Magnetic resonance angiography of the rat cerebrovascular system without the use of contrast agents

We describe and discuss the application of three-dimensional (3D) time-of-f light (TOF) magnetic resonance angiography (MRA) to visualize non-invasivel y the cerebral vasculature of the rat. MR angiograms of healthy spontaneous ly hypertensive rats were obtained without the use of contrast agents. Tota l imaging time ranged from 1 to 50 min for a 3D data set. The influences of the data matrix and the inflow delay on the image quality and the total im aging time are assessed and discussed. Varying the inflow delay yielded in addition semiquantitative information on hemodynamics. The method was appli ed to obtain angiograms in rat models of permanent and temporal middle cere bral artery occlusion. Occlusion and reopening of the vessel could easily b e verified by MRA. However, after reperfusion a slight reduction in blood f low was observed. Copyright (C) 1999 John Wiley & Sons, Ltd.