Specific absorption rate study for radiofrequency current density imaging using a two-dimensional finite element model

Radiofrequency current density imaging is an MR technique that images tissu e conductivity contrast. Compared to conventional MRI, RF-CDI uses two addi tional sources of RF power to be absorbed and that must be evaluated in ter ms of proper parameter optimization to prevent excessive tissue heating and effects on the nervous system. In view of possible future clinical use of RF-CDI, a simple 2D finite element model of a rat brain was built to simula te current density distribution and distribution of absorbed RF power, i.e. , SAR and related tissue heating. Current density in the rat brain was also evaluated qualitatively and quantitatively in an in vivo RF-CDI experiment . The results demonstrate that a numerical model can predict SAR and tissue temperature changes. The study also shows that substantial sensitivity and resolution of RF-CDI can be achieved using imaging parameters that produce SAR and temperature changes within allowed limits. (C) 2000 Wiley-Liss, In c.