Effect of granulocyte colony-stimulating factor on bone marrow: evaluation by intravoxel incoherent motion and dynamic contrast-enhanced magnetic resonance imaging

Objective: To report our experience with the use of intravoxel incoherent motion (IVIM) magnetic resonance imaging (MRI) and dynamic contrast-enhanced (DCE)-MRI in bone marrow before and after administration of granulocyte colony-stimulating factor (GCSF). Moreover, a small series of patients with bone metastases from breast cancer have been evaluated by IVIM DW-MRI and DCE-MRI before and after GCSF administration. Materials and methods: We studied with IVIM-MRI and DCE-MRI 14 patients with rectal or uterine cervix cancer studied before and 4–18 days after administration of GCSF; the second MR examination was obtained after three chemotherapy courses. IVIM perfusion fraction (f), pseudo-diffusion coefficient (D*), true diffusion coefficient (D) and apparent diffusion coefficient (ADC) as well area under the curve at 60 s (AUC60) were calculated for bone marrow before and after GCSF administration. Moreover, two different IVIM parametric maps (i.e., ADC and ADClow) were generated by selecting two different intervals of b values (0–1000 and 0–80, respectively). Furthermore, four patients affected by pelvic bone metastases from breast adenocarcinoma who received GCSF administration were also qualitatively evaluated for evidence of lesions on ADC maps, ADClow maps and DCE-MRI. Results: ADC, D, D*, f and AUC60 values were significantly higher in hyperplastic bone marrow than in untreated bone marrow (p values < 0.0001, < 0.0001, < 0.001, < 0.001, < 0.0001, respectively). All bone metastases were clearly differentiable from hyperplastic bone marrow on ADClow maps, but not on ADC maps and DCE-MRI. Conclusion: MR functional imaging techniques, such as DW-, IVIM DW- and DCE-MRI are effective tools in assessing the response of bone marrow to the administration of growth factors. Although an overlap between signal of hyperplastic bone marrow and lytic bone metastases can occur on ADC maps and DCE-MRI, evaluation of ADClow maps by IVIM DW-MRI could permit to differentiate hyperplastic bone marrow from lytic bone metastases. Further studies are needed to confirm our data.