MRT zum Monitoring bei hochintensivem fokussiertem Ultraschall

With respect to monitoring of high intensity focused ultrasound (HIFU), synonym focused ultrasound (FUS) treatment, magnetic resonance imaging (MRI) is characterized by several advantageous properties: the precise definition and morphological characterization of the target area (before and after the intervention), the real-time visualization of the treatment effect by thermal imaging (during the intervention) and in the sense of a stereotactic system, the 3-dimensional localization of the target lesion, planning of the target volume and assessment of the achieved ablation volume (before and during the intervention). Non-enhanced T2-weighted multislice MR images are acquired for planning of the intervention. For temperature monitoring (comprising thermometry and thermodosimetry), the temperature-dependent shift of proton resonance frequency (PRFS) is most frequently employed. This method is independent of the treated tissue type or thermally induced tissue changes and facilitates a relative measurement of the temperature change based on a reference value. Future MRI applications include diffusion-weighted MRI (DWI-MRI; for the intrainterventional estimation of treatment efficacy), dynamic contrast-enhanced MRI (DCE-MRI, for the prediction of the potential and assessment of the treatment effect achieved) and motion-corrected temperature monitoring (referenceless and multibaseline thermometry).