Figure 9.

In-vivo spectra acquired by semi-LASER and the double spin echo 3D SPSP pulses. (a) Spectroscopic imaging slice planning on MP2RAGE anatomic images of the brain of a volunteer where the VOI is shown in the posterior cingulate cortex. OVS pulses are also shown as planned for use in the 3D SPSP acquisition. The spatially resolved spectra acquired using 3D SPSP pulses without and with OVS are shown from 1.0 to 4.5 ppm in (b), (c), respectively. Residual lipid peaks in (b) were located at approximately 1.59 ppm. Single voxel spectra (SVS) and selected CSI spectra collected from the VOI are shown for the 3D SPSP pulses designed using a Gaussian spatial profile with OVS in (d) and semi-LASER (g). The upper (blue) and lower (orange) selected CSI spectra come from primarily white and gray matter from the indicated voxels on the zoomed in CSI datasets for the 3D SPSP (e) and semi-LASER (f) acquisitions, both shown from 1.5 to 4.5 ppm. Chemical shift images of NAA calculated by integrating the magnitude of the spectra are shown in (f) for 3D SPSP pulses and (i) for semi-LASER. The effective VOI in (f) appears slightly larger than (i) due to a broader transition band in Gaussian profile. Spectra in (d), (g) are shown in real, whereas (b), (c), (e), (h) are displayed in magnitude.