Cpnhelp.org

One thing to keep in mind about reading MRIs is that the images they show you are two-dimensional slices. The vein on the right side of the image which the blue arrow is pointing to, for instance, does have a faint place (as pointed to by the arrow), but that is likely just a place where the vein dips out of the particular slice that is being presented. If you looked at the next slice, you might find the dip, and only the dip. (But not necessarily; sometimes there are thin gaps between slices, and since this vein mostly stays in this slice, it might not be visible in the next.) Likewise, the bottoms of the visible portion of the veins, where they fade out, don't represent their disappearance but rather just them going out of this slice.

I don't see much abnormality where the other arrow is pointing. I suppose there's a bit of fading as it goes behind the other vein, but that too could just be going out-of-slice.