Example of sequential FDG-PET findings in 2 patients. Panels A-C show scans from a patient with truly negative “early PET,” predicting CR. (A) Pretherapeutic scan shows diffuse involvement of jugular chains, axillae, mediastinum, mesenteric chains, spleen, and lateroaortic and iliac chains. No residual uptake is seen after 2 cycles (B) and after 4 cycles (C) of chemotherapy, whereas a medullar uptake is evidenced, due to hematopoietic activation. Panels D-F show scans from a patient with truly positive “early PET,” predicting relapse. (D) Pretherapeutic scan shows a cluster of hypermetabolic nodes in the right pulmonary hilum, supraclavicular and mesenteric nodes, and involvement of the spleen, right lung, liver, and lumbar spine. Three hilar foci persist after 2 cycles (E, arrows); their extent increases after 4 cycles (F, arrows), whereas subdiaphragmatic sites reappear (arrowheads), indicating progression of the disease.