Abstract
T1 relaxation values of rat liver and spleen tissue were measured over 6 mo. while feeding with [the carcinogen] p-dimethyl-aminoazobenzene (DAB). Measurements of tissue water and Fe content also were made. A small rise in liver T1 value during the early stages of DAB feeding, from a control value of 296 .+-. 12 ms to 318 .+-. 12 ms after 3 wk, probably reflected toxic reaction to the diet rather than preneoplastic changes. Spleen T1 value showed a considerable decreased over this same period, from a mean control value of 505 .+-. 14 ms to 394 .+-. 21 ms after 3 wk on the diet. The possible origins of this change are discussed.