Fig. 5

Renal cell carcinoma. A lesion in the right kidney of a 73-year-old male is confirmed as being a hypernephroma through biopsy. The patient is treated with RF ablation, while cooling the pyelum with a double j-stent. a The DECT obtained 24 h post ablation shows a hyperdense region in the ablation zone on the water map images (white arrow). On the synthesised monochromatic 40-keV images, a sharp delineation of the ablation border is assessed, without the presence of any internal hyperdensity in the ablation zone. A post-procedural, streaky, soft-tissue attenuation can be seen in the surrounding perirenal fat (arrowheads). The avascular zone is well depicted on the greyscale- and colour-coded iodine images. In this window level, some yellowish coloured pixels are seen in the centre of the ablation zone on the colour-coded iodine images (black arrow), lying in the extension of a branch of the renal artery, explainable as being spilled iodine due to arterial perfusion. b DECT reconstructions at a 3-month follow-up stage show an overall stability in the size of the ablation zone. The ablated zone is still slightly hyperdense on the water map image (arrow). There is no uptake of iodinated contrast on the greyscale- and colour-coded iodine images, which proves that this area is completely avascular and confirms that the colour pixels seen in a were not a sign of tumour activity