Functional Imaging of Malignant Pleural Mesothelioma and other Pleural and Chest Wall Lesions

Abstract

Malignant pleural mesothelioma (MPM) is a highly aggressive neoplasm arising mainly in the pleural and with tendency to invasion to adjacent structures, such as chest wall, mediastinum and diaphragm. Lymph node metastasis and extension to other organs also can occur. Management is extremely difficult with a described median survival period of 9 to 17 months. Neoplastic extension and VEGF expression have direct relationship to prognosis.

Although computed tomography is the primary imaging modality for diagnosis, staging and follow – up of therapeutic response to MPM, functional techniques such as diffusion weighted imaging (DWI), dynamic contrast enhanced MR imaging (DCE – MRI), and 2-deoxy-2-[¹⁸F]fluoro-D-glucose-(FDG)-positron emission tomography-computed tomography (18FDG-PET/CT) allow better differentiation of benign versus malignant pleural disease, assessment of local infiltration of adjacent structures, whole body extension and monitoring therapeutic response. Because the importance of accurate staging, cell type and neoangiogenesis in the prognosis of this kind of tumors, some DWI, DCE and ¹⁸FDG-PET/CT related parameters have been related directly to good or poor outcome previous to applying antiangiogenic agents.

Functional MRI (DCE-MRI and DWI) and 18FDG-PET/CT have the potential to provide valuable information in the characterization of primary and metastatic chest wall tumors, but also in the differentiation of benign of malignant ones and therapeutic response monitorization.

In the next few lines we are going to review different aspects of MPM with special focus on functional techniques and its role in staging and assessment of therapeutic response and recurrence. Also functional imaging of other benign and malignant (non-MPM) diseases, which could be false positives, and chest wall tumors are discussed.