Palpation is a basic technique used to detect breast tumors, but it is subjective and qualitative. Mammography on the other hand can provide discomfort to subjects and has poor sensitivity and specificity in detecting tumors in dense breasts [1-3]. Dynamic contrast enhanced MRI has been currently used to detect cancerous tumors; however, it involves injection of contrast agent. Magnetic resonance elastography (MRE), a non-invasive technique to estimate stiffness of soft tissues and has been applied in the breast [4,5]. However, none of the earlier studies have extensively tested MRE to induce vibrations in the breast using a soft sternum driver at higher field strength and its repeatability of stiffness measurements. The aim of the study is to estimate breast stiffness using MRE by inducing vibrations using a soft sternum driver in normal volunteers at 3T and to determine the reproducibility of stiffness measurements. All imaging was performed using a 3T MRI scanner (Skyra, Siemens Healthcare, Germany). Written informed consent was obtained from all volunteers (n=19, women aged: 24-63yrs). Axial slices were obtained using a gradient echo (GRE) MRE sequence. Experimental set up with patient lying on the breast coil face down is shown in figure 1. 60Hz vibrations were introduced through a soft sternum driver that sits on the MRI breast coil as shown in figure 2. Imaging parameters included: FOV=320x320mm2, matrix size=256x256, slice thickness=5mm, number of slices=5, MRE phase offsets=4. Motion encoding gradient of 60Hz was applied separately in the x, y and z directions to encode in-plane and through plane displacement fields. For reproducibility study, after the first scan each volunteer was asked to step out of scanner and repositioned for a repeat scan within 5 minutes while all the imaging parameters remained the same as first scan. MRE images were masked to obtain the breast and a curl processing was performed to remove longitudinal component of motion. Additionally, directional filter was applied to remove the reflected waves. Finally, 3D local frequency estimation was performed to obtain weighted stiffness map using MRE-Lab (Mayo Clinic, Rochester, MN). Figure 3 displays the short-axis magnitude image (a) in one of the volunteers, and snapshot of one of the time points of wave propagation in three spatial directions (b-d) and the corresponding 3D weighted stiffness map (e). Figure 4 shows mean stiffness values of two repeat scans (scan 1 and scan 2) from the center slice in all the volunteers. Mean stiffness of the breast across all 19 normal volunteers was found to be 0.88±0.12 kPa. Figure 5 shows the correlation plot of mean stiffness between scan 1 and scan 2 demonstrating a good correlation with R2=0.82. Preliminary results demonstrate that MRE of the breast is reproducible at higher field strength using a soft sternum driver. This driver demonstrated better wave penetration without the need of contacting the breast. Furthermore, the soft pad (i.e. sternum driver) provided no discomfort to the subjects. Currently, more studies are further warranted for its applicability in diagnosing breast tumors.MRE can be used to estimate the stiffness of breast tissue with good reproducibility at higher field strength and vibrations are introduced using a soft sternum driver without any discomfort to the subjects.