Fig. 2

Brain magnetic resonance imaging on the day of admission and on day 261 (showing recurrence). a–c Images on the day of admission; d–f images obtained on day 261 when the patient’s central nervous system symptoms deteriorated. a and d Diffusion-weighted sequences images. b and e Apparent diffusion coefficient images. c and f Fluid-attenuated inversion recovery images. a, b, d, e show that central nervous system lesions did not derive from vasculitis and cerebrovascular diseases because those were not along the vessels. Hyperintensity in the cortex and subcortical white matter can be seen in c and f. c Margins of the lesion are clearly visualized. f Margins of the lesion are unclear