Earlier this week U.S. News and World Report announced the results of its annual Best Hospitals evaluation.  Of the nearly 5,000 hospitals that were evaluated for the 2011-2012 rankings, 17 qualified for a place on the Best Hospitals Honor Roll, which is reserved for medical centers that demonstrate unusually high expertise across multiple specialties by scoring at or near the top in at least six of 16 specialties.  Heading the Honor Roll are Johns Hopkins Hospital in Baltimore, Md., Massachusetts General Hospital in Boston, Mass., and Mayo Clinic in Rochester, Minn.