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Harald Busse - One of the best experts on this subject based on the ideXlab platform.
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Abdominal Subcutaneous Fat quantification in obese patients from limited field-of-view MRI data.
Scientific Reports, 2020Co-Authors: Sophia Michel, Nicolas Linder, Tobias Eggebrecht, Alexander Schaudinn, Matthias Blüher, Arne Dietrich, Timm Denecke, Harald BusseAbstract: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 (VASAT) were considered: two simple ASAT lengths, two partial areas (Ap-FH, Ap-ASIS) and two partial volumes (Vp-FH, Vp-ASIS) limited by either the femoral heads (FH) or the anterior superior iliac spine (ASIS). Least-squares regression between each measure and VASAT 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 (sd%) between V~ASAT and VASAT. Best agreement was observed for partial volume Vp-FH (sd% = 14.4% and R2 = 0.78), followed by Vp-ASIS (sd% = 18.1% and R2 = 0.69) and AWFASIS (sd% = 23.9% and R2 = 0.54), with minor gender differences only. Other estimates from simple lengths and partial areas were moderate only (sd% > 23.0% and R2 < 0.50). Gender differences in R2 generally ranged between 0.02 (dven) and 0.29 (Ap-FH). The common FOV restriction for MRI volumetry of ASAT in obese subjects can best be overcome by estimating VASAT from Vp-FH using the equation derived here. The very simple AWFASIS can be used with reservation.
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Abdominal Subcutaneous Fat quantification in obese patients from limited field-of-view MRI data
Scientific reports, 2020Co-Authors: Sophia Michel, Nicolas Linder, Tobias Eggebrecht, Alexander Schaudinn, Matthias Blüher, Arne Dietrich, Timm Denecke, Harald BusseAbstract: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 (VASAT) were considered: two simple ASAT lengths, two partial areas (Ap-FH, Ap-ASIS) and two partial volumes (Vp-FH, Vp-ASIS) limited by either the femoral heads (FH) or the anterior superior iliac spine (ASIS). Least-squares regression between each measure and VASAT 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 (sd%) between V~ASAT and VASAT. Best agreement was observed for partial volume Vp-FH (sd% = 14.4% and R2 = 0.78), followed by Vp-ASIS (sd% = 18.1% and R2 = 0.69) and AWFASIS (sd% = 23.9% and R2 = 0.54), with minor gender differences only. Other estimates from simple lengths and partial areas were moderate only (sd% > 23.0% and R2
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estimation of Abdominal Subcutaneous Fat volume of obese adults from single slice mri data regression coefficients and agreement
European Journal of Radiology, 2020Co-Authors: Nicolas Linder, Sophia Michel, Tobias Eggebrecht, Alexander Schaudinn, Matthias Blüher, Arne Dietrich, Timm Denecke, Harald BusseAbstract:Abstract Purpose Cross-sectional imaging is increasingly used to quantify adipose tissue compartments in subjects with overweight or obesity. The lack of ionizing radiation makes magnetic resonance imaging (MRI) highly preferable to computed tomography (CT) although it is generally less standardized and time-consuming. Fat areas of single or stacks of neighboring slices have previously been considered as surrogates to avoid laborious processing of whole Abdominal data–but studies are inconsistent in design and results. The present work therefore analyzed a relatively large number of overweight or obese adults and involved a total of eight landmarks and two surrogates (slice and stack). The goals were to identify the most reliable estimators of Abdominal Subcutaneous adipose tissue (ASAT) volume for both genders and to relate the findings to the pertinent literature. Material and methods Anthropometric and Fat-sensitive 1.5 T MRI data of 193 patients (116 female, 77 male) from different IRB-approved studies at a single clinical research institution (IFB Adiposity Diseases, University Medicine Leipzig, Germany) were analyzed retrospectively. Mean (± SD) age and BMI were 51.5 (± 12.4) years and 33.7 (± 3.9) kg/m2 for females versus 57.6 (± 12.4) years and 32.1 (± 3.7) kg/m2 for males. Areas of selected axial slices (10 mm thick, 0.5 mm gap) and of stacks of five slices at common landmarks – intervertebral disc spaces L1/L2 to L5/S1, anterior superior iliac spine (ASIS), femoral head (FH) and umbilicus (UM) – were considered as estimators for ASAT volume (reference). Agreement between simple areas and reference volumes was asssessed by linear regression (coefficient of determination R2) as well as standard deviations of percent differences sd% between estimated and measured volumes. Results ASAT volumes ranged from 6.61 to 21.94 L for females (mean: 13.37 L) and from 5.42 to 17.90 L (mean: 9.89 L) for males. The smallest sd% (8.4 %–10.1 %) and largest R2 values (0.86–0.92) for single slices were observed for three candidate slice positions that were also associated with the highest ASAT volume fraction: L4/L5, L5/S1 and UM. The stack estimates for these landmarks were overall somewhat better (7.3 %–9.7 %, 0.88–0.94, respectively). The differences in sd% between genders ranged between 0.2 % and 1.1 %. Conclusion ASAT volume in overweight or obese patients can be readily estimated with good accuracy from a single MRI slice centered at intervertebral disc space L5/S1 for both genders. Disc space L4/L5 or the umbilicus are nearly equivalent landmarks, in particular for male subjects. The extension to stack measures may yield too little improvement to justify the extra effort. Landmarks like ASIS, FH or the remaining lumbar disc spaces are considered as unreliable.
