Reproducibility and validity of ultrasound for the measurement of visceral and subcutaneous adipose tissues

Background. Ultrasound represents a low-cost and widely available field method for assessing visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) but its measurement properties are uncertain. The aim of the current study was to examine the reproducibility and validity of ultrasound to quantify abdominal fat compartments. Methods. In two study centers, VAT and SAT thicknesses were quantified by ultrasound two times by two observers each among 127 adults aged 20-70 years. In a separate sample of 30 adults, the ultrasound method was validated by comparing VAT and SAT thicknesses with VAT and SAT areas at vertebrae L2/L3 as obtained by a single magnetic resonance imaging (MRI) slice. Results. For VAT, the intra-rater reproducibility values for observers 1 and 2 were r = 0.996 (95% CI = 0.994-0.997) and r = 0.999 (95% CI = 0.999-0.999), respectively. For SAT, the intra-rater reproducibility values were r = 0.992 (95% CI = 0.989-0.994) and r = 0.993 (95% CI = 0.990-0.995), respectively. The inter-rater reproducibility values for VAT and SAT were r = 0.998 (95% CI = 0.997-0.999) and r = 0.990 (95% CI = 0.986-0.993), respectively. For VAT and SAT, the correlation coefficients between ultrasound and MRI measurements were r = 0.898 (P < 0.001) and r = 0.705 (P < 0.001), respectively. Conclusion. Ultrasound provides reproducible and valid estimates of VAT and SAT and represents a useful method to assess abdominal fat in large scale epidemiologic studies. (C) 2014 Elsevier Inc. All rights reserved.