MRI Protocols: Limitations of the MRI Brain

Limited ability in imaging the skull and facial bones -- conventional X-ray or CT scan is better in demonstrating bone details.
Compared to CT scanning, MRI is less sensitive in demonstrating acute hemorrhage, as in subarachnoid hemorrhage and hemorrhagic infarction.
Hard to depict calcifications
MRI does not always distinguish tumor tissue from edema fluid
Less sensitive in detecting small abnormalities compared to CT scans (poor spatial resolution)
Inability to scan critically-ill patients requiring life support systems and monitoring devices that employ ferromagnetic materials.
May be dangerous in scanning patients with metal implants and other metal objects
May provoke claustrophobia
Longer exam time compared to CT scans
Safety in scanning pregnant women is not known.

MRI Protocols