Monitoring Cryoablation using Short Inversion Recovery Ultrashort Echo Time (STIR-UTE) MRI

We propose a new technique to delineate the area below the critical temperature in the frozen tissue during cryoablation using STIR UTE MRI. It relies on the temperature-dependency of the T1 in the frozen tissue. We demonstrated the technique in an ex vivo swine kidney sample using a 3T MRI scanner with a STIR PETRA sequence. To create a uniform temperature gradient, the sample was placed between dry-ice and warm bath, while UTE and STIR UTE images were being acquired. The STIR UTE image demonstrated hyper-intensity in the frozen area, relative to hypo-intensity in the UTE image.