Hi Paul,

The somewhat random collection of labeled brain scans was put together by David Kennedy starting in 1996 at the Center for Morphometric Analysis (Massachusetts General Hospital).  I did the web site (which now redirects to NITRC).  It was not easy to convince the PIs of the various studies to give away their expensive results for nothing.  It took weeks of work to label each scan.  One of the stipulations was that not much information was to be given about the scans so all there is to know can be found in the associated README files.  The scans were from various studies, but all, as far as I know, came from the same couple of scanners.  

Andy.