The number of women using magnetic resonance imaging (MRI) nearly tripled from 2005 to 2009, according to a new study in JAMA Internal Medicine. The study was led by Dr. Karen J. Wernli, an assistant investigator at Group Health Research Institute in Seattle and affiliate assistant professor of health services at the University of Washington School of Public Health. The study is believed to be the first large-scale report of its kind on how women are using breast MRI. Researchers collected data on nearly 9,000 breast MRIs and more than 1.2 million screening mammograms from five national Breast Cancer Surveillance Consortium registries. They found the overall rate of breast MRI for the four-year-period increased from 4.2 to 11.5 examinations per 1,000 women.