Assessment of metabolic activity by PET-CT with F-18-FDG in patients with T-cell Lymbphoma

International audience18F-fluorodeoxyglucose positron emission tomography (PET/CT) is highly sensitive for the imaging of B-cell lymphomas; its usefulness in T-cell lymphomas (TL) is less defined. We retrospectively evaluated the metabolic activity in TL patients scheduled to receive chemotherapy. Methods: 20 consecutive patients with TL underwent PET/CT and the results were correlated to Ki-67 and compared with those from indolent B-NHL and extranodal aggressive B-NHL. Results: Mean Ki-67 was 64% ± 15% in TL. No relationship between individual mean SUVmax and Ki-67 values was observed (r = 0.1; p = 0.6). The mean SUVmax in TL was lower as compared to both indolent and extranodal aggressive B-NHL (6.1 ± 4 vs 9.1 ± 6 and 8.9 ± 5, respectively; p< 0.01). Within extra-nodal locations the TL still presented values lower than the other groups (5.3 ± 3 vs 9.5 ± 6 and 8.9 ± 5, respectively; p< 0.05). Nodal SUVmax of TL was lower than nodal indolent B-NHL (6.4 ± 3 vs 8.8 ± 6; p< 0.05). Conclusion: Although clinically aggressive and high Ki-67 values, TL have a low metabolic activity at PET/CT. TL patients had an uptake index lower than patients presenting indolent or extranodal aggressive B-NHL