Breast
density, which is a representation in mammography of the amount of breast
parenchyma present in the breast, can be assessed on MRI on both T2- and
T1-weighted images. Breasts are characterized using BI-RADS (Breast Imaging
Reporting and Data System) criteria:
1: almost entirely fatty;
2: scattered fibroglandular densities;
3: heterogeneously dense; and
4: extremely dense as with mammography
Unlike
mammography, dense breasts generally do not pose a significant problem on MRI as
contrast is used and thin slices are obtained, thus overlapping parenchyma is
not a hindrance. There are, however, a small set of patients who exhibit very early
rapid enhancement of the parenchyma, which can obscure small enhancing
suspicious foci. In these cases, it may be
helpful to communicate the lowered sensitivity of MRI to the referring
physician.
 |
| (A) MLO Mammography image and (B) Contrast-enhanced MRI breast image. |