Giant cerebral aneurysm

Dr Maxime St-Amant and Dr Henry Knipe et al.

Giant cerebral aneurysms are ones that measure >25 mm in greatest dimension. 

Giant cerebral aneurysms account for ~5% of all intracranial aneurysms 1,3. They occur in the 5th-7th decades and are more common in females 2.

Patients can present with symptoms and signs of mass effect or subarachnoid hemorrhage 1,2.

Most commonly represent saccular cerebral aneurysms but may also be fusiform or serpentine in morphology 1. They are thought to develop via two pathways 2:

  • internal elastic lamina de novo defect
  • enlargement from a smaller aneurysm

Compared to non-giant cerebral aneurysms there is an increased incidence in the posterior circulation (~35%) 3.

Appearances will depend on whether the aneurysm is non-thrombosed, or partially or completely thrombosed.

  • non-contrast: slightly hyperdense, well-defined round extra-axial masses 2
  • may demonstrate a peripheral calcified rim

There are a variety of endovascular and open surgical techniques to treat these aneurysms. Endovascular options have a lower morbidity 3.

Share article

Article information

rID: 39214
Synonyms or Alternate Spellings:
  • Giant intracranial aneurysms
  • Giant intracranial aneurysms

Support Radiopaedia and see fewer ads

Cases and figures

  • Case 1
    Drag here to reorder.
  • Case 2: serpentine
    Drag here to reorder.
  • The lesion is  pr...
    Case 3: basilar tip on MRI
    Drag here to reorder.
  • Case 4
    Drag here to reorder.
  • Case 5: MCA on MRI
    Drag here to reorder.
  • Case 6
    Drag here to reorder.
  • Case 7
    Drag here to reorder.
  • Case 8
    Drag here to reorder.
  • Updating… Please wait.

     Unable to process the form. Check for errors and try again.

     Thank you for updating your details.