Development of imaging methods to assess adiposity and metabolism.

Body composition studies were first recorded around the time of the renaissance, and advances by the mid-twentieth century facilitated growth in the study of physiology, metabolism and pathological states. The field developed during this early period around the 'two-compartment' molecular level model that partitions body weight into fat and fat-free mass. Limited use was also made of X-rays as a means of estimating fat-layer thickness, but the revolutionary advance was brought about by the introduction of three-dimensional images provided by computed tomography (CT) in the mid 1970s, followed soon thereafter by magnetic resonance imaging (MRI). Complete in vivo reconstruction of all major anatomic body compartments and tissues became possible, thus providing major new research opportunities. This imaging revolution has continued to advance with further methodology refinements including functional MRI, diffusion tensor imaging and combined methods such as positron emission tomography+CT or MRI. The scientific advances made possible by these new and innovative methods continue to unfold today and hold enormous promise for the future of obesity research.