HP ¹²⁹Xe distribution in the rat brain.

<p>(<b>3a</b>) HP ¹²⁹Xe CSI image acquired with a 2D CSI pulse sequence from rat head under normal breathing conditions (slice thickness 10 mm). (<b>3b</b>) same image with false color applied. Warmer colors indicate increased HP ¹²⁹Xe signal intensity. (<b>3c</b>) Proton MRI of a rat head showing a 1 mm coronal slice through the brain acquired with a RARE pulse sequence. (<b>3d</b>) Proton image shown with overlay of HP ¹²⁹Xe MRI, in which only HP ¹²⁹Xe signal with an SNR above 2 are shown. FOV was 25 mm.</p

HP ¹²⁹Xe spectrum obtained from rat brain <i>in vivo</i> after the administration of HP ¹²⁹Xe gas.

<p>The spectrum was acquired from 50 averages using an RF pulse with a flip angle of 90°, and a frequency of 55.477 MHz. At least four separate peaks are discernable, the largest of which occurs at 194.7 ppm downfield from the HP ¹²⁹Xe gas peak at 0 ppm. The SNR of the largest peak is 476.</p

RF coil used for image acquisition.

<p>The dual frequency coil combines a Helmholtz pair proton coil (transmit and receive, 200 MHz) nested on a single loop ¹²⁹Xe coil (transmit and receive, 55.35 MHz). This coil architecture allowed proton and ¹²⁹Xe images to be acquired sequentially while maintaining exact co-registration (Clinical MR Solutions, Brookfield, WI). The two coils were intrinsically decoupled.</p

Superimposition of a rat brain atlas [<b>18</b>] showing four regions of interest (ROIs) analyzed for changes in HP ¹²⁹Xe signal following forepaw stimulation, including cingulate cortex (Cg), primary somatosensory cortex and SS1 forelimb region (SS1 and SS1 fl), and secondary samatosensory cortex (SS2).

<p>Superimposition of a rat brain atlas <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0021607#pone.0021607-Paxinos1" target="_blank">[<b>18</b>]</a> showing four regions of interest (ROIs) analyzed for changes in HP ¹²⁹Xe signal following forepaw stimulation, including cingulate cortex (Cg), primary somatosensory cortex and SS1 forelimb region (SS1 and SS1 fl), and secondary samatosensory cortex (SS2).</p

Vital Signs Data (N = 3).

<p>Vital Signs Data (N = 3).</p

HP ¹²⁹Xe fMRI data from three animals.

<p>The HP ¹²⁹Xe signal is shown as a false colour overlay on the corresponding 1 mm thick coronal proton reference image taken from the same animal. The left panel shows HP ¹²⁹Xe signal intensity during baseline and the right panel shows HP ¹²⁹Xe signal intensity after injection of capsaicin 20 ul (3 mg/ml) into the right forepaw. Colour scale represents SNR and only signal with SNR above 2 are shown. Superimposition of a rat brain atlas (18) demarcates specific areas of the brain: cingulate cortex (Cg), motor cortex (M), primary somatosensory cortex and SS1 forelimb region (SS1 and SS1 fl), secondary samatosensory cortex (SS2), and striatum (CPu).</p

Percent HP ¹²⁹Xe signal change in four brain regions^*.

<p>*Measured from regions of interest (ROIs) in hemisphere contralateral to pain stimulus.</p