Contribution of diffusion-weighted imaging (DWI) and apparent diffusion coefficient (ADC) measurements in determining response to treatment in lung cancer

Abstract

Purpose: The purpose of this study was to evaluate the role of diffusion-weighted imaging (DWI) in evaluating tumor response to chemotherapy in stage III-IV lung cancer.
 Materials and Methods: Chest and DWI were performed with 3T MRI before and after 3 courses of chemotherapy on 32 patients diagnosed with stage III-IV lung cancer. DWI were acquired with a b factor of 50, 400 and 800 s/mm using a single-shot echo-planar sequence. Histopathological types before and after chemotherapy were compared by measuring mean apparent diffusion coefficient (mADC) values on the basis of regression and progression groups.
 Results: 32 cases, 7 (18.5%) were in the progression group (PG), and 25 (81.5%) were in the regression group (RG). mADC in the PG was 1.06±0.43 x 10ˉ³ before chemotherapy and 0.85±0.24 x 10ˉ³ after chemotherapy. mADC in the RG was 0.92±0.27 x 10ˉ³ before chemotherapy and 1.20±0.26 x 10ˉ³ after chemotherapy. There was a statistically significant difference between the mADC values in the PG and RG before and after chemotherapy. There was no statistically significant difference in mADC values before and after chemotherapy in small cell lung cancer (SCLC) tumor type in the PG . There was a statistically significant difference in mADC values before and after chemotherapy in SCLC and non-small cell lung cancer (NSCLC) tumor types in the RG and NSCLC tumor type in the PG
 Conclusion: DWI and ADC measurements can be used in assessing response to treatment in malignant pulmonary tumors.