Diffuusiotensorikuvaus

Diffuusiotensorikuvaus, often abbreviated DTI, is an advanced magnetic resonance imaging (MRI) technique used to study the diffusion of water molecules in biological tissues. This diffusion is not random but is influenced by the microscopic structure of the tissue, particularly the orientation and integrity of white matter tracts in the brain. DTI measures the directionality of this diffusion, providing information about the underlying tissue architecture.

The fundamental principle behind DTI is that water molecules move more freely in certain directions than others. In white matter, for instance, the tightly packed axons and their myelin sheaths create barriers that restrict water diffusion perpendicular to the fiber direction, while allowing freer movement along the axis of the fibers. DTI applies magnetic field gradients in multiple directions to map this anisotropic diffusion.

The data acquired from DTI can be processed to generate various metrics and visualizations. Fractional anisotropy (FA) is a common scalar value that quantifies the degree of anisotropy, with higher FA values indicating more directional diffusion. Mean diffusivity (MD) measures the average magnitude of water diffusion. Tractography is another significant application of DTI, where the diffusion directionality is used to reconstruct the pathways of white matter tracts, allowing for visualization and analysis of neural connections.

DTI has become an invaluable tool in neuroscience and clinical practice. It is used for diagnosing and monitoring neurological conditions that affect white matter, such as stroke, traumatic brain injury, multiple sclerosis, and neurodegenerative diseases. Researchers utilize DTI to investigate brain development, aging, and the effects of learning and rehabilitation on neural pathways. Its ability to non-invasively probe white matter integrity and connectivity makes it a cornerstone of modern neuroimaging.