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

Purpose: 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. Materials and Methods: 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 Ã - 1.6 Ã - 4 mm;bsupesup, a;circ5 seconds). Responses in R₂* and amplitudes of each peak were also measured as a function of temperature simultaneously. Results: Calibrations demonstrate that lipid signal may be used to compensate for B₀ 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. Conclusion: Overall, we demonstrate that accurate and precise temperature measurements can be made in bone marrow. In addition, the relationship of R₂* and signal amplitudes with respect to temperature are shown to differ significantly where conformal changes are predicted by Arrhenius rate model analysis. J. Magn. Reson. Imaging 2011;33:1128-1135.