Cerebral magnetic resonance imaging for subarachnoid hemorrhage diagnosis
Cerebral magnetic resonance imaging may be proposed if the patient's clinical condition allows it. FLAIR imaging is more sensitive than CT to demonstrate a subarachnoid hemorrhage and offers greater degrees of sensitivity for the diagnosis of restricted subarachnoid hemorrhage in cortical sulcus. A lumbar puncture should be performed if these investigations are normal while clinical suspicion is high 1).
The T2* sequence can detect and localize a previous SAH a few months after aneurysmal bleeding 2). 3).
By combining Susceptibility weighted imaging (SWI) and FLAIR, MRI yields a distinctly higher detection rate for SAH than CT alone, particularly due to their complementary detection characteristics in different anatomical regions. Detection strength of SWI is high in central areas, whereas FLAIR shows a better detection rate in peripheral areas 4).