Fig. 6

Renal cell carcinoma. A 40-year-old female is diagnosed with a suspicious lesion in the right kidney on ultrasound. After consulting her urologist, the patient opts for RF ablation. a CECT shows a thick-walled cystic lesion in the right upper pole, graded as a Bosniak 4 cyst. b The true unenhanced polychromatic CT image (left), 24 h post ablation, shows a hyperdense change in the ablation zone (arrow). This finding cannot be confirmed on the water map reconstructions. c The imaging appearance of the ablation zone 24 h (first row), 3 months (second row), and 18 months (third row) after RF ablation. On the 24-h post-ablation series, the delineation of the ablation zone is clearly observable on all reconstructed images; however, the 40 keV image is of superior quality when compared to the 70-keV image (arrowheads). On the iodine-coded images, the internal high attenuation is unexpectedly (no iodine content) still visible within the avascular zone (arrows). No suspicious nodular enhancement is observed at the border of the ablation zone. DECT from 3- and 18-month follow-up depicts an involution of the avascular zone. There is a loss of the internal high-attenuation changes. There is no evidence of local tumour progression