Comparison of anthropometric, area- and volume-based assessment of abdominal subcutaneous and visceral adipose tissue volumes using multi-detector computed tomography

Development of a sex-specific visceral fat area estimation using discrete multi-wavelength near-infrared spectroscopy measurements in Korean individuals

BACKGROUND/OBJECTIVES

A high level of visceral fat area (VFA) is associated with obesity and cardiometabolic risk factors. VFA measured by computer tomography (CT) scan is accurate but has limitations for everyday use. Meanwhile, near-infrared (NIR) light penetrates the superficial layers of the human body so that fat content can be measured just as CT imaging measures fat accumulation.

SUBJECTS/METHODS

This study evaluated whether discrete multi-wavelength NIR spectroscopy (DMW-NIRS) can be used to measure abdominal fat as a satisfactory alternative to a CT scan. 290 subjects were enrolled in this study, and each subject underwent DMW-NIRS NIR measurement and CT scan. A sex-specific DMW-NIRS-based VFA estimation formula was developed by multiple linear regression, including lipid density, age, and body mass index (BMI).

RESULTS

The model of DMW-NIRS estimated VFA gave the least Akaike Information Criterions (AIC), Root Mean Squared Errors (RMSE), and the greatest Coefficient of determination (R2) to predict VFA (1199, 29.5, 0.544 in female, and 1714, 41.3, 0.504 in male, respectively). Also, the DMW-NIRS estimated that VFA was highly performed to determine visceral obesity, which is comparable with other obesity surrogates.

CONCLUSIONS

This study suggested that lipid density can be used as a valid, noninvasive method to determine visceral obesity.

Sensitivity improvement of a deuterium-deuterium neutron generator based in vivo neutron activation analysis (IVNAA) system

Our lab has been developing a deuterium-deuterium (DD) neutron generator-based neutron activation analysis (NAA) system to quantify metals and elements in the human body in vivo. The system has been used to quantify metals such as manganese, aluminum, sodium in bones of a living human. The technology provides a useful way to assess metal exposure and to estimate elemental deposition, storage and biokinetics. It has great potential to be applied in the occupational and environmental health fields to study the association of metal exposure and various health outcomes, as well as in the nutrition field to study the intake of essential elements and human health. However, the relatively low sensitivity of the system has greatly limited its applications. Neutron moderation plays an important role in designing an IVNAA facility, as it affects thermal neutron flux in irradiation cave and radiation exposure to the human subject. This study aims to develop a novel thermal neutron enhancement method to improve the sensitivity of the in vivo neutron activation analysis (IVNAA) system for elemental measurement but still maintain radiation dose. Utilizing a compact DD neutron source, we propose a new and practical moderator design that combines high density polyethylene with heavy water to enhance thermal neutrons by reducing thermal neutron absorption. All material dimensions are calculated by PHITS, a general-purpose Monte Carlo simulation program. The improvement of the new design predicted by the Monte Carlo simulation for the quantification of one of the elements, manganese was verified by experimental irradiation of manganese-doped bone equivalent phantoms. For the same radiation dose, a 67.9% thermal neutron flux enhancement is reached. With only 4.2% increase of radiation dose, the simulated thermal neutron flux and activation can be further increased by 84.2%. A 100% thermal neutron enhancement ratio is also achievable with a 20% dose increase. The experimental results clearly show higher manganese activation gamma ray counts for each specific phantom, with a significantly reduced minimum detection limit. Additionally, the photon dose was suppressed. The thermal neutron enhancement method can increase the number of useful neutrons significantly but maintain the radiation dose. This greatly decreased the detection limit of the system for elemental quantification at an acceptable dose, which will broadly expand the application of the technology in research and clinical use. The method can also be applied to other neutron medical applications, including neutron imaging and radiotherapy.

Short-term outcomes of preoperative computed tomography angiography versus standard assessment in patients with BMI ≥ 25.0 kg/m2 undergoing laparoscopic gastrectomy: the GISSG20-01 randomized clinical trial

BACKGROUND

Laparoscopic gastrectomy lacks hand-direct tactile sense and has a limited surgical field compared to laparotomy. Apart from textbook classification, there are anatomical variations in the gastric arteries. Laparoscopic gastrectomy presents technical difficulties and necessitates a more comprehensive comprehension of regional anatomy than open surgical procedures. We aimed to compare efficacy and safety of preoperative computed tomography angiography (CTA) associated with surgical decision-making for laparoscopic gastrectomy.

METHODS

The GISSG 20-01 study was a multicenter, open-label, randomized clinical trial. The enrollment criteria mainly included histologically confirmed gastric cancer patients with BMI ≥ 25 kg/m2. Eligible patients were randomly assigned to the CTA group or the non-CTA group in a 1:1 ratio. The primary endpoint was the volume of intraoperative blood loss.

RESULTS

Between November 2020 and December 2021, 382 patients were enrolled and randomly assigned. After exclusion of 25 patients, 357 patients were included in the modified intention-to-treat population (179 in the CTA group and 178 in the non-CTA group). The mean intraoperative blood loss (CTA vs non-CTA; 74.2 vs 95.0 mL, P = 0.005) and operation time (215.4 vs 231.2 min, P = 0.004) was significantly lower in the CTA group. Total number of retrieved lymph nodes was similar in two groups (32.2 vs 30.2, P = 0.070). The CTA group had a significantly lower surgery task load index sore than the non-CTA group (36.6 vs 41.7, P < 0.001). There was no significant difference in postoperative complications rate of 14.5% in the CTA group and 22.5% in the non-CTA group (difference, - 8.0% [95% CI, - 16.0 to 0.1]; P = 0.053).

CONCLUSION

Preoperative CTA associated with surgical decision-making could relieve surgery burden and lead to a better surgical performance compared with non-CTA support, which including decreased blood loss volume, vessel damage and operation time.

TRIAL REGISTRATION

NCT04636099.

Influence of body fat tissue on outcomes in patients undergoing hepatectomy or liver transplantation: a systematic review and meta-analysis

OBJECTIVE

The purpose of this study is to investigate potential associations between body fat composition and postoperative outcomes in patients with hepatectomy or liver transplantation.

METHODS

Three online databases, including Embase, PubMed, and the Cochrane Library, were thoroughly searched for literature describing the relationship between body fat composition and outcomes of patients with liver surgery from the start of each database to 29 October 2023. The Newcastle-Ottawa Scale was used to rate the quality of the studies.

RESULTS

This analysis included a total of 29 articles with a combined patient cohort of 6435 individuals. The results demonstrated that patients with high intramuscular fat content (IMFC) had significantly inferior overall survival (OS) [hazard ratio (HR): 2.07, 95% CI: 1.69-2.53, P <0.001] and recurrence-free survival (RFS) (HR: 1.61, 95% CI: 1.20-2.16, P =0.002) and a higher risk of major complications (HR: 2.20, 95% CI: 1.59-3.05, P <0.001). We also found that the presence of high visceral-to-subcutaneous fat tissue ratio (VSR) in patients with liver surgery was significantly related to poorer OS (HR: 1.70, 95% CI: 1.44-2.00, P <0.001) and progression-free survival (PFS) (HR: 1.29, 95% CI: 1.11-1.50, P =0.001) and a higher major complication rate (HR: 2.31, 95% CI: 1.17-4.56, P =0.016). Besides, the synthesized findings indicated there is no significant correlation between visceral fat tissue and survival outcomes or postoperative complications.

CONCLUSION

In summary, preoperative IMFC and VSR have the potential to forecast poorer OS and RFS and a higher risk of complications for patients undergoing hepatectomy or liver transplantation.

Low HDL-C/ApoA-I index is associated with cardiometabolic risk factors and coronary artery calcium: a sub-analysis of the genetics of atherosclerotic disease (GEA) study

BACKGROUND

The high-density lipoprotein cholesterol to apolipoprotein A-I index (HDL-C/ApoA-I) may be practical and useful in clinical practice as a marker of atherosclerosis. This study aimed to investigate the association between the HDL-C/ApoA-I index with cardiometabolic risk factors and subclinical atherosclerosis.

METHODS

In this cross-sectional sub-analysis of the GEA study, 1,363 individuals, women (51.3%) and men (48.7%) between 20 and 75 years old, without coronary heart disease or diabetes mellitus were included. We defined an adverse cardiometabolic profile as excess adipose tissue metrics, non-alcoholic liver fat measured by non-contrasted tomography, metabolic syndrome, dyslipidemias, and insulin resistance. The population was stratified by quartiles of the HDL-C/Apo-AI index, and its dose-relationship associations were analysed using Tobit regression, binomial, and multinomial logistic regression analysis.

RESULTS

Body mass index, visceral and pericardial fat, metabolic syndrome, fatty liver, high blood pressure, and CAC were inversely associated with the HDL-C/ApoA-I index. The CAC > 0 prevalence was higher in quartile 1 (29.2%) than in the last quartile (22%) of HDL-C/ApoA-I index (p = 0.035). The probability of having CAC > 0 was higher when the HDL-C/ApoA-I index was less than 0.28 (p < 0.001). This association was independent of classical coronary risk factors, visceral and pericardial fat measurements.

CONCLUSION

The HDL-C/ApoA-I index is inversely associated with an adverse cardiometabolic profile and CAC score, making it a potentially useful and practical biomarker of coronary atherosclerosis. Overall, these findings suggest that the HDL-C/ApoA-I index could be useful for evaluating the probability of having higher cardiometabolic risk factors and subclinical atherosclerosis in adults without CAD.

