Relaxation time measurements of bone marrow protons in the calcaneus using a compact MRI system at 0.2 Tesla field strength
✍ Scribed by Sadanori Tomiha; Nachiko Iita; Fumi Okada; Shinya Handa; Katsumi Kose
- Publisher
- John Wiley and Sons
- Year
- 2008
- Tongue
- English
- Weight
- 257 KB
- Volume
- 60
- Category
- Article
- ISSN
- 0740-3194
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✦ Synopsis
Abstract
Relaxation times (T~1~ and T~2~) of the bone marrow protons and trabecular bone volume fraction (TBVF) in the calcaneus were measured for 100 female volunteers using a compact MRI system at 0.2 T field strength. The speed of sound (SOS) through the calcaneus was measured also for the same subjects using a quantitative ultrasound system. Both relaxation times were found to have positive correlations with age (R = 0.40; P < 0.0001 and R = 0.31; P < 0.002, respectively) and negative correlations with SOS (R = −0.38; P < 0.0001 and R = −0.38; P < 0.0001, respectively). Although TBVF had a fairly high positive correlation with the SOS (R = 0.67), neither T~1~ nor T~2~ were correlated with TBVF (R = −0.062 and −0.024, respectively). These results suggest that the age dependence of both T~1~ and T~2~ is caused by the microdynamic properties of the lipid molecules in bone marrow observed using acoustic or elastic modalities. Magn Reson Med 60:485–488, 2008. © 2008 Wiley‐Liss, Inc.