[Clinical value of FDG PET using coincident gamma cameras in staging and restaging of malignant lymphoma--compared with convenitonal diagnostic methods]

Abstract

AIM of the present retrospective study was to validate the clinical value of F-18-FDG PET imaging in lymphoma patients with a dual head camera modified 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 FDG-Hybrid-PET scans. Pretherapeutic staging was realized in 28 patients, 9 of them had control studies after they had completed therapy. Totally 29 persons were examined for post-therapeutic restaging. Computed tomography imaging and lymph node 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 significance at p > 0.05 by Fisher's t-test. Hybrid-PET obtained a sensitivity of 93%, a specificity 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 more accurate than standard morphologic diagnostic methods for prestaging in malignant lymphoma. Additionally, there is a substantial benefit for therapy monitoring of residual disease using coincidence detection PET with a 3/4-inch crystal gamma camera.