Effect of spatial resolution on Gradient Echo Magnetic Resonance Elastography at 3T
Iron-mediated T2* effects are more prominent in MRE data acquired at 3T compared to 1.5 T, and have been suggested to lead to failure rates of up to 15% for MRE at 3T. MRE based liver stiffness was measured using the QIBA recommendation with a 2D gradient‐recalled‐echo MRE sequence using a 1.5x4.5x10 mm3 acquisition. For comparison, MRE data was also collected at 4.5mm isotropic spatial resolution. A larger voxel volume in the MRE acquisition provided higher SNR which in turn resulted in a higher proportion of voxels being fit for stiffness with confidence >0.95.
Figure: T2* and MRE derived liver stiffness maps shown for the non-isotropic and isotropic MRE protocols for subjects with short (A) and long (B) liver T2*. For MRE, the intersection of ROI and confidence masks are shown, in addition the ROI from the confidence mask of the non-isotropic map is applied to the isotropic map. Participant A, low T2*, has a lower area of confidence for the non-isotropic MRE. In contrast, a larger area of fit confidence was found for isotropic MRE. Participant B with a longer T2* has a similar fit in stiffness values between resolutions.