OBJECTIVE: To test the feasibility and safety of the laser-induced thermotherapy (LITT) for liver metastases in open MR imaging system operating at 0.2 Tesla. METHOD: Laser therapy using the Nd:YAG laser was performed on 25 patients with a total of 41 liver metastases. An open low-field MRI scanner was used for puncture, positioning of the laser applicator, and monitoring the therapy. A true FISP sequence was used to track the puncture in close to real-time. Localization diagnostics and temperature monitoring were aided by T1-weighted gradient echo sequences in the breath-holding technique. In the first follow up after 24-48 hours, a contrast-enhanced T1-weighted gradient-echo sequence was performed in an MRI scanner at 1.5T. The pre-, intra- and postinterventional volumes of the liver metastases as well as the thermolesions and the thermonecroses were determined. RESULTS: LITT in an open MRI system was technically feasible in all patients with no clinically relevant complications. The mean volumes of the thermolesions measured during intervention in low-field MRI were lower than the volumes of the thermonecroses measured after intervention in high-field MRI. CONCLUSION: The technique presented here of laser-induced thermotherapy for liver metastases in an open MRI system is technically feasible and safe.
OBJECTIVE: To test the feasibility and safety of the laser-induced thermotherapy (LITT) for liver metastases in open MR imaging system operating at 0.2 Tesla. METHOD: Laser therapy using the Nd:YAG laser was performed on 25 patients with a total of 41 liver metastases. An open low-field MRI scanner was used for puncture, positioning of the laser applicator, and monitoring the therapy. A true FISP sequence was used to track the puncture in close to real-time. Localization diagnostics and temperature monitoring were aided by T1-weighted gradient echo sequences in the breath-holding technique. In the first follow up after 24-48 hours, a contrast-enhanced T1-weighted gradient-echo sequence was performed in an MRI scanner at 1.5T. The pre-, intra- and postinterventional volumes of the liver metastases as well as the thermolesions and the thermonecroses were determined. RESULTS: LITT in an open MRI system was technically feasible in all patients with no clinically relevant complications. The mean volumes of the thermolesions measured during intervention in low-field MRI were lower than the volumes of the thermonecroses measured after intervention in high-field MRI. CONCLUSION: The technique presented here of laser-induced thermotherapy for liver metastases in an open MRI system is technically feasible and safe.
Authors: Jens Ricke; Markus Thormann; Matthias Ludewig; Kerstin Jungnickel; Oliver Grosser; Christian Wybranski; Nils Peters; Peter Hass; Jürgen Bunke; Frank Fischbach Journal: Eur Radiol Date: 2010-03-20 Impact factor: 5.315