Measurement of temperature dependent changes in bone marrow using a rapid chemical shift imaging technique

Abstract

To provide quantitative temperature monitoring for thermal therapies in bone marrow by measuring temperature-dependent signal changes in the bone marrow of ex vivo canine femurs heated with a 980-nm laser at 1.5T and 3.0T. Using a multi-gradient echo (≤ 16) acquisition and signal modeling with the Stieglitz-McBride algorithm, the temperature sensitivity coefficients (TSC, ppm/°C) of water and multiple lipid components' proton resonance frequency (PRF) values are measured at high spatiotemporal resolutions (1.6 × 1.6 × 4 mm(3) , ≤ 5 seconds). Responses in R(2) * and amplitudes of each peak were also measured as a function of temperature simultaneously. Calibrations demonstrate that lipid signal may be used to compensate for B(0) errors to provide accurate temperature readings (<1.0°C). Over a temperature range of 17.2-57.2°C, the TSCs after correction to a bulk methylene reference are -0.87 × 10(-2) ± 4.7 × 10(-4) ppm/°C and -0.87 × 10(-2) ± 4.0 × 10(-4) ppm/°C for 1.5T and 3.0T, respectively. Overall, we demonstrate that accurate and precise temperature measurements can be made in bone marrow. In addition, the relationship of R(2) * and signal amplitudes with respect to temperature are shown to differ significantly where conformal changes are predicted by Arrhenius rate model analysis.