CHICAGO—MRI has outrun other modalities in a screening trial involving high-risk women. Such research helps justify an estimated $1.4 billion a year in direct costs for the United States if new American Cancer Society guidelines (see box on page 33) are followed.
At the 2007 RSNA annual meeting, Lily Kernagis, MD, a fellow in women's imaging at the University of Pennsylvania, presented results of a large prospective study comparing screen-film mammography, digital mammography, whole-breast ultrasound, and contrast-enhanced MRI in a screening population of 569 high-risk asymptomatic women. All participants had had a negative mammogram and negative physical exam.
High-risk was defined as including the following risk factors:
• A 25% lifetime risk based on genetic testing, Gail or Claus models.
• Diagnosis of lobular carcinoma in situ, atypical ductal hyperplasia, or atypical lobular hyperplasia.
• Exposure to radiation prior to puberty.
• History of cancer in the contralateral breast.