MR-guided interstitial laser-induced thermotherapy of hepatic with arterial blood flow metastasis combined reduction: Technique and first clinical results in an open MR system

The feasibility and safety of percutaneous laser-induced thermotherapy (LIT T) of liver metastases in an open low-field magnetic resonance imaging (MRI ) system combined with microsphere-modulated blood flow reduction were test ed. Nd:YAG laser therapy with an Internally cooled laser applicator was per formed under local anesthesia on 20 patients with 34 liver metastases. To i ncrease the effectivenes of LITT, degradable starch microspheres were injec ted into the proper hepatic artery through an MR-visible catheter Initially inserted under fluoroscopy. Near real-time Imaging was used for positionin g the laser applicator. A T1-weighted gradient-echo breath-hold sequence wa s used for catheter localization and temperature monitoring. The volumes of the liver metastases and the thermonecroses were determined. MRI-guided LI TT could be performed in all patients with no clinically relevant complicat ions. Intraprocedural imaging underestimated the extent of thermonecrosis. In conclusion, percutaneous LITT of liver metastases after injection of sta rch microspheres Is both technically feasible and safe in an open MRI syste m. (C) 2001 Wiley-Liss, Inc.