Which imaging modality is used to map white matter tracts and support neurosurgical planning?

• A. Diffusion Tensor Imaging
• B. Functional MRI
• C. Spectroscopy
• D. X-ray CT

Answer: (A)

Mapping white matter tracts relies on how water diffuses through brain tissue. In white matter, water tends to move along the length of axons, creating directional diffusion. Diffusion Tensor Imaging is an MRI technique that measures diffusion in many directions and fits a tensor at each voxel. This lets us estimate fiber orientations and perform tractography to reconstruct likely pathways, such as language or motor tracts. This information is crucial for neurosurgical planning because it helps surgeons avoid essential tracts during tumor removal or lesion surgery, reducing the risk of new neurological deficits.

Functional MRI, by contrast, shows regions activated during tasks based on blood flow, not the physical tracts themselves. Spectroscopy looks at chemical compounds in tissue and provides metabolic information, not tract anatomy. X-ray CT offers detailed bone and gross structural anatomy but has limited soft-tissue contrast for white matter mapping.