How it works: The white matter is the wiring of your brain. This wiring delivers the electrical signals from your cortex to your extremities. Diffusion Tensor imaging or DTI, uses the magnetic properties of water to create a map of the white matter in the brain. This data can be modeled into a 3 dimensional map of the white matter called tractography.
Equipment: Our MRI suite uses the latest Phillips 3.0 tesla magnet coupled with a state of the art post processing system. Our exams are personally tailored and monitored by a CAQ board certified neuroradiologist.
Benefits: DTI is used for presurgical and preradiation planning for an intracranial lesion that could potentially involve eloquent cerebral cortex. The DTI exam is tailored to the location of the brain lesion and the normal brain adjacent to it. The goal is to allow the neurosurgeon to plan the optimal, least invasive approach to a mass, and to allow the surgeon to more completely excise a mass while preserving as much normal function as possible. DTI also allows a patient to better understand the potential risks of having surgery. Our neurosurgical colleagues at OHSU (http://www.ohsu.edu/xd/health/services/clinics/NeurologicalSurgeryAdult.cfm) can integrate the Tractography information into the operating suite using a 3D stereotactic software so the surgeons can see the location of the white matter tracts during the surgery. Many studies have shown improved morbidity and increased survival rates in patients who have had preoperative DTI (http://journals.lww.com/neurosurgery/Abstract/2007/11000/Clinical_Evaluation_and_Follow_Up_Outcome_of.7.aspx).
Exam Preparation: The technologist will interview you prior to scan to make sure you have no contraindications to being in the MRI scanner. Patients with braces or other metal near the head or neck may not be suitable for DTI because of the artifacts the metal can cause. The exam is usually done in conjunction with a functional MRI (FMRI).
What to expect: DTI alone takes approximately 8 minutes of scanner time. During this time it is very important to remain still. The post-processing of the data to generate the tractography by the neuroradiologist can take up to 1 hour. The DTI is usually done along with an FMRI examination.