ARS Scientists Test MRI Device to Measure Body Fat in Piglets

A new magnetic resonance imaging (MRI)-based device--more advanced than the technology used today for body composition tests--can accurately and precisely measure total body fat in piglets using the principles of quantitative magnetic resonance (QMR), according to Agricultural Research Service (ARS) scientists who evaluated the new technology.

The new device, called EchoMRI, was tested by ARS researchers to measure not only total body fat, but lean tissue mass, free water mass and total body water in piglets. The research was done under a grant from the National Institutes of Health, which wants to know if the new technology could have future applications for human pediatric use.

Standard MRI systems are commonly used to scan and visualize tissue in humans. However, when used for body composition analysis, imaging systems are subject to substantial error rates caused by the interpretation of visual images using software that relies on population averages.

EchoMRI uses a new type of QMR methodology to obtain body composition results. Its measurement principle depends on the density of hydrogen nuclei and the physical state of the tissue.

ARS animal scientist Alva Mitchell at the Animal Biosciences and Biotechnology Laboratory in Beltsville, Md., tested the device, developed by Echo Medical Systems, to determine EchoMRI's precision and accuracy in piglets as compared to dual x-ray (DXA) technology and chemical analysis.

Twenty-five piglets, each weighing between 3.5 pounds and 8 pounds, were screened live, anesthetized, and post-mortem, using a prototype EchoMRI device for infants. The piglets were also scanned using DXA and then subjected to chemical analysis.

After DXA scans, EchoMRI screenings, and chemical analyses were completed, EchoMRI was found to be a precise and accurate method suitable for measuring piglet whole body composition, total body fat, lean tissue mass, free water mass, and total body water. While these studies were conducted on piglets, EchoMRI may be transferable to market-weight pigs.

EchoMRI allows for measurements to be conducted in only a few minutes without anesthesia or sedation, is radiation-free, and does not require the subject to remain completely motionless. This facilitates convenient, low-stress repeated tracking of small changes in body composition and can be advantageous to researchers to optimize feed utilization. It could also help researchers identify high-value hogs for breeding.

ARS is a scientific research agency of the U.S. Department of Agriculture.