Preliminary Study of Diffusion Kurtosis Imaging in Mild Traumatic Brain Injury

Traumatic brain injury (TBI) can result from blunt trauma or acceleration/deceleration force and is considered to be one of the most important public health problems. Many patients of TBI lose professional competence and independence. They may eventually suffer serious sequelae, such as cognitive impairment, memory loss, and long-term headache. In craniocerebral trauma patients, mild traumatic brain injury accounts for 70% - 80% of the cases. Early diagnosis and intervention can decrease the post-concussional sequelae for mild TBI (mTBI).
To investigate the value of diffusion kurtosis imaging (DKI) in mild traumatic brain injury (mTBI) patients.
Patients and Conventional MRI sequences (T1 and T2 weighted images) and DKI scans of 25 healthy controls and 24 mTBI patients were obtained. Regions of interests (ROIs) were drawn and analyzed on several planes including white matter, deep gray matter nuclei, peri-contusion and contusion lesion on fused fractional anisotropy (FA), mean diffusion (MD) maps, and mean kurtosis (MK) maps, respectively. FA, MD, and MK values were measured in a certain region (he area of bilateral centrum semiovale (CS), corona radiate (CR), caudate nucleus head (CNH), genu of corpus callosum (CCG), corpus callosum splenium (CCS), anterior limb of the internal capsule (ALIC), posterior limb of internal capsule (PLIC), external capsule (EC), lenticular nucleus (LN), and thalamus). Student’s t test was used to compare the average values of FA, MD, and MK between mTBI patients and healthy controls. Paired t-test was also used to compare contusion lesions and mirror symmetrical areas.
FA and MK values were significantly different in all of the white matter and grey matter, while MD values among the various ROIs were insignificantly different in the healthy control group. In mTBI patients, the FA values of genu of corpus callosum, splenium of corpus callosum, and external capsule were decreased. Whereas, MD value of genu of corpus callosum in trauma group was increased. Except for the head of the caudate nucleus and posterior limb of the internal capsule, the MK values of the rest of the ROIs in the trauma group decreased significantly. Moreover, compared with the contra-lateral, there were more significant contusion lesions of FA and MK reductions than increased MD values. FA and MD values of peri-contusion had no significant difference compared with the contra-lateral while MK values decreased significantly.
Compared with conventional MRI sequences, DKI can detect micro white matter injury, and MK parameter is more sensitive than FA and MD. In addition, DKI can find these changes not only in the white matter but also in deep gray matter nucleus, making it a promising imaging tool to assist the detection of mild traumatic brain injury.