Ultrasound Measurement of Total Body Fat in Obese Adolescents

Abstract

Background/Aims: To compare body fat (BF) measurements obtained with a new ultrasound method with those assessed by dual-energy X-ray absorptiometry (DEXA) in obese adolescents. Methods: In 94 adolescents (57 females and 37 males) aged 12–19 years and body mass index (BMI) exceeding 30 kg·m^–2, the z-score BMI for age was 6.7 (adolescent girls) and 6.6 (adolescent boys) >97th percentile. BF was measured using DEXA and a method based on ultrasound measurements, body weight, height, abdominal circumference and mid-thigh circumference. Results: Obesity class I was noted in 39%, II in 28% and III in 33% of the patients. BF by ultrasound correlated closely with BF by DEXA, in both females (r = 0.958) and males (r = 0.981), with standard errors of the estimates (SEE) being 2.9 and 2.5 kg, respectively. The ultrasound method was more accurate than the skinfold technique (n = 24; SEE: 2.2 vs. 6.5 kg, respectively). In 13 adolescents who had marked weight loss after 6 months of treatment, the decrease in DEXA-measured BF correlated closely with the decrease in ultrasound-measured BF (r = 0.95). Conclusions: Our innovative portable ultrasound technique has advantages in terms of reliability, reproducibility, accuracy and costs for screening and monitoring obese adolescents. A patent application has been submitted. Our method should prove valuable for epidemiological studies.

Ultrasound as a Tool to Assess Body Fat

“…The higher the ultrasound frequency the greater the resolution, but there is a decrease in penetration. There is not yet any standardized protocol for using ultrasound to measure subcutaneous fat, but the majority of the studies included in this review have used a 5 MHz, B-mode transducer; however, a relatively new portable ultrasound device (BodyMetrix, BX2000, IntelaMetrix, Inc., Livermore, CA) designed and marketed specifically for body composition assessment uses a 2.5 MHz, A-mode transducer, and Pineau and colleagues [18, 19] validated body fat measurements against DXA using an A-mode transducer with a 2.25 MHz frequency.…”

“…Skinfold thicknesses and anthropometric indices such as waist-to-hip ratio have poor validity in evaluating the intra-abdominal fat of obese children [52]. In contrast, ultrasound was found to be reliable, reproducible, and accurate for measuring the body fat of 94 obese adolescents [19]. The fat mass estimated from ultrasound correlated closely with DXA measurements in both females ( r = 0.958, SEE = 2.9 kg) and males ( r = 0.981, SEE = 2.5 kg).…”

“…The ultrasound estimates of body fat percentage ( r 2 = 0.96, SEE = 2.03, and TE = 1.00) were superior to estimates from BIA ( r 2 = 0.85, SEE = 4.38, and TE = 2.57) and air displacement plethysmography ( r 2 = 0.88, SEE = 3.68, and TE = 2.99). Subsequently, this research team validated this device for use on obese adolescents [19] and recently recalibrated it with a more conventional DXA [61]. …”

Imaging methods for analyzing body composition in human obesity and cardiometabolic disease

“…Measurement of mesenteric fat thickness by US is strongly associated with cardiovascular risk factors in healthy young adults, but comparison of US measures for adipose tissue (VAT and SAT) to those acquired by CT and MRI suggest that, while there is strong correlation with VAT, there may be less accuracy and reliability with measurement of SAT . However, US‐detected changes in total body fat after weight loss were comparable to DXA measures in obese adolescents …”

High-tech adjuncts to emergency weight estimation: Point-of-care ultrasound and point-of-care bioelectrical impedance measurements can increase the accuracy of length-based weight estimation in children

“…Ultrasound has been proven to be useful for predicting body composition [12,26,27]. While multiple sites of ultrasound measurement are generally used for body composition analysis, only two easily-accessible sites were used in this study, to simulate real-world access restrictions in sick children.…”