Investigation Of High Intensity Focused Ultrasound Ablation In Isolated Kidneys By MRI — Preliminary Results

High intensity focused ultrasound (HIFU) under magnetic resonance imaging (MRI) guidance is an attractive instrument to ablate tissue non‐invasively. The aim of this work was to investigate the coagulation volume and the perfusion changes after HIFU‐ablation in an isolated kidney model using MRI. Ablation was performed at least at two regions of the renal cortex. Morphological T1‐/T2‐weighted, temperature sensitive images and contrast‐enhanced perfusion measurements were performed. The detection of single HIFU induced coagulation necroses and HIFU induced tissue cavities was feasible. Perfusion changes could only be detected in few experiments because of relatively inhomogeneous kidney perfusion patterns. MR‐imaging is a sensitive method to detect and to quantify the HIFU‐focus. Moreover, MRI is a valuable approach for the detection of HIFU induced coagulation necroses. The investigation of perfusion changes, particularly important in tumor treatment, was sometimes hampered due to limitations in the used organ model. However, in patients MR perfusion imaging as well as volumetric and morphological imaging can be used to control the outcome of HIFU‐therapy.