Limiting breast compression during biopsy is recommended, except when clinically necessary, as it affects breast lesion detection, lesion size, and dynamic contrast-enhanced MRI interpretation and performance, according to a study published online Mar. 12 by Radiology.

Breast compression, which is especially important to MRI-guided biopsy, is used to minimize motion artifacts and improve image quality. However, research on how compression influences breast lesion enhancement and interpretation of dynamic contrast-enhanced MRI images is scarce. Lead author Riham H. El Khoull, MD, PhD, of the Johns Hopkins University School of Medicine in Baltimore, and colleagues investigated breast compression’s effects on cancer masses, glandular tissue enhancement, and MRI quality in identification and characterization of lesions.

The retrospective study included 300 MRI exams from 149 consecutive patients who underwent MRI-guided biopsy and diagnostic MRI. The researchers calculated breast compression as a percentage relative to the noncompressed breast. The following elements were evaluated: breast density, lesion type, lesion size, percentage compression, and kinetic curve type.

Khoull and colleagues discovered that the mean percentage compression was 31.3 percent. Percentage enhancement was higher in noncompressed breasts, at 146 percent, than compressed breasts at 107 percent. Of the breast lesions, 12 percent were significantly smaller when compressed, which lead to underestimation of their classifications. Breast masses exhibited significantly higher early percentage enhancement (157 percent) than lesions with non-masslike enhancement (120 percent). Percentage enhancement difference was also significantly higher for breast masses at 47.5 percent versus 17 percent for lesions with non-masslike enhancement.

Importantly, kinetic curve performance for identifying invasive cancers decreased after compression. Underestimation of lesion size was seen after compression in 80 percent of the study’s cases. Breast compression caused complete loss of enhancement in 4 percent, or nine of the 210 lesions.

“Owing to the wide variation in the applied compression with the lack of a quantitative method to assess and apply compression in a standard manner, we recommend limiting breast compression application to situations where compression is indicated clinically, such as for biopsy and clip placement,” wrote the authors.