Phase-based arterial input function measurements in the femoral arteries for quantification of dynamic contrast-enhanced (DCE) MRI and comparison with DCE-CT.

Dynamic contrast-enhanced (DCE) MRI is useful for diagnosis, treatment monitoring and follow-up of prostate cancer. However, large differences have been reported in the parameter range of the transfer constant K(trans) , making longitudinal studies and comparison of DCE-MRI findings between studies difficult. Large part of this inconsistency in K(trans) values can be attributed to problems with the accurate measurement of the arterial input function (AIF) from the magnitude signal (AIF(MAG) (N) ). Phase-based AIF measurements (AIF(PHASE) ) have been proposed as a more robust alternative to AIF(MAG) (N) measurements. This study compares AIF(PHASE) with AIFs measured with DCE-CT (AIF(CT) ), and the corresponding K(trans) maps in 12 prostate cancer patients. The shape of AIF(PHASE) and AIF(CT) are similar, although differences in the peak height and peak width exist as a result of differences in injection protocol. No significant differences in K(trans) values were found between the DCE-MRI and DCE-CT exams, with median K(trans) values of 0.10 and 0.08 min(-1) for healthy peripheral zone tissue and 0.44 and 0.36 min(-1) for regions suspected of tumor respectively. Therefore, robust quantification of K(trans) values from DCE-MRI exams in the cancerous prostate is feasible with the use of AIF(PHASE) .