FIG 3. Proton MR spectra (TR/TE, 2000/135) before and after continuous spinal drainage in the lateral ventricle of a patient with NPH. The spectra were obtained from a intraventricular voxel (black arrow in VOI). Before treatment, lactate peaks are observed as inverted doublet peaks at 1.3 ppm from the intraventricular voxel of NPH (upper middle). Cho, Cr, and NAA peaks suggest partial volume artifact from periventricular brain tissue. A metabolic image of lactate (upper right) before treatment shows that lactate is confined to the lateral ventricles and surroundings. After treatment, lactate is not observed clearly (lower right). The reduced CBF (upper left) returned to normal after continuous spinal drainage (lower left) at SPECT