Fig. 3

Comparison of lesion morphology of “iron dot” lesions in Susac syndrome (bottom) and multiple sclerosis (top). The figure illustrates differences in morphology on 7T T2*w images between “iron dots” in Susac syndrome (red arrows) and the central vein sign (white and black arrow) as well as T2*w hypointense core lesions (blue arrows with zoom) in multiple sclerosis (MS). All exemplary T2*w images in the bottom are from different Susac patients. Please note that the “iron dots” in Susac syndrome (red arrows) appear punctate and sharply delineated on T2*w. Contrarily, the T2*w hypointense core lesions (blue arrows with zoom) in MS often appear just slightly less hyperintense on T2*w in comparison to other MS lesions. Only when the lesion is viewed on strongly susceptibility weighted sequences (right) does a rather diffuse signal loss become apparent. The central vein sign in MS also appears as a point-like, pronounced hypointensity on T2*w images when the slice plane is perpendicular to the long axis of the MS lesion (white arrow). However, if the slice plane is parallel to the long axis of the lesion, the CVS can be recognized as a straight line running through the center of MS lesions (black arrow)