Hi John,

I have no idea how the difference in versions of Mathematica could play a role. Actually this should not be like this. Looking into the DICOM-header of your file using

dcmHeader = Import["https://dl.dropboxusercontent.com/u/68983831/46405725", "MetaInformation"];

makes me believe that somehow this file is corrupt. One can still see a lot of information, e.g. that the data were acquired by a Siemens MR Verio, but there also seems to be a lot of unreadable garbage in there - but I may be wrong.

Anyway, you can extract (or at least I could extract) a better image by importing as "Data" or as "Graphics":

PS: My System:

In[53]:= $Version    
Out[53]= "10.2.0 for Linux x86 (32-bit) (July 6, 2015)"

Regards -- Henrik

Hm... okay... I have no idea, sorry. I get the same image as your Mathematica 10.2 output (using 10.3, Windows 10), so at least it looks like a general problem (as opposed to just a strange setting or graphics issue in some part of your system). Perhaps you can convert the image to a different format in another application, but that's probably not what you want. You could also try playing around with contrast settings and other image processing functions, although I'm not sure you'd get a solution that will work for future images without adjustment. Sorry I can't be of more help here.