In the United States, breast cancer is the most common cancer in women, and is the second leading cause of cancer deaths among women (American Cancer Society). The current clinical standard to screen for breast cancer is X-ray-based mammography; however, several clinical studies have shown that MRI has much higher sensitivity for detecting cancer, especially in women who are at elevated risk for developing breast cancer. But, MRI is the more complex exam and comes at a much higher cost, which are the key reasons why it currently cannot be offered to all women.

Scientists in our group, in close collaboration with breast clinicians at Stanford Clinics, have made substantial and impactful contributions to the development of breast MRI techniques. Our ongoing research includes breast imaging at higher spatial resolution to better depict tumor features, faster data acquisition to reduce the overall time in the scanner, as well as enabling contrast-injection-free imaging.

Current breast MRI research in our group focuses on two main areas:

• Breast MRI without the injection of contrast (Diffusion-weighted MRI)

Breast cancers in MRI are shown by injecting a contrast agent, typically a Gadolinium-based substance. This method is referred to as Dynamic Contrast Enhanced (DCE) MRI. Because of the increased and "leaky" blood supply to the tumor, the tumor becomes brighter than the healthy tissue soon after injection.  Advanced methods are necessary to image quickly enough to resolve the brightness changes with high image resolution.

Alternative MRI methods to assess breast cancer include T2-weighted imaging and diffusion-weighted imaging (DWI). We are exploring faster and sharper techniques to acquire these images. These methods do not require injection of a contrast agent, so may offer cheaper and wider access to MRI for many patients.

• Breast MRI with the patient laying on their back (Supine patient positioning)

During a breast MRI exam, the patient typically lays on her stomach in a position that is very uncomfortable for the patient, and it limits the sensitivity, consistency, and resolution of the imaging. Also, it limits access to a breast MRI exam for some women who are physically not able to lay in this position inside the MRI scanner. We develop methods to enable MRI with the patient laying on her back and propose that we can achieve higher image quality and improve diagnostic accuracy of detecting breast cancer even more. Supine positioning is much more comfortable for the patient, and it is also much more relevant when breast MRI images are used to guide interventional procedures (e.g. breast biopsies), which are mostly done with the patient laying on their back.