investigations
Last edited 11/2018
Imaging for suspected meningioma/glioma
- standard structural MRI (defined as T2 weighted, FLAIR, DWI series and
T1 pre- and post-contrast volume) should be offered as the initial diagnostic
test for suspected meningioma/glioma, unless MRI is contraindicated
- consider CT imaging for meningioma (if not already performed) to assess bone involvement if this is suspected.
Notes:
- skull x-ray - 15% of meningiomas show areas of calcification; look for hyperostosis of adjacent bone; dilatation of the middle meningeal groove in the parasagittal and convex regions; demineralisation of the dorsum sella from long standing raised intracranial pressure.
- CT scan
- calcification evident in 20-30% of cases; characteristically, there is a well circumscribed lesion of iso- or hyper-density with a surrounding area of hypodensity due to cerebral oedema
- non-contrast CT
- 60% slightly hyperdense to normal brain, the rest are more isodense (2)
- 20-30% have some calcification
- post-contrast CT
- 72% brightly and homogeneously contrast enhance (2)
- malignant or cystic variants demonstrate more heterogeneity/less intense enhancement
- hyperostosis (5%) (3)
- typical for meningiomas that abut the base of the skull need to
distinguish reactive hyperostosis from:
- direct skull vault invasion by adjacent meningioma
- primary intraosseous meningioma
- typical for meningiomas that abut the base of the skull need to
distinguish reactive hyperostosis from:
- enlargement of the paranasal sinuses (pneumosinus dilatans) has also been suggested to be associated with anterior cranial fossa meningiomas
- lytic/destructive regions may be seen in higher grade tumours
- however should also consider alternative pathology (e.g. haemangiopericytoma or metastasis)
- angiography - indicates the vascular supply of the tumour and confirms the diagnosis. Characteristically this demonstrates 'blushing' which is a result of the tumour's vascularity and a blood supply from the external carotid artey
Reference:
- NICE (July 20180. Brain tumours (primary) and brain metastases in adults
- Greenberg H, Chandler WF, Sandler HM. Brain tumors. Oxford University Press, USA. (1999) ISBN:019512958X
- Parizel PM, Carpentier K, Van Marck V et-al. Pneumosinus dilatans in anterior skull base meningiomas. Neuroradiology. 2013;55 (3): 307-11. doi:10.1007/s00234-012-1106-9
- Lee JH. Meningiomas. Springer. (2008) ISBN:1846287847