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Estimation of Abdominal Subcutaneous Fat volume of obese adults from single-slice MRI data – Regression coefficients and agreement
European Journal of Radiology, 2020Co-Authors: Nicolas Linder, Sophia Michel, Tobias Eggebrecht, Alexander Schaudinn, Matthias Blüher, Arne Dietrich, Timm Denecke, Harald BusseAbstract:Abstract Purpose Cross-sectional imaging is increasingly used to quantify adipose tissue compartments in subjects with overweight or obesity. The lack of ionizing radiation makes magnetic resonance imaging (MRI) highly preferable to computed tomography (CT) although it is generally less standardized and time-consuming. Fat areas of single or stacks of neighboring slices have previously been considered as surrogates to avoid laborious processing of whole Abdominal data–but studies are inconsistent in design and results. The present work therefore analyzed a relatively large number of overweight or obese adults and involved a total of eight landmarks and two surrogates (slice and stack). The goals were to identify the most reliable estimators of Abdominal Subcutaneous adipose tissue (ASAT) volume for both genders and to relate the findings to the pertinent literature. Material and methods Anthropometric and Fat-sensitive 1.5 T MRI data of 193 patients (116 female, 77 male) from different IRB-approved studies at a single clinical research institution (IFB Adiposity Diseases, University Medicine Leipzig, Germany) were analyzed retrospectively. Mean (± SD) age and BMI were 51.5 (± 12.4) years and 33.7 (± 3.9) kg/m2 for females versus 57.6 (± 12.4) years and 32.1 (± 3.7) kg/m2 for males. Areas of selected axial slices (10 mm thick, 0.5 mm gap) and of stacks of five slices at common landmarks – intervertebral disc spaces L1/L2 to L5/S1, anterior superior iliac spine (ASIS), femoral head (FH) and umbilicus (UM) – were considered as estimators for ASAT volume (reference). Agreement between simple areas and reference volumes was asssessed by linear regression (coefficient of determination R2) as well as standard deviations of percent differences sd% between estimated and measured volumes. Results ASAT volumes ranged from 6.61 to 21.94 L for females (mean: 13.37 L) and from 5.42 to 17.90 L (mean: 9.89 L) for males. The smallest sd% (8.4 %–10.1 %) and largest R2 values (0.86–0.92) for single slices were observed for three candidate slice positions that were also associated with the highest ASAT volume fraction: L4/L5, L5/S1 and UM. The stack estimates for these landmarks were overall somewhat better (7.3 %–9.7 %, 0.88–0.94, respectively). The differences in sd% between genders ranged between 0.2 % and 1.1 %. Conclusion ASAT volume in overweight or obese patients can be readily estimated with good accuracy from a single MRI slice centered at intervertebral disc space L5/S1 for both genders. Disc space L4/L5 or the umbilicus are nearly equivalent landmarks, in particular for male subjects. The extension to stack measures may yield too little improvement to justify the extra effort. Landmarks like ASIS, FH or the remaining lumbar disc spaces are considered as unreliable.
