The Clinical Value Of ～(18)F-FDG PET/CT In Diagnosis And Differential Diagnosis Of Malignant Lymphomas

Purpose: An accurate early diagnosis of lymphoma patients is critical for betterstaging and selection of reasonable treatment. The main purpose of this retrospectivestudy was to find out the extent to which ¹⁸F-FDG PET/CT can be used to diagnosenodal and extra nodal lymphomas, with some possible comparison to conventionalimaging modalities, and differentiates malignant lymphomas from other causes ofincreased FDG uptake in lymphoma patients.Patients and Methods: 62 patients with signs and symptoms of lymphoma, with orwithout previous laboratory/imaging support, were included in this study. On the basisof clinical suspection they were divided into 3 groups. The clinical information like CTwas made available. Even very mild uptake was taken under consideration at eachsuspected site incase to rule out malignancy. Size and number criteria was set for CTreaders as in departmental routine. Clinical follow up was performed for all patientsfor at least one year. For 6 patients we lost contact and were not used for furtheranalysis.Results: The PET/CT conclusions were divided into three categories i.e. lymphoma,not-lymphoma and uncertain for malignancy; lymphoma: 34 total, not-lymphoma: 7total, uncertain: 15 total. So there were total 35TP, 13TN, 8FP and 0FN. Uncertainresults suspected for other diseases and negative for lymphomas were added to TN anduncertain result patients positive for lymphoma were added to TP. Among 8FP, fivewere because of inflammatory disease and 3 were because of other malignant tumors.¹⁸F-FDG PET/CT resulted in identification of lymph nodes smaller than 1cm andextranodal involvements without any marked organomegaly. ¹⁸F-FDG PET/CT ruled out any malignancy in 7 patients. Over all positive predictive value was: 73%, negativepredictive value was: 100%, sensitivity was: 100% specificity was: 62%, and accuracywas: 86%.Conclusion: ¹⁸F-FDG PET/CT is a powerful tool for diagnosing nodal and extra nodallymphomas, in patients with different clinical suspection. ¹⁸F-FDG PET/CT is usefulin differentiation of primary or metastatic lymphomas and is a whole body scanningwith high sensitive and negative predictive value to rule out malignancy. It is superiorover ¹⁸F-FDG PET and CT alone. It may differentiate malignancy from inflammationbut ¹⁸F-FDG is not tumor specific that results in lower specificity. Pathology of majorsuspected sites remains the gold standard...