Metabolite images are produced with an MRI system using a priori information about the resonant peaks of the metabolites and their relative sizes to reduce the amount of NMR data needed for proper spectral resolution. A guide assembly of the apparatus includes opposed first and second channels facing one another for guiding the object in the machine direction, with the channels extending upwardly to thereby define an uphill path of travel for the object. Each slide member is both pivotally and slidingly engaged with the horizontal platform, and each slide member has a normally horizontal position.