Evaluation of Mucosal Healing in Crohn's Disease: Radiomics Models of Intestinal Wall and Mesenteric Fat Based on Dual-Energy CT

This study aims to assess the effectiveness of radiomics signatures obtained from dual-energy computed tomography enterography (DECTE) in the evaluation of mucosal healing (MH) in patients diagnosed with Crohn's disease (CD). In this study, 106 CD patients with a total of 221 diseased intestinal segments (79 with MH and 142 non-MH) from two medical centers were included and randomly divided into training and testing cohorts at a ratio of 7:3. Radiomics features were extracted from the enteric phase iodine maps and 40-kev and 70-kev virtual monoenergetic images (VMIs) of the diseased intestinal segments, as well as from mesenteric fat. Feature selection was performed using the least absolute shrinkage and selection operator (LASSO) logistic regression. Radiomics models were subsequently established, and the accuracy of these models in identifying MH in CD was assessed by calculating the area under the receiver operating characteristic curve (AUC). The combined-iodine model formulated by integrating the intestinal and mesenteric fat radiomics features of iodine maps exhibited the most favorable performance in evaluating MH, with AUCs of 0.989 (95% confidence interval (CI) 0.977-1.000) in the training cohort and 0.947 (95% CI 0.884-1.000) in the testing cohort. Patients categorized as high risk by the combined-iodine model displayed a greater probability of experiencing disease progression when contrasted with low-risk patients. The combined-iodine radiomics model, which is built upon iodine maps of diseased intestinal segments and mesenteric fat, has demonstrated promising performance in evaluating MH in CD patients.

Influence of nutritional status and body composition on postoperative events and outcome in patients treated for primary localized retroperitoneal sarcoma

BACKGROUND

Retroperitoneal sarcomas (RPS) are rare tumours of mesenchymal origin, commonly presented as a large tumour mass at time of diagnosis. We investigated the impact of body composition on outcome in patients operated on for primary localized RPS.

PATIENTS AND METHODS

We retrospectively analysed data for all patients operated on for primary RPS at our institution between 1999 and 2020. Preoperative skeletal muscle area (SMA), visceral and subcutaneous adipose tissue area (VAT and SAT) and muscle radiation attenuation (MRA) were calculated using computed tomography scans at the level of third lumbar vertebra. European Working Group on Sarcopenia in Older People (EWGSOP2) criteria were applied to define myopenia. Using maximum log-rank statistic method we determined the optimal cut-off values of body composition parameters. Myosteatosis was defined based on determined MRA cut-offs.

RESULTS

In total 58 patient were eligible for the study. With a median follow-up of 116 months, the estimated 5-year overall survival (OS) and local-recurrence free survival (LRFS) were 66.8% and 77.6%, respectively. Patients with myopenia had significantly lower 5-year OS compared to non-myopenic (p = 0.009). Skeletal muscle index and subcutaneous adipose tissue index predicted LRFS on univariate analysis (p = 0.052 and p = 0.039, respectively). In multivariate analysis high visceral-to-subcutaneous adipose tissue area ratio (VSR) independently predicted higher postoperative complication rate (89.2% vs. 10.8%, p = 0.008). Myosteatosis was associated with higher postoperative morbidity.

CONCLUSIONS

Myopenia affected survival, but not postoperative outcome in RPS. Visceral obesity, VSR (> 0.26) and myosteatosis were associated with higher postoperative morbidity. VSR was better prognostic factor than VAT in RPS.

Muscle Reference Values From Thoracic and Abdominal CT for Sarcopenia Assessment: The Framingham Heart Study

BACKGROUND

Loss of muscle mass is a known feature of sarcopenia and predicts poor clinical outcomes. Although muscle metrics can be derived from routine computed tomography (CT) images, sex-specific reference values at multiple vertebral levels over a wide age range are lacking.

OBJECTIVE

The aim of this study was to provide reference values for skeletal muscle mass and attenuation on thoracic and abdominal CT scans in the community-based Framingham Heart Study cohort to aid in the identification of sarcopenia.

MATERIALS AND METHODS

This secondary analysis of a prospective trial describes muscle metrics by age and sex for participants from the Framingham Heart Study without prior history of cancer who underwent at least 1 CT scan between 2002 and 2011. Using 2 previously validated machine learning algorithms followed by human quality assurance, skeletal muscle was analyzed on a single axial CT image per level at the 5th, 8th, 10th thoracic, and 3rd lumbar vertebral body (T5, T8, T10, L3). Cross-sectional muscle area (cm 2 ), mean skeletal muscle radioattenuation (SMRA, in Hounsfield units), skeletal muscle index (SMI, in cm 2 /m 2 ), and skeletal muscle gauge (SMRA·SMI) were calculated. Measurements were summarized by age group (<45, 45-54, 55-64, 65-74, ≥75 years), sex, and vertebral level. Models enabling the calculation of age-, sex-, and vertebral-level-specific reference values were created and embedded into an open access online Web application.

RESULTS

The cohort consisted of 3804 participants (1917 [50.4%] males; mean age, 55.6 ± 11.8 years; range, 33-92 years) and 7162 CT scans. Muscle metrics qualitatively decreased with increasing age and female sex.

CONCLUSIONS

This study established age- and sex-specific reference values for CT-based muscle metrics at thoracic and lumbar vertebral levels. These values may be used in future research investigating the role of muscle mass and attenuation in health and disease, and to identify sarcopenia.

Biomarkers of Body Composition

The importance and impact of imaging biomarkers has been increasing over the past few decades. We review the relevant clinical and imaging terminology needed to understand the clinical and research applications of body composition. Imaging biomarkers of bone, muscle, and fat tissues obtained with dual-energy X-ray absorptiometry, computed tomography, magnetic resonance imaging, and ultrasonography are described.

CT-based measurement of visceral adipose tissue volume as a reliable tool for assessing metabolic risk factors in prediabetes across subtypes

Visceral adipose tissue (VAT) is a well-established risk factor for the development of diabetes in individuals with prediabetes. We aimed to evaluate various adiposity and metabolic indices, including visceral adipose tissue (VAT) volume measured by CT, in individuals with prediabetes, based on their different subtypes. This retrospective study included 78 prediabetes individuals aged ≥ 20 years whose VAT volumes were evaluated by CT. Individuals were classified into prediabetes subtypes: impaired fasting glucose (IFG), impaired glucose tolerance (IGT), and combined IFG and IGT (C-IFG/IGT). We conducted a comparison of the patients' adiposity indices and their associations with one other, as well as with insulin resistance, based on the different prediabetes subtypes. Individuals with C-IFG/IGT had higher levels of visceral obesity than those with IFG or IGT. VAT volume was more strongly associated with insulin resistance than other adiposity indices, regardless of prediabetes subtypes. Additionally, VAT volume and liver attenuation index showed a significant correlation with the other indices studied across the prediabetes subtypes. CT-based measurement of VAT volume may be a valuable tool for evaluating metabolic risk factors among individuals with prediabetes.

Relationship of computed tomography quantified visceral adiposity with the severity and complications of acute pancreatitis: a systematic review

Whilst obesity and visceral adipose tissue (VAT) have been reported to be associated with an increased risk of severe AP, the established predictive scoring systems have not yet encompassed the impact of obesity or visceral adiposity. In the acute setting, computed tomography (CT) is often performed to assess AP severity and associated complications. With the added benefit of quantifying body fat distribution, it can be opportunistically used to quantify visceral adiposity and assess its relationship with the course of AP. This systematic review identified fifteen studies evaluating the relationship between visceral adiposity measured on CT and the severity of presentations of acute pancreatitis from January 2000 to November 2022. The primary outcome was to assess the relationship between CT quantified VAT and AP severity. The secondary outcomes were to assess the impact of VAT on patients developing local and systemic complications associated with AP. Whilst ten studies showed there was a significant correlation between an increased VAT and AP severity, five studies found otherwise. The majority of current literature demonstrate a positive correlation between increased VAT and AP severity. CT quantification VAT is a promising prognostic indicator with the potential to guide initial management, prompt more aggressive treatment measures or earlier re-evaluation and to aid disease prognostication in patients with acute pancreatitis.

Association of pericoronary adipose tissue with atrial fibrillation recurrence after ablation based on computed tomographic angiography

PURPOSE

Quantitative measurement of pericoronary adipose tissue volume (PCATV) and fat attenuation index (FAI) has mostly been used in the study of coronary artery related diseases but rarely in the relationship with atrial fibrillation (AF). This study was conducted to investigate the correlation of PCATV and FAI with the AF recurrence after ablation and the clinical significance.

MATERIALS AND METHODS

Patients with continuous AF who underwent radiofrequency ablation and computed tomographic angiography (CTA) were retrospectively enrolled. The PCATV, FAI, epicardial adipose tissue volume (EATV) and EAT density (EATD) arround the three main branches of the coronary arteries (LAD, LCX, and RCA) were measured quantitatively with cardiac function software and analyzed.

RESULTS

189 patients with continuous AF who underwent radiofrequency ablation for the first time were enrolled. After 12-month follow-up with a mean follow-up time of 10.93 ± 0.16 months, 47 (24.9%) patients were confirmed to have AF recurrence. The 3 V-FAI (- 81.17 ± 4.27 vs. - 83.31 ± 4.59 HU, P = 0.005), LCX-FAI (median - 77 vs. median - 81HU, P < 0.001), EATV (median 141.14vs. median 125.39 ml, P = 0.010), and EATVI (median 70.77 vs. 66.73 ml/m2, P = 0.008) were significantly increased in the recurrence group. EATVI (OR 1.043, 95% CI 1.020-1.066) and LCX-FAI (OR 1.254, 95% CI 1.145-1.374) were two significant independent risk factors for AF recurrence. In the comparison of ROC, the predictive value of LCX-FAI (cut-off value of >- 81.5 HU, area under the curve (AUC) of 0.722) was higher than that of EATVI (cut-off value > 81.07 ml/m2, AUC of 0.630).

CONCLUSION

EATVI and LCX-FAI were related to recurrence of AF after ablation and have important clinical value in predicting the AF recurrence.

Visceral fat percentage for prediction of outcome in uterine cervical cancer

OBJECTIVE

The prognostic role of adiposity in uterine cervical cancer (CC) is largely unknown. Abdominal fat distribution may better reflect obesity than body mass index. This study aims to describe computed tomography (CT)-assessed abdominal fat distribution in relation to clinicopathologic characteristics, survival, and tumor gene expression in CC.

METHODS

The study included 316 CC patients diagnosed during 2004-2017 who had pre-treatment abdominal CT. CT-based 3D segmentation of total-, subcutaneous- and visceral abdominal fat volumes (TAV, SAV and VAV) allowed for calculation of visceral fat percentage (VAV% = VAV/TAV). Liver density (LD) and waist circumference (at L3/L4-level) were also measured. Associations between CT-derived adiposity markers, clinicopathologic characteristics and disease-specific survival (DSS) were explored. Gene set enrichment of primary tumors were examined in relation to fat distribution in a subset of 108 CC patients.

