Follow-Up of Cryoablated Renal Cell Carcinoma with Residual Contrast Enhancement on CT and MRI

Laparoscopic renal cryoablation is increasingly being used in patients with small (≤ 4 cm) unilateral localized renal cell carcinoma (RCC) as a minimally invasive surgery that is alternative to open partial nephrectomy (1). In contrast to partial nephrectomy, in cryoablation there is no surgical specimen with which to identify ablative margins and therefore, recognizing the imaging characteristics of RCC after cryoablation is important. Multiphasic CT and MRI with contrast material are usually used for postablation imaging for the detection of complications related to cryoablation and residual or recurrent tumors. In previous studies, successful ablation has been defined as the absence of contrast enhancement. Any enhancing lesion at the location of the ablated tumor suggests residual viable neoplasm or tumor recurrence (2). However, some residual contrast enhancement may persist for several months and may not be associated with any residual or recurrent tumor (3). Porter et al. (4) suggested that it may be reasonable to wait six months after technically successful renal cryoablation before performing contrast-enhanced MRI because of the resolution of enhancement at six months after cryoablation. However, we recently Original Article