There are generally considered to be four common types of brain MRI sequences used in a typical MRI session to provide a comprehensive view of the brain.
These different MRI sequences, or image types, highlight different tissue characteristics and can help doctors identify a range of conditions and abnormalities. While many variations and specialized techniques exist, the core types are typically:
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T1-weighted images: These images provide excellent anatomical detail. They show fat as bright and water as dark. They are useful for visualizing the structure of the brain and detecting gross abnormalities.
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T2-weighted images: These images are the opposite of T1-weighted images; they show water as bright and fat as dark. They are helpful for detecting edema (swelling) and other fluid-related abnormalities.
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FLAIR (Fluid-Attenuated Inversion Recovery): This is a special type of T2-weighted image where the signal from cerebrospinal fluid (CSF) is suppressed, making it easier to detect subtle abnormalities near the CSF spaces. This sequence is particularly useful for identifying lesions like multiple sclerosis plaques.
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Diffusion-Weighted Imaging (DWI): This sequence measures the movement of water molecules in the brain. It is highly sensitive to acute stroke, where water diffusion is restricted.
It's important to note that more advanced MRI techniques, such as fMRI (functional MRI), DTI (diffusion tensor imaging), and MR angiography, can also be performed. These are often used for specific research or clinical purposes. The "four common types" generally refers to the foundational sequences often obtained in a standard clinical brain MRI.