L Niskanen - One of the best experts on this subject based on the ideXlab platform.
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changes in Abdominal Subcutaneous Fat water content with rapid weight loss and long term weight maintenance in Abdominally obese men and women
International Journal of Obesity, 2003Co-Authors: David E Laaksonen, J Nuutinen, T Lahtinen, Aila Rissanen, L NiskanenAbstract:OBJECTIVE: Insulin resistance decreases blood flow and volume in Fat tissue. We hypothesised that Fat tissue nutritive blood flow and volume, and thereby water content, would increase during weight loss and weight maintenance in obese persons. DESIGN: Longitudinal clinical intervention with a 9-week very-low-calorie diet (VLCD) followed by one year of weight maintenance. SUBJECTS: Obese men (n=13) and women (n=14) with the metabolic syndrome. MEASUREMENTS: Water content of Abdominal Subcutaneous Fat tissue as estimated by a sensor on the skin surface measuring the dielectric constant at 300 MHz. Anthropometric measures of Fatness and Fat distribution. Biochemical measures related to insulin resistance. RESULTS: Subjects lost 14.5±3.4% of body weight during the VLCD, and generally sustained this weight loss during weight maintenance. Insulin sensitivity as estimated by an index (qualitative insulin sensitivity check index) increased during the VLCD, and remained increased throughout weight maintenance. The dielectric constant increased from 23.3±2.3 to 25.0±2.1 (P<0.001) during the VLCD, and further to 27.8±1.9 (P<0.001) during weight maintenance, indicating an increase in the water content of Subcutaneous Fat. The increase in Subcutaneous Fat water content did not correlate with weight loss and other measures of adiposity during the VLCD, but there was an inverse correlation that strengthened in significance from baseline to 6, 9 and 12 mo (r=−0.32 to −0.64, P=0.079–0.002). Increases in Subcutaneous Fat water content also correlated with improvements in insulin sensitivity at 6, 9 and 12 months of weight maintenance (r=0.34–0.54, P=0.094–0.006). CONCLUSIONS: Water content of Abdominal Subcutaneous adipose tissue increases with weight loss in obese persons with the metabolic syndrome, and may reflect increased Subcutaneous Fat tissue nutritive blood flow. The increase in water content correlates with the increase in insulin sensitivity, suggesting that weight loss and consequent improved insulin sensitivity could mediate the increase in Abdominal Subcutaneous Fat hydration.
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Changes in Abdominal Subcutaneous Fat water content with rapid weight loss and long-term weight maintenance in Abdominally obese men and women
International Journal of Obesity, 2003Co-Authors: David E Laaksonen, J Nuutinen, T Lahtinen, Aila Rissanen, L NiskanenAbstract:OBJECTIVE: Insulin resistance decreases blood flow and volume in Fat tissue. We hypothesised that Fat tissue nutritive blood flow and volume, and thereby water content, would increase during weight loss and weight maintenance in obese persons. DESIGN: Longitudinal clinical intervention with a 9-week very-low-calorie diet (VLCD) followed by one year of weight maintenance. SUBJECTS: Obese men (n=13) and women (n=14) with the metabolic syndrome. MEASUREMENTS: Water content of Abdominal Subcutaneous Fat tissue as estimated by a sensor on the skin surface measuring the dielectric constant at 300 MHz. Anthropometric measures of Fatness and Fat distribution. Biochemical measures related to insulin resistance. RESULTS: Subjects lost 14.5±3.4% of body weight during the VLCD, and generally sustained this weight loss during weight maintenance. Insulin sensitivity as estimated by an index (qualitative insulin sensitivity check index) increased during the VLCD, and remained increased throughout weight maintenance. The dielectric constant increased from 23.3±2.3 to 25.0±2.1 (P
Wilfred Y. Fujimoto - One of the best experts on this subject based on the ideXlab platform.
