1. Women currently undergoing treatment for breast cancer, or planning surgery for a high-risk lesion (ADH, ALH, LCIS, papilloma, radial scar).

2. Women who have had the following are not eligible:

1. a mammogram less than 11 months prior to study entry.
2. screening breast ultrasound within 11 months prior to study entry.
3. breast MRI less than 36 months prior to study entry.
4. contrast-enhanced spectral mammography less than 36 months prior to study entry.
5. molecular breast imaging (MBI) less than 36 months prior to study entry.
6. breast prosthetic implants (silicone or saline).
7. suspected of being at high-risk for breast cancer, as defined by the ACS breast MR screening recommendations (lifetime risk of ≥20%-25%) unless they are unable to undergo an MRI. (Reference Appendix I)
8. a history of sickle cell disease.

3. Women with known or suspected renal impairment. Requirements for glomerular filtration rate (GFR) determination prior to IV iodinated contrast administration are determined by local site standard practice. Criteria that should be considered include, but are not limited to, the following:

Age >60 years old

History of renal disease, including dialysis, kidney transplant, single kidney, renal cancer, and renal surgery

History of hypertension requiring medical therapy

History of diabetes mellitus

Use of metformin or metformin-containing drug combinations

4. Women who are pregnant, breast feeding, or planning to become pregnant from screening until 30 days after the last administration of Omnipaque (iohexol).

5. Large breasted women that require multiple images per standard view of the breast (Tiling) as determined by their most recent mammogram.