Assessment of early treatment response after CT-guided radiofrequency ablation of unresectable lung tumours by diffusion-weighted MRI: a pilot study

Abstract

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.

Thermal Ablation of Lung Tumors: Focus on Microwave Ablation

“…If not affected by artifacts, MRI offers good visualization with the same concentric rings aspect as seen on CT. Okuma et al have shown that higher apparent diffusion coefficient values of the tumor measured three days after ablation can predict complete ablation, but there are no other studies confirming these findings [75]. MRI offers no clear advantages over CT except for the lack of radiation, and because of its susceptibility to artifacts and higher costs, MRI follow-up has not become part of the clinical routine in most centers.…”

Mechanism and non-mechanism based imaging biomarkers for assessing biological response to treatment in non-small cell lung cancer

“…Standard of care imaging therefore fails to differentiate treatment effect from local recurrence in the first year [129]. DW-MRI has potential in this context, as an increasing ADC has been demonstrated following therapy and favours treatment response [131].…”

Pulmonary radiofrequency ablation (Part 2): Procedure and follow-up

“…12) that assess the size, appearance and metabolic activity of the lesion. 14,20,27,34 The WHO criteria are less indexed and also include enhancement and distance dissemination 27 (Fig. 12).…”