Figure 4.

A representative collage of Gd-DTPA and Gd-BSA-Evans Blue (EB) enhancements during MRI, corresponding T_1sat maps and fluorescence images from one experiment. A – Gd-DTPA enhancement in a rat 24 hours after 3 hours of MCA occlusion. A large area of brightness is seen in the preoptic area and striatum. The small, bilateral, bright regions below this enhancement are parts of medium eminence and hence, naturally leaky. Contrast enhancement in such regions, ventricles (large arrows), and pial vasculature surrounding the brain were routinely observed. B – Subsequent Gd-BSA-EB enhancement in this rat. It is a much smaller area. Other normally leaky regions are also visible. In C, the T_1sat map for this slice is shown in gray scale. On the calibration bar on the left, hyperintense/bright areas indicate increased values. The ventricles and circumventricular organs appear bright on this map due to the inherent sensitivity of T_1sat to water/proton shifts. The low-magnification, reconstructed fluorescence image shown (D) has extravascular red fluorescence in the same regions of interest as the Gd-BSA-EB–enhancing area in B. The greenish-yellow hue in the rest of the vasculature is due to the combination of red (EB) and green (fluorescein isothiocyanate–dextran) fluorescence. This image was constructed by collecting the coronal brain section as a series of low magnification (X2.5) images and tiling them together. (From Nagaraja et al. Stroke. 2008;39:427-432).