Thermal diffusivity and perfusion constants from in vivo MR-guided focussed ultrasound treatments: a feasibility study

AbstractPurpose: This study investigates the feasibility of non-invasively determining thermal diffusivity (α) and the Pennes perfusion parameter (w) from preclinical and clinical magnetic resonance-guided focused ultrasound (MRgFUS) temperature data.Materials and Methods: Pre-clinical MRgFUS experiments were performed in rabbit muscle (N = 3, 28 sonications) using three-dimensional MR thermometry. 8 sonications were made in a clinical QA phantom with two-dimensional thermometry. Retrospective property determination was performed on clinical uterine fibroid (N = 8, 9 sonications) and desmoid tumor (N = 4, 7 sonications) data.The property determination method fits an analytical solution to MRgFUS temperatures in the coronal MR plane, including all temperatures acquired during heating and one cooling image. When possible, additional cooling data were acquired for property determination.Results: Rabbit α and w from Heating Data (α=0.164 mm2s−1, w = 7.9 kgm−3s−1) and Heating & Cooling Data (α=0.146 mm2s−1, w ...