Table 1.
Demographics.
Figure 1.
An example of the end-tidal gas control with the MPET device.
The end-tidal CO2 controlled response is shown in the upper panel. The period of time when the MPET device was active is shown by the horizontal line below. This occurred while the patient was undergoing BOLD EPI. The breathing sequence at baseline 1 (BL1), hypocapnia (Hypo), BL2, hypercapnia (Hyper) and BL3 is seen. In the lower panel the end-tidal O2 trace is seen. The stable end-tidal values during the period of MPET control can be seen.
Figure 2.
The relationship between whole brain BOLD EPI signal and end-tidal CO2 as controlled by the MPET device.
The R2-value for the regression between the two signals was 0.93 in this instance.
Table 2.
Hemodynamics and End-tidal Gases.
Figure 3.
A and B: A 1st level analysis of a control subject and a symptomatic PCS patient.
The CO2 response was assessed at the p = 0.001 level in both. The number of voxels responding to CO2 in the control patient (C-013) was 94% of the total brain voxel count at this level of statistical significance. In the symptomatic PCS patient (mTBI-004) the voxel response ratio was 46%. The numbers at the left below each axial slice represent the level below or above the anterior commissure – posterior commissure (AC–PC) line. The numbers related to the colour bar are the t-values for the statistical parametric mapping (SPM) 1st level analysis.
Table 3.
1st Level Analysis.
Figure 4.
A and B: A 2nd level analysis for a control subject (C-004) compared to the grouped control atlas and a symptomatic PCS patient (mTBI-004) compared to the same atlas of control subjects.
The ‘hot’ color scale shows ‘blobs’ where the CO2 response was less than seen in the controls at the p = 0.05 level. The ‘cold’ colour scale shows where the CO2 response was greater than in the controls at the p = 0.05 level. The levels below and above the AC–PC line are the same as in Figure 3. The numbers related to the colour bar are the t-values for the SPM 2nd level analysis.
Table 4.
2nd Level Analysis.