The need for mechanical standardisation of mammographic compression

A study just published in the European Journal of Radiology (EJR), (Branderhorst W et al. Mammographic compression – a need for mechanical standardization. Eur J Radiol. 2014;doi: 10.1016) .compared mammographic compression in sites in the Netherlands and the United States and concluded that calculating and tracking compression pressure could help standardize mammography quality and patient experience. The lack of consistent guidelines regarding mammographic compression has led to wide variation in its technical execution. Breast compression is accomplished by means of a compression paddle, resulting in a certain contact area between the paddle and the breast, which can result in varying levels of discomfort or pain. On current mammography systems, the only mechanical parameter available in estimating the degree of compression is the physical entity of force (daN). Recently it has been suggested that pressure (kPa), resulting from a specific force divided by contact area on a breast, might be a more appropriate parameter for standardisation.



The recent study, involving a total of 44000 screening and diagnostic mammographic images, investigated whether the compression protocols could be improved by standardization of pressure (kPa) as an objective parameter.  All images were analysed using VolparaAnalytics and VolparaDensity software, so that average force, pressure, breast thickness, breast volume, volumetric breast density and average glandular dose as a function of the size of the contact area between the breast and the paddle could be compared between populations. A large variation in compression was observed for the Dutch and U.S. datasets and statistically significant differences were observed for the mean forces and pressures used in both the Dutch and U.S. datasets.  As a result of the lack of standardisation, extreme pressures were observed in both datasets, resulting 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.  I expect that this will enable the industry to enhance quality control of mammographic compression procedures and help maintain exam quality and patient comfort,” said Gerard J. den Heeten, LRCB Dutch Reference Center for Screening, Nijmegen, The Netherlands. 

Volpara Solutions , Wellington, New Zealand