Characterization of Contrast Enhancement in the Ablation Zone Immediately after Radiofrequency Ablation of Renal Tumors

Radiation dose during CT-guided percutaneous cryoablation of renal tumors: Effect of a dose reduction protocol

“…It is likely that many patients treated with CT-guided cryoablation also undergo a diagnostic CT scan, a pre-ablation CT-guided biopsy, and several follow-up CT scans [20,21]. Furthermore, some patients may require additional cryoablation procedures, either to retreat a recurrent tumor or to treat other renal tumors.…”

ACR Appropriateness Criteria® Post-Treatment Follow-up and Active Surveillance of Clinically Localized Renal Cell Cancer

“…A lack of contrast enhancement (ie, increase in attenuation <10-20 Hounsfield units on the postcontrast images) is considered the hallmark of successful treatment, which occurs via disruption of tumor vascularity. However, many completely ablated lesions show enhancement in the immediate post-treatment period, and in some cases, this enhancement may persist for several weeks to months [50,51]. The lack of spontaneous decline in enhancement and involution of the mass over time or the development of new areas of enhancement in the treatment zone or new satellite or port site soft-tissue nodules irrespective of contrast enhancement should raise concern for residual or recurrent disease; in these circumstances, a biopsy could be considered to identify the presence of viable neoplasm [6].…”

Percutaneous Ablation for Small Renal Masses—Imaging Follow-Up

“…It has been reported that mild, homogenous enhancement (> 10 HU) may be seen throughout the treated tissue within the ablation zone on immediate posttreatment imaging and should not be mistaken for residual viable tumor. 38 To avoid confusion, the authors usually wait to administer IV contrast until 1 month after treatment, and subsequently obtain an additional early follow-up imaging study at 3 months.…”