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change in ct measured Abdominal Subcutaneous and visceral but not thigh Fat areas predict future insulin sensitivity
Diabetes Research and Clinical Practice, 2019Co-Authors: Amy W Liu, Donna L Leonetti, Tomoshige Hayashi, Steven E Kahn, Wilfred Y. Fujimoto, Kyoko Kogawa Sato, Sun Ok Song, Edward J. BoykoAbstract:Abstract Aims We examined the longitudinal association between change in body composition directly measured by computed tomography (CT) and future insulin sensitivity. Methods This was a prospective study with 10 years of follow-up with 297 Japanese-American without diabetes. Intra-Abdominal Fat area (IAFA) and Abdominal Subcutaneous Fat area (SCFA), and thigh SCFA were measured by CT. Insulin sensitivity was calculated by HOMA-IR and the Matsuda index. Results Baseline and change in IAFA were significantly and independently associated with change in HOMA-IR and Matsuda index during follow-up. In multivariate analysis, IAFA and 10-year change in IAFA (Δ IAFA) was significantly and positively associated with 10-year HOMA-IR (p Conclusions An increase in visceral adiposity predicts diminished insulin sensitivity over 10 years of follow-up independent of the size of this adipose depot at baseline.
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Change in Intra-Abdominal Fat Predicts the Risk of Hypertension in Japanese Americans
Hypertension, 2015Co-Authors: Catherine A. Sullivan, Donna L Leonetti, Tomoshige Hayashi, Steven E Kahn, Wilfred Y. Fujimoto, Edward J. BoykoAbstract:In Japanese Americans, intra-Abdominal Fat area measured by computed tomography is positively associated with the prevalence and incidence of hypertension. Evidence in other populations suggests that other Fat areas may be protective. We sought to determine whether a change in specific Fat depots predicts the development of hypertension. We prospectively followed up 286 subjects (mean age, 49.5 years; 50.4% men) from the Japanese American Community Diabetes Study for 10 years. At baseline, subjects did not have hypertension (defined as blood pressure ≥140/90 mm Hg) and were not taking blood pressure or glucose-lowering medications. Mid-thigh Subcutaneous Fat area, Abdominal Subcutaneous Fat area, and intra-Abdominal Fat area were directly measured by computed tomography at baseline and 5 years. Logistic regression was used to estimate odds of incident hypertension over 10 years in relation to a 5-year change in Fat area. The relative odds of developing hypertension for a 5-year increase in intra-Abdominal Fat was 1.74 (95% confidence interval, 1.28–2.37), after adjusting for age, sex, body mass index, baseline intra-Abdominal Fat, alcohol use, smoking status, and weekly exercise energy expenditure. This relationship remained significant when adjusted for baseline fasting insulin and 2-hour glucose levels or for diabetes mellitus and pre–diabetes mellitus classification. There were no significant associations between baseline and change in thigh or Abdominal Subcutaneous Fat areas and incident hypertension. In conclusion, in this cohort of Japanese Americans, the risk of developing hypertension is related to the accumulation of intra-Abdominal Fat rather than the accrual of Subcutaneous Fat in either the thigh or the Abdominal areas.
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Visceral adiposity, not Abdominal Subcutaneous Fat area, is associated with high blood pressure in Japanese men: the Ohtori study
Hypertension Research, 2011Co-Authors: Hideo Koh, Tomoshige Hayashi, Edward J. Boyko, Wilfred Y. Fujimoto, Kyoko Kogawa Sato, Nobuko Harita, Isseki Maeda, Yoshiki Nishizawa, Ginji Endo, Yonezo HikitaAbstract:Visceral adiposity is considered to have a key role in cardiometabolic diseases. The purpose of this study is to investigate cross-sectionally the association between intra-Abdominal Fat area (IAFA) measured by computed tomography (CT) and high blood pressure independent of Abdominal Subcutaneous Fat area (ASFA) and insulin resistance. Study participants included 624 Japanese men not taking oral hypoglycemic medications or insulin. Abdominal, thoracic and thigh Fat areas were measured by CT. Total Fat area (TFA) was calculated as the sum of Abdominal, thoracic and thigh Fat area. Total Subcutaneous Fat area (TSFA) was defined as TFA minus IAFA. Hypertension and high normal blood pressure were defined using the 1999 criteria of the World Health Organization. Multiple-adjusted odds ratios of hypertension for tertiles of IAFA were 2.64 (95% confidence interval, 1.35–5.16) for tertile 2, and 5.08 (2.48–10.39) for tertile 3, compared with tertile 1 after adjusting for age, fasting immunoreactive insulin, diabetes status, ASFA, alcohol consumption, regular physical exercise and smoking habit. IAFA remained significantly associated with hypertension even after adjustment for ASFA, TSFA, TFA, body mass index or waist circumference, and no other measure of regional or total adiposity was associated with the odds of hypertension in models, which included IAFA. Similar results were obtained for the association between IAFA and the prevalence of high normal blood pressure or hypertension. In conclusion, greater visceral adiposity was associated with a higher odds of high blood pressure in Japanese men.
