diffusiongewichtete

Diffusiongewichtete refers to a type of magnetic resonance imaging (MRI) sequence that is sensitive to the diffusion of water molecules within tissues. This technique measures the random motion of water protons, which is influenced by the cellular structure and integrity of the surrounding tissue. In areas where water molecules can move more freely, the signal in a diffusion-weighted image will be different compared to areas where their movement is restricted.

The principle behind diffusion weighting relies on applying magnetic field gradients. These gradients are designed to dephase the MRI signal based on the motion of water molecules during the sequence. If water molecules move significantly during the application of these gradients, they will not rephase properly, leading to a reduced signal intensity in the resulting image. Conversely, if water movement is restricted, the signal will be better preserved.

Diffusion-weighted imaging (DWI) is a powerful diagnostic tool. It is particularly valuable in the early detection of acute ischemic stroke, where restricted diffusion due to cellular swelling is a hallmark sign. It can also be used to assess other neurological conditions, such as tumors, abscesses, and traumatic brain injury, by characterizing tissue microstructural changes. The degree of diffusion is often quantified using the apparent diffusion coefficient (ADC) map, which provides a numerical measure of water molecule diffusivity.