What is the role of diffusion tensor imaging (DTI) in MRI?

• A. Detects calcifications in arteries
• B. Maps neural tracts by measuring directional water diffusion; used for planning in neurosurgery and assessing white matter integrity
• C. Evaluates bone density
• D. Measures the amount of fat in tissues

Answer: (B)

DTI in MRI uses the way water moves in tissue to reveal white matter architecture. In healthy white matter, water diffuses more easily along the length of axons than across them because myelin sheaths and membranes hinder perpendicular movement. By measuring diffusion in many directions, the diffusion tensor describes this anisotropic movement, and tractography can reconstruct major neural pathways. This enables planning to spare important tracts during neurosurgery and provides a way to assess white matter integrity in various conditions. It isn’t used for detecting calcifications in arteries—that’s seen better with CT or susceptibility imaging—nor for evaluating bone density, nor for measuring fat content in tissues, which rely on other imaging techniques. So the role of diffusion tensor imaging is to map neural tracts by measuring directional water diffusion and to aid surgical planning and integrity assessment.