MRI and 18FDG-PET in the assessment of bone marrow infiltration of the spine in cancer patients

The aim of this study was to evaluate the diagnostic value of MRI and ¹⁸FDG-PET in bone marrow infiltration of the spine due to metastases of solid tumours and lymphoma in cancer patients. In 35 cancer patients (solid tumours n = 26, lymphoma n = 9) MRI of the spine and ¹⁸FDG-PET were reviewed and the detectability of metastases, infiltration of the spine, extent of disease, and therapeutic implications were compared. In 8/35 cases (23%) imaging technique showed concordantly no bone marrow infiltration. In 19/35 patients (54%), both MRI and ¹⁸FDG-PET revealed bone marrow infiltration of the axial skeleton. In 12/19 patients (63%), MRI showed more extensive disease which lead to subsequent therapy. The imaging findings of MRI and ¹⁸FDG-PET were discordant in 8/35 cases (23%). ¹⁸FDG-PET was false positive in two patients. In six patients, ¹⁸FDG-PET failed to detect bone metastases and bone marrow infiltration of the spine, which was detected by MRI and proven by clinical follow-up with subsequent therapy in two cases. MRI is more sensitive and specific than ¹⁸FDG-PET detecting bone marrow metastases and infiltration of the spine and has a great impact in staging cancer patients.