The total complication rate for all treatment sessions was 58%, and 25% of patients did not have any complications after RF ablation. Although major complications can occur, RF ablation of lung tumors can be considered a safe and minimally invasive procedure.

Ground-glass attenuation on CT led to overestimation of the size of necrotic lesions. The layered structural findings on CT were consistent with the histopathologic findings. Although CT findings reflect the histopathologic findings, attention should be paid to the dissociation of ablated lesions and high-density areas in clinical interpretation of CT images.

Continuous use of EGFR-TKI beyond PD may prolong overall survival compared with switching to cytotoxic chemotherapy in patients with activating EGFR mutations. A prospective study will be needed to confirm our results.

Background The aims of this study were to retrospectively assess the change in findings on followup CT scans of patients with non-specific interstitial pneumonia (NSIP; median, 72 months; range, 3e216 months) and to clarify the correlation between the baseline CT findings and mortality. Methods The study included 50 patients with a histologic diagnosis of NSIP. Two observers evaluated the highresolution CT (HRCT) findings independently and classified each case into one of the following three categories: (1) compatible with NSIP, (2) compatible with UIP or (3) suggestive of alternative diagnosis. The correlation between the HRCT findings and mortality was evaluated using the KaplaneMeier method and the log-rank test, as well as Cox proportional hazards regression models.

ABSTRACT. The aim of this study was to evaluate prospectively the early treatment response after CT-guided radiofrequency ablation (RFA) of unresectable lung tumours by MRI including diffusion-weighted imaging (DWI). The study protocol was approved by the ethics committee of our hospital and signed consent was obtained from each patient. We studied 17 patients with 20 lung lesions (13 men and 4 women; mean age, 69¡9.8 years; mean tumour size, 20.8¡9.0 mm) who underwent RFA using a LeVeen electrode between November 2006 and January 2008. MRI was performed on a 1.5T unit before and 3 days after ablation. We compared changes in the apparent diffusion coefficient (ADC) on DWI and response evaluation based on subsequent follow-up CT. 14 of the 20 treatment sessions showed no local progression on follow-up CT, whereas 6 treatment sessions showed local progression (range, 3-17 months; mean, 6 months). For the no-progression group, the ADC pre-and post-RFA were 1.15¡0. . The ADC of the ablated lesion was significantly higher than before the procedure (p,0.05). There was a significant difference in the ADC post-RFA between no-progression and local progression groups (p,0.05). Our prospective pilot study showed that the ADC without local progression was significantly higher than with local progression after RFA, suggesting that the ADC can predict the response to RFA for lung tumours.