The relaxation rates (1/T(1) and 1/T(2)) in cysts have already been analyzed in terms of materials such as albumin, cholesterol, manganese, iron, and copper. However, the relaxivities of these materials have not been determined yet. In this work, five sets containing the ions, albumin, and cholesterol were prepared by addition of increasing concentration of one material to each set. The relaxation times in these sets were measured by MRI, and the relaxation rates were fitted versus concentrations. The slopes of the fits were used as relaxivities. The (r(1), r(2)) values of manganese, iron, and copper in mM(-1) s(-1), and those of albumin and cholesterol in (g/dl)(-1) s(-1) were found to be (32.64, 89.77), (0.31, 1.19), (0.5, 1.479), (0.01, 0.066) and (0.03, 0.458), respectively. The r(2)/r(1) ratio ranged from 2.75 to 15.27. Manganese is an efficient relaxer, but iron and copper are poor ones. Albumin and cholesterol are efficient relaxers for only T(2). The contribution of water associated with native manganese of the cystic fluid to T(1) was 0.268 s(-1), whereas those of water associated with native manganese, albumin, cholesterol, and iron to T(2) were 0.736, 0.185, 0.092, and 0.076 s(-1), respectively. The other contributions were much smaller than 0.076 s(-1). Manganese is most likely the compound altering T(1)-weighted images between different jaw cysts, whereas manganese and albumin are most likely the compounds altering the T(2)-weighted images. Present data suggest that such alterations may be used to separate jaw cysts from other jaw masses. The high r(2)/r(1) suggests that T(2) is a more convenient parameter than T(1) for diagnostic use.
