Haruyuki Takaki MD, Presenter: Nothing to Disclose

Koichiro Yamakado MD, PhD, Abstract Co-Author: Nothing to Disclose

Atsuhiro Nakatsuka MD, Abstract Co-Author: Nothing to Disclose

Francois Cornelis MD, Abstract Co-Author: Nothing to Disclose

Junji Uraki MD, Abstract Co-Author: Nothing to Disclose

Takashi Yamanaka MD, Abstract Co-Author: Nothing to Disclose

Masashi Fujimori MD, Abstract Co-Author: Nothing to Disclose

Takaaki Hasegawa, Abstract Co-Author: Nothing to Disclose

Kiminobu Arima, Abstract Co-Author: Nothing to Disclose

Yoshiki Sugimura, Abstract Co-Author: Nothing to Disclose

Hajime Sakuma MD, Abstract Co-Author: Research Grant, Siemens AG Research Grant, Koninklijke Philips NV Research Grant, General Electric Company Research Grant, Bayer AG Research Grant, Guerbet SA

To prospectively evaluate the frequency and duration of false positive tumor enhancement after cryoablation in patients with renal cell carcinoma (RCC).

Thirty-three patients who underwent cryoablation for the treatment of RCCs smaller than 7 cm were enrolled in this IRB-approved prospective study after a written informed consent was obtained from each of them. Contrast-enhanced MR studies were performed at 6 different time point (3 days, 7 days, 1, 3, 6, 12 months) after cryoablation. The false-positive rates to detect residual tumors were evaluated at each time point. Factors affecting false-positive tumor enhancement was evaluated.

A planned MR protocol was completed in 30 patients (90.9%, 30/33). Residual tumor was histologically proven in 5 patients (16.7%). False-positive rates at each time points were 60.0% (12/25) at 3 days, 52.0% (13/25) at 7 days, 4.0% (1/25) at 1 month, 0% (0/25) at 3 months, 0% (0/25) at 6 months, and 0% at 12 months, respectively. The false-positive tumor enhancement rate at 7 days was significantly higher in patients with RCC with clear cell carcinoma (63.2%, 12/19) than those with other histology (16.7%, 1/6) (p=0.0469). Either tumor size or tumor geometry did not affect false positive tumor enhancement.

Tumor enhancement frequentry remains even in completely ablated RCCs up to one month after cryoablation, in particular in clear cell carcinoma.

Residual tumor enhancement is frequently observed within one month after cryoablation for RCC, and this finding is more common in clear cell carcinoma.

Takaki, H, Yamakado, K, Nakatsuka, A, Cornelis, F, Uraki, J, Yamanaka, T, Fujimori, M, Hasegawa, T, Arima, K, Sugimura, Y, Sakuma, H, False-positive Tumor Enhancement after Cryoablation in Renall Cell Carcinoma: A Prospective Study.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14013317.html