Article Figures & Data
Figures
- Fig 1.
Spin-echo MR images. Axial view FLAIR image (left) shows extensive hyperintensity involving the left hemisphere white matter and basal ganglia, bilateral thalami, and splenium of corpus callosum, with mild mass effect. Comparison between unenhanced T1-weighted image (center) and contrast-enhanced T1-weighted image (right) reveals no appreciable enhancement.
- Fig 2.
Single voxel spectroscopy. Localized STEAM (TE 20) spectra were acquired from the normal appearing right periatrial region (A1) and from the hyperintense left periatrial region (B1). PRESS (TE 135) spectra were acquired from the same locations (A2 and B2, respectively). The right and left STEAM spectra are displayed by using the same vertical scale factor, as are the right and left PRESS spectra.
- Fig 3.
Spectroscopic imaging. Multi-voxel spectra (TE 135) from five different locations (marked by Xs) indicated on the axial FLAIR localizer. A, Right periatrial region. B, Left periatrial region. C, Right basal ganglia region. D, Left basal ganglia region. E, Left thalamus.
- Fig 4.
Histopathology of left thalamic biopsy specimen. Moderately cellular infiltrating glioma (hematoxylin and eosin; original magnification, ×400).
Tables
Ratio STEAM PRESS Left PAβ Right PA Controlγ Left PA Right PA Controlγ NA/Cr 0.81 0.92 1.11 ± 0.12 1.16 1.45 1.61 ± 0.17 Cho/Cr 0.23 0.21 0.17 ± 0.05 0.23 0.25 0.23 ± 0.03 m-Ins/Cr 0.73 0.43 0.46 ± 0.05 ndδ nd nd Cho/NA 0.28 0.23 0.15 ± 0.04 0.2 0.18 0.15 ± 0.02 m-Ins/NA 0.9 0.47 0.42 ± 0.04 nd nd nd α Metabolite concentration ratios must be multiplied by the ratios of protons contributing to the corresponding resonances in order to obtain “peak area ratios.” The ratios for the protons are as follows: NA/Cr = 3/3, Cho/Cr = 9/3, m-Ins/Cr = ∼3.4/3, Cho/NA = 9/3, m-Ins/NA = ∼3.4/3. Thus, the “peak area ratio” for STEAM, left PA Cho/Cr = 0.23 (9/3) = 0.69. The peak area ratios calculated in this way from the concentration ratios yield results that are qualitatively in agreement with the relative peak areas in Figure 2. If the linewidths of the resonances are not excessively broadened or variable, similar qualitative agreement is achieved when relative peak amplitudes, rather than peak areas, are assessed. {Addendum: The estimate of 3.4 protons contributing to the 3.56-ppm myo-Ins resonance was based on two approaches: (1) analysis of synthetic spectra generated with the TE/TM values used in this case, (2) analysis of metabolite peak area ratios (from a standard peak fitting algorithm) relative to concentration ratios (from LCModel) in a database of 124 similarly acquired control spectra (JB Murdoch, unpublished results).}
β PA = periatrial region.
γ Control data reported as mean ± standard deviation.
δ nd = not determined.
