Which imaging technique can provide information about brain function?

Choice A rationale A skull radiograph (X-ray) is a two-dimensional imaging technique that primarily visualizes bone structure and density, which is useful for identifying fractures, calcification, or foreign objects. It provides no information on the metabolic activity or blood flow of brain tissue, which are the biological substrates of brain function. Choice B rationale Magnetic resonance imaging (MRI) uses strong magnetic fields and radio waves to generate detailed anatomical images of soft tissues, including the brain. It provides excellent structural resolution (detecting tumors or lesions) but, in its standard form, offers limited direct, quantitative data on real-time cellular energy consumption or neurotransmitter activity, which characterize function. Choice C rationale Positron Emission Tomography (PET) scan is a nuclear medicine technique that uses a small amount of a radioactive tracer, such as fluorodeoxyglucose (FDG), to measure metabolic processes like glucose metabolism and regional cerebral blood flow. Since glucose is the brain's primary energy source, areas of higher uptake indicate greater neuronal activity, thus providing crucial functional information. Choice D rationale A Computed Tomography (CT) scan uses X-rays from multiple angles to create cross-sectional images of the body. It provides detailed structural information (e.g., hemorrhage, edema, atrophy) but, similar to MRI, does not offer direct, specific quantification of ongoing, real-time metabolic rate or neurotransmitter release, which are hallmarks of brain function.