diffuusiokuvauksella

Diffuusiokuvauksella, often translated as diffusion imaging or diffusion-weighted imaging, is an advanced magnetic resonance imaging (MRI) technique. It exploits the random motion of water molecules within biological tissues to generate contrast. This molecular motion, known as diffusion, is not uniform throughout the body; it is influenced by the microstructure of the tissues.

In a healthy brain, for example, water molecules diffuse more freely in some directions than others due to the organized structure of white matter tracts. Conversely, in areas of stroke or other pathologies, cell membranes can become damaged, leading to an increase in water diffusion. Diffuusiokuvauksella is highly sensitive to these changes, allowing for the early detection of conditions like ischemic stroke, often within minutes of its onset.

The technique works by applying magnetic field gradients that are sensitive to the movement of water molecules. If a water molecule moves significantly during the application of these gradients, its signal in the MRI is attenuated. By acquiring images with gradients applied in different directions, it is possible to map the directionality and magnitude of water diffusion. This information can be further processed to generate various derived maps, such as fractional anisotropy (FA) and mean diffusivity (MD), which provide quantitative measures of tissue integrity and water movement. These derived maps are valuable for diagnosing and monitoring a wide range of neurological conditions beyond stroke, including tumors, traumatic brain injury, and neurodegenerative diseases.