1H MR Spectroscopy of the Normal Human Brains: Comparison of Automated Prescan Method with Manual Method

ABSTRACT

PURPOSE: To evaluate regional differences in relative metabolite ratios in the normal human brain by 1H MRspectroscopy (MRS), and compare the spectral quality obtained by the automated prescan method (PROBE) and themanual method. MATERIALS AND METHODS: Localized 1H MRS was performed on a GE 1.5T SIGNA MRI/MRS system (version5.5) with active shielded gradients. For 20 normal volunteers aged 8-47 years, spectral parameters were adjustedby the auto-prescan routine provided by a PROBE package(N=34)and manually (N=33). Five regions of the human brainwere examined (N=PROBE,manual) frontal white matter(N=6,10), parietal white matter(N=8,9), basal ganglia(N=6,5),thalamus(N=4,5), and cerebellum(N=4,4). For all spectra, a STEAM localization sequence with three-pulse CHESS H2Osuppression was used, with the following acquisition parameters TR=3.0 sec, TE=30 msec, TM=13,7 msec, SW=2500Hz,SI=2048 pts, AVG=48, and NEX=2. RESULTS: A total of 61 reliable spectra were obtained by PROBE (28/34=82%success) and by the manual method (33/33=100% success). Regional differences in the spectral patterns of the fiveregions were clearly demonstrated by both PROBE and the manual methods. For prescanning, the manual method tookslightly longer than PROBE (3-5 mins and 2 mins,respectively). There were no significant differences in spectralpatterns and relative metabolic ratios between the two methods. However, auto-prescan by PROBE seemed to be veryvulnerable to slight movement by patients, and in three cases, an acceptable spectrum was thus not obtained. CONCLUSION: PROBE is a highly practical and reliable method for single voxel 1H MRS of the human brain; the twomethods of prescanning do not result in significantly different spectral patterns and the relative metaboliteratios. PROBE, however, is vulnerable to slight movement by patients, and if the success rate for obtainingquality spectra is to be increased, regardless of the patient's condition and the region of the brain, it must beused in conjunction with the manual method.