RESULTS

High TAV, VAV and VAV% and low LD were associated with higher age (≥44 yrs.; p ≤ 0.017) and high International Federation of Gynecology and Obstetrics (FIGO) (2018) stage (p ≤ 0.01). High VAV% was the only CT-marker predicting high-grade histology (p = 0.028), large tumor size (p = 0.016) and poor DSS (HR 1.07, p < 0.001). Patients with high VAV% had CC tumors that exhibited increased inflammatory signaling (false discovery rate [FDR] < 5%).

CONCLUSIONS

High VAV% is associated with high-risk clinical features and predicts reduced DSS in CC patients. Furthermore, patients with high VAV% had upregulated inflammatory tumor signaling, suggesting that the metabolic environment induced by visceral adiposity contributes to tumor progression in CC.

Adipose Tissue Distribution and Body Mass Index (BMI) Correlation With Daily Image-Guided Radiotherapy (IGRT) Shifts of Abdominal Radiation Therapy Patients

Purpose There are several studies suggesting a correlation between image-guided radiotherapy (IGRT) setup errors and body mass index (BMI). However, abdominal fat content has visceral and subcutaneous components, which may affect setup errors differently. This study aims to analyze a potential workflow for characterizing adipose content and distribution in the region of the target that would allow a quickly calculated metric of abdominal fat content to stratify these patients. Methods IGRT shift data was retrospectively tabulated from daily fan-beam CT-on-rails pre-treatment alignment for 50 abdominal radiation therapy (RT) patients, and systematic and random errors in the daily setup were characterized by tabulating average and standard deviations of shift data for each patient and looking at differences for different distributions of adipose content. Visceral and subcutaneous fat content were defined by visceral fat area (VFA) and subcutaneous fat area (SFA) using a region-growing algorithm to contour adipose tissue on CT simulation scans. All contours were created for a single slice at the treatment isocenter, on which the VFA and SFA were calculated. A log-rank test was used to test trends in shifts over quartiles of adiposity. Results VFA ranged from 1.9-342.8c m², and SFA from 11.8-756.0 cm². The standard definition (SD) of random error (σ) in the lateral axis for Q1 vs. Q4 VFA was 0.10cm vs. 0.29cm, 0.12cm vs. 0.28cm for SFA, and 0.12cm vs. 0.31cm for BMI. The percentage of longitudinal shifts greater than 10mm for Q1 vs. Q4 VFA was 0% vs. 9%, 2% vs. 19% for SFA, and 0% vs. 20% for BMI. Statistically significant trends in shifts vs. the BMI quartile were seen for both pitch and the longitudinal direction, as well as for pitch corrections vs. the VFA quartile. Conclusion Within this dataset, abdominal cancer patients showed statistically significant trends in shift probability vs. BMI and VFA. Also, patients in the upper quartiles of all adiposity metrics showed an increased SD of σ in the lateral direction and increased shifts over 10 mm in the longitudinal direction. However, despite these relationships, neither VFA nor SFA offered discernible advantages in their relationship to shift uncertainty relative to BMI.

Fat Hounsfield Unit Reference Interval Derived through an Indirect Method

BACKGROUND

In vivo Hounsfield Unit (HU) values have traditionally been determined using direct CT image measurements. These measurements are dependent on the window/level used to examine the CT image and the individual conducting the fat tissue tracing.

METHODS

Using an indirect method, a new reference interval (RI) is proposed. A total of 4000 samples of fat tissues were collected from routine abdominal CT examinations. A linear regression equation was then calculated using the linear part of the cumulative frequency plot of their average values.

RESULTS

The regression function for total abdominal fat was determined to be y = 35.376*x - 123.48, and a 95% confidence RI of -123 to -89 was computed. A significant difference of 3.82 was observed between the average fat HU values of visceral and subcutaneous areas.

CONCLUSIONS

Using statistical methods and the in vivo measurements of patient data, a series of RIs were determined for fat HU that is consistent with theoretical values.

Comparison of CT and Dixon MR Abdominal Adipose Tissue Quantification Using a Unified Computer-Assisted Software Framework

PURPOSE

Reliable and objective measures of abdominal fat distribution across imaging modalities are essential for various clinical and research scenarios, such as assessing cardiometabolic disease risk due to obesity. We aimed to compare quantitative measures of subcutaneous (SAT) and visceral (VAT) adipose tissues in the abdomen between computed tomography (CT) and Dixon-based magnetic resonance (MR) images using a unified computer-assisted software framework.

MATERIALS AND METHODS

This study included 21 subjects who underwent abdominal CT and Dixon MR imaging on the same day. For each subject, two matched axial CT and fat-only MR images at the L2-L3 and the L4-L5 intervertebral levels were selected for fat quantification. For each image, an outer and an inner abdominal wall regions as well as SAT and VAT pixel masks were automatically generated by our software. The computer-generated results were then inspected and corrected by an expert reader.

RESULTS

There were excellent agreements for both abdominal wall segmentation and adipose tissue quantification between matched CT and MR images. Pearson coefficients were 0.97 for both outer and inner region segmentation, 0.99 for SAT, and 0.97 for VAT quantification. Bland-Altman analyses indicated minimum biases in all comparisons.

CONCLUSION

We showed that abdominal adipose tissue can be reliably quantified from both CT and Dixon MR images using a unified computer-assisted software framework. This flexible framework has a simple-to-use workflow to measure SAT and VAT from both modalities to support various clinical research applications.

Accumulation in Visceral Adipose Tissue Over 6 Years Is Associated With Lower Paraspinal Muscle Density

CONTEXT

Visceral adipose tissue (VAT) has been recognized to be a metabolically active fat depot that may have paracrine effects on surrounding tissues, including muscle. Since many adults accumulate VAT as they age, the effect of changes in VAT on muscle is of interest.

OBJECTIVE

We determined the association between 6-year changes in VAT and paraspinal muscle density, an indicator of fatty infiltration.

METHODS

This study included 1145 participants from the Framingham Study third-generation cohort who had both quantitative computed tomography scans of the spine at baseline and 6-year's follow-up, on whom muscle density was measured along with VAT. We implemented multiple regression to determine the association of muscle density at follow-up as primary outcome measure with changes in VAT (follow-up minus baseline divided by 100), adjusting for VAT at baseline, age, sex, height, menopausal status, presence of diabetes, and physical activity. Analyses were performed in men and women separately.

RESULTS

After adjustment for covariates, individuals with the greatest accumulation of VAT over 6 years had significantly lower paraspinal density at the follow-up with an estimated 0.302 (95% CI, -0.380 to -0.224) and 0.476 (95% CI: -0.598 to -0.354) lower muscle density (HU) per 100-cm3 increase in VAT (both P values < .001) in men and women, respectively.

CONCLUSION

These results highlight that age-related accumulation of VAT in men and women is associated with lower muscle density. VAT may represent a modifiable risk factor for poor musculoskeletal outcomes with aging.

Metabolic role of the hepatic valine/3-hydroxyisobutyrate (3-HIB) pathway in fatty liver disease

BACKGROUND

The valine (branched-chain amino acid) metabolite 3-hydroxyisobutyrate (3-HIB), produced by 3-Hydroxyisobutyryl-CoA Hydrolase (HIBCH), is associated with insulin resistance and type 2 diabetes, but implicated tissues and cellular mechanisms are poorly understood. We hypothesized that HIBCH and 3-HIB regulate hepatic lipid accumulation.

METHODS

HIBCH mRNA in human liver biopsies ("Liver cohort") and plasma 3-HIB ("CARBFUNC" cohort) were correlated with fatty liver and metabolic markers. Human Huh7 hepatocytes were supplemented with fatty acids (FAs) to induce lipid accumulation. Following HIBCH overexpression, siRNA knockdown, inhibition of PDK4 (a marker of FA β-oxidation) or 3-HIB supplementation, we performed RNA-seq, Western blotting, targeted metabolite analyses and functional assays.

FINDINGS

We identify a regulatory feedback loop between the valine/3-HIB pathway and PDK4 that shapes hepatic FA metabolism and metabolic health and responds to 3-HIB treatment of hepatocytes. HIBCH overexpression increased 3-HIB release and FA uptake, while knockdown increased cellular respiration and decreased reactive oxygen species (ROS) associated with metabolic shifts via PDK4 upregulation. Treatment with PDK4 inhibitor lowered 3-HIB release and increased FA uptake, while increasing HIBCH mRNA. Implicating this regulatory loop in fatty liver, human cohorts show positive correlations of liver fat with hepatic HIBCH and PDK4 expression (Liver cohort) and plasma 3-HIB (CARBFUNC cohort). Hepatocyte 3-HIB supplementation lowered HIBCH expression and FA uptake and increased cellular respiration and ROS.

INTERPRETATION

These data implicate the hepatic valine/3-HIB pathway in mechanisms of fatty liver, reflected in increased plasma 3-HIB concentrations, and present possible targets for therapeutic intervention.

FUNDING

Funding was provided by the Research Council of Norway (263124/F20), the University of Bergen, the Western Norway Health Authorities, Novo Nordisk Scandinavia AS, the Trond Mohn Foundation and the Norwegian Diabetes Association.

Anthropometric estimators of abdominal fat volume in adults with overweight and obesity

BACKGROUND/OBJECTIVES

To evaluate anthropometric measures for the prediction of whole-abdominal adipose tissue volumes V_XAT (subcutaneous V_SAT, visceral V_VAT and total V_TAT) in patients with obesity.

SUBJECTS/METHODS

A total of 181 patients (108 women) with overweight or obesity were analyzed retrospectively. MRI data (1.5 T) were available from independent clinical trials at a single institution (Integrated Research and Treatment Center of Obesity, University of Leipzig). A custom-made software was used for automated tissue segmentation. Anthropometric parameters (AP) were circumferences of the waist (WC) and hip (HC), waist-to-hip ratio (WHR), waist-to-height ratio (WHtR) and the (hypothetical) hip-to-height ratio (HHtR). Agreement was evaluated by standard deviations s_d% of percent differences between estimated volumes (using results of linear AP-V_XAT regression) and measured ones as well as Pearson's correlation coefficient r.

