Which imaging method reveals blood flow and brain activity by comparing successive scans and can show both structure and function?

Which imaging method reveals blood flow and brain activity by comparing successive scans and can show both structure and function?

• A. EEG
• B. PET
• C. fMRI
• D. CT

Answer: (C)

Functional MRI reveals blood flow and brain activity by tracking changes in the blood oxygen level dependent signal over time. When a brain area becomes more active, its blood flow increases, altering the balance of oxygenated and deoxygenated hemoglobin, which MRI detects as signal change. By comparing successive scans taken during different tasks or over time, fMRI maps where and when the brain is active. Because MRI also provides high-resolution anatomical images, the functional data can be overlaid on the brain's structure, showing both where and how strongly activity occurs. Other methods either measure electrical activity (which has limited spatial precision), rely on radioactive tracers to show metabolism (PET), or primarily image anatomy with radiation (CT), making fMRI the technique that best captures both structure and function through blood-flow–based activity.

Functional MRI reveals blood flow and brain activity by tracking changes in the blood oxygen level dependent signal over time. When a brain area becomes more active, its blood flow increases, altering the balance of oxygenated and deoxygenated hemoglobin, which MRI detects as signal change. By comparing successive scans taken during different tasks or over time, fMRI maps where and when the brain is active. Because MRI also provides high-resolution anatomical images, the functional data can be overlaid on the brain's structure, showing both where and how strongly activity occurs. Other methods either measure electrical activity (which has limited spatial precision), rely on radioactive tracers to show metabolism (PET), or primarily image anatomy with radiation (CT), making fMRI the technique that best captures both structure and function through blood-flow–based activity.