Brain MRI CO2 stress testing: a pilot study in patients with concussion

Area of Science:

• Neuroimaging
• Vascular Physiology
• Concussion Research

Background:

• Concussion lacks reliable, quantifiable neuro-imaging biomarkers.
• Assessing cerebrovascular function is crucial for understanding concussion pathophysiology.

Purpose of the Study:

• To develop and validate a brain BOLD-MRI CO2 stress test for concussion assessment.
• To investigate alterations in cerebrovascular responsiveness in individuals with post-concussion syndrome (PCS).

Main Methods:

• BOLD-MRI scans were performed on healthy controls and PCS patients (symptomatic and asymptomatic) under varying CO2 conditions (hypocapnia and hypercapnia).
• Statistical parametric mapping (SPM) was used for first and second-level analyses to compare CO2 stress responses between groups.
• Quantifiable metrics, such as reactive voxel counts, were calculated to assess cerebrovascular responsiveness.

Main Results:

• PCS patients, both symptomatic and asymptomatic, exhibited altered cerebrovascular responses to CO2 challenge compared to controls.
• Quantifiable differences in whole-brain voxel counts were observed, indicating significant alterations in regional cerebrovascular responsiveness in PCS patients.
• Specific statistical significance was noted for symptomatic patients with a CO2 response less than controls (p=0.012).

Conclusions:

• The BOLD-MRI CO2 stress test effectively identifies quantifiable alterations in cerebrovascular responsiveness in concussion patients.
• These findings suggest the potential of this test as a neuro-imaging biomarker for concussion.
• Further longitudinal studies are needed to correlate CO2 responsiveness with patient symptoms and outcomes.