A precise and fast temperature mapping using water proton chemical shift

Abstract

A new temperature measurement procedure using phase mapping was developed that makes use of the temperature dependence of the water proton chemical shift. Highly accurate and fast measurements were obtained during phantom and in vivo experiments. In the pure water phantom experiments, an accuracy of more than +/- 0.5 degrees C was obtained within a few seconds/slice using a field echo pulse sequence (TR/TE = 115/13 ms, matrix = 128 x 128, number of slices = 5). The temperature dependence of the water proton chemical shift was found to be almost the same for different materials with a chemical composition similar to living tissues (water, glucide, protein). Using this method, the temperature change inside a cat's brain was obtained with an accuracy of more than +/- 1 degree C and an in-plane resolution of 0.6 x 0.6 mm. The temperature measurement error was affected by several factors in the living system (B0 shifts caused by position shifts of the sample, blood flow, etc.), the position shift effect being the most serious.

Simultaneous temperature and magnetization transfer (MT) monitoring during high‐intensity focused ultrasound (HIFU) treatment: Preliminary investigation on ex vivo porcine muscle

“…Several MR parameters, such as the equilibrium magnetization (M 0 ), T1, T2, and the diffusion coefficient of water molecules, are known to exhibit temperature dependence (4 -10). The temperature sensitivity of these parameters, however, is tissue-dependent, nonlinear, or varies with tissue conditions such as thermal coagulation or denaturation (5,11,12). Currently, the MR parameter that is sensitive to temperature and stable under various tissue conditions is the water proton resonant frequency (PRF) shift (5).…”

“…Using a radio frequency (RF)-spoiled gradient-echo sequence, the change in temperature ⌬T (°C) can be determined from the difference in phase of the MR signal ⌬ between the current image and a reference (baseline) image (5,13):…”

Modulation of in Vivo Tumor Radiation Response via Gold Nanoshell-Mediated Vascular-Focused Hyperthermia: Characterizing an Integrated Antihypoxic and Localized Vascular Disrupting Targeting Strategy

“…The thermocouple measurements were subsequently validated by noninvasive in vivo MRTI 23 in an additional cohort of mice (see Supporting Information for details). Upon laser illumination with a power of 0.6 W, real-time MRTI measurements demonstrated a temperature difference (ΔT) of ~11.0 °C consistent with the thermocouple measurements.…”

Combining phase images from array coils using a short echo time reference scan (COMPOSER)

“…It can also be used to measure changes in temperature 7 and encode flow velocity in phase contrast angiography 8. Phased array radiofrequency (RF) coils provide higher signal to noise ratio (SNR) than volume coils 9, allow acceleration through parallel imaging and simultaneous multislice methods 10, 11, 12, 13, and enable control over patterns of transmit RF (B 1 + ) via parallel transmit excitation 14, 15.…”