2D 1H spectroscopic imaging of the human brain at 4.1 T

A two-dimensional spectroscopic imaging sequence consisting of an inversion recovery pulse, a plane selective prefocused pulse, and a semiselective water suppression pulse has been used to create ¹H spectroscopic images of the human brain with nominal voxels of 0.5 cc. Due to the excellent lipid suppression provided by the inversion recovery pulse and subsequent delay, only planar volume selection is required enabling the entire brain within the slice to be imaged without contamination from extracerebral lipids in the brain voxels. The use of a semiselective refocusing pulse for water suppression permits any echo evolution time to be used, minimizing J-modulation and T₂ losses, while retaining full sensitivity in the lactate resonance. Using this sequence we have visualized the lactate elevation in the peri-infarct region about a 6-week-old stroke.