Background and objective: Magnetic resonance imaging's (MRI) potential to monitor interstitial laser photocoagulation (ILP) has been previously demonstrated and is further tested here with improved spatial and temporal resolution.
Study design/materials and methods: In vivo experiments employed fiber-delivered 1,064 nm light (3.0 W, 150 sec) in six rabbit livers monitored under T1-weighted FSE MRI as 1 image/10 sec and a 3 mm thick 8 cm FOV. Image signal intensities (SI) were compared with temperatures (T) at 7, 10, and 15 mm from the fiber.
Results: Data showed 33 degrees C < T < 60 degrees C. SI did not vary inverselinearly with T; changes in the tissue altered the MRI signal interfering with the SI changes due to temperature.
Conclusion: MRI cannot map SI-derived temperatures over the entire treatment site. The role of MRI's temperature sensitivity must be coordinated with organ- and dose-specific tissue changes.