In vivo proton MR spectroscopy of primary and nodal nasopharyngeal carcinoma.
OBJECTIVE
The aim of this study was to determine the feasibility of performing in vivo proton ((1)H) MR spectroscopy of nasopharyngeal carcinoma (NPC) and to document the (1)H spectrum of this cancer.


METHODS
Twenty-seven patients with NPC lesions >1 cm(3) underwent localized (1)H MR spectroscopy performed at 1.5 T. Water-suppressed spectra from both primary tumors (nine cases) and metastatic nodes (18 cases) were obtained at TE 136 and 272. Spectra were analyzed in the time domain by using a nonlinear least squares fitting algorithm with incorporation of previous knowledge. Choline (Cho)/creatine (Cr) ratios for primary NPC and metastatic nodes were calculated and compared. Spectra from normal neck muscle of five volunteers were acquired as control data.


RESULTS
(1)H MR spectroscopy was successfully obtained in seven (78%) of nine primary tumors and 16 (89%) of 18 metastatic nodes. Intense lipid signals in the range of 0.89 to 2.02 ppm were observed in 95% of spectra at TE 136 and 91% of spectra at TE 272. At TE 136, Cho/Cr for metastatic nodes (5.3 +/- 1.6) was significantly higher than the ratio for primary (2.6 +/- 0.5) NPC lesions (P =.02). Cho/Cr ratios for NPC lesions were higher than those for normal neck muscles, for which values ranged from 0 to 0.97 and 0 to 1.1 at TE 136 and 272, respectively.


CONCLUSIONS
(1)H MR spectroscopy is a feasible technique for the evaluation of NPC tumors >1 cm(3). Cho/Cr ratios for the lesions were high compared with those for normal neck muscle.
King
Ann D
AD
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.
Yeung
David K W
DK
Ahuja
Anil T
AT
Leung
S F
SF
Tse
Gary M K
GM
van Hasselt
Andrew C
AC
D000328:Adult; D000368:Aged; D000465:Algorithms; D002794:Choline / Q000378:metabolism; D003401:Creatine / Q000378:metabolism; D003627:Data Interpretation, Statistical; D004734:Energy Metabolism / Q000502:physiology*; D004867:Equipment Design; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D016018:Least-Squares Analysis; D008198:Lymph Nodes / Q000473:pathology*; D008207:Lymphatic Metastasis / Q000473:pathology*; D008279:Magnetic Resonance Imaging / Q000295:instrumentation*; D009682:Magnetic Resonance Spectroscopy / Q000295:instrumentation*; D008297:Male; D008875:Middle Aged; D009303:Nasopharyngeal Neoplasms / Q000473:pathology*; D009305:Nasopharynx / Q000473:pathology; D009334:Neck Muscles / Q000473:pathology; D017711:Nonlinear Dynamics; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012016:Reference Values
D003401:Creatine; D002794:Choline