A new approach to analysis of the impulse response function (IRF) in dynamic contrast-enhanced MRI (DCEMRI): a simulation study.

The purpose of this research was to develop a novel numerical procedure to deconvolute the arterial input function (AIF) from contrast concentration vs. time curves and to obtain the impulse response functions (IRFs) from dynamic contrast-enhanced MRI (DCEMRI) data. Numerical simulations were performed to study variations of contrast concentration vs. time curves and the corresponding IRFs. The simulated contrast media concentration curves were generated by varying the parameters of an empirical mathematical model (EMM) within reasonable ranges based on a previous experimental study. The AIF was calculated from plots of contrast media concentration vs. time in muscle under assumption that they are well approximated by the "two-compartment model" (TCM). A general simple mathematical model of the IRF was developed, and the physiological meaning of the model parameters was determined by comparing them with the widely accepted TCM. The results demonstrate that the deconvolution procedure developed in this research is a simple, robust, and useful technique. In addition, "impulse response analysis" leads to the derivation of novel parameters relating to tumor vascular architecture, and these new parameters may have clinical utility.