Calculating and tracking compression pressure could help standardize mammography quality and patient comfort, according to a study published in the European Journal of Radiology.
The article, “Mammographic compression – A need for mechanical standardization,” compared mammographic compression between sites in the Netherlands and the United States. Specifically, researchers used VolparaAnalytics from Volpara Solutions to compare average force, pressure, breast thickness, breast volume, volumetric breast density and average glandular dose between patient populations.
According to the study, there is a current lack of consistent guidelines regarding mammographic compression, resulting in wide variation in its technical execution. Furthermore, breast compression is accomplished by means of a compression paddle, which involves a particular contact area between the paddle and the breast, leading to different levels of discomfort or pain. The sole mechanical parameter available in estimating the degree of compression is the physical entity of force (daN).
However, researchers have suggested that pressure (kPa), resulting from a specific force divided by contact area on a breast, might be a more appropriate parameter for standardization. For example, although a large breast requires more force to compress and a small breast requires less force, optimal compression pressure should be similar for all breast sizes, according to the study.
Exploring whether the compression protocols could be improved by standardization of pressure (kPa) as an objective parameter, the study compared the current compression practice in mammography between two sites in the Netherlands and one in the United States. The Dutch dataset included 37,518 screening mammographic images (from 9,188 women) obtained from the Dutch national breast cancer screening program. The U.S. dataset included 7,171 screening and diagnostic mammographic images (from 1,851 women).
Large variation in compression was observed for the both countries’ datasets, with relative standard deviations of 19.6% and 41.9% for force and 43.1% and 50.6% for pressure, respectively. Significant differences (p<0.001) were observed for the mean forces and pressures used in both datasets. Furthermore, both datasets contained extreme pressures due to the lack of standardization; this resulted in an inability to predict the compression pressure for a given individual.
“Now that software like VolparaAnalytics, which enables device-independent cross-comparisons of key mammographic metrics between patient populations, has become available, we may be able to better standardize mammographic compression, which could decrease variation and improve reproducibility, minimize unnecessary pain, and reduce radiation dose and inadequate image quality,” said Gerard J. den Heeten, LRCB Dutch Reference Center for Screening, Nijmegen, The Netherlands.
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