In Vivo Proton MR Spectroscopy of Primary and Nodal Nasopharyngeal Carcinoma
Ann D. Kinga,
David K.W. Yeungb,
Anil T. Ahujaa,
S.F. Leungb,
Gary M.K. Tsec and
Andrew C. van Hasseltd
a Department of Diagnostic Radiology & Organ Imaging, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, New Territories, Hong Kong, Special Administrative Region, China
b Department of Clinical Oncology, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, New Territories, Hong Kong, Special Administrative Region, China
c Department of Anatomical and Cellular Pathology, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, New Territories, Hong Kong, Special Administrative Region, China
d Department of Surgery Faculty of Medicine, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, New Territories, Hong Kong, Special Administrative Region, China
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FIG 1. Images of patient 1.
A, Axial view fat-suppressed T2-weighted MR image shows the position of the volume of interest for spectroscopy represented by the white square placed within the primary NPC tumor.
B, Spectrum acquired at 1H MR spectroscopy with TE 136 from the primary NPC tumor shown in A. The nominal voxel volume was 3.9 cm3. Prominent peaks detected were Cho (3.2 ppm), Cr (3.03 ppm), and lipids (1.30 ppm).
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, and the top trace represents the residual signal intensity.
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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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