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重要的健康问题。虽然在美国成年人中，全身脂肪组织（AT）占体重的四分之一以上，但只有某些相对较小的高活性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目前是对人类受试者进行肥胖表型分型的核心，并且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。用于量化VAT的传统成像方法是使用CT或MRI测量L4-L5椎骨水平的横截面VAT“面积”。L4-L5节段是一个解剖位置，主要是为了方便而确定的，作为总VAT的代表。我们小组最近完成的一项广泛的综述显示，通过成像方法测量VAT的研究存在很大差异。鉴于迫切需要改进表型和监测干预对重要脂肪组织区室的小但代谢显著的影响，这种缺乏共识的情况令人不安。最近的研究表明，腹膜内AT，主要是网膜和肠系膜AT，是VAT的组成部分，最强烈的肥胖症与不良生物学结果和发病率。腹膜内AT并不主要位于L4-L5，而是位于更高的水平，我们有初步数据表明其他解剖位置可能与代谢指标的不良水平更密切相关。此外，总VAT包括多个AT组分，可能不是腹膜内AT或结局的最佳标志物。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）和最受试者多样化的全身MRI数据库，这些数据库与相关的身体成分和实验室研究有关。合并的图像和数据将提供所需的初始数据和理由，将MRI研究扩展到高分辨率图像采集的新兴领域。它还将允许测试与方法，模型开发和生物学利益有关的许多其他重要假设。我们的研究结果可能有助于为VAT和脂肪组织亚室测量建立新的标准，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.