J Nucl Med 1999 Sep;40(9):1456-62
Splenic fluorodeoxyglucose uptake increased by granulocyte colony-stimulating
factor therapy: PET imaging results.
Sugawara Y, Zasadny KR, Kison PV, Baker LH, Wahl RL.
Using PET, we investigated the change in 18F-fluorordeoxyglucose (FDG) uptake in
the spleen after granulocyte colony-stimulating factor (G-CSF) treatment.
METHODS: Forty-two FDG PET scans in 12 patients with locally advanced breast
cancer who received G-CSF treatment were studied (12 baseline, 10 during G-CSF,
20 after G-CSF treatment). The PET images obtained at 50-60 and 60-70 min after
intravenous FDG (370 MBq) injection were assessed visually and were compared
with those before G-CSF treatment. For a semiquantitative index of FDG uptake,
we determined the standardized uptake value calculated on the basis of predicted
lean body mass (SUL) on these images, and we calculated the SUL ratios
normalized to their baseline SUL values. RESULTS: During G-CSF treatment (n =
10), 9 scans (90%) showed increased splenic FDG uptake (3 slightly, 6
substantially). After G-CSF treatment (n = 20), 13 (65%) showed no change, 7
(35%) showed slightly increased uptake, but no case showed substantially
increased FDG uptake in the spleen (P = 0.0003). Out of 30 PET scans obtained
during and after G-CSF treatment, 16 (53%) showed increased FDG uptake in the
spleen (10 slightly, 6 substantially), whereas 26 (87%) showed increased bone
marrow FDG uptake (14 slightly, 12 substantially). The FDG uptake in other
normal organs (liver, blood and lung) showed no change during or after G-CSF
treatment. Similar to the change in the bone marrow, the SULs in the spleen
significantly increased during G-CSF treatment (baseline, 1.50+/-0.31, versus
during G-CSF, 2.69+/-0.84; P = 0.0004), then decreased after discontinuation of
G-CSF (1.65+/-0.23). There was a significant correlation between the SUL ratios
in the spleen and those in the bone marrow (r = 0.778, P < 0.0001), whereas
there were no correlations between those in other organs and those in the bone
marrow. CONCLUSION: Substantially increased FDG uptake was observed in the
spleen during and after G-CSF treatment, although this change was less frequent
and not as marked as the change observed in the bone marrow. The recognition and
understanding of this phenomenon will be increasingly important when
interpreting FDG PET images in cancer patients to avoid confusing this normal
phenomenon with pathological splenic (tumor) involvement.
