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Dynamic Contrast-enhanced MR Imaging Parameters in Bone Metastases from Non-Small Cell Lung Cancer: Comparison between Lesions with and Lesions without Epidermal Growth Factor Receptor Mutation in Primary Lung Cancer.

Purpose To compare dynamic contrast material-enhanced (DCE) magnetic resonance (MR) imaging parameters between metastatic bone lesions with and without the epidermal growth factor receptor (EGFR) mutation in consecutive patients with primary non-small cell lung cancer (NSCLC). Materials and Methods This study was approved by the institutional review board. Forty-seven patients with NSCLC and a confirmed EGFR mutation status (27 patients were positive and 26 were negative for EGFR mutation), who underwent DCE MR imaging for bone metastases between November 2012 and March 2016, were included in this study. Two radiologists independently analyzed the volume transfer constant (Ktrans), reflux rate (kep), and volume fraction of the extravascular extracellular matrix (ve) using image processing software. Intergroup comparisons of the mean measured parameters were performed with the Mann-Whitney U test. Interobserver agreement was calculated with the intraclass correlation coefficient. Results There was a high level of agreement between the two reviewers for all three parameters (intraclass correlation coefficient = 0.95 for Ktrans, 0.97 for kep, and 0.91 for ve). Ktrans was significantly higher in the EGFR mutation-positive group (P = .039 for reviewer 1, P = .032 for reviewer 2). kep was also higher in the EGFR mutation-positive group but showed statistical significance only in the evaluation performed by one reviewer (P = .048 for reviewer 2, P = .058 for reviewer 1). No significant difference was observed in ve (P = .873 for reviewer 1, P = .889 for reviewer 2). Conclusion The differences in the DCE MR imaging parameters between metastatic bone lesions with and without EGFR mutations in primary NSCLC may be attributed to differences in the vascular structure related to angiogenesis stimulated by the activation of the EGFR signaling pathway. © RSNA, 2017 Online supplemental material is available for this article.