What is the role of MRI in the workup of cerebral aneurysms?

Updated: Dec 06, 2018
  • Author: David S Liebeskind, MD, FAAN, FAHA, FANA; Chief Editor: Helmi L Lutsep, MD  more...
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Fluid-attenuated inversion recovery (FLAIR) sequences are very sensitive for SAH, although the comparison of CT scan and MRI in detection of SAH is controversial.

MRI may be impractical for patients in unstable condition. Flow voids may be seen extending from the parent vessel into the aneurysm.

Heterogeneous signal intensity adjacent to the aneurysm wall may be seen with thrombus of varying ages, although MRI is relatively insensitive to the presence of calcium.

Dolichoectatic and giant aneurysms are identified readily with MRI. Pulsation artifacts and the presence of turbulence may help to differentiate these aneurysms from other mass lesions, but slow and turbulent flow may preclude visualization on MRA.

MRA may reliably provide 3-dimensional imaging of aneurysms 4 mm or larger.

Phase-contrast techniques may facilitate detection of flow patterns and slow flow. Although phase-contrast MRA is preferable for large aneurysms, 3-dimensional time-of-flight techniques are preferable for small aneurysms. Source images should be inspected routinely in conjunction with the reconstructed views.

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