Assessing changes in tumour vascular function using dynamic contrast-enhanced magnetic resonance imaging

Dynamic contrast-enhanced MRI (DCE-MRI) is widely used in the diagnosis and staging of cancer and is emerging as a promising method for monitoring tumour response to treatment. However, DCE-MR imaging techniques are still evolving and methods of image analysis remain variable and non-standard. and range from relative chances in the pattern of enhancement to pharmacokinetic modelling of contrast agent uptake. The combination of results front different institutions is therefore difficult and the sensitivities of different methods, have not been compared. The purpose of this study is to investigate correlation,, between qualitatative and. quantitative methods of analysis for DCE-MR images from breast cancer patients undergoing neo-adjuvant chemotherapy. Fifteen patients underwent DCE-MRI examinations before and after one course of chemotherapy. Changes in the temporal pattern of signal enhancement. the rate and amplitude of enhancement and the volume transfer constant of contrast agent between the blood plasma and the extravascular extracellular space (EES). K-trans, and the EES fractional volume, v(e), were determined. In addition. hole tumour region-of-interest analysis was compared with histogram analysis to investigate the extent of tumour heterogeneity. It was found that changes in the rate of enhancement correlated strongly with changes in K-trans values (Kendall's tau = 0.68. P < 0.001), Furthermore. it as found that the shape of the signal enhancement curve only changed when the K-trans values changed by 50% or more. Median K-trans values determined following histogram analysis of pixel maps of K-trans were approximately equal to those determined by whole tumour re-ion-of-interest analysis. The absolute change in the K-trans values correlated negatively with the pretreatment values. particularly for responding patients. Thus. for higher pre-treatment K-trans values. a greater decrease as observed. Greater changes were observed in the upper extremes of the K-trans histogram than in the median values after one Course of treatment. Copyright (C) 2002 John Wiley Sons. Ltd.