Investigation Of Diagnostic Efficacy Of CT,MRI And PET/CT For Lymphoma

Objective:To investigate of the diagnostic efficacy of CT,MRI and ¹⁸F-FDG PET/CT for malignant lymphoma.Materials and methods:Images obtained by different modalities of CT,MRI and PET/CT and relevant data of 124 untreated patients with lymphoma were retrospectively analyzed.Analysis was based on comparing the scan results to the pathological sections or biopsy histopathological results of the same patient.1)In the CT scan group of 108 patients,there were 10 patients with Hodgkin Lymphoma（HL）,98 patients with Non-Hodgkin Lymphoma（NHL,including 74 patients with B-cell Lymphoma and 24 patients with T/NK cell Lymphoma）.In the MRI scan group of 87patients,there were 9 patients with HL,78 patients with NHL（including 62 patients with B-cell Lymphoma and 16 patients with T/NK cell Lymphoma）.CT/MRI specific characteristics of HL and NHL of two different cell types were observed.2)In the PET/CT scan group of 53 patients,patients were divided into groups according to their cell types and histological types:9 patients with HL and 44 patients with NHL that included 35 patients with B-cell and 9 patients with T/NK-cell,according to cell types;34 patients with primary nodaltype,and 19 patients with primary extra-nodal type according to areas of presentation;33 patients with aggressive NHL and 11patients with indolent NHL according to the rate of growth.The maximum standardized uptake value（SUVmax）was obtained in each group.Independent samples t-test was used to examine the variability among samples.3)PET/CT scan group of 53 patients with lymphoma were classified into different stages using the Ann Anbor staging system.There were 12 patients with stage I,17 patients with stage II,13 patients with stage III and 11 patients with stage IV.SUVmax was obtained in all infected regions and examined by one-way between group ANOVA for significance level.In addition,a total of 102 patients with suspected"lymphoma"（CT examination,MR examination and PET/CT examination were 46 cases,31 cases and25 cases respectively）from the first affiliated hospital of Hainan Medical College from February 2019 to February 2020,with pathological results as the"gold standard",81 cases were finally diagnosed with lymphoma,the diagnostic efficacy of CT,MR and PET/CT three methods were compared,and the corresponding area under the curve（AUC）,Sensitivity,specificity,positive predictive value and negative predictive value.Results:1)The most common signs of intranodal lymphoma on CT and MR were swollen lymph nodes,and the signs of extranodal lymphoma varied greatly among different organs.The common feature was the high incidence of tumors and the uniform density/signal.Cystic change,calcification and necrosis were rare signs.There were no significantly different CT-specific characteristics frequencies of tumor mass,shape,cystic change,calcification,enlargement of lymph node and necrosis,between HL and NHL group,or B-cell and T/NK-cell group（P>0.05）.Neither was there any significant differences between different ways of contrast enhancement（homogenous contrast enhancement,heterogenous contrast enhancement and no enhancement）.Cystic change and ring-enhancement were rare in the MR scan of lymphoma.The characteristics frequencies of MR appearance,signal distribution,signal mixing and cystic change were of no significant differences between patients with HL and NHL group,B-cell and T/NK-cell group（P>0.05）.Neither were significant differences found in their homogenous contrast enhancement,heterogenous contrast enhancement,and ring-enhancement comparisons.2)Among PET/CT patients,the SUVmax values of patients with aggressive NHL and patients with indolent NHL were 15.48±7.25 and 8.26±2.64,respectively,and of significant difference（t=3.211,P<0.05）.There were no significant differences between the SUVmax values of patients with HL and NHL group,patients with B-cell and T/NK-cell NHL group,patients with primary nodal and primary extra-nodal group（P=0.219,0.652,0.760）.3)In PET/CT scan,the SUVmax values of different stages（average±standard deviation）were:6.23±2.45,6.58±4.12,11.12±5.04,10.55±4.38（F=5.086,P<0.05）.There were significant differences between the SUVmax values of patients with stage I&III,stage I&IV（P=0.005,0.015）,stage II&III,and stage II&IV（P=0.004,0.016）.The sensitivity values of CT,MR and PET/CT in diagnosing lymphoma were 86.1%,88.0%,and 90.0%.The specificity values were 40%,66.7%,80.0%.The positive predicative values were 83.8%,91.7%,91.7%.The negative predicative values were 44.4%,57.1%,66.7%.The ROC AUC values were AUC=0.641（P=0.0358）,AUC=0.744（P=0.0026）,and AUC=0.807（P=0.0008）.Conclusion:The CT and MR signs of malignant lymphoma are mainly lymphadenopathy,those with lump have more density/uniform signal.Necrosis,cystic change,calcification are rare,Signs between categories and types lack specificity.The SUVmax of PET/CT is a certain valueable in judging between the invasive NHL and indolent NHL,and is a certain valueable in the clinical staging of lymphoma.PET/CT has a higher sensitivity in the detection of lymphoma,better than CT and MRI,and has a high application value in the examination and clinical staging of lymphoma.