Comparison of the Standard Gadolinium Concentration and Signal Difference Methodologies for Computation of Perfusion Parameters in DCE-MRI at Various SNRs

Introduction: In standard DCE-MRI, T1-weighted images are acquired rapidly during gadolinium contrast injection, and the concentration [Gd] in tissue is estimated based on the measured T1s, from which the tumor perfusion parameters can be computed. Since the time-intensity curve first needs to be normalized to the pre-contrast signal, noisy baselines can lead to measurement biases. Recently, methods to compute perfusion without the need to first compute T1 or gadolinium concentration have been reported (1-3). The technique is based on the observation that the signal difference, after pre-contrast value is subtracted, is approximately proportional to [Gd]. Since normalization (division) by the baseline signal is unnecessary, the latter method for computing perfusion may be more robust in the presence of increased noise levels. The goal of this work is to systematically investigate the performance of the signal difference technique and compare it to the conventional method for computing perfusion under various image SNRs.