Characterizing the imaging environment for supine
breast MRI
We believe that a key aspect of making breast MRI more widely available is to be able to perform the exam with the patient lying on their back (supine), rather than the conventional face-down (prone) position. Supine imaging could improve patient comfort, streamline workflow to achieve shortened exam times, and better match the positioning used in surgery and biopsies. Also, with appropriate hardware - specifically the type of radiofrequency coil that is used to receive the MR signal from the body - we want to show that we are able to push the image resolution and decrease unwanted noise, compared to prone breast MRI.
This present study characterizes several technical challenges associated with supine breast MRI. Based on a study that included both healthy volunteers and breast cancer patients, we found that magnetic field uniformity (B₀ inhomogeneity) worsens in the supine position, potentially affecting image quality. Similarly, the uniformity of the radiofrequency field (B₁⁺) showed greater variation when supine, which could lead to uneven image contrast. We also characterized and measured how much the breast tissue moves during breathing and found substantial motion which would impact image quality, so we need to apply motion-correction techniques. Additionally, breast shape varied significantly among individuals, which has implications for designing imaging equipment tailored for supine positioning. Overall, while supine breast MRI holds great promise, overcoming these technical limitations will be essential to make it clinically viable.
Zimmermann J, Vincent J, Robb F, Daniel BL, Hargreaves BA, Moran CJ. Characterizing the imaging environment for supine breast MRI. Magn Reson Med. 2025;1-13. doi: 10.1002/mrm.70029
Static field inhomogeneities in three example subjects, in the prone (top) and supine (bottom) position. Results show that field imperfections are greater in the supine position, which is valuable information that needs to be taken into account when developing robust imaging sequences for supine breast MRI.
