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
    • 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