The present invention relates to methods for imaging annulus fibrosus tissue and a quantitative measurement of its local concentration in a sample using an agent comprising the compound of Formula I, a 13C or 2H enriched compound of Formula I, an 19F-labeled derivative of Formula I, a metal-DOTA complex of Formula I, or a radioisotope derivative of Formula I. Second stopper face is provided on a tooth portion of a click piece. The picture element groups from a sequence of a predetermined number of successive picture elements each define individual partial code words, existing exactly once within the code word. Methods for making the fluorescent nanoparticle are also described. In an alternate embodiment, the wands are comprised of several pieces of wand material interconnected to one another, such that the wand can be collapsed for consolidation and storage when not in use.