Magnetic Resonance Imaging (MRI) of the breast has some clear advantages over traditional breast imaging modalities (x-ray mammography and ultrasound). Breast MRI has been shown to be at least twice as sensitive as mammography or ultrasound in detection of breast cancer and can provide true three dimensional volumetric imaging, enabling clinicians to image with exceptional soft tissue contrast for visualization of tumors in the context of the surrounding structures. In 2007 the American Cancer Society announced new surveillance guidelines that include annual MRI screening for women known to be at high risk for breast cancer. As a consequence, many lesions are detected early only by MRI and thus require MRI guided biopsy for diagnosis. There are major barriers to MR Image Guided Biopsy, including the high magnetic field environment of the MRI scanner and inaccessibility of the patient during imaging. The result is that MRI serves to identify the lesions, but the biopsy must proceed blindly outside the bore of the magnet, without real-time image guidance, resulting in higher potential for error, higher biopsy/pathology discordance rates for MRI- guided biopsies and the need to repeat biopsies. The proposed work intends to develop and commercialize an MRI accessory system to enable Magnetic Resonance Image Guided breast Biopsy (MR-IGB) completely inside the bore of the MRI scanner with real-time MR imaging guidance. This Phase-I work will demonstrate the technical feasibility of a compact, multi-axis robotically controlled positioner mechanism that will operate in a high-field, closed bore MRI scanner, as these scanners dominate current breast MRI procedures. The total effort will involve the development of the MRI compatible biopsy mechanism, the precision robotics guidance system, and a Physician Workstation software interface that integrates imaging, robotics control and physician intervention. With the patient positioned in the bore of the MRI scanner, the robotically controlled mechanism will allow an interventionist to plan, monitor, and interactively fine tune the biopsy trajectory for lesions in the highly deformable tissue of the breast. The robotic IGB positioner mechanism will be driven by the interventionist from the remote Physician Workstation where the biopsy trajectory planning, as well as the actual trocar insertion, can be performed under real-time imaging guidance. Development will be streamlined by utilizing a proven breast coil design previously developed by the team, extending previous work on the IGB mechanism design and robotic actuator development, and integrating advanced real-time MRI, scanner control and advanced visualization software platforms developed for other, more rigorous applications. Phase-I testing with a 1.5 T magnet will be done using tissue mimicking phantoms to quantify the operational characteristics of the system, and with normal human volunteers to assess the impact on image quality of robotics actuation during concurrent imaging.
For society, successful demonstration of the potential for significantly improved clinical utility of a new approach for Magnetic Resonance Imaging Guided Interventions (MR-IGI), such as breast biopsies, may result in more efficient and more accurate procedures, lower cost procedures, and potentially improved access for more patients to the superior soft tissue imaging capability of MRI technology. The proposed technology uses MRI compatible robotics, a real-time MRI interface and computer control to enable interventional procedures to be done inside the scanner bore during concurrent imaging and with interactive control of the procedure. The digital nature of the visualization and control technology offers the further potential benefit of long-distance remote control of MR-IGI procedures, thereby broadening the reach of scarce specialized clinical skills to remote and/or underserved populations. Specifically, improved access to the new MR-IGI technology for breast biopsies may increase levels of participation in breast cancer screening. Breast Cancer screening with either mammography or MRI currently represents the most effective means for breast cancer early detection. In time, additional benefits could include less aggressive recommendations for MRI detected lesions and, more importantly, a paradigm shift for breast cancer detection, diagnosis and treatment in general.