Innumerable rim enhancing, thick-walled lesions of variable size are demonstrated throughout the cerebral parenchyma bilaterally, in both a supra and infratentorial distribution. The largest of these lesions measures 14mm x 13mm and is seen anterosuperior to the third ventricle, immediately inferior to the right lateral ventricle, and compressing the right foramen of Monro.
The lesions are relatively isointense to grey matter on T1 and hypointense on T2/FLAIR. No convincing diffusion restriction is identified; certainly, the largest lesion described above does not restrict. There is a significant volume of FLAIR hyperintense signal surrounding the lesions and surrounding the dilated lateral ventricles (transependymal oedema).
A tectal lesion also noted and contributing to the obstructive hydrocephalus. There is slight effacement of the 4th ventricle resulting from a lesion immediately anterior.
Fluid fills the mastoid air cells and middle ear cavity in keeping with mastoiditis/otitis media.
Conclusion:
The most likely cause of this appearance in a returned traveller is neurocysticercosis (lack of cystic component suggests this would be granular-nodular stage) with an unrelated, second pathology of left mastoiditis/otitis media. Alternatively, the possibility of infective mastoiditis as the primary pathology causing secondary cerebral abscesses should be considered, but lack of diffusion restriction on DWI make this atypical and thus raises the possibility of an atypical infective aetiology such as TB.