In and Ex Vivo Techniques for Chemical Composition and Molecular Neuroimaging

Advances in technology have made it possible to visualize specific chemical components of the living brain. Bespoke sequences for MRI have been developed for in vivo imaging of inorganic (such as paramagnetic metals) and organic components (such as myelin) of the brain, PET imaging uses radiotracers targeted to specific neurotransmitter receptors and disease biomarkers, and the properties of Doppler ultrasonography used to visualize blood flow are readily transferable to imaging iron. Each method has and continues to lead to new discoveries about the chemical pathology of neurological diseases. However, in vivo imaging is inherently indirect, and questions regarding the accuracy, precision, and specificity of each technique has limited its use outside of the research laboratory. Ex vivo chemical imaging is less restrictive, and a range of spectrometric and spectroscopic techniques have been used to directly assess the spatial distribution and absolute amounts of these same analytes, as well as other neurochemical targets not amenable to in vivo imaging. Independently, these imaging techniques have also revealed new insight into neuropathology and represent a unique opportunity to validate in vivo imaging methods and accelerate clinical translation.

This Research Topic welcomes original research papers and reviews from all scientists working in neuroimaging research, including analytical chemists, physicists, radiologists, and end-users applying these techniques to answer pertinent biological questions. Submissions can focus on a specific technique and/or analyte, with multi-modal methods and applications particularly encouraged. Commentaries on the future directions of chemical neuroimaging are also welcome.