[Quantification of brain metabolites by 1H spectroscopy using cyclohexane as an external reference].
We tested the reliability of quantifying brain metabolite concentrations by MR spectroscopy. We employed a PRESS sequence and used a cyclohexane sample as an external standard. The signal intensity ratios of water and cyclohexane were measured by changing the geometrical arrangement of the cyclohexane sample and water phantom with various loading factors of the coil. Choline (Cho) concentrations were calculated from the signal intensity ratios of Cho and water and compared with actual Cho concentrations (1.0 to 2.6 mmol/L). The brain metabolites Cho, creatine/phosphocreatine (Cr/PCr) and N-acetylaspartate (NAA) were evaluated in five normal volunteers and six patients with metastatic brain cancer before (0 Gy), after 20 Gy and after 40 Gy of whole brain radiotherapy. Variation in the ratio of spectrum intensity between water and cyclohexane was less than 1.5% for various geometrical arrangements and loading factors. The error in quantification of Cho concentrations in the phantom study was 0.05 +/- 0.10 mmol/L. The concentrations measured in the volunteers were: Cho 1.6 +/- 0.4 mmol/L, Cr/PCr 6.4 +/- 1.1 mmol/L and NAA 8.2 +/- 0.1 mmol/L. There was no significant difference (p > 0.05) in these concentrations between the control group and the patients before, during, or after radiotherapy.
Maeda
H
H
Department of Radiology, Nagoya First Red Cross Hospital.
Taki
I
I
Ando
Y
Y
Matsushima
S
S
D000328:Adult; D000368:Aged; D001224:Aspartic Acid / Q000031:analogs & derivatives / Q000378:metabolism; D001921:Brain / Q000378:metabolism*; D001932:Brain Neoplasms / Q000175:diagnosis* / Q000378:metabolism / Q000556:secondary; D002794:Choline / Q000378:metabolism; D003401:Creatine / Q000378:metabolism; D003510:Cyclohexanes / Q000378:metabolism; D005260:Female; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D008875:Middle Aged; D008961:Models, Structural; D010725:Phosphocreatine / Q000378:metabolism; D012015:Reference Standards; D015203:Reproducibility of Results
D003510:Cyclohexanes; D010725:Phosphocreatine; D001224:Aspartic Acid; C000179:N-acetylaspartate; D003401:Creatine; D002794:Choline