TRANS-FUSIMO: preliminary in-vivo animal results of MR-guided focused ultrasound of liver under respiratory motion

Purpose: Treating liver tumors using Focused Ultrasound (FUS) is a great challenge. Prior to human applications, an in-vivo animal trial using the TRANS-FUSIMO treatment system (TTS) is ongoing in order to evaluate the safety and the technical efficacy and efficiency of generating predefined necrotic lesions. Methods and Materials: The trial includes a crossbred porcine model of thirty large white swine (all females; 55-85Kg) that will be treated using the TTS under general anaesthesia with intubation. All treatments haven been performed under ventilator-controlled breathing and using an improved non-clinical prototype FUS transducer integrated with a 1,5T MRI unit; a set of interventional flexible coils were used. Before the treatment, a 3D LAVA sequence was scanned; 3D FIESTA sequences were then used for planning. During each sonication, real-time multi reference thermal monitoring was achieved using a 3mm istotropic EPI-GRE slice (8Hz). At the end of the treatment session we injected 2ml/Kg of gadobenate dimeglumine and a 3D LAVA sequence was than scanned to identified any necrotic lesion. Results: The results from the first successfully treated animals will be presented. Liver lesioning was possible during both breath-hold and ventilator-controlled breathing due to the TTS motion compensation algorithm which allows the HIFU electronic steering to be controlled according to the MRI images. During all pre-clinical sessions, the TTS was used, including real-time multi reference thermal monitoring. Conclusion: Although the TRANS-FUSIMO animal trial is still ongoing and subject to further optimizations the TRANS-FUSIMO treatment system is capable of perform liver lesions compensating respiratory motion.