Which neuroimaging technique is primarily used to measure blood flow in the brain?

Single Photon Emission Computed Tomography (SPECT) is the neuroimaging technique primarily used to measure blood flow in the brain. SPECT works by utilizing a radioactive tracer that is injected into the bloodstream. As blood flows through the brain, the tracer emits gamma rays which are detected by the SPECT camera to create images showing blood flow and activity in different regions of the brain. This provides valuable information about cerebral perfusion, which is crucial for diagnosing conditions such as stroke, tumors, and other neurological disorders.

Other imaging techniques, while useful for various types of brain analysis, do not focus specifically on measuring blood flow. Magnetic Resonance Imaging (MRI) provides detailed structural images of the brain and can show some dynamics related to blood flow through different sequences, but it is not primarily a blood flow measurement tool. Computed Tomography (CT) scans are also primarily used for structural imaging rather than assessing blood flow. Electroencephalogram (EEG) measures electrical activity in the brain, not blood flow, making it unsuitable for this purpose. Thus, SPECT's functionality in visualizing and quantifying blood flow makes it the correct choice.