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visceral adiposity not Abdominal Subcutaneous Fat area is associated with an increase in future insulin resistance in japanese americans
Diabetes, 2008Co-Authors: Tomoshige Hayashi, Donna L Leonetti, Steven E Kahn, Edward J. Boyko, Marguerite J Mcneely, Wilfred Y. FujimotoAbstract:OBJECTIVE— Visceral adiposity is generally considered to play a key role in the metabolic syndrome. We sought to determine whether greater visceral adiposity directly measured by computed tomography (CT) is associated with increased future insulin resistance independent of other adipose depots. RESEARCH DESIGN AND METHODS— We followed 306 nondiabetic Japanese Americans over 10–11 years. Baseline variables included BMI; waist circumference; and Abdominal, thoracic, and thigh Fat areas measured by CT. Total Fat area was estimated by the sum of all of these Fat areas. Visceral adiposity was measured as intra-Abdominal Fat area at the umbilicus level. Total Subcutaneous Fat area was defined as total Fat area minus intra-Abdominal Fat area. Insulin resistance was evaluated by homeostasis model assessment for insulin resistance (HOMA-IR), fasting plasma insulin level, Matsuda index, and area under the oral glucose tolerance test curve (AUC) of insulin. RESULTS— Both baseline intra-Abdominal Fat area ( P = 0.002) and HOMA-IR ( P CONCLUSIONS— Greater visceral adiposity is associated with an increase in future insulin resistance.
Edward J. Boyko - One of the best experts on this subject based on the ideXlab platform.
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change in ct measured Abdominal Subcutaneous and visceral but not thigh Fat areas predict future insulin sensitivity
Diabetes Research and Clinical Practice, 2019Co-Authors: Amy W Liu, Donna L Leonetti, Tomoshige Hayashi, Steven E Kahn, Wilfred Y. Fujimoto, Kyoko Kogawa Sato, Sun Ok Song, Edward J. BoykoAbstract:Abstract Aims We examined the longitudinal association between change in body composition directly measured by computed tomography (CT) and future insulin sensitivity. Methods This was a prospective study with 10 years of follow-up with 297 Japanese-American without diabetes. Intra-Abdominal Fat area (IAFA) and Abdominal Subcutaneous Fat area (SCFA), and thigh SCFA were measured by CT. Insulin sensitivity was calculated by HOMA-IR and the Matsuda index. Results Baseline and change in IAFA were significantly and independently associated with change in HOMA-IR and Matsuda index during follow-up. In multivariate analysis, IAFA and 10-year change in IAFA (Δ IAFA) was significantly and positively associated with 10-year HOMA-IR (p Conclusions An increase in visceral adiposity predicts diminished insulin sensitivity over 10 years of follow-up independent of the size of this adipose depot at baseline.
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Change in Intra-Abdominal Fat Predicts the Risk of Hypertension in Japanese Americans
Hypertension, 2015Co-Authors: Catherine A. Sullivan, Donna L Leonetti, Tomoshige Hayashi, Steven E Kahn, Wilfred Y. Fujimoto, Edward J. BoykoAbstract:In Japanese Americans, intra-Abdominal Fat area measured by computed tomography is positively associated with the prevalence and incidence of hypertension. Evidence in other populations suggests that other Fat areas may be protective. We sought to determine whether a change in specific Fat depots predicts the development of hypertension. We prospectively followed up 286 subjects (mean age, 49.5 years; 50.4% men) from the Japanese American Community Diabetes Study for 10 years. At baseline, subjects did not have hypertension (defined as blood pressure ≥140/90 mm Hg) and were not taking blood pressure or glucose-lowering medications. Mid-thigh Subcutaneous Fat area, Abdominal Subcutaneous Fat area, and intra-Abdominal Fat area were directly measured by computed tomography at baseline and 5 years. Logistic regression was used to estimate odds of incident hypertension over 10 years in relation to a 5-year change in Fat area. The relative odds of developing hypertension for a 5-year increase in intra-Abdominal Fat was 1.74 (95% confidence interval, 1.28–2.37), after adjusting for age, sex, body mass index, baseline intra-Abdominal Fat, alcohol use, smoking status, and weekly exercise energy expenditure. This relationship remained significant when adjusted for baseline fasting insulin and 2-hour glucose levels or for diabetes mellitus and pre–diabetes mellitus classification. There were no significant associations between baseline and change in thigh or Abdominal Subcutaneous Fat areas and incident hypertension. In conclusion, in this cohort of Japanese Americans, the risk of developing hypertension is related to the accumulation of intra-Abdominal Fat rather than the accrual of Subcutaneous Fat in either the thigh or the Abdominal areas.
