| Purpose: To demonstrate the correlation between the etiologies of increased diffuse bone marrow(BM)FDG uptake and PET/CT imaging features as well as clinical features,and to establish a predicting model of bone marrow malignant infiltration(MI)in this kind of image.Further we elevate the prognosis of different bone marrow uptake patterns in baseline PET/CT of patients with newly diagnosed diffuse large B cell lymphoma(DLBCL),and validate the prognostic value of the predicting model in diffuse BM uptake patterns.Methods: 84 cases with diffuse BM uptake were retrospectively analyzed.The differences in PET/CT imaging/clinical features between MI and non-MI groups were compared by t-test and chi-square test in order to find significant factors associated with bone marrow MI.Based on C5.0 algorithm and cross-validation approach,we use SPSS Clementine software to establish a decision tree model predicting malignant infiltration of bone marrow.193 cases with newly diagnosed DLBCL were retrospectively analyzed.According to whether the bone marrow FDG uptake was higher than the normal liver background or whether the hypermetabolic lesions were diffuse or focal,the bone marrow FDG uptake patterns were divided into focal PET(fPET +),diffuse Diffuse PET(dPET +)and normal PET(nPET).We analyzed the relationship between different BM patterns and prognosis through survival curves.The decision tree model was applied to DLBCL patients with dPET + to validate its ability to predict disease progression.Results: Among 84 patients with diffuse bone marrow hypermetabolism,comparison between groups suggested that older age,lower proportion of fever,higher maximal standardized uptake value of bone marrow(SUVmaxBM),the ratio of SUVmaxBM in appendicular skeleton to that in axial skeleton(SUVmaxAP/AX)?1 and hepatosplenomegaly were significantly associated with BM malignant infiltration.After the above factors were incorporated into the decision tree model,the age factor was automatically removed.Combined with the remaining four factors,the sensitivity and specificity for predicting malignant infiltration of bone marrow were 81.0%,98.4% and 94.0%,respectively.Of 193 DLBCL patients,the numbers of fPET+,dPET+ and nPET were 28,18 and 147,respectively.fPET + was significantly associated with poor prognosis with a 5-year PFS of 32.7%,significantly lower than 67.1%(p = 0.010)for dPET + and 77.1% for nPET(p <0.001).In multivariate Cox analysis,fPET + was independent predictive factor for PFS.However,there was no significant in 5-year PFS between nPET group and dPET + group(p = 0.701).The decision tree model was applied to the dPET + group,and 4 of dPET+ cases were positive in the model judgment,of which 3 cases had disease progression(75%).14 cases were negative in the model judgment,of which 1 case had progression(7.1%).the former proportion of disease progression was significantly higher than the latter(Correction ?2 = 5.237,p = 0.022).Conclusion: Increased diffuse BM FDG uptake is associated with benign and malignant etiology of bone marrow.Combining imaging and clinical features,the decision tree model has a high diagnostic efficacy for predicting BM malignant infiltration.In patients with newly diagnosed DLBCL,baseline bone marrow fPET + suggests a poor prognosis,and dPET + is not associated with poor prognosis.Decision tree model is useful in differentiating patients with poor prognosis from dPET + and has potential value in predicting prognosis. |
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