Using medical imaging to diagnose and treat stroke leads to better outcomes and shorter hospital stays, which yields a net economic benefit of about $8 billion over 10 years.
Johnston, S. Claiborne, John Rootenberg, Sarosh Katrak, W.S. Smith, and Jacob Elkins. Effect of a U.S. National Institute of Health Programme of Clinical Trials in Public Health and Costs. The Lancet. April 22, 2006; 367: 1319-27. http://www.ncbi.nlm.nih.gov/sites/entrez?cmd=retrieve&db=pubmed&list_uids=16631910&dopt=AbstractPlus