BRAIN TUMOR
Case Presentation
A 73-year-old man presented to his local emergency department after experiencing a generalized seizure. He had moderate left-sided weakness in the initial postictal period which quickly resolved. In retrospect, the patient had noted subjective left-hand “clumsiness” for a month prior to the seizure, but had not reported it to his family or physician.
Imaging Discussion
While CT scans are often used first for glioblastoma, especially in emergencies, MRI scans provide more detailed and diagnostic information. Hence, MRI is the preferred method for a comprehensive diagnosis.
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On MRI scans, almost all glioblastomas react to gadolinium contrast, typically displaying a thick, uneven layer of tumor around a dead tissue cavity.
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Variations in signal strength and contrast enhancement within glioblastomas, as well as an irregular shape, are common.
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Increased permeability of blood vessels leads to surrounding swelling (vasogenic edema), which appears as a bright area on T2-weighted images.
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Hemorrhage can complicate glioblastoma imaging. Acute and early subacute hemorrhages appear less intense (darker) on T2 and vary in intensity on T1 images.
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This T1 hyperintensity (brightness) can mimic gadolinium enhancement. Thus, always compare postcontrast and precontrast T1 images for accurate assessment.
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What We Are Looking For ?
(A) Unenhanced CT shows there are abnormal area of the brain. (B) T2-weighted FLAIR, the abnormal area appears bright after fluid attenuation and shows the abnormal area, (C) Gradient echo T1-weighted, the abnormal area appears dark compared to normal areas. (D) post-gadolinium spin echo T1-weighted images depict a relatively circumscribed mass in the left superior temporal lobe with both solid, enhancing components and some cystic or necrotic areas. Moderate edema signal surrounds a portion of the mass.