M. Reese Pepper

Evaluation of a rotary laser body scanner for body volume and fat assessment

This paper reports the evaluation tests on the reliability and validity of a 3-dimensional (3D) laser body scanner for estimation of body volume and % fat. Repeated measures of body imaging were performed for reproducibility analysis. Validity of the instrument was assessed by comparison of measures of body volume by imaging to hydrodensitometry, and body fat was compared to hydrodensitometry and dual energy X-ray absorptiometry. Reproducibility analysis showed little difference between within-subjects measurements of volume (ICC ≥ 0.99, p < 0.01). Body volume estimations by laser body scanner and hydrodensitometry were strongly related (r = 0.99, p < 0.01), and agreement was high (ICC = 0.99, p < 0.01). Measurements of % body fat also agreed strongly with each other between methods (ICC = 0.86, p < 0.01), and mean % fat estimates by body imaging did not differ from criterion methods (p > 0.05). These findings indicate that the 3D laser body scanner is a reliable and valid technique for the estimation of body volume. Furthermore, body imaging is an accurate measure of body fat, as compared to dual energy X-ray absorptiometry. This new instrument is promising as a quick, simple to use, and inexpensive method of body composition analysis.

Validation of a 3-dimensional laser body scanner for assessment of waist and hip circumference.

Objectives: To evaluate the reliability and validity of a 3-dimensional laser body scanner for estimation of waist and hip circumferences and waist:hip ratio. Methods: Seventy women were evaluated for waist and hip circumference and waist∶hip ratio via laser scanner and tape measure. In a subset of 34 participants, 8 repeated measures of laser scanning were performed for reproducibility analysis. Validity of the instrument was assessed by regression and Bland-Altman comparison of measures of waist and hip circumferences and waist∶hip ratio to tape measure. Results: Reproducibility analysis showed little difference between within-subjects measurements of circumferences (intraclass correlation coefficient ≥0.992, p < 0.01). Evaluation of waist and hip circumferences measured by body scanning did not differ significantly from tape measure (p > 0.05). Bland-Altman analysis showed no bias between laser scanning and tape measure. Conclusion: These findings indicate that the 3-dimensional laser body scanner is a reliable and valid technique for the estimation of waist and hip circumferences as compared with tape measure. This instrument is promising as a quick and simple method of body circumference analysis.

Three-dimensional surface imaging system for assessing human obesity

The increasing prevalence of obesity suggests a need to develop a convenient, reliable, and economical tool for assessment of this condition. Three-dimensional (3-D) body surface imaging has emerged as an exciting technology for the estimation of body composition. We present a new 3-D body imaging system, which is designed for enhanced portability, affordability, and functionality. In this system, stereo vision technology is used to satisfy the requirement for a simple hardware setup and fast image acquisition. The portability of the system is created via a two-stand configuration, and the accuracy of body volume measurements is improved by customizing stereo matching and surface reconstruction algorithms that target specific problems in 3-D body imaging. Body measurement functions dedicated to body composition assessment also are developed. The overall performance of the system is evaluated in human subjects by comparison to other conventional anthropometric methods, as well as air displacement plethysmography, for body fat assessment.

Predictive equations for central obesity via anthropometrics, stereovision imaging, and MRI in adults

Abdominal visceral adiposity is related to risks for insulin resistance and metabolic perturbations. Magnetic resonance imaging (MRI) and computed tomography are advanced instruments that quantify abdominal adiposity; yet field use is constrained by their bulkiness and costliness. The purpose of this study is to develop prediction equations for total abdominal, subcutaneous, and visceral adiposity via anthropometrics, stereovision body imaging (SBI), and MRI.

Efficacy of thigh volume ratios assessed via stereovision body imaging as a predictor of visceral adipose tissue measured by magnetic resonance imaging

The research examined the efficacy of regional volumes of thigh ratios assessed by stereovision body imaging (SBI) as a predictor of visceral adipose tissue measured by magnetic resonance imaging (MRI). Body measurements obtained via SBI also were utilized to explore disparities of body size and shape in men and women.

Prediction of Android and Gynoid Body Adiposity via a Three-dimensional Stereovision Body Imaging System and Dual-Energy X-ray Absorptiometry

Objective: Current methods for measuring regional body fat are expensive and inconvenient compared to the relative cost-effectiveness and ease of use of a stereovision body imaging (SBI) system. The primary goal of this research is to develop prediction models for android and gynoid fat by body measurements assessed via SBI and dual-energy x-ray absorptiometry (DXA). Subsequently, mathematical equations for prediction of total and regional (trunk, leg) body adiposity were established via parameters measured by SBI and DXA. Methods: A total of 121 participants were randomly assigned into primary and cross-validation groups. Body measurements were obtained via traditional anthropometrics, SBI, and DXA. Multiple regression analysis was conducted to develop mathematical equations by demographics and SBI assessed body measurements as independent variables and body adiposity (fat mass and percentage fat) as dependent variables. The validity of the prediction models was evaluated by a split sample method and Bland-Altman analysis. Results: The R2 of the prediction equations for fat mass and percentage body fat were 93.2% and 76.4% for android and 91.4% and 66.5% for gynoid, respectively. The limits of agreement for the fat mass and percentage fat were −0.06 ± 0.87 kg and −0.11% ± 1.97% for android and −0.04 ± 1.58 kg and −0.19% ± 4.27% for gynoid. Prediction values for fat mass and percentage fat were 94.6% and 88.9% for total body, 93.9% and 71.0% for trunk, and 92.4% and 64.1% for leg, respectively. Conclusions: The three-dimensional (3D) SBI produces reliable parameters that can predict android and gynoid as well as total and regional (trunk, leg) fat mass.

Evaluation of Adult Body Adiposity, Size, and Shape by Stereovision Imaging

Overweight and obesity status is often categorized by body mass index (BMI), although this is not a measurement of body fat. Adiposity, especially in the abdominal area, is a better predictor of obesity-related diseases. However, current methods for assessment of body composition have limitations of bulkiness and expense. The purpose of this study was to evaluate a stereovision imaging system for analysis of body fat. A sample of 105 subjects was measured for body volume using the stereovision imaging system, as compared to air displacement plethysmography and hydrodensitometry. Body density was calculated from total body volume via stereovision imaging, air displacement plethysmography, and hydrodensitometry with weight. Then fat was computed via the Siri equation, and compared to body fat measurements via dual energy X-ray absorptiometry. Mean volume and fat measurements by stereovision and air displacement plethysmography did not differ significantly (mean differences −0.07 ± 0.17 L, −0.36 ± 0.82 kg, respectively, P > 0.05). Stereovision measurements of regional body volumes, lengths, and circumferences were used to develop a prediction equation via internal cross-validation for improved estimation of fat mass. This prediction equation reduced variation in individuals and improved effectiveness of the stereovision imaging system.