The study was terminated as the PI left the institution.

Magnetic resonance imaging (MRI) is commonly used for the detection of breast lesions in genetically high-risk women due to its high sensitivity. As non-cancerous conditions including normal changes due to a woman's menstrual cycle may have the appearance of cancer on MR images, a biopsy (generally performed under ultrasound-guidance) of the suspicious mass is required for definitive diagnosis. However, only a limited percentage of MRI-visible lesions are also visible on ultrasound (US). Even if found, it is often unclear whether the lesion identified on US corresponds to the MRI-detected lesion in question. The investigators have developed a visualization tool to assist the visualization of MRI-detected lesions in US-guided procedures (e.g., biopsy). This tool provides a simultaneous display of the previously acquired MRI data alongside real-time US images. The investigators propose a pilot study to assess the usefulness of this tool in identifying MRI-detected lesions using real-time US-guidance.

Inclusion Criteria:

• Patients with MRI-identified lesions that cannot be visualized under the second-look ultrasound examination, and who will undergo the recommended unilateral MRI follow-up.

Exclusion Criteria:

• US-visible lesion.
• Any contraindications to MRI (e.g., pacemakers, metal implants).
• Any contraindications to US imaging.
• Pregnancy.
• Claustrophobia.
• Inability to lie still for 45 minutes-1 hour.
• In excess of 250 pounds.
• Incapability to provide informed consent.

Patients clinically suspicious for breast cancer will undergo the standard bilateral MRI protocol, with the patient in the prone position and both breasts immobilized. Patients with a BIRADS reading of 4 or 5 based on the initial MRI are called back for a second-look US examination to determine if the lesion can be found using US imaging. If the lesion is occult to US during this second-look examination, the radiologist may recommend a follow-up high-resolution unilateral MRI to further characterize the lesion.

For this feasibility study, 10 patients with MRI-identified lesions that cannot be visualized under the second-look ultrasound examination, and who will undergo the recommended unilateral MRI follow-up will be asked to participate in our research study.