The Clinical Application Value Of 18F-FDG PET/CT In Lymphoma-associated Hemophagocytic Lymphohistiocytosis

BackgroundHemophagocytic syndrome(HPS),also known as hemophagocytic lymphohi-stiocytosis(HLH),is a syndrome caused by excessive activation of T lymphocytes and mononuclear-macrophage system,and the production of cytokine storm.Clinical symptoms were characterized by fever,hepatosplenomegaly,and hematocytopenia.The disease onsets dangerously,progresses rapidly and has high fatality rate.According to different etiology,it is divided into primary and secondary types.Primary HLH include familial hemophagocytic syndrome and severe primary immunodeficiency with inherited genes.While,it is more common in children.Secondary HLH(sHLH)has a variety of causes(which can be caused by infection,malignant tumor,autoimmune disease,drugs,transplantation and other factors),and its clinical symptoms are non-specific.Therefore,it is very difficult for making diagnosis and illness often delays due to missed diagnosis and misdiagnosis.Among them,the incidence of LAHS is next only to infection-associated hemophagocytic syndrome(IAHS).While,the fatality rate of LAHS is far higher.Therefore,the early diagnosis and treatment of LAHS are particularly important.In recent years,safe and non-invasive 18F deoxyglucose positron emission tomography(18F-FDG PET/CT)examination has been widely used in malignant tumors,especially in the early diagnosis,clinical staging and efficacy monitoring of lymphoma.This study retrospectively analyzed the clinical data of 55 patients diagnosed as sHLH in our hospital who underwent PET/CT examination to explore the clinical application value of 18F-FDG PET/CT in LAHS.AimsThe purpose of this study was to investigate the clinical application value of18F-FDG PET/CT in Lymphoma-associated hemophagocytic syndrome(LAHS).MethodsPET/CT imaging results of 55 patients with secondary hemophagocytic lymphohistiocytosis were analyzed retrospectively.The specificity,sensitivity and accuracy of PET/CT in the diagnosis of LAHS were determined by taking pathology as the standard.Patients were divided into LAHS group and non-LAHS group according to etiology,and PET parameters and laboratory indicators between the two groups were analyzed and compared.At the same time,the data were statistically analyzed.ResultsThe results showed that the difference of SUVmax and SUVsp between the two groups was statistically significant(P=0.009 and 0.046,respectively).However,there was no statistically significant difference between SUVLN and SUVBM(both P>0.05).The optimal cut-off value of SUVmax in the diagnosis of LAHS was 9.The specificity,sensitivity and accuracy of 18F-FDG PET/CT in the diagnosis of LAHS were 88.6%,72.7%and 85.5%,respectively.There was a negative correlation between SUVBM and platelet count(rho=-0.271,P=0.045).However,SUVmax,SUVsp and SUVLN had no significant correlation with the measured laboratory indexes(P>0.05).Survival curve analysis showed that there was no significant difference in survival time between LAHS group and non-LAHS group(P>0.05).However,the survival time of patients with SUVmax>5.65 was significantly shorter than that of patients with SUVmax<5.65(P=0.001).Meantime,patients with serum fibrinogen(Fbg)<1.0g/L and platelet count(PLT)<50*10~9/L had a shorter survival time than those with Fbg>1.0g/L and PLT>50*10~9/L(P=0.00 and 0.01,respectively).In addition,the survival time of patients with lactate dehydrogenase(LDH)<690U/L was significantly longer than that of patients with LDH<690U/L(P=0.009).Conclusion18F-FDG PET/CT plays a role in the diagnosis of LAHS and prediction of prognosis of sHLH patients.Laboratory indicators(such as Fbg,PLT,LDH)are also of certain value for the prognosis of patients.