Diffusion tensor imaging (DTI) is a Magnetic Resonance Imaging (MRI) method that analyzes the anatomy of nerve cells and the complex neuronal network of the brain. It is most commonly used to provide imaging of the brain.
Diffusion Tensor Imaging is a method which measures how water moves along the nerves. This movement is known as Fractional Anisotropy (FA). If a disruption in the water pathway is detected, we know that there is damage in that specific area of the brain.
DTI is an improved version of conventional MRI where signals are solely generated from the movement of water molecules. Random thermal motion of water molecules is known as “diffusion”. DTI uses the diffusion of water as a probe to determine the anatomy of a brain network. The results provide information on static anatomy that is not influenced by brain functions.
DTI testing is performed on Capitol Imaging Services (CIS) 3T ultra-high field MRI systems that have specific advanced neurological software and post-exam data processing capabilities. Combining 3T MRI with this advanced analysis, radiologists segment brain DTI scans into 48 regions to identify nerve damage.
When would I get Diffusion Tensor Imaging?
Your medical provider may consider Diffusion Tensor Imaging to be an appropriate imaging method to detect nerve damage in the brain caused by a concussion (mild Traumatic Brain Injury or mTBI). Concussion symptoms include:
- A stunned or shocked feeling
- Loss of memory
- Amnesia surrounding the particulars of the injury
- Blurred vision
- Changes in sleeping patterns
- Nausea or vomiting
- Not feeling “right”
About 70% of concussion patients experience improvement or are considered back to normal about two weeks after the injury. However, some individuals continue to experience problems that can affect them with their ability to perform daily tasks at home, work or at school.
In cases of mild Traumatic Brain Injury or mTBI, routine MRI or CT Scans may appear normal, but a brain scan with Diffusion Tensor Imaging may detect microscopic injuries that were previously undetected. Unseen injuries of concussions remained elusive to physicians. Now, injuries are identified and test results provide valuable insight for doctors treating brain injury.
What Will I Experience?
For the patient, Diffusion Tensor Imaging is an additional analysis that can be included in a brain MRI exam. It is usually performed without the use of a contrast dye.
MRI exams are painless. However, some patients find it challenging to remain still. Others may feel closed-in (claustrophobia) while in a conventional closed MRI scanner. The scanner can be noisy. Nervous or anxious patients may be offered a mild sedative.
It is normal for the area of your body being imaged to feel slightly warm. It is important that you remain perfectly still while the images are being recorded, which is typically only a few seconds to a few minutes at a time. You will know when images are being recorded because you will hear tapping or thumping sounds when the coils that generate the radiofrequency pulses are activated. You will be able to relax between imaging sequences, but will be asked to maintain your position as much as possible.
You will usually be alone in the exam room during the MRI procedure. However, the technologist will be able to see, hear and speak with you at all times using a two-way intercom.
You will be offered earplugs or a headset to reduce the noise of the MRI, which produces loud thumping and humming noises during imaging. MRI scanners are air-conditioned and well-lit. Some of our scanners have music you can listen to during the test.
Most MRI scans of the brain with Diffusion Tensor Imaging will last approximately 45-60 minutes.