Steps in evaluating brain tumors

Identify images (CT, MR): Evaluate all MR sequences.
MRI is superior to CT.

Locate the lesion: Intra-axial vs. extra-axial.
Location suggests tumors likely to occur in that site based on the structure that is present at that site.

MR signal: Evaluate T1 and T2 wtd. signals to characterize cyst, calcification, blood, fat, etc.

Enhancement: Look at pre-contrast T1 and post-contrast T1 images as a pair. Most tumors enhance with contrast because blood brain barrier is broken. It is the character of enhancement that is helpful.

Age of the patient: First decade vs. adult.

Clinical history:

Differential diagnosis: Common lesions


Anatomical sites of tumor

Intra-axial: Metastasis, Astrocytoma

Ventricles: Ependymoma

Skull base/extra-axial tumors:

Anterior cranial fossa:

  • Meningioma

Middle cranial fossa:

  • Sellar: Pituitary Macroadenoma
  • Parasellar: Meningioma/Schwannoma

Posterior cranial fossa:

  • Cerebellopontine angle: Schwannoma / Meningioma
  • Foramen magnum: Meningioma


Age group

Children and young adults:

  • Medulloblastoma
  • Ependymoma
  • Craniopharyngioma
  • Gliomas grade 1 astrocytoma
    • Pilocytic Astrocytoma
    • Ganglioglioma


  • Metastasis most common
  • Astrocytomas
    • grade II Astrocytoma
    • grade III Astrocytoma
    • grade IV Glioblastoma
  • Meningioma
  • Schwannoma
  • Pituitary Macroadenomas