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Abstract #3458

Excitation and Preparation Pulses Affect UTE Bi-Component Analysis of Bound and Free Water in Cortical Bone

Shihong Li1, 2, Monica Tafur1, Won C. Bae1, Eric Chang1, Christine Chung1, Graeme M. Bydder3, Jiang Du1

1Radiology, University of California, San Diego, San Diego, CA, United States; 2Huadong Hospital, Fudan University, Shanghai, China; 3Radiology, University of California San Diego, San Diego, CA, United States

Biological tissues frequently contain distinct water compartments with different transverse relaxation times. Multi-component fitting techniques are important for realistic analysis of T2 relaxation curves. For cortical bone it is impractical to generate T2 relaxation curves using whole-body clinical MR systems due to the relatively long minimum TEs of spin echo sequences. It is much easier to generate T2* relaxation curves which potentially can be used to separate bound water with a shorter T2* from free water with a longer T2*. In this study we investigated the effect of excitation pulse shape, fat saturation pulse, long T2 saturation pulse and adiabatic inversion pulse on ultrashort echo time (UTE) bi-component analysis of bound and free water in bovine and human cortical bone samples.

Keywords

achieved acquisition adiabatic affect affected automated automatically background band basic biological body bone bound bovine bromide built chemical china cleared clinical coil combination compartments component components contain cortical cross curve curves derived detected developed diameter direct distinct distribution duration easier efficient eight errors estimation excellent excitation excitations existence external field fitting five fraction fractions free frequently generate half hard harvested height histogram home hospital human hydration important impractical inversion invert investigated junctions leading leads least length likelihood long longer maintain materials matrix minimize minutes model modes much muscle negative noise null partial placed potentially preceded prep preparation program protocol pulse pulses radiology realistic reception recovery rectangular reduced relatively representative residual residuals respective respectively sample samples saturation scanner sectional selected selective semi separate shanghai shape short shorter since slightly soft specimens spin square subject suggesting summary suppressed suppression susceptibility syringe systems tends tibial tissues transverse trends ultrashort view volume water whole width