BI-RADS Lexicon for Ultrasound Useful For Differentiating Benign from Malignant Solid Masses

Descriptors from the Breast Imaging Reporting and Data System (BI-RADS) lexicon for ultrasound can be useful in differentiating benign from malignant solid masses, according to a new study by researchers at Duke University School of Medicine in Durham, NC, and supported by the National Institutes of Health.

For the study, the researchers analyzed 403 sonograms of solid masses, 141 of which were found to be malignant at biopsy. Each lesion was described using features from the BI-RADS lexicon for ultrasound. The results were then compared to the biopsy findings. The researchers found that the descriptors were highly predictive for both malignant and benign masses. For malignant lesions, descriptors such as “spiculated margin” were accurate in 86% of the instances, “irregular shape” in 62% and “nonparallel orientation” in 69%. For benign lesions, descriptors such as “circumscribed margin” were accurate in 90% of the instances, “parallel orientation” in 78% and “oval shape” in 84%.

A BI-RADS lexicon has been in use for mammography for a number of years and, according to the authors, has greatly improved the organization of mammography reports. The BI-RADS lexicon for ultrasound was published more recently, and radiologists are only now beginning to gain experience using this lexicon on a daily basis.

“It is important for radiologists making decisions about biopsy recommendations to base those decisions on science rather than gestalt. For example, we are taught in general that margins that appear circumscribed at ultrasound are generally seen with benign masses. While this is true in general, our study showed that 10% of masses with circumscribed margins at sonography were malignant. Therefore, circumscribed margins alone would not be sufficient to skip a biopsy of a circumscribed mass,” said Jay A. Baker, MD, one of the authors of the study.

According to the study authors, this information is valuable for counseling patients. “By evaluating the morphology of a particular mass, a radiologist can use the data from this study to either reassure a woman who has a mass with benign features that the biopsy is likely to be benign or to more confidently advocate a biopsy in a reluctant patient who has a mass with more worrisome features,” said Dr. Baker.

The study appears in the April 2005 issue of the American Journal of Roentgenology.