弥漫大B细胞淋巴瘤18F-FDGPET／CT的显像特征及其诊断价值

摘要

目的：分析弥漫大 B 细胞淋巴瘤（DLBCL）18 F-FDG PET／CT 显像特征，并探讨18 F-FDG PET／CT 对 DL-BCL 的诊断价值。方法48例经病理确诊为弥漫大 B 细胞淋巴瘤的患者化疗前均行18 F-FDG PET／CT 全身显像。采用 Fisher 确切概率法比较 PET／CT 融合图像及同机 CT 图像诊断淋巴结和结外组织、器官受累的敏感性。结果DLBCL 肿大淋巴结在 PET／CT 融合图像表现为单个或多个类圆形软组织密度结节影，部分淋巴结内见钙化点，边界清楚，部分肿大淋巴结相互融合成形状不规则的肿块时，边界欠清楚；累及的结外组织器官大多数结构改变较为隐秘或无明显改变；病灶摄取18 F-FDG 明显增高，呈结节样或团块样放射性浓聚；淋巴结或结外受累病灶内部出现坏死时，坏死部位形成圆圈样的18 F-FDG 摄取增高灶。PET／CT 融合图像与同机 CT 图像诊断 DLBCL 淋巴结受累敏感性分别为94．85％、82．35％；诊断结外组织器官受累敏感性分别为95．23％、21．43％，两者比较 P 均＜0．05。结论 DLBCL 18 F-FDG PET／CT 显像典型的影像特征是：淋巴结显示为单个或多个类圆形软组织密度结节影并摄取18 F-FDG 明显增高，肿大的淋巴结相互融合或呈融合趋势，部分形成不规则的肿块，少数肿大淋巴结内可见钙化点；受累结外组织器官出现或不出现结构改变，但摄取18 F-FDG 明显升高。PET／CT 融合图像较同机 CT 图像诊断DLBCL 累及的淋巴结或结外组织器官更加敏感，但仍存在一定的假阳性和假阴性。%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.