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Visceral adiposity, not Abdominal Subcutaneous Fat area, is associated with high blood pressure in Japanese men: the Ohtori study
Hypertension Research, 2011Co-Authors: Hideo Koh, Tomoshige Hayashi, Edward J. Boyko, Wilfred Y. Fujimoto, Kyoko Kogawa Sato, Nobuko Harita, Isseki Maeda, Yoshiki Nishizawa, Ginji Endo, Yonezo HikitaAbstract:Visceral adiposity is considered to have a key role in cardiometabolic diseases. The purpose of this study is to investigate cross-sectionally the association between intra-Abdominal Fat area (IAFA) measured by computed tomography (CT) and high blood pressure independent of Abdominal Subcutaneous Fat area (ASFA) and insulin resistance. Study participants included 624 Japanese men not taking oral hypoglycemic medications or insulin. Abdominal, thoracic and thigh Fat areas were measured by CT. Total Fat area (TFA) was calculated as the sum of Abdominal, thoracic and thigh Fat area. Total Subcutaneous Fat area (TSFA) was defined as TFA minus IAFA. Hypertension and high normal blood pressure were defined using the 1999 criteria of the World Health Organization. Multiple-adjusted odds ratios of hypertension for tertiles of IAFA were 2.64 (95% confidence interval, 1.35–5.16) for tertile 2, and 5.08 (2.48–10.39) for tertile 3, compared with tertile 1 after adjusting for age, fasting immunoreactive insulin, diabetes status, ASFA, alcohol consumption, regular physical exercise and smoking habit. IAFA remained significantly associated with hypertension even after adjustment for ASFA, TSFA, TFA, body mass index or waist circumference, and no other measure of regional or total adiposity was associated with the odds of hypertension in models, which included IAFA. Similar results were obtained for the association between IAFA and the prevalence of high normal blood pressure or hypertension. In conclusion, greater visceral adiposity was associated with a higher odds of high blood pressure in Japanese men.
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visceral adiposity not Abdominal Subcutaneous Fat area is associated with an increase in future insulin resistance in japanese americans
Diabetes, 2008Co-Authors: Tomoshige Hayashi, Donna L Leonetti, Steven E Kahn, Edward J. Boyko, Marguerite J Mcneely, Wilfred Y. FujimotoAbstract:OBJECTIVE— Visceral adiposity is generally considered to play a key role in the metabolic syndrome. We sought to determine whether greater visceral adiposity directly measured by computed tomography (CT) is associated with increased future insulin resistance independent of other adipose depots. RESEARCH DESIGN AND METHODS— We followed 306 nondiabetic Japanese Americans over 10–11 years. Baseline variables included BMI; waist circumference; and Abdominal, thoracic, and thigh Fat areas measured by CT. Total Fat area was estimated by the sum of all of these Fat areas. Visceral adiposity was measured as intra-Abdominal Fat area at the umbilicus level. Total Subcutaneous Fat area was defined as total Fat area minus intra-Abdominal Fat area. Insulin resistance was evaluated by homeostasis model assessment for insulin resistance (HOMA-IR), fasting plasma insulin level, Matsuda index, and area under the oral glucose tolerance test curve (AUC) of insulin. RESULTS— Both baseline intra-Abdominal Fat area ( P = 0.002) and HOMA-IR ( P CONCLUSIONS— Greater visceral adiposity is associated with an increase in future insulin resistance.