RESULTS

For SAT volume estimation, the smallest s_d% for all patients was seen for HC (25.1%) closely followed by HHtR (25.2%). Sex-specific results for females (17.5% for BMI and 17.2% for HC) and males (20.7% for WC) agreed better. VAT volumes could not be estimated reliably by any of the anthropometric measures considered here. TAT volumes in a mixed population could be best estimated by BMI closely followed by WC (roughly 17.5%). A sex-specific consideration reduced the deviations to around 16% for females (BMI and WC) and below 14% for males (WC).

CONCLUSIONS

We suggest the use of sex-specific parameters-BMI or HC for females and WC for males-for the estimation of abdominal SAT and TAT volumes in patients with overweight or obesity.

The visceral pancreatic neck anterior distance may be an effective parameter to predict post-pancreaticoduodenectomy clinically relevant postoperative pancreatic fistula

BACKGROUND

The clinically relevant postoperative pancreatic fistula (CR-POPF) is significantly correlated with a high post-pancreaticoduodenectomy (PD) mortality rate. Several studies have reported an association between visceral obesity and CR-POPF. Nevertheless, there are many technical difficulties and controversies in the measurement of visceral fat. The aim of this research was to determine whether the visceral pancreatic neck anterior distance (V-PNAD) was a credible predictor for CR-POPF.

METHODS

We retrospectively analyzed the data of 216 patients who underwent PD in our center between January 2016 and August 2021. The correlation of patients' demographic information, imaging variables, and intraoperative data with CR-POPF was assessed. Furthermore, areas under the receiver operating characteristic curves for six distances (abdominal thickness, visceral thickness, abdominal width, visceral width, abdominal PNAD, V-PNAD) were used to identify the best imaging distance to predict POPF.

RESULTS

In the multivariate logistic analysis, V-PNAD (P < 0.01) was the most significant risk factor for CR-POPF after PD. Males with a V-PNAD >3.97 cm or females with a V-PNAD >3.66 cm were included into the high-risk group. The high-risk group had a higher prevalence of CR-POPF (6.5% vs. 45.1%, P < 0.001), intraperitoneal infection (1.9% vs. 23.9%, P < 0.001), pulmonary infection (3.7% vs. 14.1%, P = 0.012), pleural effusion (17.8% vs. 33.8%, P = 0.014), and ascites (22.4% vs. 40.8%, P = 0.009) than the low-risk group.

CONCLUSION

Of all imaging distances, V-PNAD may be the most effective predictor of CR-POPF. Moreover, high-risk patients (males, V-PNAD >3.97 cm; females, V-PNAD >3.66 cm) have a high incidence of CR-POPF and poor short-term post-PD prognosis. Therefore, surgeons should perform PD carefully and take adequate preventive measures to reduce the incidence of pancreatic fistula when the patient has a high V-PNAD.

Efficacy of fermented grain using Bacillus coagulans in reducing visceral fat among people with obesity: a randomized controlled trial

Background

Obesity is a socioeconomic problem, and visceral obesity, in particular, is related to cardiovascular diseases or metabolic syndrome. Fermented grains and various microorganisms are known to help with anti-obesity effects and weight management. Studies on the relationship between Bacillus coagulans and anti-obesity effects are not well known, and studies on the application of fermented grains and microorganisms to the human body are also insufficient.

Objectives

This study aimed to evaluate the efficacy of Curezyme-LAC, an ingredient mixed with six-grain types fermented by B. coagulans, in reducing fat mass in adults with obesity.

Methods

In this randomized double-blinded placebo-controlled study, 100 participants [aged 40-65 years; body mass index (BMI) ≥ 25 to ≤ 33 kg/m²) were randomly allocated to two groups: 4 g/day Curezyme-LAC administered as a granulated powder or placebo (steamed grain powder mixture).

Results

After 12 weeks, visceral adipose tissue decreased significantly in the Curezyme-LAC group compared with that in the placebo group (mean ± standard error, SE of -9.3 cm² ± 5.1) vs. (6.8 cm² ± 3.4; p = 0.008). Compared to the placebo group, the Curezyme-LAC group also showed significant reductions in total fat mass (-0.43 ± 0.24 kg vs. 0.31 ± 0.19 kg, p = 0.011), body weight (-0.4 ± 0.3 kg vs. 0.3 ± 0.2 kg, p = 0.021), BMI (-0.14 ± 0.12 vs. 0.10 ± 0.07, p = 0.028), and waist circumference (-0.6 ± 0.2 cm vs. -0.1 ± 0.2 cm, p = 0.018) without a change in dietary intake and physical activity.

Conclusion

Curezyme-LAC supplementation for 12 weeks may benefit individuals with obesity by reducing visceral fat mass.

A simple and reproducible measure of adipose depots with non-contrast post-mortem computed tomography

Background and aim

Obesity is associated with an increase in different adipose depots. The anatomic distribution of internal adipose confers different risks. Recently, significant interest has emerged in the expansion of epicardial adipose tissue (EAT) as a mediator of adverse cardiovascular events. Often, post-mortem examination remains the best method of investigating morphological changes in health and disease. This study aimed to develop a simple, reproducible, and non-invasive protocol for the measurement of internal adiposity using post-mortem computed tomography (PMCT).

Patients and methods

101 consecutive post-mortem subjects underwent non-contrast computed tomography scans. Measurements were performed using the open-source software 3D Slicer by a non-expert researcher. An expert radiologist and cardiologist verified the abdominal and cardiac sites of adiposity, respectively. We aimed to develop a protocol to measure total EAT, sub-depots of EAT, extra-pericardial adipose, visceral and subcutaneous adipose, and suprasternal adipose.

Results

We found excellent reproducibility for our measures of total EAT, anterior right atrial EAT, extra-pericardial adipose, and visceral adipose tissue, with intraclass correlations between 0.82 and 0.99 for each measure. Due to a lack of suitable anatomical boundaries, other sub-depots of EAT, including in the interventricular groove, were not reproducible.

Conclusions

Quantification of total EAT and anterior right atrial EAT are readily reproducible using 3D Slicer on post-mortem CT. They can be reliably measured by non-expert researchers with a small amount of training, and therefore be used to investigate morphological changes in adiposity in health and disease.

Probiotics' effect on visceral and subcutaneous adipose tissue: a systematic review of randomized controlled trials

Probiotics are shown to alter the microbiota, leading to a favorable environment, in which weight loss and metabolic parameters are improve. However, the results on probiotics' effect on specific types of central adipose tissues, mainly visceral (VAT) and subcutaneous adipose tissue (SAT), are conflicting. Therefore, we conducted a systematic review, aimed to evaluate the effects of probiotics on VAT and SAT. PubMed, SCOPUS, EBSCO, and LILACS databases were searched for studies that investigated the effect of probiotics on VAT and SAT. Fixed effects were used to calculate the pooled difference in means (DM) and 95% confidence intervals (95%CI). Fourteen publications met the inclusion criteria, which consisted of 1523 participants. For VAT, overall, there was a significant decrease (DM = -3.63 cm2, 95% CI: -5.08 to -2.17, p < 0.001). When stratified by type of probiotic, single Bifidobacterium (DM = -4.49 cm2, 95% CI:-7.37 to -1.61, p = 0.002) and single Lactobacillus probiotics (DM = -3.84 cm2, 95% CI:-5.74 to -1.93, p < 0.001) resulted in significant reductions. Mixed probiotics had no effect. For SAT, overall, there was a significant decrease (DM = -2.91 cm2, 95% CI:-4.82 to -1.01, p = 0.003), and when stratified by type of probiotic, single Lactobacillus (DM = -3.39 cm2, 95% CI:-5.90 to -0.88, p = 0.008) and mixed probiotics (DM = -5.97 cm2, 95% CI:-10.32 to -1.62, p = 0.007) resulted in a significant decrease. Single Bifidobacterium probiotics had no effect. Using meta-regression, no association was observed between the total daily probiotic dose and VAT or SAT reduction. This study shows that probiotics have a beneficial effect on central adiposity. Single Lactobacillus-based probiotics reduced VAT and SAT, whereas Bifidobacterium-based probiotics reduce VAT.

Development of automated segmentation of visceral adipose tissue in computed tomography

PURPOSE

Imaging modalities such as computed tomography (CT) or magnetic resonance imaging have been used to measure adiposity. However, manual segmentation of visceral adipose tissue (VAT) in the entire abdomen is laborious and time-consuming. We aimed to develop a new method for accurate visceral fat segmentation by automatically dividing the three anatomical compartments of the lung, soft tissue, and post-vertebral spaces.

METHODS

To automatically separate visceral fat, a three-step process was performed that sequentially divided tissues and regions in a three-dimensional CT image. Manual segmentation was performed in 99 individuals who underwent 18-fluoro-2-deoxyglucosepositron emission tomography/CT for cancer screening between January 2010 and December 2018 to validate the automated segmentation. The similarity index and Pearson's correlation analysis were performed to compare automated segmentation with manual segmentation. Clinical data, such as weight, height, and glucose and insulin levels, were measured. Pearson's correlation analysis was performed to investigate the association between the two methods.

RESULTS

VAT volume of automated segmentation (3,594.6 ± 1,776.5 cm³) strongly correlated with that of manual segmentation (3,375.7 ± 1567.5 cm³) (r = 0.9676, p < 0.0001). The similarity index positively correlated with the VAT volume (r = 0.6396, p < 0.0001) and negatively correlated with the mean Hounsfield units (HU) (r = -0.4328, p < 0.0001). Bland-Altman plots are presented with 5.1 % for VAT volume and 7.1 % for mean HU were outside 1.96 standard deviation from the mean value.

CONCLUSION

We developed an automated segmentation method for VAT in the entire abdomen. This automated segmentation method is feasible for measuring the VAT volume and VAT HU. This method could be employed in daily clinical practice to provide more detailed information about VAT.

Accuracy of Y-scope, a newly developed portable abdominal impedance analyzer, for the assessment of abdominal visceral fat area

Aim

This study was conducted to evaluate the accuracy of a newly developed multifrequency segmental (MFS) bioelectrical impedance analysis (BIA) method using an additional portable abdominal (PA) impedance analyzer, in the assessment of abdominal visceral fat area (VFA).

