty liver. For NECT, four different criteria have been proposed in the literature to diagnose fatty liver: (i) liver Hounsfield Units (HU) less than 48 HU, (ii) ratio of liver to spleen HU less than 0.8, (iii) HU difference between liver and spleen less than -10, and (iv) hepatic vessel HU greater than or equal to liver HU. For CECT, the criteria was attenuation difference between liver and spleen HU, in the portal venous phase of up to -20 to -25 HU. Laboratory results (low-density lipoprotein, high-density lipoprotein, triglycerides) were documented. Matched analyses and conditional logistic regression analysis were carried out for matched variables.

RESULTS

There were statistically significant differences in triglyceride values, between the cases and controls (P=0.02), when all criteria were considered. Also, statistically significant differences were found between cases and controls on the basis of NECT criterion 2 and high-density lipoprotein (P=0.04), as well as CECT criteria and triglyceride levels (P=0.02). In addition, the data indicate that criteria for steatosis on CECT may be more broad than traditionally utilized.

CONCLUSION

Incidental reporting of fatty liver on NECT/CECT should prompt consideration of clinical follow-up and lipid profile testing in an otherwise asymptomatic patient. Additional metrics for the diagnosis of steatosis in CECT exam should also be considered.

The effect of diet or exercise on ectopic adiposity in children and adolescents with obesity: a systematic review and meta-analysis

OBJECTIVE

Ectopic fat depostion in youth with obesity is associated with an increased cardiovascular disease risk. The aim of this meta-analysis was to summarize the evidence for the use of diet and/or exercise on ectopic adiposity in this population.

METHODS

A systematic literature search was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-analysis statement. Clinical trials that assessed ectopic fat deposition and included study arms with diet and/or exercise were searched in PubMed, PEDro and the Cochrane database.

RESULTS

Hepatic fat content and intramyocellular lipid content were described in nine studies and three studies, respectively. Most studies included teenagers, and study duration ranged between 3 and 12 months without follow-up. Using random-effects weights, the standardized mean difference of the change in hepatic adiposity (totalling 320 subjects) was -0.54 Hedges' g (95% confidence interval: -0.69 to -0.38 with p < 0.0001). By re-expressing this effect size, it is seen that diet and/or exercise results in an absolute reduction of intrahepatic lipid with 2%, which accords with a relative reduction up to 70%. Although there were significant ameliorations of insulin sensitivity, no significant changes in intramyocellular lipid were observed.

CONCLUSIONS

This meta-analysis showed that diet and/or exercise is effective to reduce hepatic adiposity in youth with obesity.