Sophia Michel - One of the best experts on this subject based on the ideXlab platform.
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Abdominal Subcutaneous Fat quantification in obese patients from limited field-of-view MRI data.
Scientific Reports, 2020Co-Authors: Sophia Michel, Nicolas Linder, Tobias Eggebrecht, Alexander Schaudinn, Matthias Blüher, Arne Dietrich, Timm Denecke, Harald BusseAbstract: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 (VASAT) were considered: two simple ASAT lengths, two partial areas (Ap-FH, Ap-ASIS) and two partial volumes (Vp-FH, Vp-ASIS) limited by either the femoral heads (FH) or the anterior superior iliac spine (ASIS). Least-squares regression between each measure and VASAT 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 (sd%) between V~ASAT and VASAT. Best agreement was observed for partial volume Vp-FH (sd% = 14.4% and R2 = 0.78), followed by Vp-ASIS (sd% = 18.1% and R2 = 0.69) and AWFASIS (sd% = 23.9% and R2 = 0.54), with minor gender differences only. Other estimates from simple lengths and partial areas were moderate only (sd% > 23.0% and R2 < 0.50). Gender differences in R2 generally ranged between 0.02 (dven) and 0.29 (Ap-FH). The common FOV restriction for MRI volumetry of ASAT in obese subjects can best be overcome by estimating VASAT from Vp-FH using the equation derived here. The very simple AWFASIS can be used with reservation.
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Abdominal Subcutaneous Fat quantification in obese patients from limited field-of-view MRI data
Scientific reports, 2020Co-Authors: Sophia Michel, Nicolas Linder, Tobias Eggebrecht, Alexander Schaudinn, Matthias Blüher, Arne Dietrich, Timm Denecke, Harald BusseAbstract: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 (VASAT) were considered: two simple ASAT lengths, two partial areas (Ap-FH, Ap-ASIS) and two partial volumes (Vp-FH, Vp-ASIS) limited by either the femoral heads (FH) or the anterior superior iliac spine (ASIS). Least-squares regression between each measure and VASAT 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 (sd%) between V~ASAT and VASAT. Best agreement was observed for partial volume Vp-FH (sd% = 14.4% and R2 = 0.78), followed by Vp-ASIS (sd% = 18.1% and R2 = 0.69) and AWFASIS (sd% = 23.9% and R2 = 0.54), with minor gender differences only. Other estimates from simple lengths and partial areas were moderate only (sd% > 23.0% and R2
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estimation of Abdominal Subcutaneous Fat volume of obese adults from single slice mri data regression coefficients and agreement
European Journal of Radiology, 2020Co-Authors: Nicolas Linder, Sophia Michel, Tobias Eggebrecht, Alexander Schaudinn, Matthias Blüher, Arne Dietrich, Timm Denecke, Harald BusseAbstract:Abstract Purpose Cross-sectional imaging is increasingly used to quantify adipose tissue compartments in subjects with overweight or obesity. The lack of ionizing radiation makes magnetic resonance imaging (MRI) highly preferable to computed tomography (CT) although it is generally less standardized and time-consuming. Fat areas of single or stacks of neighboring slices have previously been considered as surrogates to avoid laborious processing of whole Abdominal data–but studies are inconsistent in design and results. The present work therefore analyzed a relatively large number of overweight or obese adults and involved a total of eight landmarks and two surrogates (slice and stack). The goals were to identify the most reliable estimators of Abdominal Subcutaneous adipose tissue (ASAT) volume for both genders and to relate the findings to the pertinent literature. Material and methods Anthropometric and Fat-sensitive 1.5 T MRI data of 193 patients (116 female, 77 male) from different IRB-approved studies at a single clinical research institution (IFB Adiposity Diseases, University Medicine Leipzig, Germany) were analyzed retrospectively. Mean (± SD) age and BMI were 51.5 (± 12.4) years and 33.7 (± 3.9) kg/m2 for females versus 57.6 (± 12.4) years and 32.1 (± 3.7) kg/m2 for males. Areas of selected axial slices (10 mm thick, 0.5 mm gap) and of stacks of five slices at common landmarks – intervertebral disc spaces L1/L2 to L5/S1, anterior superior iliac spine (ASIS), femoral head (FH) and umbilicus (UM) – were considered as estimators for ASAT volume (reference). Agreement between simple areas and reference volumes was asssessed by linear regression (coefficient of determination R2) as well as standard deviations of percent differences sd% between estimated and measured volumes. Results ASAT volumes ranged from 6.61 to 21.94 L for females (mean: 13.37 L) and from 5.42 to 17.90 L (mean: 9.89 L) for males. The smallest sd% (8.4 %–10.1 %) and largest R2 values (0.86–0.92) for single slices were observed for three candidate slice positions that were also associated with the highest ASAT volume fraction: L4/L5, L5/S1 and UM. The stack estimates for these landmarks were overall somewhat better (7.3 %–9.7 %, 0.88–0.94, respectively). The differences in sd% between genders ranged between 0.2 % and 1.1 %. Conclusion ASAT volume in overweight or obese patients can be readily estimated with good accuracy from a single MRI slice centered at intervertebral disc space L5/S1 for both genders. Disc space L4/L5 or the umbilicus are nearly equivalent landmarks, in particular for male subjects. The extension to stack measures may yield too little improvement to justify the extra effort. Landmarks like ASIS, FH or the remaining lumbar disc spaces are considered as unreliable.
