Quantitative DTI measures

Diffusion tensor imaging (DTI) has revolutionized the visualization of white matter in vivo. However, it is far more than a qualitative tool and can also be used to generate quantitative measures related to diffusion magnitude and its degree of anisotropy, which indirectly reflect microstructural organisation. Although highly sensitive to microstructural change, DTI measures lack specificity and are influenced by a wide range of biological and methodological factors. This makes the interpretation of DTI metric changes extremely challenging. This chapter introduces the most common DTI measures and how they relate to tissue microstructure. Important confounds are addressed, including how DTI metrics are influenced by biological factors such as ageing and pathology, and by methodological factors such as data acquisition, modeling, and analysis