MRI monitoring of laser ablation using optical flow

The optical now method is used for visualizing and quantifying the dynamics of tissue changes observed by MRI during thermal ablations. An approach wa s implemented for parallel two-dimensional optical now calculations includi ng the replacement of spurious velocities. Velocity magnitude results were found to be accurate in low-noise cases in tests using series of synthetic images. Optical now results are presented from thermal ablation experiments utilizing a homogeneous polyacrylamide gel phantom and heterogeneous rabbi t liver tissue in vivo, exhibiting heating and cooling with the accompanyin g quantitative characterization of the dilation and contraction of the ther mally affected region. Results demonstrate that optical now is capable of n oninvasive real-time monitoring and control of interstitial laser therapy ( ILT).