Materials and methods

One hundred healthy Korean subjects aged 19 years or over (43 men and 57 women) were recruited, and VFA was estimated by a conventional MFS-BIA machine and a new MFS-BIA machine with a PA-BIA device, indicating MFS-VFA and MFS&PA-VFA, respectively. The accuracy of the VFA values was compared with those evaluated with CT at the level of the umbilicus (CT-VFA).

Results

The mean age was 41 years and mean body mass index (BMI) was 24.4 kg/m². The mean ± SD VFAs measured by CT, conventional MFS-BIA, and new MFS&PA-BIA together were 93.4 ± 60.9, 92.7 ± 53.4, and 93.6 ± 55.4 cm², respectively. Correlation coefficients comparing CT-VFA with MFS-VFA and MFS&PA-VFA were 0.612 and 0.932, respectively (P < 0.001 for both). The mean difference between CT-VFA and MFS&PA-VFA was less affected by age, sex, and BMI compared with that between CT-VFA and MFS-VFA. Intraclass correlation coefficient (95% CI) between CT-VFA and MFS&PA-VFA was also greater than that between CT-VFA and MFS-VFA, 0.96 (0.95–0.98) vs. 0.76 (0.64–0.84), respectively.

Conclusion

In this study, application of a newly developed MFS-BIA machine combined with a PA-BIA device significantly improved the correlation with CT-measured VFA without proportional error. This novel approach using advanced technology may be able to provide more reliable estimates of abdominal VFA.

Diets differing in carbohydrate cellularity and amount similarly reduced visceral fat in people with obesity - a randomized controlled trial (CARBFUNC)

BACKGROUND & AIMS

Visceral adipose tissue (VAT) volume is associated with common lifestyle diseases. Dietary quality, including food matrix and degree of carbohydrate cellularity, as well as the carbohydrate/fat ratio, may influence VAT volume. We aimed to determine the effects of isocaloric diets differing in either "cellularity", a novel marker of dietary carbohydrate quality, or carbohydrate amount on visceral fat volume and anthropometric measures in adults with obesity.

METHODS

In a randomized controlled trial of 193 people with obesity/central adiposity, we compared changes in VAT volume after 6 and 12 months, measured by abdominal computed tomography, on three isocaloric eating patterns based on "acellular" carbohydrate sources (e.g., flour-based whole-grain products; comparator arm), "cellular" carbohydrate sources (minimally processed foods with intact cellular structures such as fruits, potatoes/tubers, and rice), or low-carbohydrate high-fat (LCHF) principles. Outcomes were compared by an intention-to-treat (ITT) analysis using constrained linear mixed-effects modelling (cLMM) providing baseline-adjusted change scores and proper missing data handling without imputation.

RESULTS

78 and 57 participants completed 6 and 12 months, respectively, with similar intakes of energy (females: 1820-2060 kcal, males: 2480-2550 kcal) and protein (16-17 energy percent, E%) throughout the intervention, and only modest reductions in energy from baseline. Reported dietary intakes were 42-44, 41-42, and 11-15 E% carbohydrate and 36-38, 37-38, and 66-70 E% fat in the acellular, cellular and LCHF groups, respectively. There were no significant between-group differences in VAT volume after 6 months (cellular vs. acellular [95% CI]: -55 cm³ [-545, 436]; LCHF vs. acellular [95% CI]: -225 cm³ [-703, 253]) or after 12 months (cellular vs. acellular [95% CI]: -122 cm³ [-757, 514]; LCHF vs. acellular [95% CI]: -317 cm³ [-943, 309]). VAT volume decreased significantly within all groups by 14-18% and 12-17% after 6 and 12 months, respectively. Waist circumference was reduced to a significantly greater degree in the LCHF vs. acellular group at 6 months (LCHF vs. acellular [95% CI]: -2.78 cm [-5.54, -0.017]).

CONCLUSIONS

Despite modest energy restriction, the three isocaloric eating patterns, differing in carbohydrate cellularity and amount, decreased visceral fat volume significantly and to a similar clinically relevant degree.

CLINICAL TRIALS IDENTIFIER

NCT03401970. https://clinicaltrials.gov/ct2/show/NCT03401970.

Visceral Fat Area Measured by Abdominal Bioelectrical Impedance Analysis in School-Aged Japanese Children

Abdominal bioelectrical impedance analysis (aBIA) has been in use to measure visceral fat area (VFA) in adults. Accurately measuring visceral fat using aBIA in children is challenging. Forty-six school-aged Japanese children aged 6–17 years (25 boys and 21 girls) were included in this study. All were measured, and their VFA obtained using aBIA (VFA-aBIA) and abdominal computed tomography (CT) (VFA-CT) were compared. VFA-aBIA was corrected using the Passing–Bablok method (corrected VFA-aBIA). The relationships between corrected VFA-aBIA and obesity-related clinical factors were analyzed, including non-alcoholic fatty liver disease (NAFLD) and serum leptin and adiponectin levels. Boys had higher VFA-CT than girls (p = 0.042), although no significant differences were found in their waist circumference, waist-to-height ratio, and body mass index. The corrected VFA-aBIA using y = 9.600 + 0.3825x (boys) and y = 7.607 + 0.3661x (girls) correlated with VFA-CT in both boys and girls. The corrected VFA-aBIA in patients with NAFLD was higher than that in those without NAFLD. Serum leptin and adiponectin levels were positively and negatively correlated with corrected VFA-aBIA, respectively. In conclusion, corrected VFA-aBIA was clearly correlated with VFA-CT and was related to NAFLD and serum leptin and adiponectin levels in school-aged Japanese children.

Standardized measurement of abdominal muscle by computed tomography: association with cardiometabolic risk in the Framingham Heart Study

Objectives

To provide a standard for total abdominal muscle mass (TAM) quantification on computed tomography (CT) and investigate its association with cardiovascular risk in a primary prevention setting.

Methods

We included 3016 Framingham Heart Study participants free of cardiovascular disease (CVD) who underwent abdominal CT between 2002 and 2005. On a single CT slice at the level of L3/L4, we segmented (1) TAM-Area, (2) TAM-Index (= TAM-Area/height) and, (3) TAM-Fraction (= TAM-Area/total cross-sectional CT-area). We tested the association of these muscle mass measures with prevalent and incident cardiometabolic risk factors and incident CVD events during a follow-up of 11.0 ± 2.7 years.

Results

In this community-based sample (49% women, mean age: 50.0 ± 10.0 years), all muscle quantity measures were significantly associated with prevalent and incident cardiometabolic risk factors and CVD events. However, only TAM-Fraction remained significantly associated with key outcomes (e.g., adj. OR 0.68 [0.55, 0.84] and HR 0.73 [0.57, 0.92] for incident hypertension and CVD events, respectively) after adjustment for age, sex, body mass index, and waist circumference. Moreover, only higher TAM-Fraction was associated with a lower risk (e.g., adj. OR: 0.56 [0.36–0.89] for incident diabetes versus TAM-Area: adj. OR 1.26 [0.79–2.01] and TAM-Index: 1.09 [0.75–1.58]).

Conclusion

TAM-Fraction on a single CT slice at L3/L4 is a novel body composition marker of cardiometabolic risk in a primary prevention setting that has the potential to improve risk stratification beyond traditional measures of obesity.

Key Points

• In this analysis of the Framingham Heart Study (n = 3016), TAM-F on a single slice CT was more closely associated with prevalent and incident cardiometabolic risk factors as compared to TAM alone or TAM indexed to body surface area.

• TAM-F on a single abdominal CT slice at the level of L3/L4 could serve as a standard measure of muscle mass and improve risk prediction

Association of Cardiometabolic Disease With Cancer in the Community

Background

Obesity and cardiometabolic dysfunction have been associated with cancer risk and severity. Underlying mechanisms remain unclear.

Objectives

The aim of this study was to examine associations of obesity and related cardiometabolic traits with incident cancer.

Methods

FHS (Framingham Heart Study) and PREVEND (Prevention of Renal and Vascular End-Stage Disease) study participants without prevalent cancer were studied, examining associations of obesity, body mass index (BMI), waist circumference, visceral adipose tissue (VAT) and subcutaneous adipose tissue depots, and C-reactive protein (CRP) with future cancer in Cox models.

Results

Among 20,667 participants (mean age 50 years, 53% women), 2,619 cancer events were observed over a median follow-up duration of 15 years. Obesity was associated with increased risk for future gastrointestinal (HR: 1.30; 95% CI: 1.05-1.60), gynecologic (HR: 1.62; 95% CI: 1.08-2.45), and breast (HR: 1.32; 95% CI: 1.05-1.66) cancer and lower risk for lung cancer (HR: 0.62; 95% CI: 0.44-0.87). Similarly, waist circumference was associated with increased risk for overall, gastrointestinal, and gynecologic but not lung cancer. VAT but not subcutaneous adipose tissue was associated with risk for overall cancer (HR: 1.22; 95% CI: 1.05-1.43), lung cancer (HR: 1.92; 95% CI: 1.01-3.66), and melanoma (HR: 1.56; 95% CI: 1.02-2.38) independent of BMI. Last, higher CRP levels were associated with higher risk for overall, colorectal, and lung cancer (P < 0.05 for all).

Conclusions

Obesity and abdominal adiposity are associated with future risk for specific cancers (eg, gastrointestinal, gynecologic). Although obesity was associated with lower risk for lung cancer, greater VAT and CRP were associated with higher lung cancer risk after adjusting for BMI.

