[The determination of the T2* relaxation time for characterizing trabecular bone]

Spongy bone produces local magnetic field inhomogeneities and leads to shortening of the transverse relaxation time from bone marrow. This increased signal decay affects the T2 relaxation time. Measurements of the T2* time from the 4th lumbar vertebra were carried out in 48 normals and 20 patients with osteoporosis. A special multigradient echo technique was used, the echo times selected in relation to phase coherence of the water and fat signals. T2* times showed slight increase in relation to age. Patients with osteoporosis showed significantly increased T2* times (19.9 +/- 3.8 ms) compared to the normal control group (13.4 +/- 1.9 ms). From these findings it is possible to judge the quality of the trabecular structure.