Meningioma
- Commonest primary intracranial tumour in adults (~35–40%); women, middle age; radiation, NF2; usually WHO grade 1.
- Sites: parasagittal/falx, convexity, sphenoid wing, olfactory groove, tuberculum sellae, CPA (second commonest CPA mass), optic nerve sheath (tram‑track enhancement), intraventricular (trigone).
- CT: extra‑axial, hyperdense (60%), calcification (psammomatous, 20–25%), hyperostosis, pneumosinus dilatans.
- MRI: iso to grey matter on T1/T2, intense homogeneous enhancement, dural tail (~60%, reactive, not specific), CSF cleft, "sunburst" vessels.
- Angiography: dual supply: ECA meningeal branches (centre: sunburst/spoke‑wheel) + ICA pial (periphery); prolonged blush ("mother‑in‑law sign": comes early, stays late).
- MRS: alanine peak. Ga‑68 DOTATATE avid (SSTR2).