Rarely a day goes by when there are not several news items published about the role of neuro-imaging in detecting, treating, or monitoring the progression of Alzheimer's disease. Here are a few comments to bear in mind as you consume the daily press.
Magnetic Resonance Imaging (MRI) yields an image of brain structure and will reveal tumors, strokes, and (importantly for Alzheimer's disease) atrophy (or shrinkage) in particular parts of the brain that can be helpful in reaching an accurate diagnosis.
Positron Emission Tomography (PET) yields an image of brain metabolism and reveals where brain cells are engaged the healthy activities of their daily function. In some instances, this can reveal an earlier stage of a problem than MRI would reveal because cells may have stopped functioning but remained intact structurally.
Many news stories report on "tracers" or agents such as PIB that, once injected into the blood, make their way to the brain and bind with the beta amyloid, rendering it clearly visible in the scan. This is important because many scientists believe beta amyloid accumulation may be the cause of Alzheimer's disease.