Combined MR-relaxation and MR-cryoporometry in the study of bone microstructure

MR-Relaxation (MRR) of H-1 nuclei and MR-Cryoporometry (MRC) are combined t o assess their feasibility and their potential in the study of bone microst ructure. In principle, both techniques are able to give information on the structure of the pore space confining the fluids. Cow femur samples were ca refully cared and cleaned in order to remove the natural fluids inside. For MRR analysis quasi-continuous distributions of T-1 and T-2 were obtained a n samples fully saturated with water. Cyclohexane was used as a saturating fluid for MRC analysis. All T-1 and T-2 quasi-continuous distributions of w ater confined in bone samples are more than three decades wide, showing suf ficient details to differentiate the samples. Pore size distributions obtai ned by MRC also differentiate the samples showing different characteristics of the pore space structure in the range of the highest sensitivity of the method (typically 3 to 100 nm, mesopore range). In particular, in samples where MRR shows a large fraction of signal with relaxation times below 10(2 ) ms, MRC indicates a large fraction of pore volume with pore sizes in the mesopore range. (C) 2001 Elsevier Science Inc. All rights reserved.