Fig. 2
From: Long-term follow-up of CT-guided percutaneous radiofrequency ablation of T1 renal cell carcinoma
a 55-year-old man, non-contrast CT done to exclude renal stones, shows contour bulge of the right kidney due to a lower polar mass 3 cm in diameter; stage T1a. b Same patient, image obtained during CT-guided RFA procedure, note the clue of successful ablation during procedure is the presence of air densities inside the mass, and outside in the perirenal fat. c Same patient, after 1 month, T1 weight MRI with fat sat image shows no discernible enhancement following IV contrast administration. d Same MRI study, the T2 image shows hypointensity replacing the mass secondary to fibrosis and hyperintensity in the anterior perirenal space due to fat necrosis. e Same patient after 1 year, showing non-enhancing fibrous tissue, with small peripheral fat component