Two axial slices from a younger and an older individual illustrating increased bilateral recruitment with age. These data were collected as part of the Dallas Lifespan Brain Study led by Dr. Denise Park of the Center for Vital Longevity.
One of the main applications of magnetic resonance imaging (MRI) is to assess brain structure and function non-invasively. Researchers can use MRI to measure the size of the brain, detect potential tissue lesions, evaluate biochemical composition, determine biophysical properties, quantify blood supply to the brain, and probe electrical activity of the neuron. Investigators at the AIRC are working on the development and application of these novel MRI technologies to understand how the brain works and how it changes with disease. Illustrated below are three examples of brain MRI techniques.
Functional MRI (fMRI): Lying inside the MRI scanner, the participant performs a cognitive task while brain images are continuously taken. By applying computational analysis on the images, brain regions that were utilized during the task can be identified. The figure illustrates the brain regions "activated" when the person looks at a scene displayed on a computer screen.
Diffusion tensor imaging (DTI): The MRI signal can be made sensitive to motion (diffusion) of water molecules. Because the pattern of water motion is dependent on the tissue orientation, this biophysical property can be utilized to identify anatomic organization of the brain. The figure on the left shows major white matter tracts that connect between various regions of the brain.
Magnetic resonance spectroscopic imaging (MRSI) offers a tool to assess biochemical content of the human brain. The figure shows MRSI data overlaid on an anatomic image from a patient with a high grade brain tumor. The spectra displayed in yellow are located in the tumor regions which exhibit abnormal spectral pattern with increased choline and decreased creatine and N-acetylaspartate.