Assessment of 3D proton MR echo-planar spectroscopic imaging using automated spectral analysis

For many clinical applications of proton MR spectroscopic imaging (MRSI) of the brain, diagnostic assessment is limited by insufficient coverage provi ded by single- or multislice acquisition methods as well as by the use of v olume preselection methods. Additionally, traditional spectral analysis met hods may limit the operator to detailed analysis of only a few selected bra in regions. It is therefore highly desirable to use a fully 3D approach, co mbined with spectral analysis procedures that enable automated assessment o f 3D metabolite distributions over the whole brain. In this study, a 3D ech o-planar MRS[ technique has been implemented without volume preselection to provide sufficient spatial resolution with maximum coverage of the brain. Using MRSI acquisitions in normal subjects at 1.5T and a fully automated sp ectral analysis procedure, an assessment of the resultant spectral quality and the extent of viable data in human brain was carried out. The analysis found that 69% of brain voxels were obtained with acceptable spectral quali ty at TE = 135 ms, and 52% at TE = 25 ms. Most of the rejected voxels were located near the sinuses or temporal bones and demonstrated poor B-o homoge neity and additional regions were affected by stronger lipid contamination at TE = 25 ms. (C) 2001 Wiley-Liss, Inc.