Mammography can miss tumors in women with dense breasts, so their doctors often include ultrasound or M.R.I. scans. Patients often wind up paying the bill.Mammography can miss tumors in women with dense breasts, so their doctors often include ultrasound or M.R.I. scans. Patients often wind up paying the bill.Read Moreyour-feed-science, Breast Cancer, Tests (Medical), Mammography, Women and Girls, Medicare, Disease Rates, Ultrasonic Imaging and Sonograms, Cancer, Tumors, Preventive Medicine, Centers for Medicare and Medicaid ServicesNYT > Health