Article Figures & Data
Figures
- Fig 1.
A, Pulse diagram for CSSMRS. The first radiofrequency pulse has a flip angle of α (where α is <90°) and is cosine modulated, such that the subsequent spin echo after the third radiofrequency pulse excites 2 voxels. Shaded gradients are crusher gradients. The section-select rephasing lobe for the y gradient is added directly to the first crusher. The gradient-echo readout in the dotted box is optional for voxel localization verification. RF indicates radiofrequency; DAQ, data acquisition. B, An anatomic T1-weighted image of patient 6 with the nominal voxel locations overlaid and a brain tumor evident in the left middle temporal gyrus. The 2 spectra for this patient are displayed in the bottom row of Fig 2.
- Fig 2.
Spectra from a healthy volunteer (A and B) and a patient with brain cancer (C and D) measured with both CSSMRS and PRESS. Spectra from patient 6 are shown, because this patient exhibited the median g-factor, typifying CSSMRS reconstruction quality. Errors represent the standard deviation over 128 excitations. a.u. indicates arbitrary units.
- Fig 3.
A, Spectra from a healthy volunteer at 30-millisecond echo time, obtained by using both CSSMRS and PRESS. The labeled metabolites are myo-inositol (mI), Cho, Cr, Glx, and NAA. B, The unapodized spectrum obtained from CSSMRS from patient 1 (highest g-factor) along with the automated quantitation of short echo time MR spectroscopy spectra (AQSES) fit.
- Fig 4.
Measured and simulated differences between the CSSMRS and PRESS measurement for 6 different voxel separations for the 3 main metabolites within a healthy adult brain: NAA, Cho, and Cr. The signal from the CSSMRS voxel that was kept in a fixed position was reconstructed and compared with the PRESS measurement obtained from the same location. The black and gray lines represent the measured and simulated values, respectively. The g factors are also displayed for reference above the top x-axis, though there is a nonlinear relationship between g factor and voxel separation. Error bars represent Cramer-Rao bounds.
- Fig 5.
Simulated metabolite quantification values for 7 different voxel separations for the 4 main metabolites within the tumor spectra for patient 6: NAA, Cho, Cr, and lactate (Lac). The quantified values were from the stationary voxel placed within the tumor and are plotted in gray. The black data points located at 62 cm in each plot are the experimental results for this patient, corresponding to the first difference column values listed in Tables 2–5 for patient 6. The estimated g factors are also displayed above the top x-axis for reference, though there is a nonlinear relationship between the g factor and voxel separation.
Tables
Patient No. Age (yr) Sex Disease Radiation Treatment Status Tumor Location Tumor Size (vs Voxel Size) 1 36 F Grade II oligodendroglioma None Right cingulate gyrus Larger 2 84 M Grade IV glioblastoma Currently undergoing focused radiation Left middle temporal gyrus Comparable 3 79 M Grade IV glioblastoma Currently undergoing focused radiation Left superior temporal gyrus Larger 4 61 F Brain metastases from breast cancer 60 days since completion of focused radiation Left middle temporal gyrus Smaller 5 79 M Brain metastases from colon cancer 70 days since completion of focused radiation Right superior temporal gyrus Smaller 6 61 M Grade IV glioblastoma Currently undergoing focused radiation Left middle temporal gyrus Larger Note:—F indicates female; M, male.
Patient No. CSSMRS Tumor Voxel (a.u.) PRESS Tumor Voxel (a.u.) Difference (a.u.) CSSMRS Healthy Voxel (a.u.) PRESS Healthy Voxel (a.u.) Difference (a.u.) 1 5.70 ± 0.65 4.86 ± 0.58 0.83 ± 0.87 9.73 ± 0.28 9.88 ± 0.20 −0.15 ± 0.35 2 2.70 ± 0.44 2.08 ± 0.40 0.62 ± 0.59 9.34 ± 0.35 8.84 ± 0.35 0.50 ± 0.49 3 1.70 ± 0.19 1.60 ± 0.20 0.10 ± 0.28 9.14 ± 0.12 9.42 ± 0.14 −0.28 ± 0.18 4 3.33 ± 0.54 0.14 ± 0.25 3.19 ± 0.59 8.09 ± 0.38 8.89 ± 0.36 −0.81 ± 0.52 5 5.27 ± 0.29 4.22 ± 0.21 1.05 ± 0.35 8.87 ± 0.38 10.93 ± 0.55 −2.06 ± 0.66 6 5.89 ± 0.27 5.41 ± 0.33 0.48 ± 0.43 6.81 ± 0.21 6.98 ± 0.20 −0.17 ± 0.29 Note:—a.u. indicates arbitrary units.
