Features high-resolution CT combined with 2D, 3D and 4D optical imaging to enabling correlative imaging applications. This system allows not only imaging of hard tissues such as bone but also soft tissues, including lung, liver, adipose tissue, vascular systems, or cancerous. An integrated, non-invasive, non-destructive capability to track the spatial and temporal distribution of tissue structures and physiologically relevant labels in tissue-engineered constructs, and tissue samples in live animals.