Central Obesity and Health Risk: Optimal MRI Measurement & Location in Children

描述（由申请人提供）：儿童日益成为国家肥胖人口的重要组成部分，过度肥胖对儿童长期健康的影响可能超过成人。脂肪组织（AT）代谢活动和分布的研究为儿童肥胖的健康相关风险提供了见解。在成人中，尽管全身AT质量可能很大，但只有特定的、相对较小的、高度活跃的隔室与发病率密切相关。内脏脂肪组织（VAT）是这些隔室中研究最多的，是人类肥胖表型的核心。测量VAT量的参考方法是磁共振成像（MRI）和计算机断层扫描（CT）。由于相关的辐射暴露，CT在儿科中的应用有限。表征和测量的AT室在儿童提出了特殊的问题。传统上，VAT是从L4-L5椎间隙的单个横截面积来估计的。最近的研究表明，主要由精神和肠系膜组成的腹腔内应激反应是肥胖与不良健康后果最密切相关的成分。然而，在儿童L4-L5水平可能很少或没有腹腔内AT，尽管在上腹部高于L4-L5的解剖水平可能发现沉积。我们最近对大量成人样本的研究表明，L4-L5级以上5至10厘米的图像切片最能代表VAT总量。另一个问题是，使用目前的成人MRI方案，包括图像之间的“间隙”（例如4厘米），可能无法准确测量儿童的全身VAT和其他区域AT组件。这些限制评估区域肥胖，特别是增值税，在儿童中，促使目前提出的调查。我们提出的目标是收集和分析现有的不同主题的儿童全身MRI扫描数据库，包括一个独特的连续切片扫描子集，以确定并提出解决儿童肥胖成像挑战的解决方案。组装的数据库将使我们能够测试与测量方法、成像模型开发和儿童健康风险相关的重要假设。我们的研究结果可能为儿科全身和局部AT的评估制定标准，并提高研究的有效性。

DESCRIPTION (provided by applicant): Children are increasingly becoming an important segment of the nation's obese population and the impact of excess adiposity on the long-term health of children may exceed that of their adult counterparts. The study of adipose tissue (AT) metabolic activity and distribution provides insights into health-associated risks of pediatric obesity. In adults, although total body AT mass may be large, only specific relatively small, highly-active compartments are strongly associated with morbidity. Visceral adipose tissue (VAT), the most studied of these compartments, is central to phenotyping humans for obesity. Reference methods for measuring the amount of VAT, are magnetic resonance imaging (MRI) and computed tomography (CT). CT is of limited use in pediatrics because of the associated radiation exposure. The characterization and measurement of AT compartments in children poses special problems. VAT has traditionally been estimated from a single cross-sectional area at the L4-L5 intervertebral space. Recent studies suggest that intraperitoneal AT, consisting mainly of mental and mesenteric AT, is the component that most strongly links adiposity with adverse health consequences. However, there may be little or no intraperitoneal AT at the L4-L5 level in children, although deposits may be found at anatomical levels higher than L4-L5, in the upper abdomen. Our recent studies in a large sample of adults showed that an image slice at 5 to 10 cm above the L4-L5 level best represents total VAT volume. Another concern is that whole-body VAT and other regional AT components may not be accurately measured in children using current adult MRI protocols that include a "gap" (e.g., 4 cm) between images. These limitations on evaluating regional adiposity, especially VAT, in children, prompted the present proposed investigation. Our proposed aim is to assemble and analyze a database of existing subject-diverse whole-body MRI scans of children, including a unique subset of contiguous-slice scans, to identify and propose solutions to the unique adiposity imaging challenges posed by children. The assembled database will allow us to test important hypotheses related to measurement methods, imaging model development, and health risks in children. Our findings could potentially set standards for the evaluation of total body and regional AT in pediatrics, and improve study power.