↵a Shown are means and standard deviations (Cramer-Rao bounds).
Patient No. CSSMRS Tumor Voxel (a.u.) PRESS Tumor Voxel (a.u.) Difference (a.u.) CSSMRS Healthy Voxel (a.u.) PRESS Healthy Voxel (a.u.) Difference (a.u.) 1 2.93 ± 0.39 2.89 ± 0.24 0.04 ± 0.45 1.72 ± 0.18 1.73 ± 0.13 −0.01 ± 0.22 2 1.86 ± 0.27 1.67 ± 0.17 0.19 ± 0.32 1.89 ± 0.20 2.22 ± 0.22 −0.33 ± 0.30 3 0.67 ± 0.12 0.96 ± 0.17 −0.28 ± 0.21 2.06 ± 0.07 2.31 ± 0.08 −0.25 ± 0.11 4 0.97 ± 0.93 0.83 ± 0.33 0.15 ± 0.99 1.36 ± 0.18 2.05 ± 0.21 −0.69 ± 0.75 5 1.66 ± 0.12 1.81 ± 0.11 −0.15 ± 0.16 1.56 ± 0.26 3.02 ± 0.66 −1.46 ± 0.71 6 1.56 ± 0.17 1.59 ± 0.20 −0.02 ± 0.26 1.75 ± 0.13 1.80 ± 0.12 −0.05 ± 0.17 Note:—a.u. indicates arbitrary units.
↵a Shown are means and standard deviations (Cramer-Rao bounds).
Patient No. CSSMRS Tumor Voxel (a.u.) PRESS Tumor Voxel (a.u.) Difference (a.u.) CSSMRS Healthy Voxel (a.u.) PRESS Healthy Voxel (a.u.) Difference (a.u.) 1 10.62 ± 2.44 7.77 ± 1.07 2.85 ± 2.66 6.34 ± 0.77 6.50 ± 0.61 −0.16 ± 0.98 2 3.82 ± 1.68 1.66 ± 0.55 2.16 ± 1.77 9.09 ± 0.89 10.40 ± 1.07 −1.32 ± 1.39 3 2.41 ± 0.77 1.56 ± 0.67 0.85 ± 1.02 8.73 ± 0.32 8.37 ± 0.35 0.36 ± 0.48 4 4.66 ± 4.17 0.42 ± 0.63 4.24 ± 4.22 8.94 ± 1.03 8.60 ± 0.95 −0.25 ± 1.40 5 6.19 ± 0.61 5.98 ± 0.48 0.21 ± 0.77 10.44 ± 1.76 10.58 ± 2.97 −0.15 ± 3.45 6 8.21 ± 0.74 8.00 ± 0.88 0.22 ± 1.15 6.13 ± 0.56 6.19 ± 0.52 −0.05 ± 0.77 Note:—a.u. indicates arbitrary units.
↵a Shown are means and standard deviations (Cramer-Rao bounds).
Patient No. CSSMRS Tumor Voxel (a.u.) PRESS Tumor Voxel (a.u.) Difference (a.u.) CSSMRS Healthy Voxel (a.u.) PRESS Healthy Voxel (a.u.) Difference (a.u.) 1 1.31 ± 0.09 1.46 ± 0.08 −0.16 ± 0.12 0.03 ± 0.04 0.23 ± 0.07 −0.20 ± 0.08 2 3.36 ± 0.11 3.16 ± 0.10 0.20 ± 0.15 0.60 ± 0.11 0.51 ± 0.11 0.09 ± 0.16 3 2.83 ± 0.04 2.77 ± 0.04 0.06 ± 0.05 0.25 ± 0.04 0.28 ± 0.05 0.03 ± 0.06 4b 3.22 ± 0.14 2.76 ± 0.13 0.46 ± 0.19 1.84 ± 0.10 1.59 ± 0.10 0.25 ± 0.14 5 2.26 ± 0.08 2.32 ± 0.07 −0.06 ± 0.10 0.73 ± 0.13 0.87 ± 0.17 −0.14 ± 0.21 6 0.54 ± 0.07 0.76 ± 0.08 −0.22 ± 0.11 0.22 ± 0.05 0.29 ± 0.05 −0.08 ± 0.07
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