Basal meningeal enhancement with hydrocephalus and infarcts in the basal ganglia is tuberculous meningitis; T2-dark ring lesions are tuberculomas; the report grades hydrocephalus and infarcts because they drive outcome.
Orient first
- TB meningitis: thick exudate in the basal cisterns, hydrocephalus, vasculitis with infarcts in the medial lenticulostriate territory ("TB zone").
- Tuberculomas: solid caseating or liquefied (the latter mimics abscess); paradoxical enlargement on treatment occurs.
- Pott spine and chest disease are often present — look beyond the brain.
Acquire the study
- Post-gadolinium 3D T1 and post-contrast FLAIR, T2, DWI, SWI.
The manoeuvre
- Post-contrast T1/FLAIR: thick enhancement in the basal cisterns, sylvian fissures and around the brainstem.
- Ventricles: hydrocephalus with transependymal FLAIR signal.
- DWI: infarcts in the caudate, anterior thalamus and internal capsule.
- Tuberculomas on T2: dark centre (solid caseation) with ring enhancement; measure in mm.
What confirms it
- Basal meningeal enhancement with hydrocephalus and/or infarcts and compatible CSF.
What licenses you to exclude it
- Normal post-contrast MRI makes TB meningitis unlikely but does not exclude early disease.
The classic misread
- A T2-dark ring lesion called a metastasis — tuberculoma is darker and usually multiple in endemic settings.