Magnetic resonance imaging of microwave induced tissue heating

MR-guided interstitial thermotherapy offers a minimally invasive treatment for localized tumors and tissue structures exhibiting functional abnormalities. In this study, microwaves (2.45 GHz) were used for tissue irradiation to overcome some limitations of the heating sources used so far. To this end, a microwave antenna was positioned in a specimen of porcine myocardium and irradiated for 10 min under MRI control using a T1-weighted FLASH sequence. The heating procedure resulted in a spherical tissue lesion of 26 mm in diameter. Thus, we could demonstrate the feasibility to monitor the microwave-induced coagulation process by MR-imaging in vitro.