The Suppression Ratio as a Surrogate Marker of in vivo Cortical Bone Porosity

Cheng Li¹, Yusuf A. Bhagat¹, Felix W. Wehrli¹

Ultra-short echo-time (UTE) MRI enables detection of cortical bone water. Quantification of pore water would permit an indirect estimation of porosity, currently unachievable in vivo. In this study, we examined the role of the suppression ratio (SR, unsuppressed/soft-tissue suppressed UTE signal) as a surrogate measure for porosity in 18 healthy women (27-81 years old) who underwent scanning of the mid-diaphyseal tibia at 3T with three soft-tissue suppression UTE-MRI schemes. SR was found to increase with age and was inversely correlated with bone mineral density. SR may provide an in vivo surrogate measure of porosity.