In dMRI, a sequence of diffusion-weighted images is acquired by applying pulsed magnetic field gradients. These gradients cause the phase of the MR signal to shift in a direction-dependent manner, which can be measured and used to calculate the diffusion of water molecules. The diffusion of water molecules is influenced by the tissue microstructure, such as the size and orientation of cellular compartments and the presence of barriers like cell membranes. By analyzing the diffusion properties, dMRI can provide insights into tissue integrity, connectivity, and organization.
One of the most common applications of dMRI is in the study of the brain, where it is used to investigate white matter tracts, which are responsible for connecting different brain regions. dMRI can reveal information about the integrity of these tracts, which is crucial for understanding and diagnosing conditions such as multiple sclerosis, traumatic brain injury, and neurodegenerative diseases. Additionally, dMRI is used in the evaluation of musculoskeletal disorders, such as tendinopathy and ligament injuries, by assessing the diffusion of water molecules in soft tissues.
dMRI has several advantages over traditional MRI techniques. It provides quantitative measurements of tissue microstructure, allowing for more objective and reproducible assessments. Furthermore, dMRI can be used to study the connectivity of different brain regions, enabling the mapping of neural pathways and the investigation of functional networks. However, dMRI also has limitations, including longer acquisition times and sensitivity to motion artifacts, which can affect the quality of the images.