Distinguishing Cortical Bone Bound and Pore Water by T2* at Multiple Magnetic Field Strengths

Alan C. Seifert¹, Cheng Li¹, Jeremy F. Magland¹, Felix W. Wehrli¹

Bone tissue is composed of both phosphorus-containing mineral and collagen matrix. Solid-state 1H MRI can image total bone water, of which only a portion corresponds to matrix. Collagen-bound water can be distinguished from mobile pore water based on T2, but differentiation based on T2* is complicated by susceptibility-induced field inhomogeneities and may not be possible at high field strength. To assess separability, we have generated and examined T2* relaxation spectra of lamb cortical bone specimens at 1.5T, 3T, and 7T. Identification of bound and pore water was possible at 1.5T, but is problematic at 3T and impossible at 7T.