Extracting parametric images from dynamic contrast-enhanced MRI studies ofthe brain using factor analysis

Factor analysis of dynamic studies (FADS) is a technique that allows struct ures with different temporal characteristics to be extracted from dynamic c ontrast enhanced studies without making any a priori assumptions about phys iology. These dynamic structures may correspond to different tissue types o r different organs or they may simply be a useful way of characterising the data. This paper describes a method of automatically extracting factor ima ges and curves from contrast enhanced MRI studies of the brain. This method has been applied to 107 studies carried out on patients with acute stroke. The results show that FADS is able to extract factor curves correlated to arterial and venous signal intensity curves and that the corresponding fact or images allow a distinction to be made between areas of the brain with no rmal and abnormal perfusion. The method is robust and can be applied routin ely to dynamic studies of the brain. The constraints described are sufficie ntly general to be applicable to other dynamic MRI contrast enhanced studie s where an increase in contrast concentration produces an increase in signa l intensity. (C) 2001 Elsevier Science B.V. All rights reserved.