 |
Vol.43 No.3 contents | Japanese/English |
 | Full Text of PDF (488K) Article in Japanese |
- Original Article -
Usefulness of Computed Tomography for Evaluating Recurrence After Radiofrequency Ablation
Yoshimasa Oyama1, Toshiyuki Matsuoka1, Masami Toyoshima2, Tomonao Okuma1, Akira Yamamoto1, Yukimasa Sakai1, Masao Hamuro1, Norifumi Nishida1, Kenji Nakamura1, Yuichi Inoue11Department of Radiology, Osaka City University, Medical School, Japan, 2Department of Radiology, Kobe Nishi Shimin Hospital, Japan.
Objective. To determine the usefulness of computed tomography (CT) for evaluating local recurrence, lung nodule size and form were observed, after radiofrequency ablation (RFA), with contrast-enhanced CT to measure the mean CT number. Patients and Methods. Since June 2000, a total of 21 nodules in 10 patients who received RFA were examined using CT. We performed non-contrast CT before RFA and at 1 day, 3 days, 1 week, 1 month, and 3 months after RFA. After that, we performed non-contrast CT every 3 months. Also, we performed contrast-enhanced CT on 14 nodules in 8 patients before and after RFA and calculated the mean CT numbers. Results. (1) Form and size (n=21): three days after RFA there was only a slight reduction and the area ratio was 95.7% compared to the 1st day. However, it reduced to 79.7% on the 7th day, then to 57.7% one month after RFA. From 3 months after RFA, non-recurrent nodules (n=16) decreased over time on CT. (2) Recurrent nodules (n=3) were enhanced 39.17 H.U. on average, but non-recurrent nodules (n=14) were not enhanced by contrast medium. Two nodules among the recurrent nodules were enhanced but had not increased in size. Conclusion. All non-recurrent nodules decreased in size over time and were not enhanced compared with recurrent nodules. Some recurrent nodules were enhanced from the time when they showed no increase in size. We considered that even without evidence of tumor progression, we should perform contrast-enhanced CT for early detection of local recurrence.
key words: Lung tumor, Radiofrequency ablation (RFA), Computed tomography (CT)
Received: December 5, 2002
Accepted: March 5, 2003
JJLC 43 (3): 247-252, 2003
