"My breasts were very very dense where a mammogram was difficult to read," said Ostrowski.
A new study in the Journal of the American Association has important suggestions for women like Bonnie Ostrowski.
In 2001, Bonnie's mammogram detected no cancer. But her doctor decided she needed to undergo another type of screening test.
"So we did a screening ultrasound and did find a mass in the left breast," said Dr. Wendie Berg.
An ultrasound revealed a small irregular mass on her left side. And a biopsy confirmed she had invasive breast cancer.
"The cancers can be hidden by the normal breast tissue. It has been likened to find a polar bear in a snow storm," said Dr. Berg.
Johns Hopkins' Dr. Wendie Berg analyzed just how effective ultrasound can be. As part of their study they recruited more than 2,000 women. Each had dense breast tissue and each underwent both mammography and ultrasound.
"We found that overall mammography did pretty well. But it did miss a large number of cancers," said Dr. Berg.
Forty women were diagnosed with cancer and 20 of those cancers were revealed with mammography. When ultrasound was added to mammography 12 more cancers were revealed. Although eight cancers went undetected with both.
"The overall performance of mammography we have had an accuracy of 78 percent. If we added ultrasound to that the overall accuracy was much better at 91 percent," said Dr. Berg.
Bonnie's cancer was caught early. She's been cancer free for seven years.
"I really do believe that the ultrasound did save my life," said Ostrowski.
Researchers say a screening ultrasound is meant to supplement a mammogram not replace it, because there are so many cancers that are not seen on ultrasound.
Also you need to know that ultrasound screening increases your chance of a false positive exam result which can lead to unnecessary biopsies.
The Journal of the American Association contributed to this report.