Yulin Ge MD, Presenter: Nothing to Disclose

Lin Tang, Abstract Co-Author: Nothing to Disclose

Elan Grossman, Abstract Co-Author: Nothing to Disclose

Joesph Reaume, Abstract Co-Author: Nothing to Disclose

Daniel Sodickson MD, PhD, Abstract Co-Author: Nothing to Disclose

Robert I. Grossman MD, Abstract Co-Author: Nothing to Disclose

Research interests on the study of fMRI during resting state (RS-fMRI) have demonstrated a consistent pattern of slow fluctuations in the BOLD signal as referred as “default mode” of brain function. Such spontaneous activity plays a role in maintaining the baseline human cognition. This study was to investigate whether this default mode associated with thalamic function is disrupted in patients with mild traumatic brain injury (MTBI) using RS-fMRI.

Six patients who have clinically definite MTBI with GCS scale of 13~15 and 5 healthy volunteers were studied. All the patients have various neurocognitive symptoms due to TBI with a median disease duration of 3.6 years.  fMRI was acquired on a 3T scanner using a gradient echo EPI sequence. One motor task (right finger tapping) session and 2 resting-state sessions with eyes closed but awake were performed in all subjects. The repeated RS-fMRI was also performed in two volunteers from a different day. For RS-fMRI data analysis, we performed an event-related general linear model analysis to generate the maps of resting-state networks (RSNs) by calculating the correlation coefficient between the fMRI signal time course around the whole brain to ROI which is placed in thalamus.

A consistent pattern of thalamic functional activation map was found in healthy volunteers during resting state in different sessions including data acquired in different days. The thalamic functional network shown on RS-fMRI mainly includes both sides of thalamus, basal ganglia, and cingulate cortex regions. Compared to healthy controls, patient with MTBI have shown largely differed and increased resting-state brain activities in bilateral frontal, temporal, and parietal lobes in line with thalamic activities (positive correlation, R>0.6) although their conventional motor cortex maps generated from finger tapping tasks did not show much difference.

This study demonstrates for the first time the disruption of default functional network during resting state in patients with MTBI. Our data using RS-fMRI provide important information associated to persistent post traumatic symptoms in these patients that are difficult to be explained with their structural MR imaging.

The newly defined default pattern thalamus-associated functional network could be relevantly used to study thalamo-cortical dysrhthemia, particularly in patients with MTBI.

Ge, Y, Tang, L, Grossman, E, Reaume, J, Sodickson, D, Grossman, R, Disruption of Default Thalamic Functional Activities in Patients with Mild Traumatic Brain Injury: A Resting-state fMRI Study at 3 T.  Radiological Society of North America 2008 Scientific Assembly and Annual Meeting, February 18 - February 20, 2008 ,Chicago IL. http://archive.rsna.org/2008/6009615.html