Healthy US population reference values for CT visceral fat measurements and the impact of IV contrast, HU range, and spinal levels

Measurements of visceral adipose tissue cross-sectional area and radiation attenuation from computed tomography (CT) scans provide useful information about risk and mortality. However, scan protocols vary, encompassing differing vertebra levels and utilizing differing phases of contrast enhancement. Furthermore, fat measurements have been extracted from CT using different Hounsfield Unit (HU) ranges. To our knowledge, there have been no large studies of healthy cohorts that reported reference values for visceral fat area and radiation attenuation at multiple vertebra levels, for different contrast phases, and using different fat HU ranges. Two-phase CT scans from 1,677 healthy, adult kidney donors (age 18–65) between 1999 and 2017, previously studied to determine healthy reference values for skeletal muscle measures, were utilized. Visceral adipose tissue cross-sectional area (VFA) and radiation attenuation (VFRA) measures were quantified using axial slices at T10 through L4 vertebra levels. T-tests were used to compare males and females, while paired t-tests were conducted to determine the effect (magnitude and direction) of (a) contrast enhancement and (b) different fat HU ranges on each fat measure at each vertebra level. We report the means, standard deviations, and effect sizes of contrast enhancement and fat HU range. Male and female VFA and VFRA were significantly different at all vertebra levels in both contrast and non-contrast scans. Peak VFA was observed at L4 in females and L2 in males, while peak VFRA was observed at L1 in both females and males. In general, non-contrast scans showed significantly greater VFA and VFRA compared to contrast scans. The average paired difference due to contrast ranged from 1.6 to − 8% (VFA) and 3.2 to − 3.0% (VFRA) of the non-contrast value. HU range showed much greater differences in VFA and VFRA than contrast. The average paired differences due to HU range ranged from − 5.3 to 22.2% (VFA) and − 5.9 to 13.6% (VFRA) in non-contrast scans, and − 4.4 to 20.2% (VFA) and − 4.1 to 12.6% (VFRA) in contrast scans. The − 190 to − 30 HU range showed the largest differences in both VFA (10.8% to 22.2%) and VFRA (7.6% to 13.6%) compared to the reference range (− 205 to − 51 HU). Incidentally, we found that differences in lung inflation result in very large differences in visceral fat measures, particularly in the thoracic region. We assessed the independent effects of contrast presence and fat HU ranges on visceral fat cross-sectional area and mean radiation attenuation, finding significant differences particularly between different fat HU ranges. These results demonstrate that CT measurements of visceral fat area and radiation attenuation are strongly dependent upon contrast presence, fat HU range, sex, breath cycle, and vertebra level of measurement. We quantified contrast and non-contrast reference values separately for males and females, using different fat HU ranges, for lumbar and thoracic CT visceral fat measures at multiple vertebra levels in a healthy adult US population.

Segmentation and characterization of visceral and abdominal subcutaneous adipose tissue on CT with and without contrast medium: influence of 2D- and 3D-segmentation

Background

Adipose tissue is a valuable biomarker. Although validation and correlation to clinical data have mostly been performed on non-enhanced scans (NES), a previous study has shown conversion of values of contrast enhanced scan (CES) into those of NES to be feasible with segmentation of the entire abdomen (3D-segmentation). In this study we analyzed if density and area of abdominal adipose tissue segmented in a single slice (2D-segmentation) of CES may be converted into that of NES. Furthermore, we compared the precision of conversion between 2D- and 3D-segmentation.

Methods

Thirty-one multi-phasic abdominal CT examinations at identical scan settings were retrospectively included. Exams included NES (n=31), arterial (ART) (n=23), portal-venous (PVN) (n=10), and/or venous scan (VEN) (n=31). Density and area of visceral (VAT) and subcutaneous adipose tissue (SAT) were quantified semi-automatically with fixed thresholds. For conversion of values from CES into those of NES regression analyses were performed and tested. 2D- and 3D-segmentation were compared with respect to conversion accuracy (normalized deviations of converted NES values from original measurements).

Results

After the application of contrast medium 2D-segmented adipose tissue increased in density (max. +5.6±2.4 HU) and decreased in area (max. -10.91%) (10.47%), with few exceptions (P<0.05). This was more pronounced in later scans (VEN ≈ PVN > ART) and more marked in VAT than SAT. Density and area in CES correlated very well with NES, allowing for conversion with only small error. While converted density is slightly more precise applying 3D-segmentation, conversion error of quantity was occasionally smaller with 2D-segmentation.

Conclusions

Contrast medium changes density and quantity of segmented adipose tissue in differing degrees between compartments, contrast phases and 2D- and 3D-segmentation. However, changes are fairly constant for a given compartment, contrast phase and mode of segmentation. Therefore, conversion of values into those of NES may be achieved with comparable precision for 2D- and 3D-segmentation.

A neurobiological link between transportation noise exposure and metabolic disease in humans

BACKGROUND

Chronic transportation noise exposure associates with cardiovascular events through a link involving heightened stress-associated neurobiological activity (as amygdalar metabolic activity, AmygA) on ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG-PET/CT). Increased AmygA also associates with greater visceral adipose tissue (VAT) and type 2 diabetes mellitus (DM). While relationships between noise exposure and VAT and DM have been reported, the underlying mechanisms remain incompletely understood. We tested whether: (1) transportation noise exposure associates with greater (a) baseline and gains in VAT and (b) DM risk, and (2) heightened AmygA partially mediates the link between noise exposure and these metabolic diseases.

METHODS

VAT was measured in a retrospective cohort (N = 403) who underwent clinical ¹⁸F-FDG-PET/CT. AmygA was measured in those with brain imaging (N = 238). Follow-up VAT was remeasured on available imaging (N = 67). Among individuals (N = 224) without baseline DM, incident DM was adjudicated over 2 years from clinical records. Noise (24-h average) was modeled at each individual's home address. Linear regression, survival, and mediation analyses were employed.

RESULTS

Higher noise exposure (upper tertile vs. others) associated with greater: baseline VAT (standardized β [95% confidence interval (CI)]= 0.230 [0.021, 0.438], p = 0.031), gains in VAT (0.686 [0.185, 1.187], p = 0.008 adjusted for baseline VAT), and DM (hazard ratio [95% CI]=2.429 [1.031, 5.719], p = 0.042). The paths of: ↑noise exposure→↑AmygA→↑baseline VAT and ↑noise exposure→↑AmygA→↑subsequent DM were significant (p < 0.05).

CONCLUSIONS

Increased transportation noise exposure associates with greater VAT and DM. This relationship is partially mediated by stress-associated neurobiological activity. These findings suggest altered neurobiology contributes to noise exposure's link to metabolic diseases.

Tesamorelin improves fat quality independent of changes in fat quantity

OBJECTIVES

Fat quality and quantity may affect health similarly or differently. Fat quality can be assessed by measuring fat density on CT scan (greater density = smaller, higher quality adipocytes). We assessed the effects of tesamorelin, a growth hormone-releasing hormone analogue that reduces visceral fat (VAT) quantity in some people living with HIV (PWH), on fat density.

DESIGN

Participants from two completed, placebo-controlled, randomized trials of tesamorelin for central adiposity treatment in PWH were included if they had either a clinical response to tesamorelin (VAT decrease ≥8%, ≈70% of participants) or were placebo-treated.

METHODS

CT VAT and subcutaneous fat (SAT) density (Hounsfield Units, HU) were measured by a central blinded reader.

RESULTS

Participants (193 responders, 148 placebo) were 87% male and 83% white. Baseline characteristics were similar across arms, including VAT (-91 HU both arms, P = 0.80) and SAT density (-94 HU tesamorelin, -95 HU placebo, P = 0.29). Over 26 weeks, mean (SD) VAT and SAT density increased in tesamorelin-treated participants only [VAT: +6.2 (8.7) HU tesamorelin, +0.3 (4.2) HU placebo, P < 0.0001; SAT: +4.0 (8.7) HU tesamorelin, +0.3 (4.8) HU placebo, P < 0.0001]. The tesamorelin effects persisted after controlling for baseline VAT or SAT HU and area, and VAT [+2.3 HU, 95% confidence interval (4.5-7.3), P = 0.001) or SAT (+3.5 HU, 95% confidence interval (2.3-4.7), P < 0.001] area change.

CONCLUSION

In PWH with central adiposity who experienced VAT quantity reductions on tesamorelin, VAT and SAT density increased independent of changes in fat quantity, suggesting that tesamorelin also improves VAT and SAT quality in this group.

Deep Learning-Based Quantification of Visceral Fat Volumes Predicts Posttransplant Diabetes Mellitus in Kidney Transplant Recipients

Background: Because obesity is associated with the risk of posttransplant diabetes mellitus (PTDM), the precise estimation of visceral fat mass before transplantation may be helpful. Herein, we addressed whether a deep-learning based volumetric fat quantification on pretransplant computed tomographic images predicted the risk of PTDM more precisely than body mass index (BMI).

Methods: We retrospectively included a total of 718 nondiabetic kidney recipients who underwent pretransplant abdominal computed tomography. The 2D (waist) and 3D (waist or abdominal) volumes of visceral, subcutaneous, and total fat masses were automatically quantified using the deep neural network. The predictability of the PTDM risk was estimated using a multivariate Cox model and compared among the fat parameters using the areas under the receiver operating characteristic curves (AUROCs).

Results: PTDM occurred in 179 patients (24.9%) during the median follow-up period of 5 years (interquartile range, 2.5–8.6 years). All the fat parameters predicted the risk of PTDM, but the visceral and total fat volumes from 2D and 3D evaluations had higher AUROC values than BMI did, and the best predictor of PTDM was the 3D abdominal visceral fat volumes [AUROC, 0.688 (0.636–0.741)]. The addition of the 3D abdominal VF volume to the model with clinical risk factors increased the predictability of PTDM, but BMI did not.

Conclusions: A deep-learning based quantification of visceral fat volumes on computed tomographic images better predicts the risk of PTDM after kidney transplantation than BMI.

Sex Differences in the Associations of Visceral Adipose Tissue and Cardiometabolic and Cardiovascular Disease Risk: The Framingham Heart Study

Background

Men and women are labeled as obese on the basis of a body mass index (BMI) using the same criterion despite known differences in their fat distributions. Subcutaneous adipose tissue and visceral adipose tissue (VAT), as measured by computed tomography, are advanced measures of obesity that closely correlate with cardiometabolic risk independent of BMI. However, it remains unknown whether prognostic significance of anthropometric measures of adiposity versus VAT varies in men versus women.

