The state of the art MRI has become a powerful and primary tool for non-invasive imaging of living systems both in laboratory research and clinical practices.  The guidance and applications of physics principles have played critical roles in many aspects of magnetic resonance imaging (MRI), from the discovery of magnetic resonance phenomenon to the development of a library of imaging methods and technology.  As MRI becomes a junction of sciences, engineering, biomedical discoveries and clinical applications, we should reflect the impact of physics and look forward to its continuous influences to the development and direction of magnetic resonance imaging field and beyond.  With this in mind, I will share with you my laboratory’s current research and experiences in developing MRI methods and applications for diagnostic imaging and medical research.  The implementation and applications of diffusion and diffusion tensor imaging to study brain diseases, such as Alzheimer’s disease, will be discussed in the presentation.  In addition, I will introduce our work in developing novel magnetic nanoparticles as MR molecular imaging probes for biomarker targeted imaging of cancers as well as some new MRI methods for molecular imaging.  Looking into the future, we anticipate that MRI will continue to provide great opportunities for physics to make ground-breaking contributions to biomedical research and discoveries.