Pancreatic Fat Levels Seen with MRS May Help Predict Diabetes

Researchers have long believed that overweight individuals tend to have large fat deposits in their pancreases, but they have been unable to validate or measure how much fat resides there because of the organ's location. Now, however, scientists at a U.S. medical center are the first in the United States to use an imaging technique called magnetic resonance spectroscopy (MRS) to measure the amount of pancreatic fat in humans.

Although scientists worldwide already use MRS to investigate a number of diseases including breast cancer and epilepsy, the researchers, from the University of Texas (UT) Southwestern Medical (Houston, TX, USA), have successfully used the noninvasive method to measure pancreatic fat. Findings from the new UT Southwestern study, published online in mid-September 2009, in the Journal of Clinical Endocrinology and Metabolism, suggest that measuring pancreatic fat content in people could one day serve as an effective clinical tool to identify those at high risk of diabetes and monitor interventions designed to prevent the disease.

"These are very early results, but if they hold true, pancreatic MRS would be a fast and noninvasive test to screen people at risk for diabetes either because they're obese or they have a family history of type 2 diabetes, or metabolic syndrome,” said Dr. Ildiko Lingvay, assistant professor of internal medicine at UT Southwestern and lead author of the study. "It could potentially tell physicians which patients are most likely to develop diabetes in the near future and thus are in need of more aggressive interventions.”

MRS is a specialized technique similar to MR imaging (MRI). It uses no radiation and is completely noninvasive. The modality typically takes 20 to 30 minutes. Whereas an MRI can show clinicians where a tumor is located, MRS can tell those physicians whether the tumor is malignant by providing biochemical data about specific tissues in the body rather than simply detecting the existence of those tissues, according to Dr. Lingvay.

For this study, researchers used MRS to measure the amount of pancreatic fat in 79 adult volunteers. The research team obtained duplicate measurements one to two weeks apart from 33 study participants to make sure the findings could be replicated over time. The volunteers were divided into four groups according to their body mass index (BMI) and glucose tolerance. BMI is a weight-to-height ratio generally used in to gauge obesity. A normal BMI is between 18.5 and 25; someone with a BMI of 40 or more is considered morbidly obese. All participants underwent numerous physical measurements including height, weight, and blood pressure in addition to extensive clinical evaluations.

Utilizing MRS, the investigators found that the overweight and obese volunteers had significantly more pancreatic fat than did those in the lean group. The volunteers who had similar BMIs but had already developed either prediabetes or diabetes had even more pancreatic fat. MRS has not been approved for routine clinical use, but Dr. Lingvay reported that this research shows that it could be a very valuable tool for studying the pancreas without a biopsy. "This technology represents a good opportunity for clinicians to pursue research that hasn't been possible because of the lack of advanced tools,” she said.

The next step, according to Dr. Lingvay, is to determine whether reducing the amount of fat in the pancreas lowers diabetes risk.

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University of Texas Southwestern Medical