University of California, Beckman Laser Institute and Medical Clinic, Irvine, California, United States.
University of California, Pediatric Exercise and Genomic Research Center, Irvine, California, United States.
J Biomed Opt. 2022 Jun;27(6). doi: 10.1117/1.JBO.27.6.065002.
Growing levels of obesity and metabolic syndrome have driven demand for more advanced forms of body composition assessment. While various techniques exist to measure body composition, devices are typically expensive and not portable, involve radiation [in the case of dual-energy x-ray absorptiometry (DXA)], and are limited to analysis of adiposity while metabolic information from blood supply and oxygenation are not considered.
We evaluate whether diffuse optical spectroscopic imaging (DOSI) can be used to predict site-specific adiposity and percent fat (whole body) while simultaneously providing information about local tissue hemoglobin levels and oxygenation.
DOSI measures of tissue composition in gastrocnemius, quadriceps, abdomen, and biceps, DXA whole-body composition, and ultrasound-derived skin and adipose tissue thickness (SATT) in the quadriceps were obtained from 99 individuals aged 7 to 34 years old.
Various DOSI-derived parameters were correlated with SATT and an optical method is proposed for estimating SATT using a newly defined parameter, the optical fat fraction (OFF), which considers all parameters that correlate with SATT. Broadband absorption and scattering spectra from study participants with the thinnest (SATT ≈ 0.25 ± 0.02 cm) and thickest SATT (SATT ≈ 1.55 ± 0.14 cm), representing best estimates for pure in vivo lean and fatty tissue, respectively, are reported. Finally, a trained prediction model is developed which allows DOSI assessment of OFF to predict DXA body-fat percentage, demonstrating that DOSI can be used to quantify body composition.
This study shows that DOSI can be used to assess the adiposity of specific tissues or the entire human body, and the OFF parameter is defined for corroboration and further evaluation in future research.
肥胖症和代谢综合征水平的不断上升，推动了对更先进的身体成分评估方法的需求。虽然有各种技术可以测量身体成分，但这些设备通常价格昂贵且不便于携带，需要用到辐射（例如双能 X 射线吸收法，DXA），而且只能分析肥胖程度，而无法考虑来自血液供应和氧合的代谢信息。
我们评估扩散光学光谱成像（DOSI）是否可用于预测特定部位的肥胖程度和体脂肪百分比（全身），同时提供有关局部组织血红蛋白水平和氧合的信息。
从 99 名年龄在 7 至 34 岁的个体中获得了 DOSI 对小腿三头肌、股四头肌、腹部和肱二头肌的组织成分测量值、DXA 全身成分以及来自股四头肌的超声衍生皮肤和脂肪组织厚度（SATT）。
各种 DOSI 衍生参数与 SATT 相关，提出了一种光学方法来使用新定义的参数（光学脂肪分数，OFF）来估算 SATT，该参数考虑了与 SATT 相关的所有参数。分别代表体内纯瘦组织和脂肪组织的最佳估计值，报告了来自最薄（SATT≈0.25±0.02cm）和最厚 SATT（SATT≈1.55±0.14cm）研究参与者的宽带吸收和散射光谱。最后，开发了一个经过训练的预测模型，允许通过 DOSI 评估 OFF 来预测 DXA 体脂肪百分比，表明 DOSI 可用于量化身体成分。
本研究表明，DOSI 可用于评估特定组织或整个身体的肥胖程度，并且定义了 OFF 参数，以在未来的研究中进行验证和进一步评估。
