Brain MRI – Seizure search pattern
Many times when patients have a history of seizures, they undergo a workup including a physical exam, detailed EEG analysis, and finally brain MRI to try to identify any potential structural causes of seizures. In this video, Dr. Michael Hoch walks us through his approach to a brain MRI to maximize your sensitivity for finding abnormalities.
Dr. Hoch suggests a 4-step approach using the mnemonic “3-2-1 go to the hippocampus”. In this way, he divides his search into more digestible parts.
“3” indicates the 3 planes that you have in a non-contrast T1 weighted MP-RAGE MRI. On this you should focus on the cortex, particularly at the 3 poles, the frontal, temporal, and occipital poles.
“2” indicates the 2 planes of FLAIR and 2 window settings you should use. You should review FLAIR images in both the coronal and axial planes. You should also use a window that is normal and a window that is narrow, or aggressive, to highlight lesions, particularly in the cortex, which are hard to see.
“1” indicates the single plane of blood sensitive imaging, either GRE or SWI, which can often see areas of prior hemorrhage or cavernou
“Go” to the hippocampus last to look for signs of mesial temporal sclerosis, which is manifested as a small hippocampus with loss of internal architecture and abnormal T2/FLAIR hyperintensity. This can be either from primary epilepsy or secondary to another lesion.
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