Tadashi Shimizu MD, Presenter: Nothing to Disclose

Akihiro Sawada MD, Abstract Co-Author: Nothing to Disclose

Yusuke Sakuhara MD, Abstract Co-Author: Nothing to Disclose

Daisuke Abo MD, Abstract Co-Author: Nothing to Disclose

Kazuo Miyasaka MD, PhD, Abstract Co-Author: Nothing to Disclose

The frozen area is clearly visible as very low or no signal area on MR images. Tumors are, however, covered with ice ball and are not able to be detected them on MR images during cryoablation. The purpose of this study is to evaluate the possibility of tumor visualization in the frozen area on MR images using image fusion method for liver tumors.

Using an MR-compatible cryoablation system, MRI-guided percutaneous cryoablation was performed. Treatments were guided and monitored with an open MRI. Criteria for the candidates were as follows. 1. Good performance status. 2. Tumors were limited to the liver. 3. Had no other serious disease. 4. Number of tumors was less than or equal to 3. 5. The maximum diameter of the tumor was less than 5 cm when it is solitary. And the diameters were less than or equal to 3 cm when the number of tumors was 2 or 3. Fusion images were constructed by subtraction between images which tumor were pre frozen and fully frozen

Sixteen tumors in 15 cases were cryoablated. All tumors were hepatocellular carcinoma. The average age was 61.4. The maximum diameters of tumors ranged from 1.2 to 4.5 cm and the average was 2.5 cm. Superparamagnetic iron oxide was administered intravenously in 15 cases out of 16 treatments for delineating the tumor clearly. In all cases, Fusion images were constructed. Fourteen of 16 tumors were visible on the fusion images. In two cases, the image showed the margin was insufficient and local recurrences were occurred 4 months after cryoablation.

It is possible to visualize the tumor in the frozen area of cryoablation by image subtraction method.

Shimizu, T, Sawada, A, Sakuhara, Y, Abo, D, Miyasaka, K, Tumor Visualization in the Frozen Area Using Fusion-imaging for MR-guided Cryoablation.  Radiological Society of North America 2005 Scientific Assembly and Annual Meeting, November 27 - December 2, 2005 ,Chicago IL. http://archive.rsna.org/2005/4419292.html