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Abstract #0440

Endocavitary Phased Array Applicator of Therapeutic Ultrasound with an Integrated Opposed-Solenoid Coil for High Resolution MRI-Guided Thermotherapy: An in Vivo Study

Mihaela Rata1,2, Francois Cotton3,4, Christian Paquet5, Vlad Birlea1, Michael Bock6, Rares Salomir1

1INSERM U556, Lyon, France; 2UCBL Lyon 1, Lyon, France; 3UCBL Lyon 1, Lyon, France; 4CHU Lyon Sud, Radiology Department , Lyon, France; 5National Veterinary School, Lyon, France; 6DKFZ, Heidelberg, Germany

High intensity contact ultrasound (HICU) under MRI guidance may provide minimally invasive treatment of endocavitary digestive tumors (colon/rectum). In this study, opposed-solenoid receiver-only coils were integrated into an endoscopic phased array ultrasound probe to offer high resolution MRI guidance of thermotherapy. The improvement of the image quality and temperature monitoring and control using this device has been investigated in- vivo, on a clinical 1.5T. The comparison endocavitary/external standard coils (voxel: 0.88 x 0.88 x 8 mm3) showed a sensitivity gain up to a factor 4, at the limit of the cooling balloon. Infra-millimeter resolution became feasible for fast MR thermometry while providing an excellent SDT. The endoscopic device was actively operated under automatic temperature control, demonstrating accurate performance.