Objective: To investigate the value of systemic 18F-FDG PET/CT in diagnosis of aplastic anemia.Methods: Systemic PET/CT imaging results of 24 patients admitted and diagnosed with aplastic anemia (AA) in our hospital during the period from May 2011 to April 2014 were retrospectively analyzed and compared to systemic PET/CT results of normal people and patients with acute leukemia (AL) and myelodysplastic syndrome (MDS) in the same period to summarize PET/CT manifestation characteristics of AA patients.Results:Systemic PET/CT manifestations of the 24 AA patients were classified into three types: normal bone marrow metabolism, hypometabolism and hypometabolism complicated by focal hyperproliferation.Focal hyperproliferation was the most frequently found in the vertebral body, breast bones and iliac bones.Bone marrow SUVmax values of AA patients correlated, to certain extents, with the degree of proliferation and the bone marrow T/B cell ratio.The overall bone marrow SUV values of AA patients were lower than those of normal people and patients with AL and MDS, indicating hypometabolism;regarding spleen metabolism, spleen SUV values of MDS patients were higher than those of AA patients;regarding liver and mediastinal blood pool SUV values, there was no statistically significant difference between AA patients and normal people or patients with AL and MDS.SUV values of parts with focal hyperproliferation of AA patients with concurrent infections were higher, and the differences were statistically significant.With the T/B cell ratio taken into account, systemic PET/CT manifestations of AA patients can indicate treatment responses to certain degrees.Conclusion: Systemic PET/CT is highly valuable in diagnosis and differential diagnosis of aplastic anemia and may also indicate responses to treatment.