Recently, bone marrow stromal cell (BMSC) therapy for stroke is expected due to the immunomodulation effect. Here, we use PET and other detecting method to investigate the inflammatory changes of brain and lymphoid organs in rat stroke model. In this study, F344 rats were used as transient MCAO models. One part of rats were serially monitored by small-animal PET/CT system with new neuroinflammatory ligand [18F]DPA-714. The brains were removed and sliced subsequently for autoradiograph (ARG) and TTC staining. The rest of rats were sacrificed, their brains and lymphoid organs were taken out, weighed, stained, etc. In histology, cytotoxic T cell (CD8α), macrophage (Iba1 and CD68), apoptosis (TUNEL) and proliferation (ki67) antibodies were chosen and analyzed. PET and ARG represented high concentration in the ischemic area which had been confirmed by TTC. In body imaging, no significant change was found. With the increase of ischemic severity, the size of lymphoid organs have a significantly decrease as well as the body weight. Histological assay showed cd8α+ and ki67+ cells decreased in the lymphoid organs and increased in brain. Besides macrophages and apoptosis cells increased all the time in liver, in other organs, the rate of cells reached peak and gradually decreased more or less. In summary, [18F]DPA-714 PET has a great potential for evaluating brain damage. Inflammatory responses in brain and lymphoid organs are distinct after stroke. Based on these results, we will continue the study for evaluating immunomodulation effect of BMSC transplantation therapy.