Clinical value of FDG hybrid-PET in staging and restaging of malignant lymphoma - compared with conventional diagnostic methods

Aim of the present retrospective study was to validate the clinical value o f F-18-FDG PET imaging in lymphoma patients with a dual head camera modifie d for coincidence detection. Staging before and after oncological treatment was compared with a conservative diagnostic approach. Methods: 48 patients (28 non-Hodgkin lymphoma, 20 Hodgkin's disease) received FOG-Hybrid-PET sc ans. Pretherapeutic staging was realized in 28 patients, 9 of them had cont rol studies after they had completed therapy Totally 29 persons were examin ed for posttherapeutic restaging. Computed tomography imaging and lymph nod e sonography was performed in all cases. Results were validated by clinical follow-up, in three cases a recidive was proven by biopsy. Results: CT and ultrasound detected 77 lesions in 28 patients compared with 100 visualized by PET, but this difference in pretherapeutic staging did not reach signif icance at p > 0.05 by Fisher's t-test. Hybrid-PET obtained a sensitivity of 93%, a specifity of 79%, a positive of 82% and a negative predictive value of 92% for detection of residual disease. The values for CT + US were 87%, 64%, 72% and 88% respectively Conclusion: FDG Hybrid-PET is as or even mor e accurate than standard morphologic diagnostic methods for prestaging in m alignant lymphoma. Additionally, there is a substancial benefit for therapy monitoring of residual disease using coincidence detection PET with a 3/4- inch crystal gamma camera.