Pseudosubarachnoid Hemorrhage on MRI: A potential pitfall

Fluid attenuated inversion recovery (FLAIR) is one of the most effective magnetic resonance imaging (MRI) sequences in the diagnosis of subarachnoid hemorrhage (SAH). However, sometimes false positive or false negative results can occur. One of the reasons that can lead to erroneous interpretation is artifacts. Especially when metallic artifact occurs, hyperintensity may be observed in the subarachnoid space, similar to SAH. Although FLAIR hyperintensities in the sulci can be detected in many serious diseases, they are not always pathological. Artifact related hyperintensities, especially in cases with severe headache, may be mistakenly evaluated as SAH by a clinician or radiologist who is not well-experienced in MRI. However, it is extremely important to recognise these artifact related hyperintensities, to make a correct diagnosis and to prevent unnecessary interventions. In order to achieve this, the evaluation of all radiological images, especially SWI and GRE, is critical. Both radiologists and clinicians evaluating neuroradiological examinations should be knowledgeable about this subject and show maximum attention. In this report, we present the radiological images of 4 cases of pseudosubarachnoid hemorrhage, one of which was caused by conductive EEG gel and the other three due to braces artifacts, who were admitted to the hospital with headache.