MRI Visceral Adipose Tissue Partitioning:Advanced Models

描述（由申请人提供）：过度肥胖正在成为国家最严重的健康问题。尽管总体脂肪组织（AT）占美国成年人平均体重的四分之一以上，但只有某些相对较小的高度活跃的隔室与发病率密切相关。其中研究最广泛的是内脏脂肪组织（VAT）。测量VAT目前是人类肥胖表型的核心，公认的参考测量方法是磁共振成像（MRI）和计算机断层扫描（CT）。由于辐射暴露，CT的适用性有限。传统的VAT量化成像方法是使用CT或MRI在L4-L5椎体水平测量VAT横截面“面积”。L4-L5级是一个解剖位置，主要是为了方便，作为增值税总额的代表。我们小组最近完成了一项广泛的审查，揭示了成像方法在VAT测量研究中的巨大差异。鉴于迫切需要改善表型和监测干预对重要脂肪组织区室的微小但代谢显著的影响，这种共识的缺乏令人不安。最近的研究表明，腹腔内AT，主要是网膜和肠系膜AT，是与肥胖不良生物学结局和发病率最密切相关的VAT成分。腹腔内AT并不主要局限于L4-L5，而是在更高的水平，我们有初步的数据表明，其他解剖位置可能与不良的代谢测量水平更密切相关。此外，总增值包括多个AT成分，可能不是腹腔内AT或结果的最佳标志。为了研究这些问题，我们建议收集和分析迄今为止最大的（约3000次扫描）和最具主体多样性的全身MRI数据库，这些数据库与相关的身体成分和实验室研究相关联。汇集的图像和数据将为将MRI研究扩展到高分辨率图像采集的新兴领域提供所需的初始数据和基本原理。它还将允许测试与方法、模型开发和生物学兴趣有关的许多其他重要假设。我们的发现可以帮助建立VAT和脂肪组织亚室测量的新标准，降低MRI身体成分研究的成本，并提高研究能力。

DESCRIPTION (provided by applicant): Excessive adiposity is emerging as the nation's most significant health problem. Although total body adipose tissue (AT) accounts for more than one-fourth of body mass in the average American adult, only certain relatively small highly active compartments are strongly associated with morbidity. The most widely studied of these is visceral adipose tissue (VAT). Measuring VAT is currently central to phenotyping human subjects for obesity and the accepted reference measurement methods are magnetic resonance imaging (MRI) and computed tomography (CT). CT is of limited applicability due to radiation exposure. The traditional imaging approach for quantifying VAT is to measure the cross-sectional VAT "area" at the level of the L4-L5 vertebrae using CT or MRI. The L4-L5 level is an anatomic location established largely by convenience as representative of total VAT. An extensive recent review completed by our group reveals large discrepancies across studies in VAT measurement by imaging methods. This lack of consensus is troubling in view of the critical need for improved phenotyping and for monitoring small but metabolically significant effects of interventions on important adipose tissue compartments. Recent studies suggest that intraperitoneal AT, mainly omental and mesenteric AT, is the VAT component that most strongly links adiposity with adverse biological outcomes and morbidity. Intraperitoneal AT is not localized mainly at L4-L5, but at higher levels, and we have preliminary data suggesting other anatomic locations may be more strongly related to undesirable levels of metabolic measures. Moreover, total VAT includes multiple AT components and may not be the best marker of intraperitoneal AT or outcomes. To investigate these questions we propose to assemble and analyze the largest-to-date (~3000 scans) and most subject-diverse whole-body MRI database linked to associated body composition and laboratory studies. The pooled images and data will provide the needed initial data and rationale for expanding MRI studies into the emerging area of high-resolution image acquisition. It will also permit testing many other important hypotheses related to methods, model development and biological interests. Our findings could help to set new standards for VAT and adipose tissue subcompartment measurement, lower the cost of MRI body composition studies, and improve study power.