Quantitative spectroscopic imaging of the human brain

A method to provide B-1 correction and cerebrospinal fluid (CSF) referencing is developed and applied to spectroscopic imaging of the human brain at 4.1 T using a volume head coil. The B-1 image allows rapid determination of the spatially dependent B-1 that is then used to compensate for the B-1 sensitivity of the spectroscopic sequence. The reference signal is acquired from CSF located in a lateral ventricular position using a point-resolved echo spectroscopy (PRESS) acquisition. The CSF spectrum is also corrected for B-1 dependence, Together with T-2 and T-1 corrections, this method is used to provide quantitative values of N-acetylaspartate (NAA), creatine (Cr), and choline (Ch). The metabolite concentrations obtained from a spectroscopic imaging slice through the ventricles in seven normal controls are in good agreement with previously published literature values. This method is applied in a patient with secondary progressive multiple sclerosis, showing separate areas of abnormalities in both NAA and Cr.