Methods and Results

In 3482 FHS (Framingham Heart Study) participants (48.1% women; mean age, 50.8±10.3 years), we tested the associations of computed tomography–based versus anthropometric measures of fat with cardiometabolic and cardiovascular disease (CVD) risk. Mean follow‐up was 12.7±2.1 years. In men, VAT, as compared with BMI, had a similar strength of association with incident cardiometabolic risk factors (eg, adjusted odds ratio [OR], 2.36 [95% CI, 1.84–3.04] versus 2.66 [95% CI, 2.04–3.47] for diabetes mellitus) and CVD events (eg, adjusted hazard ratio [HR], 1.32 [95% CI, 0.97–1.80] versus 1.74 [95% CI, 1.14–2.65] for CVD death). In women, however, VAT, when compared with BMI, conferred a markedly greater association with incident cardiometabolic risk factors (eg, adjusted OR, 4.51 [95% CI, 3.13–6.50] versus 2.33 [95% CI, 1.88–3.04] for diabetes mellitus) as well as CVD events (eg, adjusted HR, 1.85 [95% CI, 1.26–2.71] versus 1.19 [95% CI, 1.01–1.40] for CVD death).

Conclusions

Anthropometric measures of obesity, including waist circumference and BMI, adequately capture VAT‐associated cardiometabolic and cardiovascular risk in men but not in women. In women, abdominal computed tomography–based VAT measures permit more precise assessment of obesity‐associated cardiometabolic and cardiovascular risk.

Alpha-lipoic acid supplementation increases the efficacy of exercise- and diet-induced obesity treatment and induces immunometabolic changes in female mice and women

The decrease in the regulatory T cells (Tregs) population is highly involved in adipose tissue inflammation and insulin resistance in obesity. Tregs depend on fatty acids via β-oxidation for immunosuppressive function adapting their antioxidant systems to allow survival to oxidative stress. In this study, we have hypothesized that a dietary supplementation with alpha-lipoic acid (ALA), a powerful antioxidant, would improve immunometabolism when added to the classical strategy of obesity treatment. First, we showed by in vitro experiments that ALA favors the polarization of mice CD4 + T cells toward Tregs. Next, we have carried out a translational study where female obese mice and women were supplemented with ALA or vehicle/placebo (mice: 2.5 gALA /kgfood ; 6 weeks; women: 600 mgALA /day, 8 weeks) while following a protocol including regular exercise and a change in diet. Fatty acid oxidation potential and activity of nuclear erythroid-related factor 2 (NRF2) of mouse secondary lymphoid tissues were improved by ALA supplementation. ALA reduced visceral adipose tissue (VAT) mass and preserved Tregs in VAT in mice. In women, ALA supplementation induced significant metabolic changes of circulating CD4 + T cells including increased oxidative capacity and fatty acid oxidation, ameliorated their redox status, and improved the reduction of visceral fat mass. While appropriate biological markers are still required to be used in clinics to judge the effectiveness of long-term obesity treatment, further studies in female mice and women are needed to determine whether these immunometabolic changes would reduce VAT mass-associated risk for secondary health issues arising from obesity.

Clinical Impact of Portal Vein Distance on Computed Tomography for Postoperative Pancreatic Fistula after Pancreatoduodenectomy

BACKGROUND

Pancreatic fistulas remain a significant concern after pancreatectomy owing to the associated high risk of mortality and high costs. It is not possible to perform preoperative risk stratification for all patients. This study aimed to evaluate the usefulness of the measurement of portal vein (PV) distance as a predictive indicator of pancreatic fistula development after pancreatoduodenectomy and compare it with the usefulness of other indicators such as body mass index (BMI), and abdominal fat area.

METHODS

Patient characteristics, preoperative laboratory data, radiographic findings, and their association with pancreatic fistula development after pancreatoduodenectomy were analyzed for 157 patients who underwent resection during 2011-2017. Clinically relevant postoperative pancreatic fistulas (CR-POPF) were defined as Grade B or C fistulas based on the International Study Group of Pancreatic Surgery (ISGPS) 2016 consensus.

RESULTS

CR-POPF developed in 38 patients (24.2%). Multivariate logistic regression indicated that PV distance and BMI were potential candidates for predictive models for pancreatic fistula development, and small pancreatic duct diameter, diabetes mellitus development, and pathology of non-pancreatic cancers were independent factors for CR-POPF. When comparing the two risk models (PV distance- and BMI-based models), the PV distance-derived risk model was compatible to the BMI-based stratification models (area under the curve 0.831 vs. 0.830).

CONCLUSIONS

PV distance was confirmed to be a useful risk predictor for CR-POPF. This research highlighted the efficacy of abdominal thickness measurement, which is simple and easily applicable in the clinical setting.

Posterior Left Atrial Adipose Tissue Attenuation Assessed by Computed Tomography and Recurrence of Atrial Fibrillation After Catheter Ablation

[Figure: see text].

Low Radiation Dose Implications in Obese Abdominal Computed Tomography Imaging

The aim of this study was to evaluate the implications of low radiation dose in abdominal computed tomography (CT) when combined with noise reduction filters and to see if this approach can overcome the challenges that arise while scanning obese patients. Anthropomorphic phantoms layered with and without 3-cm-thick circumferential animal fat packs to simulate different sized patients were scanned using a 128-slice multidetector CT (MDCT) scanner. Abdominal protocols (n = 12) were applied using various tube currents (150, 200, 250, and 300 mA) and tube voltages (100, 120, and 140 kVp). MOSFET dosimeters measured the internal organ dose. All images were reconstructed with filtered back projection (FBP) and different iterative reconstruction (IR) strengths (SAFIRE 3, SAFIRE 4, and SAFIRE 5) techniques and objective noise was measured within three regions of interests (ROIs) at the level of L4–L5. Organ doses varied from 0.34–56.2 mGy; the colon received the highest doses for both phantom sizes. Compared to the normal-weighted phantom, the obese phantom was associated with an approximately 20% decrease in effective dose. The 100 kVp procedure resulted in a 40% lower effective dose (p < 0.05) compared to at 120 kVp and the associated noise increase was improved by increasing the IR (5) use, which resulted in a 60% noise reduction compared to when using FBP (p < 0.05). When combined with iterative reconstruction, the low-kVp approach is feasible for obese patients in order to optimize radiation dose and maintain objective image quality.

Role of Baseline Computed-Tomography-Evaluated Body Composition in Predicting Outcome and Toxicity from First-Line Therapy in Advanced Gastric Cancer Patients

Sarcopenia is recognised as a predictor of toxicity and survival in localised and locally advanced gastric cancer (GC). Its prognostication power in advanced unresectable or metastatic GC (aGC) is debated. The survival impact of visceral and subcutaneous fat distribution (visceral fat area (VFA)/subcutaneous fat area (SFA)) is ambiguous. Our aim was to determine the influence of body composition parameters (BCp) on toxicity and survival in aGC patients undergoing palliative treatment. BCp were retrospectively assessed by baseline computed tomography for 78 aGC patients who received first-line chemotherapy from March 2010 to January 2017. Correlations between BCp and toxicity and survival were calculated by χ²-test and by log-rank-test and Cox-model, respectively. Sarcopenia fails to show association with progression-free survival (PFS) (p = 0.44) and overall survival (OS) (p = 0.88). However, sarcopenia influences the development of high-grade neutropenia (p = 0.048) and mucositis (p = 0.054). VFA/SFA (high vs. all the rest) results as a strong predictor of objective response (p = 0.02) and outcome (PFS, p = 0.001; OS, p = 0.02). At multivariate analysis for PFS, prognostic factors are VFA/SFA (p = 0.03) and a neutrophil–lymphocyte ratio >3. The same factors remain significant for OS (each p = 0.03) along with Eastern Cooperative Oncology Group (ECOG) performance status (p = 0.008) and number of metastatic sites ≥2 (p < 0.001). In our cohort of aGC, VFA/SFA exhibit a robust impact on survival, with a higher sensitivity than sarcopenia.

3D-segmentation and characterization of visceral and abdominal subcutaneous adipose tissue on CT: influence of contrast medium and contrast phase

Background

Adipose tissue as part of body composition analysis may serve as a powerful biomarker. Validation of segmented adipose tissue and correlation to clinical data has been performed on non-enhanced scans (NES). As many patients require a contrast enhanced scan (CES) for other aspects of clinical decision making, the utility of CES for body composition analysis would be most useful. Therefore, we analyzed the influence of iodinated contrast medium (ICM) and contrast phase on the characterization and segmentation of adipose tissue.

Methods

Exams of 31 patients undergoing multi-phasic CT at identical scan settings containing an NES were retrospectively included. In addition to NES, patients received an arterial (ART) (n=23), portal-venous (PVN) (n=10), and/or venous scan (VEN) (n=31) after intravenous injection of 90 mL ICM. Density and volume of adipose tissue were quantified semi-automatically with thresholds between -190 HU and -30 HU and recorded separately for visceral (VAT) and subcutaneous adipose tissue (SAT). Density and volume of total adipose tissue (TAT) were computed. For conversion of values from CES into those of NES regression analyses were performed and tested.

Results

Density of adipose tissue increased after application of ICM more on later scans (VEN ≈ PVN > ART) and more markedly in VAT than SAT (VAT > TAT > SAT). Except in SAT on ART, all changes were significant (P<0.001). Measured volume of adipose tissue decreased on all CES (VEN ≈ PVN > ART) (P<0.001), but only reached statistical significance for VAT and TAT (VAT > TAT) on all CES (P<0.05). Density and volume in CES correlate extremely well with NES and may be calculated from one another [root-mean-square error (RMSE): <6 HU; <0.85 dm³].

Conclusions

Density and volume of segmented adipose tissue are altered by the injection of ICM in differing degrees between compartments and contrast phases. However, as the effect of ICM is fairly constant for a given compartment and contrast phase, values may be converted into those of NES with relative precession. This conversion allows body composition analysis to be carried out also in contrast enhanced CT examinations, e.g., for risk stratification and the comparison of the obtained results to previous studies.

Obesity and visceral fat: Survival impact in high-grade endometrial cancer

BACKGROUND

Obesity is an important risk factor for the development of endometrial cancer (EC). Recent data showed that body fat distribution might be more relevant than Body Mass Index (BMI). High visceral fat percentage was shown to be an independent predictor for survival in EC, but mainly included grade 1-2 EC.

OBJECTIVE

To evaluate body fat distribution and its relation to outcome in high-grade endometrial cancer.

