Study On The Application Value Of ¹⁸F-FDG PET/CT In Different Pathological Types Of Gastrointestinal Lymphoma

Objective:Compare¹⁸F-FDG PET/CT imaging-related parameters with clinical and pathological data of patients suffering with different pathological types of gastrointestinal lymphoma（GIL）,and study the clinical characteristics and pathological characteristics of gastrointestinal lymphoma and¹⁸F-FDG PET/CT imaging characteristics,to explore the value of¹⁸F-FDG PET/CT in gastrointestinal lymphoma of different pathological types.Methods:A total of 42 patients with GIL diagnosed in the First Affiliated Hospital of Hainan Medical University and Hainan Affiliated Hospital of Hainan Medical University from October 2012 to December 2019 was collected as the research subjects.Clinical characteristics such as the age,gender,location,symptoms,and pathological types of GIL patients were specifically analyzed;According to the different types of pathological/types of invasion,on the basis of the WHO 2016version of lymphoma classification,all GIL patients were divided into three groups named as low-grade malignant B-cell groups,highly malignant B-cell groups and mature T and NK cell groups.The differences between PET/CT related parameters（including morphological typing,maximum standard uptake value of the lesion-SUVmax,maximum thickness of the lesion-THKmax）and immunohistochemical parameters（cell proliferation index Ki）were compared.Results:1.General clinical characteristics of gastrointestinal lymphoma:1)42 patients with gastrointestinal lymphoma were included in the study.The incidence of male patients was higher than that of female patients,including 24 male patients and 12 female patients（male:female=2:1）.2)The average age of patients was（51.6±14.5）years,of which 57.1%（24/42）were younger than 55 years old,and the age of onset was relatively young.3)Among the affected parts,all parts of the gastrointestinal tract were involved,with the stomach up to 42.9%（18/42）,followed by the small intestine and colorectal,and one case occurred in the whole intestine.4)Among the main clinical symptoms,73.8%（31/42）of which was abdominal pain and bloating,21.4%（9/42）for obstruction/lump,9.5%（4/42）for gastrointestinal bleeding,and 7.1%（3/42）for perforations,9.5%（4/42）for no obvious gastrointestinal symptoms.2.Pathological typing of gastrointestinal lymphoma:The pathological types of all patients were non-Hodgkin’s lymphoma,specifically including 22 cases of diffuse large B-cell lymphoma（DLBCL）,5 cases of mucosa-associated lymphoma（MALT）,5 cases of mantle cell lymphoma（MCL）,3 cases of bowel disease-related T-cell lymphoma（EATL）,and small B There was 1 case of cell（SLL）,1 case of Burkitt lymphoma（BL）,1 case of NK/T-nose lymphoma,1 case of anaplastic large cell lymphoma（ALCL）,and 1 case of peripheral T cell lymphoma（PTCL）.Special case sub types included one case between DLBCL and Burkitt lymphoma,and one case of DLBCL with MALT lymphoma.The common pathological type of gastrointestinal lymphoma is DLBCL.3.Comparison of ¹⁸F-FDG PET/CT imaging characteristics and immunohistoche mical values of three groups of GIL:1)The PET/CT"morphological typing"of the three groups of low-grade malignant B-cells,high-grade malignant B-cells,mature T and NK cells are all common in typeⅠ（diffuse thickening）and typeⅡ（segmental thickening）.TypeⅢ（localized thickening or bump formation）was rare,and the morphological differences between groups were not statistically significant（P=0.625）.2)The average THKmax of the lesions in the ¹⁸F-FDG PET/CT examination of the low-grade malignant B-cell group was（3.1±1.28）cm,（2.84±0.81）cm for highly malignant B-cell group,（3.08±1.29）cm for mature T and NK cells group.There was no significant difference in THKmax between the three groups（P=0.742）.3)The average SUVmax of the lesions in the ¹⁸F-FDG PET/CT examination of the low-grade malignant B-cell group was 7.71±5.50,15.84±6.55 for highly malignant B-cell group,15.95±2.26 for mature T and NK cells group,and the difference between the three groups was statistically significant（P=0.001）.In the comparison between groups,there was no difference in SUVmax between the highly malignant B cell group and the mature T and NK cell group,P>0.05.The median Ki-67 value of the cell proliferation index in the low-grade malignant B cell group was 25%,70%for the highly malignant B-cell group,80%for the mature T and NK cell group,and the three groups were compared,the difference was statistically significant（P<0.05）.There was no difference in Ki-67 between the highly malignant B cell group and the mature T and NK cell group in the comparison between groups,P>0.05.4.There was a correlation between the ¹⁸F-FDG metabolic parameter SUVmax and immunohistochemical parameter Ki-67 in patients with gastrointestinal lymphoma,r=0.534.Conclusions:1.Gastrointestinal lymphomas are almost non-Hodgkin’s lymphomas.The common pathological type is DLBCL.Mostly occurs in males and can involve various parts of the gastrointestinal tract,most commonly in the stomach.The clinical symptoms are mainly non-specific abdominal pain and bloating.Invasive GIL can touch obvious lumps or gastrointestinal bleeding or perforation.2.¹⁸F-FDG PET/CT metabolic parameter SUVmax has important reference value in distinguishing different pathological types of gastrointestinal lymphoma and its invasiveness.The SUVmax value of highly malignant B cell,mature T and NK cell lymphoma has no significant difference but higher than low-grade malignant B-cell lymphoma,morphological classification and THKmax are difficult to distinguish the pathological type of gastrointestinal lymphoma.3.There is a positive correlation between SUVmax and the pathological immunohistochemical value Ki-67,combination of the two can provide a better basis for clinical individualized decisions for patients with gastrointestinal lymphoma and promote accurate diagnosis and treatment.