Nienke Lynn Hansen MD, Presenter: Nothing to Disclose

Simone Schrading MD, Abstract Co-Author: Nothing to Disclose

Christiane Katharina Kuhl MD, Abstract Co-Author: Nothing to Disclose

Mammographic breast density is coded in order to communicate the likelihood with which a cancer can be obscured by breast parenchyma. Recently, the same has been suggested for breast MRI, where background enhancement is rated. We investigated whether mammographic breast density (ACR-category) and MR-breast “density” (MR-ACR) correlate.

A total 468 women (mean age 55.7 years, range 26-89 years), underwent standard full field digital mammography and dynamic contrast enhanced breast MRI in our institution within 6 months. Mammographic breast density was scored according to the ACR-classification; background enhancement in MRI was scored on a 4-point-scale from absent to severe (MR-ACR). Patients who received hormonal replacement or anti-hormonal therapy or who had had chemotherapy within the last six months were excluded. Breast density classes were compared by analyzing the differences between ACR scores for mammography and MRI. In addition, scores were grouped as ‘not dense’ (ACR and MR-ACR 1-2) and ‘dense’ (ACR and MR-ACR 3-4). The Spearman coefficient was used for rank correlation.

MR-ACR and ACR scores were identical in 19% of women (90/468), but differed in 81% (378/468). A deviation by one score point was observed in 33% (157/468), deviation by 2 score points in 38% (179/468), and by 3 score points in 9% (42/468) of patients. When dichotomizing the data into “non-dense” vs. “dense” classes, 23% (112/468) were concordantly scored as “non-dense” by both methods, and 16% were concordantly rated as “dense”. In the remaining 281 patients (60%), the attribution to “dense” or “non dense” classes did not match. Absence of correlation was confirmed by a Spearman rank of 0,356.

Mammographic breast density does not correlate with MR-breast “density” (background enhancement). Even the gross classification into “dense” vs. “non-dense” does not match in the majority of women. In other words: A breast that appears “dense” (difficult to read) in one imaging method may well appear as “non-dense” (easy to read) in the other.

A woman’s breast MRI “density” (degree of background enhancement) cannot be predicted based on a woman’s mammographic fibroglandular tissue appearance.

Hansen, N, Schrading, S, Kuhl, C, Does Mammographic Breast Density Correlate with MR Breast “Density” (Background Enhancement)?.  Radiological Society of North America 2012 Scientific Assembly and Annual Meeting, November 25 - November 30, 2012 ,Chicago IL. http://archive.rsna.org/2012/12027319.html