Neuroinflammation: From target selection to preclinical and clinical studies

Inflammation is a highly dynamic and complex adaptive process to preserve and restore tissue homeostasis in neurological disorders and often serves as a prognostic marker for disease outcome. The underlying cellular and factorial heterogeneity represents an opportunity in the development of disease-modifying therapies. Molecular imaging of neuroinflammation (NI) may support the characterization of key aspects of the dynamic interplay of various inducers, sensors, transducers, and effectors of the multifactorial inflammatory response in vivo in animal models and patients. The characterization of the NI response by molecular imaging will (i) support early diagnosis and disease follow-up, (ii) guide (stereotactic) biopsy sampling, (iii) highlight the dynamic changes during disease pathogenesis in a noninvasive manner, (iv) help monitoring existing therapies, (v) support the development of novel NI-modifying therapies, and (vi) aid stratification of patients, according to their individual NI profile. This book chapter will review the basic principles of NI, recent developments and applications of novel molecular imaging targets, key considerations for the selection and development of imaging targets, as well as examples of successful clinical translation of NI imaging

Response evaluation and follow-up by imaging in brain tumours

Brain tumours, either primary or secondary, are frequent. Primary brain tumours include mainly glioma, lymphoma and meningioma. Secondary tumours, i.e. brain metastases, are a frequent event during the disease course of patients with cancer. The evaluation of response to treatment is often difficult with structural imaging due to the interference of treatment effects. In this chapter, the role of advanced imaging for the differential diagnosis between pseudoprogression, radiation necrosis and tumour recurrence is described with perfusion and diffusion MR imaging, MR spectroscopy and PET imaging with amino acid analogues, fluorodeoxyglucose and other tracers. Furthermore, the commonly used response criteria for various brain tumours are described. For glioma, those set out by the response assessment in neuro-oncology (RANO) group are recommended. For brain metastases the RANO-brain metastases (RANO-BM) and RECIST criteria are commonly used. While conventional T1w post-contrast imaging is the mainstay imaging modality for basic response assessment, multimodal imaging is commonly necessary to evaluate the response to treatment of primary and secondary brain tumours