Our purpose was to develop temperature sensitive MR sequences and image-processing techniques to asses their potential of monitoring interstitial laser therapy (ILT) in brain tumors (n = 3) and liver tumors (n = 7). ILT lasted 2 to 26 minutes, while images from T1-weighted Fast-Spin-Echo (FSE)-or Spoiled Gradient-Recalled (SPGR) sequences were acquired within 5 -13 seconds.Pixel subtraction and visualization of T1-weighted images or optical flow computation was done within less than 110 msec. Alternating, phase-mapping of real-and imaginary components of SPGR sequences was performed within 220 msec.Pixel subtraction of T1-weighted images identified thermal changes in liver and brain tumors but could not evaluate the temperature values as chemical-shift based imaging, which was however, more affected by susceptibility effects and motion. Optical flow computation displayed the predicted course of thermal changes and revealed that the rate of heat deposition can be anisotropic, which may be related to heterogeneous tumor structure and/or vascularization.
The proposed PW method using the median of T2* values calculated from partial interventricular septum region provided lower intraobserver and interobserver variabilities compared with the conventional RB or typical PW methods.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.