A model of the dual effect of gadopentetate dimeglumine on dynamic brain MR images

An optimized dynamic gradient echo sequence with two echoes is used to obta in data that can be analyzed with indicator dilution theory as well as with pharmacokinetic theory. Taking advantage of the simultaneity of T*(2) and T-1 information, both theories can be employed and merged to interpret cons istently the observed effects of the redistribution of a contrast agent (ga dopentetate dimeglumine) into the tissue from first pass onward. The region al cerebral blood volume (rCBV) and the exchange rate of the contrast agent between the vascular and the interstitial space through the blood-brain ba rrier are analyzed for each pixel in a two-step algorithm. Two values for r CBV are obtained with different weighting for the microvascular fraction of the blood volume. Because the analysis, called PELEAKAN, is capable of sep arating effects related to perfusion (through intravascular blood volume) a nd to leakage in places where the blood-brain barrier is damaged, it is an appropriate tool for evaluating these parameters in brain tumors, and we sh ow clinical examples of this analysis in brain tumor patients. (C) 1999 Wil ey-Liss, Inc.