Perfusion characterization of osteosarcoma spinal metastases using advanced T1-weighted dynamic contrast enhanced MRI

Spinal osteosarcoma is rare and highly aggressive malignancy associated with poor clinical outcomes. To our knowledge, the perfusion MRI features of spinal osteosarcoma using T1-weighted DCE MRI, including plasma volume, permeability, and time-intensity analysis, have not previously been studied. In addition, changes in these features following radiation treatment have not yet been evaluated. We hypothesize that highly malignant spinal osteosarcoma demonstrates hypervascularity based on its pharmacokinetic perfusion parameters.

We analyzed 27 patients (mean age 44.5, SD 21.8) of untreated metastatic Spinal osteosarcoma who underwent DCE-MRI. Perfusion parameters, including K_trans and plasma volume (V_p) as an indicator of permeability and tumor vascularity respectively, were measured using the extended Tofts model. A subset of 12 patients underwent preradiation therapy (RT), ¹⁸F-FDG PET, and 7 patients had post-RT DCE-MRI for assessment of treatment effects. Additionally, time intensity curve analysis was conducted to evaluate post-treatment changes.

Thirty-five lesions in 27 patients were evaluated. Perfusion characteristics including mean K_trans and V_p were 0.323 and 3.54, respectively, indicating that metastatic Spinal osteosarcoma is hypervascular. In the 7 patients with post-RT DCE-MRI, the mean post-RT V_p decreased to 1.77 from a pre-RT mean of 3.28, reflecting a 46.04% decrease to radiation therapy.

DCE-MRI evaluation of metastatic Spinal osteosarcoma demonstrates a rich blood supply, consistent with hypervascular metastatic disease. Changes in the time intensity curve analysis may serve as non-invasive marker of radiation treatment response.