Deuk Jae Sung MD, Abstract Co-Author: Nothing to Disclose

Eun Kyung Park, Presenter: Nothing to Disclose

Beom Jin Park MD, Abstract Co-Author: Nothing to Disclose

Min Ju Kim, Abstract Co-Author: Nothing to Disclose

Sung Bum Cho, Abstract Co-Author: Nothing to Disclose

Yu-Whan Oh MD, Abstract Co-Author: Nothing to Disclose

Yun Hwan Kim MD,PhD, Abstract Co-Author: Nothing to Disclose

Seok Ho Kang, Abstract Co-Author: Nothing to Disclose

To describe the characteristics of residual contrast enhancement in cryoablated renal cell carcinoma (RCC) on follow-up contrast-enhanced (CE) computed tomography (CT) and magnetic resonance (MR) imaging in patients who underwent laparoscopic renal cryoablation.

Twenty two patients (men,18; women,4; average age, 62) with 24 RCCs, confirmed by intraoperative needle biopsy, underwent laparoscopic renal cryoablation and were followed up with CE CT (n=19) and MR imaging (n=3) for a mean of 28 months (range, 12-60 months). Two radiologists retrospectively assessed in consensus the CT and MR images for the tumor size change and the characteristics of residual contrast enhancement in cryolesions: peripheral rim enhancement (thickness, less than 10% of maximal tumor diameter), focal eccentric enhancement (between 10% and 25%), and thick internal enhancement (more than 25%).

Residual contrast enhancement was seen in 13 cryolesions (54%) at 3-month follow-up. Peripheral rim and focal eccentric enhancement was seen in 6 (25%) and 4 (16.7%) cryolesions, respectively, which persisted for a mean follow-up of 6 months (range, 3~9 months) and 9 months (range, 3-12 months), and disappeared completely at a mean follow-up of 10 months (range, 6-15 months) and 13.5 months (range, 6-18months), respectively. Three cryolesions (12.5%), showing persistent thick internal enhancement at 6-month follow-up, were treated with radiofrequency ablation or chemotherapy. There was no significant difference in the initial tumor size between cryolesions with and without residual enhancement (3.31±1.52 cm vs 2.56±0.67 cm, p=0.11) and between cryolesions with thick internal enhancement and with peripheral rim or focal eccentric enhancement (3.33±1.0 cm vs 3.30±1.69 cm, p=0.97). Cryolesions, except those with thick internal enhancement, decreased in size an average of 20.2% at 6 months and 39.7% at 12 months after cryoablation.

Follow-up CE CT or MR imaging at least more than 12 months is required to assess treatment outcome in patients with peripheral rim or focal eccentric contrast enhancement in cryoablated RCCs, which may persist until 12 months postoperatively without remnant viable tumor.

Eventual resolution of rim or focal residual contrast enhancement may occur along with contraction of renal cryolesion and serial radiologic surveillance is recommended at least more than 12 months.

Sung, D, Park, E, Park, B, Kim, M, Cho, S, Oh, Y, Kim, Y, Kang, S, Follow-up of Cryoablated Renal Cell Carcinoma with Residual Contrast Enhancement on CT and MR Imaging.  Radiological Society of North America 2011 Scientific Assembly and Annual Meeting, November 26 - December 2, 2011 ,Chicago IL. http://archive.rsna.org/2011/11013919.html