Identification of breast calcification using magnetic resonance imaging

MRI phase and magnitude images provide information about local magnetic field variation (DeltaB0), which can consequently be used to understand tissue properties. Often, phase information is discarded. However, corrected phase images are able to produce contrast as a result of magnetic susceptibility differences and local field inhomogeneities due to the presence of diamagnetic and paramagnetic substances. Three-dimensional (3D) susceptibility weighted imaging (SWI) can be used to probe changes in MRI phase evolution and, subsequently, result in an alternate form of contrast between tissues. For example, SWI has been useful in the assessment of negative phase induced DeltaB0 modulation due to the presence of paramagnetic substances such as iron. Very little, however, has been done to assess positive phase induced contrast changes resulting from the presence of diamagnetic substances such as precipitated calcium. As ductal carcinoma in situ, which is the precursor of invasive ductal cancer, is often associated with breast microcalcification, the authors proposed using SWI as a possible visualization technique. In this study, breast phantoms containing calcifications (0.4-1.5 mm) were imaged using mammography, computed tomography (CT), and SWI. Corrected phase and magnitude images acquired using SWI allowed identification and correlation of all calcifications seen on CT. As the approach is a 3D technique, it could potentially allow for more accurate localization and biopsy and maybe even reduce the use of gadolinium contrast. Furthermore, the approach may be beneficial to women with dense breast tissue where the ability to detect microcalcification with mammography is reduced.