Sonographic measurement of mesenteric fat thickness is a good correlate with cardiovascular risk factors: comparison with subcutaneous and preperitoneal fat thickness, magnetic resonance imaging and anthropometric indexes

Abstract

OBJECTIVE: Visceral fat, notably mesenteric fat, which is drained by the portal circulation, plays a critical role in the pathogenesis of metabolic syndrome through increased production of free fatty acids, cytokines and vasoactive peptides. We hypothesize that mesenteric fat thickness as measured by ultrasound scan could explain most of the obesity-related health risk. We explored the relationships between cardiovascular risk factors and abdominal fat as determined by sonographic measurements of thickness of mesenteric, preperitoneal and subcutaneous fat deposits, total abdominal and visceral fat measurement by magnetic resonance imaging (MRI) and anthropometric indexes. DESIGN: A cross-sectional study. SUBJECTS: Subjects included 18 healthy men and 19 women (age: 27-61 y, BMI: 19-33.4 kg/m 2 ). MEASUREMENTS:The maximum thickness of mesenteric, preperitoneal and subcutaneous fat was measured by abdominal ultrasound examination. MRI examinations of whole abdomen and pelvis were performed and the amount of total abdominal and visceral fat was quantified. The body mass index, waist circumference and waist-hip ratio were recorded. Cardiovascular risk factors were assessed by physical examination and blood taking. RESULTS: Men had more adverse cardiovascular risk profile, higher visceral fat volume and thicker mesenteric fat deposits than women. Among all the investigated obesity indexes, the mesenteric fat thickness showed the highest correlations with total cholesterol, LDL-C, triglycerides, fasting plasma glucose, HbA 1c and systolic blood pressure in men, and with triglycerides and HbA 1c in women. On stepwise multiple regression analysis with different obesity indexes as independent variables, 30-65% of the variances of triglycerides, total cholesterol, LDL-C and HbA 1c in men, and triglycerides in women were explained by the mesenteric fat thickness. CONCLUSION: Compared with sonographic measurement of subcutaneous and preperitoneal fat thickness, MRI measurement of total abdominal and visceral fat and anthropometric indexes, sonographic measurement of mesenteric fat thickness showed better associations with some of the cardiovascular risk factors. It may potentially be a useful tool to evaluate regional distribution of obesity in the assessment of cardiovascular risk.

Fully automated large-scale assessment of visceral and subcutaneous abdominal adipose tissue by magnetic resonance imaging

“…However, its relatively inconsistent inter-and intraoperator reproducibilities are major shortcomings. 7,8 Dual energy X-ray absorptiometry (DEXA) provides a relatively rapid and accurate assessment of total body fat with relatively low radiation exposure but does not directly quantify VAAT. [9][10][11] Whereas CT provides more accurate estimation of VAAT, subjects are exposed to ionizing radiation, which makes it unsuitable for large-scale research.…”

“…12,13 With the advantages of noninvasiveness and excellent soft-tissue contrast by using different imaging parameters, MRI provides a method to measure adipose tissue safely and accurately. 8,10,[14][15][16][17][18][19][20][21][22][23][24][25]27 However, measuring the fat quantity and distribution in the abdomen by MRI is generally laborious. Two steps are required to identify the volume of VAAT.…”

“…The first step is to separate fat from nonfat tissue. Thresholding on a histogram 8,[14][15][16][17]19,25 is frequently used for this task and could be accomplished automatically with good agreement between automatically and manually set thresholds. 17,19 The second step is to locate VAAT on MR image slices.…”

“…It is often timeconsuming to delineate the region of interest (ROI) of VAAT because of the complex structure of the viscera. 26 Almost all the previous studies of this step have reported requiring more or less human interventions, which are either laborious or subject to technical problems 8,10,[14][15][16][17]19,[24][25] (Table 1). For example, Elbers et al 15 measured visceral fat areas using an algorithmic seed-growing procedure.…”

Mesenteric fat thickness as an independent determinant of fatty liver

“…8 We have previously reported that the thickness of mesenteric fat measured on ultrasound scan was a more specific deposit of visceral fat and had a good correlation with cardiovascular risk factors in healthy individuals. 9 This study aims to explore the relationships between risk of fatty liver and mesenteric fat thickness as measured on ultrasound scan.…”