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FIG 2. Images of patient 20 with NPC.
A, Coronal view T2-weighted MR image shows the position of the volume of interest for spectroscopy represented by the white rectangle placed within the metastatic lymph node.
B, Spectrum acquired at 1H MR spectroscopy with TE 136 from the metastatic node. The nominal voxel volume was 2 cm3. Both Cho (3.2 ppm) and methylene lipid (1.30 ppm) peaks were present, but Cr (3.02 ppm) was not clearly seen.
C, Lipids were removed from the original spectrum shown in B with the use of Hankel-Lanczos singular value decomposition filtering before spectral fitting was performed (bottom trace). The fitted spectrum performed in the time domain is shown by the middle trace. Only the intense Cho peak was successfully estimated, whereas the Cr peak was not found. The top trace represents the residual signal intensity.
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