Abstract. The initial area under the gadolinium curve (IAUGC) is often used in addition to or as an alternative to parameters derived from pharmacokinetic modelling of T₁-weighted dynamic contrast-enhanced (DCE) MRI data in the assessment of response to treatment of cancer. However, the physiological meaning of the IAUGC has not been rigorously defined with respect to model-based parameters. Here, simulations of DCE-MRI data were used to investigate the relationship between IAUGC and the parameters K^trans (transfer constant), v_e (fractional extravascular extracellular volume) and v_p (fractional plasma volume), using two vascular input functions. It is shown that IAUGC is a mixed parameter that can display correlation with K^trans, v_e and v_p and ultimately has an intractable relationship with all three. Furthermore, it is demonstrated that the range over which IAUGC is taken and the nature of the vascular input function do not significantly affect this relationship.

Print publication: Issue 14 (21 July 2006)
Received 1 March 2006, in final form 25 May 2006
Published 6 July 2006