METHODS

Retrospective study in women diagnosed with high-grade EC between February 2006 and August 2017 at the Royal Cornwall Hospital who had abdominal CT-scan as part of routine diagnostic work-up. Subcutaneous abdominal fat volumes and visceral abdominal fat volumes were quantified based on CT-scan measurements, and visceral fat percentage calculated.

RESULTS

A total of 176 patients with high-grade EC were included. The median age was 70 years and median BMI was 29.4 kg/m². The majority of patients had non-endometrioid endometrial cancer (NEEC; 62 %). High visceral fat percentage was associated with poor overall- and disease-specific survival (p = 0.006 and p = 0.026 respectively) in NEEC patients, but not in high-grade endometrioid EC (EEC). The most frequent obesity comorbidities hypertension and diabetes mellitus were significantly associated with high BMI and high visceral fat percentage.

CONCLUSION

In high-grade EC, high visceral fat percentage was an independent predictor of poor survival only in NEEC. The strong correlation between high visceral fat and obesity-related comorbidities might be reflective of an unhealthy macroenvironment.

Abdominal subcutaneous fat quantification in obese patients from limited field-of-view MRI data

Different types of adipose tissue can be accurately localized and quantified by tomographic imaging techniques (MRI or CT). One common shortcoming for the abdominal subcutaneous adipose tissue (ASAT) of obese subjects is the technically restricted imaging field of view (FOV). This work derives equations for the conversion between six surrogate measures and fully segmented ASAT volume and discusses the predictive power of these image-based quantities. Clinical (gender, age, anthropometry) and MRI data (1.5 T, two-point Dixon sequence) of 193 overweight and obese patients (116 female, 77 male) from a single research center for obesity were analyzed retrospectively. Six surrogate measures of fully segmented ASAT volume (V_ASAT) were considered: two simple ASAT lengths, two partial areas (A_p-FH, A_p-ASIS) and two partial volumes (V_p-FH, V_p-ASIS) limited by either the femoral heads (FH) or the anterior superior iliac spine (ASIS). Least-squares regression between each measure and V_ASAT provided slope and intercept for the computation of estimated ASAT volumes (V^~_ASAT). Goodness of fit was evaluated by coefficient of determination (R²) and standard deviation of percent differences (s_d%) between V^~_ASAT and V_ASAT. Best agreement was observed for partial volume V_p-FH (s_d% = 14.4% and R² = 0.78), followed by V_p-ASIS (s_d% = 18.1% and R² = 0.69) and AWF_ASIS (s_d% = 23.9% and R² = 0.54), with minor gender differences only. Other estimates from simple lengths and partial areas were moderate only (s_d% > 23.0% and R² < 0.50). Gender differences in R² generally ranged between 0.02 (d_ven) and 0.29 (A_p-FH). The common FOV restriction for MRI volumetry of ASAT in obese subjects can best be overcome by estimating V_ASAT from V_p-FH using the equation derived here. The very simple AWF_ASIS can be used with reservation.

Radiological characterization of gilthead seabream (Sparus aurata) fat by X-ray micro-computed tomography

In fish, the fat content contributes to promoting the nutritional and organoleptic characteristics of the flesh, which is crucial for consumer acceptance. Methods to predict the fat in fish are important in nutritional and physiological research, where body content is traditionally determined by dissection followed by chemical analysis. However, X-ray micro-computed tomography (micro-CT) provides three-dimensional information in a non-destructive way. This work aims to characterize radiologically the fat, in situ, in a widely cultivated marine species, gilthead seabream (Sparus aurata). To validate the method changes in fat content in a control group (fed) and another group (unfed for 60 days) were assessed. Fish images were acquired on an Albira SPECT/PET/CT preclinical-scanner. Image analysis and measurements were performed using the Carestream Molecular Imaging Albira CT system in conjunction with Pmod and Amide packages. By micro-CT analysis the density values were determined for the whole fish body (− 1,000 to + 2,500 HU, Hounsfield units), and density ranges for the fat in S. aurata were established from − 115 to + 50 HU. As expected, significant differences were found between fed and starved groups at 60 days. The present study confirms the usefulness of high-resolution morphological analysis for evaluating the presence and distribution of fat in this important fish species.

Abdominal wall morphometric variability based on computed tomography: Influence of age, gender, and body mass index

INTRODUCTION

Ventral hernia surgery does not usually account for the individuality of the abdominal wall anatomy. This could be both because medical imaging is rarely performed before surgery and because data on abdominal wall variability are limited. The objective of the present study was to perform an exhaustive morphometric analysis of abdominal wall components based on computed tomography (CT) scans.

MATERIALS AND METHODS

A retrospective study was performed on 120 abdominopelvic CT scans of clinically normal adults aged 18-86 years equally divided between women and men and into four age groups. Each abdominal wall muscle was evaluated in terms of area, thickness, shape ratio, fat infiltration, and aponeuroses width. The influence of age, gender, and body mass index (BMI) was investigated, as well as muscular asymmetry.

RESULTS

The abdominal wall muscle area represented 8.5 ± 2.5% of the abdominal area. The internal oblique muscle had the largest area, the rectus abdominis was the thickest, the transversus abdominis was the narrowest and had the smallest area. The width of the linea alba was 20.3 ± 12.0 mm. The evolution of the abdominal wall with age was quantified, as well as the large differences between the sexes and BMI groups, resulting in strong correlations and highlighting the specific pattern of the transversus abdominis. The asymmetry of the left and right muscle areas oscillated around 17%.

CONCLUSIONS

The various components of the abdominal wall have been precisely described. Knowledge of their variability could be used to enhance the planning of ventral hernia surgery or to develop numerical modeling of the abdominal wall.

Blood Metabolites Associate with Prognosis in Endometrial Cancer

Endometrial cancer has a high prevalence among post-menopausal women in developed countries. We aimed to explore whether certain metabolic patterns could be related to the characteristics of aggressive disease and poorer survival among endometrial cancer patients in Western Norway. Patients with endometrial cancer with short survival (n = 20) were matched according to FIGO (International Federation of Gynecology and Obstetrics, 2009 criteria) stage, histology, and grade, with patients with long survival (n = 20). Plasma metabolites were measured on a multiplex system including 183 metabolites, which were subsequently determined using liquid chromatography-mass spectrometry. Partial least square discriminant analysis, together with hierarchical clustering, was used to identify patterns which distinguished short from long survival. A proposed signature of metabolites related to survival was suggested, and a multivariate receiver operating characteristic (ROC) analysis yielded an area under the curve (AUC) of 0.820–0.965 (p ≤ 0.001). Methionine sulfoxide seems to be particularly strongly associated with poor survival rates in these patients. In a subgroup with preoperative contrast-enhanced computed tomography data, selected metabolites correlated with the estimated abdominal fat distribution parameters. Metabolic signatures may predict prognosis and be promising supplements when evaluating phenotypes and exploring metabolic pathways related to the progression of endometrial cancer. In the future, this may serve as a useful tool in cancer management.

Participation of white adipose tissue dysfunction on circulating HDL cholesterol and HDL particle size in apparently healthy humans

OBJECTIVE

To use the combined presence of the elevated insulin resistance index in adipose tissue (Adipo-IR) and low values of adiponectin as a marker of dysfunctional adipose tissue, and to analyze its possible association with low values of high-density lipoprotein cholesterol (HDL-C) and small size of HDL particles.

RESEARCH DESIGN AND METHODS

The analysis included 253 subjects with functional adipose tissue and 253 with dysfunctional adipose tissue, considering similar gender, age, and body mass index (BMI). Adipo-IR was considered when index values (free fatty acids × insulin concentrations) were ≥75th percentile. Low levels of adiponectin were considered when concentration in serum was <25th percentile (determined by ELISA). HDL size was estimated by a quantitative validated equation. Small HDL size was considered when values were <25th percentile.

RESULTS

When comparing subjects with functional adipose tissue with those of dysfunctional adipose tissue, the latter had a higher prevalence of low HDL-C (51.4% vs. 64.0%; p = 0.004) and small HDL (56.9% vs. 67.6%; p = 0.009). Multivariate analysis indicated that independently from other metabolic risk factors, dysfunction of adipose tissue is significantly associated with low HDL-C (OR: 1.624 [CI 95%: 1.100-2.397]) and small HDL (OR: 1.462 [CI 95%: 1.000-2.139]). Adding BMI, waist circumference, and subcutaneous or visceral adipose tissue did not modify the association.

CONCLUSIONS

Dysfunction of adipose tissue is associated with a 65 and 50% higher probability of having low HDL-C and small HDL. Identification of dysfunctional adipose tissue could be a useful tool in the clinical setting to prevent the cardiometabolic risk independently from adiposity.

THE IMPACT OF OBESITY ON ABDOMINAL CT RADIATION DOSE AND IMAGE QUALITY

The aim of this study was to evaluate how iterative reconstruction can compensate for the noise increase in low radiation dose abdominal computed tomography (CT) technique for large size patients and the general impact of obesity on abdominal organ doses and image quality in CT. An anthropomorphic phantom layered with either none or a single layer of 3-cm- thick circumferential animal fat packs to simulate obese patients was imaged using a 128MDCT scanner. Abdominal protocols (n = 12) were applied using automatic tube current modulation (ATCM) with various quality reference mAs (150, 200, 250 and 300). kVs of 100, 120 and 140 were used for each mAs selection. Metal oxide semiconductor field effect transistor dosimeters (MOSFET) measured internal organ dose. All images produced were reconstructed with filtered back projection (FBP) and sinogram affirmed iterative reconstruction (SAFIRE) (3, 4 and 5) and objective noise was measured within three regions of interest at the level of L4-L5. Organ doses varied from 0.12 to 41.9 mGy, the spleen received the highest doses for both phantom sizes. Compared to the phantom simulating average size, the obese phantom was associated with up to twofold increase in delivered mAs, dose length product (DLP) and computed tomography dose index (CTDIvol) for the matched mAs selection (p < 0.05). However, organ dose increased by 50% only. The use of 100 kV resulted in a 40% lower dose (p < 0.05) compared to 120 kV and the associated noise increase was improved by SAFIRE (5) use, which resulted in 60% noise reduction compared to FBP (p < 0.05). When combined with iterative reconstruction, low kV is feasible for obese patients to optimise radiation dose and maintain objective image quality.