Searching for an objective and specific in vivo biomarker for normal physiology and early disease diagnosis has always been a major goal, but also one of the most challenging aspects in brain research. Possible earlier identification of the key pathological signature of diseases (for instance, Alzheimers disease (AD)) is critical for efficient treatment and disease prevention. The concept of combined imaging features is based on the recent accumulating evidence that neither PET nor MRI alone is enough for characterising the earliest AD pathology. The results of this book will, for the first time, highlight in vivo the possibility to describe the early detection and multiple biomarkers based on combined imaging features using PET-MRI, which is the most ideal model for such studies. The newly-developed hybrid imaging technology combining PET and MRI (PET/MRI) for the past few years is emerging, and has drawn much attention in technical developments and clinical applications. PET-MRI opens new horizons in multi-parametric neuroimaging for clinical research that allows simultaneous imaging of multiple parametric changes, such as blood flow and metabolism at the same time. This integration significantly decreases the potential errors in image registration, the difficulty of interpreting underlying coexisting pathophysiological events, and most importantly, patient discomfort. This book will provide the most up-to-date and current status of multiple neuroimaging techniques. The most intriguing application of multi-modality neuroimaging lies in simultaneous interpretation and unique information that each modality can offer. Therefore, this book will present some forefront and interesting examples for the first time in this field of research. This will hopefully trigger the interest of colleagues in this challenging field and help facilitate the applications of the neuroimaging techniques described.