The Clinical Features Of FUO/IUO And Combined Clinical Parameters To Improve The Diagnostic Efficacy Of 18F-FDG PET/CT In FUO/IUO

Objective: To analyze the clinical features of malignancy,noninfectious inflammatory disease(NIID),and infectious disease in Fever of unknown origin(FUO)and Inflammation of unknown origin(IUO).Method: FUO/IUO patients who were hospitalized at Tongji Hospital from January 2014 to October 2019,and eventually diagnosed with malignancy,NIID,and infectious disease were included in the study.Analyzing the clinical characteristics of three etiological diagnoses in detail,including general information,clinical symptoms and signs,and laboratory tests.Result: A total of 389 FUO/IUO patients were included in this study,with a median age(interquartile range)of 51 years(27 years): 113 cases of malignancy(male: n= 73),153 cases of NIID(male: n= 54),and 123 cases of infectious disease(male: n= 76).Young women are susceptible to NIID,and older men are susceptible to malignancy.Compared with the other two etiological diagnoses,NIID patients were able to relieve fever symptoms more quickly after admission.The most common signs and symptoms of malignancy are weight loss,lymphadenopathy,and hepatosplenomegaly.The most common signs and symptoms in NIID are muscle soreness and skin rashes.Chills are common in both NIID and infectious diseases.Among the three etiological diagnoses,the levels of immunoglobulin(Ig)G,white blood cell count(WBC),neutrophil percentage(N%),platelet(PLT)are the lowest in patients with malignancy,and the percentage of monocytes(M%)and Lactate dehydrogenase(LDH)levels were highest.NIID had the lowest levels of M% and lymphocyte percentage(L%),and the highest levels of N%,PLT,and erythrocyte sedimentation rate(ESR).Serum ferritin(SF)and LDH levels were the lowest in infectious diseases.Conclusion: Malignancy,NIID and infectious diseases in FUO/IUO are different in general information,clinical symptoms and signs,and laboratory tests.These results may provide clinicians with insight into the management of FUO.Objective: To improve the diagnostic efficacy of 18F-FDG PET/CT for Chinese patients with fever of unknown origin(FUO)and inflammation of unknown origin(IUO),with the combination of clinical parameters.Method: FUO/IUO patients who underwent a standard diagnostic work-up and were subjected to 18F-FDG PET/CT scanning were enrolled.According to the results of PET/CT,subjects were divided into a local uptake lesion subgroup and a nonspecific abnormal uptake(NAU)subgroup.In the local uptake lesion subgroup,beneficial clinical parameters were identified to improve the localization efficacy of PET/CT.In the NAU subgroup,beneficial clinical indicators were identified to improve the etiological diagnosis efficiency of PET/CT.Result: From January 2014 to January 2019,253 FUO/IUO patients were studied.Local high-uptake lesions were found in 147 patients,and NAU in 106 patients.In the local uptake lesion group,combined clinical parameters: time from admission to performing PET/CT scanning <6.5 d and C-reactive protein(CRP)level >95 mg/L,the accuracy of PET/CT can increase from 66.3% to 90.0%.In the NAU group,a combination of sex(male),bicytopenia and lactic dehydrogenase(LDH)was used to construct a predictive model of malignancy: logit(P)=1.38*sex(male=1)+1.63*SUVmax(≥2*SUVmax of the liver =1)+2.3*(bicytopenia=1)+1.32*(LDH>370U/L=1)-3.44.With the cutoff value of 0.42,the sensitivity,specificity,positive predictive value(PPV)and negative predictive value(NPV)of diagnosing malignancy can improve from 64.3%,69%,60%,72.7% to 83.3%,81%,81.4%,82.9%,respectively.Based on the combination of sex(male),white blood count(WBC),serum ferritin(SF),and hepatosplenomegaly,a prediction model for infection was constructed: logit(P)=2.0*sex(male=1)-1.88*(WBC >10*10^9/L=1)+2*(SF<600μg / L = 1)-2.15*Hepatosplenomegaly(Yes=1)+1.48.When the cut-off value is 0.59,the sensitivity was 78%,the specificity was 76.2%,the PPV was 76.6%,and the NPV was 77.6%.Conclusion: With the combination of clinical parameters,the clinical diagnostic values of 18F-FDG PET/CT have been improved in both the local uptake lesion group and the NAU group in FUO/IUO patients.