MRI and PET of bone marrow in lymphoproliferative diseases

In lymphoproliferative diseases, bone marrow involvement (BMI) is an essential parameter influencing staging, prognosis and treatment. In addition to pathological analysis of blind bone marrow biopsy, MRI and PET can help to (a) estimate initial BMI and assess the stage of disease, (b) indicate prognosis and (c) assess response to treatment. Regarding diagnosis, the MR patterns of focal and diffuse BMI will be reviewed, and compared to the MR appearance of normal marrow. The technique and the results of dynamic contrast-enhanced (DCE) MRI regarding normal and tumoral marrow will be detailed. An approach of the perfusion parameters of normal and tumoral marrow will thus be presented. The changes of MR patterns linked to BMI will be described after treatment and correlated to the response to treatment of patients with lymphoma and myeloma. Although (18)F-FDG-PET has been extensively studied in the management of lymphoma, few studies have examined its value for assessing BMI. (18)F-FDG-PET seems to be accurate for this purpose in patients with lymphoma and myeloma. The limitations of MR imaging and (18)F-FDG-PET will be detailed. In conclusion, MRI and PET imaging including the functional approach of perfusion by DCE-MR imaging and glucose uptake by (18)F-FDG-PET can contribute to the management of patients with lymphoproliferative diseases by its ability to analyse BMI.