Analysis of 18 F-FDG PET/CT Imaging Features of Nodal Diffuse Large B-Cell Lymphoma and Follicular Lymphoma

In this study, we aimed to investigate the value of 18 F-fluorodeoxyglucose positron emission tomography/computed tomography ( 18 F-FDG PET/CT) in the differential diagnosis of nodal diffuse large B-cell lymphoma (DLBCL) and follicular lymphoma (FL) and to detect early FL transformation.

We retrospectively enrolled 141 and 56 patients with pathologically confirmed DLBCL and FL, respectively, who underwent 18 F-FDG PET/CT before treatment. The most metabolically active lymph nodes in each patient were selected to compare the imaging characteristics (including shape, size, density, adjacent tissue structures, and metabolism) between DLBCL and FL. Logistic regression was performed to identify the independent risk factors for DLBCL, and receiver operating characteristic (ROC) curve analysis was used to assess the diagnostic value of the different parameters.

Compared with DLBCL, FL was more likely to affect the para-iliac (62.5% vs. 32.6%, P <0.05) and inguinal (50.0% vs. 28.4%, P <0.05) regions. Significant differences ( P <0.05) were observed between DLBCL and FL in lesion fusion, necrosis, surrounding fat stranding, adjacent organ involvement, nonround shape, SUV max , SUV peak , SUV mean , SUL max , SUL peak , SUL mean , lesion SUV max /liver SUV max (L/L), lesion SUV max /mediastinum SUV max (L/M), and total lesion glycolysis (TLG). Multivariate logistic regression analysis identified SUV max >12.35, necrosis, and surrounding fat stranding as independent risk factors of DLBCL. The diagnostic model achieved an area under the curve (AUC) of 0.882, with a sensitivity of 69.5% and specificity of 94.6% for diagnosing DLBCL.

¹⁸F-FDG PET/CT may provide greater diagnostic value in distinguishing nodal DLBCL from FL and probably aid in the early detection of FL transformation and thereby guide timely clinical intervention, which could improve the prognosis.