Increased FDG bone marrow uptake after intracoronary progenitor cell therapy

SummaryPatients with coronary artery disease who undergo FDG PET for therapy monitoring after intracoronary progenitor cell infusion (PCT) show an increased bone marrow up-take in some cases. Aim of the study was to evaluate the systemic bone marrow glucose metabolism in this patient group after PCT. Patients, methods: FDG bone marrow uptake (BMU), measured as standardized uptake value (SUVmax) in the thoracic spine, was retrospectively evaluated in 23 control patients who did not receive PCT and in 75 patients who received PCT 3 ± 2.2 days before PET scanning. Five out of them were pretreated with granulocyte colony-stimulating factor (G-CSF) 5 days prior to PCT and 10 ± 1.2 days before PET scanning. In 39 patients who received only PCT without G-CSF and underwent PET therapy monitoring 4 months later, baseline and follow up bone marrow uptake were measured. Leucocytes, C-reactive protein (CRP) levels and the influence of nicotine consumption were compared with the BMU. Results: In patients (n = 70) who received PCT without G-CSF, BMU median (1.3) was slightly, but significantly higher than in the controls (1.0) (p = 0.02) regardless nicotine consumption. BMU did not change significantly 4 months later (1.2) (p = 0.41, n.s.). After G-CSF pretreatment, patients showed a significantly higher bone marrow uptake (3.7) compared to patients only treated with PCT (1.3) (p = 0.023). Leucocyte blood levels were significantly higher in patients with a BMU ≥ 2.5 compared to patients with a bone marrow SUVmax < 2.5 (p <0.001). CRP values did not correlate with the BMU (rho -0.02, p = 0.38). Conclusion: Monitoring PCT patients, a slightly increased FDG BMU may be observed which remains unchanged for several months. Unspecific bone marrow reactions after PCT may be associated with increased leucocyte blood levels and play a role in the changed systemic glucose BMU.