Multimodality imaging of nitric oxide and nitric oxide synthases

Nitric oxide (NO) and NO synthases (NOSs) are crucial factors in many pathophysiological processes such as inflammation, vascular/neurological function, and many types of cancer. Noninvasive imaging of NO or NOS can provide new insights in understanding these diseases and facilitate the development of novel therapeutic strategies. In this review, we will summarize the current state-of-the-art multimodality imaging in detecting NO and NOSs, including optical (fluorescence, chemiluminescence, and bioluminescence), electron paramagnetic resonance (EPR), magnetic resonance (MR), and positron emission tomography (PET). With continued effort over the last several years, these noninvasive imaging techniques can now reveal the biodistribution of NO or NOS in living subjects with high fidelity which will greatly facilitate scientists/clinicians in the development of new drugs and/or patient management. Lastly, we will also discuss future directions/applications of NO/NOS imaging. Successful development of novel NO/NOS imaging agents with optimal in vivo stability and desirable pharmacokinetics for clinical translation will enable the maximum benefit in patient management.