Use of magnetic resonance imaging for diagnosis and after treatment of patients with myeloid sarcoma of the brain

The purpose of this retrospective study was to assess the utility of magnetic resonance imaging (MRI) for evaluating post-treatment responses in patients with myeloid sarcoma (MS) of the brain. We evaluated images from both conventional and advanced MR, including diffusion weighted imaging (DWI), arterial spin labeling (ASL) and susceptibility weighted imaging (SWI). Parameters of our qualitative review included lesion location, number, size, morphologic characteristics, surrounding edema, mass effect, pattern and degree of enhancement, ± restricted diffusion, ±susceptibility artifact and ± higher perfusion. Our quantitative assessments were calculated from DW and ASL MR images. The 10 patients had a total of 40 lesions in their brains (mean lesion size of 2.0 ± 0.8 cm). The majority of cases exhibited restricted diffusion (90%) and mild-to-moderate low perfusion (80%). Follow-up MRI after chemotherapy revealed that most lesions (80%) were significantly alleviated after two chemotherapy courses and further improved after four courses. Only a few lesions (5%) were residual after six courses. These findings demonstrate that brain MS can be characterized by changes in various MRI parameters and that MRI can be a useful and predictive assessment tool for brain MS diagnosis and treatment management.