OBJECTIVE: We wanted to estimate the practical improvements of 3T proton MR spectroscopy (1H MRS) as compared with 1.5T 1H MRS for the evaluation of human brain tumors. MATERIALS AND METHODS: Single voxel 1H MRS was performed at both 1.5T and 3T in 13 patients suffering with brain tumors. Using the same data acquisition parameters at both field strengths, the 1H MRS spectra were obtained with a short echo time (TE) (35 msec) and an intermediate TE (144 msec) with the voxel size ranging from 2.0 cm3 to 8.7 cm3. The signal to noise ratios (SNRs) of the metabolites (myoinositol (MI), choline compounds (Cho), creatine /phosphocreatine (Cr), N-acetyl-aspartate (NAA), lipid and lactate (LL)) and the metabolite ratios of MI/Cr, Cho/Cr, Cho/NAA and LL/Cr were compared at both TEs between the two field strengths in each brain tumor. The degrees of spectral resolution between the Cho and Cr peaks were qualitatively compared between the two field strengths in each brain tumor. RESULTS: The SNRs of the metabolites at 3T demonstrated 49-73% increase at a short TE (p < 0.01) and only 2-12% increase at an intermediate TE (p > 0.05) compared with those of 1.5T. The SNR of inverted lactate at an intermediate TE decreased down to 49% with poorer inversion at 3T (p < 0.05). There was no significant difference in the metabolite ratios between the two field strengths. The degrees of the spectral resolution at 3T were slightly superior to those of 1.5T at a short TE. CONCLUSION: As compared with 1.5T, 3T 1H MRS demonstrated 49-73% SNR increase in the cerebral metabolites and slightly superior spectral resolution only at a short TE, but little at an intermediate TE, in the brain tumors. There was no significant difference in the metabolite ratios between the two field strengths.
Sensitivity and Specificity ; Reproducibility of Results ; Protons/*diagnostic use ; Middle Aged ; Male ; Magnetic Resonance Spectroscopy/*methods ; Humans ; Female ; Brain Neoplasms/*diagnosis/*metabolism ; Biological Markers/*analysis ; Aged ; Adult ; Adolescent

OBJECTIVE: To explore the in-vivo 1H- MR spectral features of adnexal lesions and to characterize the spectral patterns of various pathologic entities. MATERIALS AND METHODS: Thirty-one patients with surgically and histopathologically confirmed adnexal lesions underwent short echo-time STEAM (stimulated echo acquisition method) 1H- MR spectroscopy, and the results obtained were analysed. RESULTS: The methylene present in fatty acid chains gave rise to a lipid peak of 1.3 ppm in the 1H- MR spectra of most malignant tumors and benign teratomas. This same peak was not observed, however, in the spectra of benign ovarian epithelial tumors: in a number of these, a peak of 5.2 ppm, due to the presence of the olefine group (-CH=CH-) was noted. The ratios of lipid peak at 1.3 ppm to water peak (lipid/water ratios) varied between disease groups, and in some benign teratomas was characteristically high. CONCLUSION: An intense lipid peak at 1.3 ppm is observed in malignant ovarian tumors but not in benign epithelial tumors. 1H- MRS may therefore be helpful in the differential diagnosis of adnexal lesions.
Adnexal Diseases/*diagnosis ; Adult ; Aged ; Cystadenoma, Mucinous/diagnosis ; Diagnosis, Differential ; Female ; Human ; Magnetic Resonance Spectroscopy/*diagnostic use ; Middle Age ; Ovarian Neoplasms/diagnosis ; Protons ; Support, Non-U.S. Gov't ; Teratoma/diagnosis ; Uterine Neoplasms/diagnosis