Diffusion-weighted MRI after cryosurgery of the canine prostate

Purpose: To evaluate the acute lesion created by cryosurgery with diffusion-weighted magnetic resonance imaging (DWI). Materials and Methods: The appearance of the acute cryolesion was evaluated in four canine prostates DWI after they were warmed to original body temperature. The prostates were excised, stained with triphenyl tetrazolium chloride (TTC), photographed, prepared for hematoxylin and eosin (H&E) staining, and examined under a light microscope. Results: A marked decrease in apparent diffusion coefficient of 38% was evident in the center of the previously frozen tissue, but not in all of the previously frozen tissue. Histologic results confirm differences between the iceball core and the periphery of the iceball, which have markedly different imaging characteristics on DWI. Conclusion: The core of the previously frozen tissue has a reduced apparent diffusion coefficient (ADC) compared to the periphery of the previously frozen tissue and previously unfrozen tissue.