ablation zones. Fifteen rats were injected with gadopentetate dimeglumine contrast agent, and subsequently subjected to IRE ablation of the liver. Two hours after the procedure, MRI measurements using conventional T1-weighted gradient echo
sequence (GRE) and inversion recovery sequence (IR)-prepared GRE methods were performed. Upon harvesting of the livers, MRI results were correlated with histologically determined areas of cell death. The investigators found that cell death by IRE corresponds to hyperintense regions measured on T1-weighted GRE images. Once smaller hyperintense regions representing live penumbra tissue were subtracted from the T1-weighted GRE measurements, the remaining penumbra-nulled IR images proved to be very close approximations of pathology-confirmed ablation zones