Imaging features and diagnostic value of 18 F-FDG PET/CT in diffuse large B-cell lymphoma

HUANG Shengcai; DING Yi; QIN Chaojun; ZHANG Zhongming; LONG Yaobin; MA Jiaqiang; YAN Limei

doi:10.3969/j.issn.1002-266X.2017.02.001

Abstract：Objective To analyze the imaging features of 18 F-FDG PET/CT in diffuse large B-cell lymphoma (DL-BCL)and to discuss its value in diagnosis of DLBCL.Methods Forty-eight cases of patients with DLBCL confirmed by pathology underwent whole-body 18 F-FDG PET/CT scan before chemotherapy.We compared the sensitivity of PET/CT fu-sion image and CT image in diagnosis of lymph nodes,extranodal tissues and organ involvements by the Fisher′s exact prob-ability test.Results Enlarged lymph nodes of DLBCL in PET/CT fusion images manifested as single or multiple rounded soft tissue density nodular images,part of the lymph nodes calcified,border was clear,and part of the boundary was less clear when the enlarged lymph nodes fused into irregular-shaped lump;most of the involved tissues and organs′structural changes were relatively hidden or not significant;lesion uptake of 18 F-FDG was significantly higher,which showed nodular or mass sample radioactive concentration.When the necrosis was found in lymph nodes or extranodal involvements,necro-sis would form a circular-like 18 F-FDG uptake increased foci.The diagnosis sensitivity of PET/CT fusion image and CT im-age to DLBCL lymph node involvements was 94.85% and 94.85%,which was 95.23% and 21.43% to extranodal in-volvements,and significant difference was found between these two groups (all P <0.05 ).Conclusions The typical characteristics of 18 F-FDG PET/CT imaging of DLBCL are:lymph nodes display as single or multiple round soft tissue den-sity nodular images and uptake 18 F-FDG obviously increases,the enlarged lymph nodes can fuse or show fusion trend,and part of them form irregular-shaped lump,and calcification can be found within a few of the lymph nodes.The uptake 18 F-FDG obviously increase when the involved tissues and organs had or not had structural changes.Using PET/CT fusion ima-ges diagnosing lymph nodes and organs involved is more sensitive than CT,but there are still some false positives and false negatives.