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Estimation of Abdominal Subcutaneous Fat volume of obese adults from single-slice MRI data – Regression coefficients and agreement
European Journal of Radiology, 2020Co-Authors: Nicolas Linder, Sophia Michel, Tobias Eggebrecht, Alexander Schaudinn, Matthias Blüher, Arne Dietrich, Timm Denecke, Harald BusseAbstract:Abstract Purpose Cross-sectional imaging is increasingly used to quantify adipose tissue compartments in subjects with overweight or obesity. The lack of ionizing radiation makes magnetic resonance imaging (MRI) highly preferable to computed tomography (CT) although it is generally less standardized and time-consuming. Fat areas of single or stacks of neighboring slices have previously been considered as surrogates to avoid laborious processing of whole Abdominal data–but studies are inconsistent in design and results. The present work therefore analyzed a relatively large number of overweight or obese adults and involved a total of eight landmarks and two surrogates (slice and stack). The goals were to identify the most reliable estimators of Abdominal Subcutaneous adipose tissue (ASAT) volume for both genders and to relate the findings to the pertinent literature. Material and methods Anthropometric and Fat-sensitive 1.5 T MRI data of 193 patients (116 female, 77 male) from different IRB-approved studies at a single clinical research institution (IFB Adiposity Diseases, University Medicine Leipzig, Germany) were analyzed retrospectively. Mean (± SD) age and BMI were 51.5 (± 12.4) years and 33.7 (± 3.9) kg/m2 for females versus 57.6 (± 12.4) years and 32.1 (± 3.7) kg/m2 for males. Areas of selected axial slices (10 mm thick, 0.5 mm gap) and of stacks of five slices at common landmarks – intervertebral disc spaces L1/L2 to L5/S1, anterior superior iliac spine (ASIS), femoral head (FH) and umbilicus (UM) – were considered as estimators for ASAT volume (reference). Agreement between simple areas and reference volumes was asssessed by linear regression (coefficient of determination R2) as well as standard deviations of percent differences sd% between estimated and measured volumes. Results ASAT volumes ranged from 6.61 to 21.94 L for females (mean: 13.37 L) and from 5.42 to 17.90 L (mean: 9.89 L) for males. The smallest sd% (8.4 %–10.1 %) and largest R2 values (0.86–0.92) for single slices were observed for three candidate slice positions that were also associated with the highest ASAT volume fraction: L4/L5, L5/S1 and UM. The stack estimates for these landmarks were overall somewhat better (7.3 %–9.7 %, 0.88–0.94, respectively). The differences in sd% between genders ranged between 0.2 % and 1.1 %. Conclusion ASAT volume in overweight or obese patients can be readily estimated with good accuracy from a single MRI slice centered at intervertebral disc space L5/S1 for both genders. Disc space L4/L5 or the umbilicus are nearly equivalent landmarks, in particular for male subjects. The extension to stack measures may yield too little improvement to justify the extra effort. Landmarks like ASIS, FH or the remaining lumbar disc spaces are considered as unreliable.
