Bone Marrow Fat May Indicate Bone Weakening

Measuring bone marrow fat (BMF) along with bone mineral density (BMD) can better predict weakening of bones than either test done alone, a new study indicates. BMD measurement with DEXA is presently the most commonly used parameter for determining bone weakening. Researchers have long questioned whether there may be other measurable bone components that influence mechanical stability of bone.

The study, conducted by researchers at Georgetown University Hospital in Washington DC, showed that increased BMF is an independent marker of bone weakening. MR spectroscopy was used to gauge BMF non-invasively. MR spectroscopy is a relatively new technique that can be done in conjunction with a spine MRI. This is a pilot study that included 26 patients who underwent both DEXA and MR spectroscopy of the lumbar spine, said Dieter Schellinger, MD, author of the study. Fifteen had normal appearing spine vertebra and eleven showed signs of bone weakening.When the results of DEXA and MR spectroscopy tests were compared, the ratio of BMF to BMD was “a significant diagnostic indicator of bone weakening,” said Dr. Schellinger. The ratio was higher in healthy people and lower in those with signs of bone weakening, he said.Dr. Schellinger said that other researchers have previously suspected that increased bone fat content represent a bone risk factor. However, before MR spectroscopy, doctors needed to examine bone fat by operatively removing bone samples from patients. A non-invasive method such as MR spectroscopy opens new diagnostic opportunities, he said.If these results are confirmed by larger studies, increased fat accumulation in bone could be treated with new medications, in an effort to avoid further bone weakening, Dr. Schellinger said.(Source: American Journal of Roentgenology, Science, December 2004)