Rapid MR Susceptibility Imaging of the Brain Using Segmented 3D Echo-Planar Imaging (3D EPI) and its Clinical Applications

MR susceptibility imaging (e.g., T2*, SWI, QSM) is a powerful tool for imaging blood vessels, hemorrhage, calcifications, and iron deposition in the normal and diseased brain with exquisite detail. To obtain such images at high resolution, very long image acquisition times are typically needed when using the conventional 3D gradient-echo sequence. Using a novel acquisition strategy called segmented (or multi-shot) 3D echo planar imaging (3D EPI)1, we have found that MR susceptibility images can be produced with high resolution and no loss in diagnostic clarity. Our experience at the NIH across the range of field strengths indicates that the 3D EPI acquisition may be used to obtain very short scan times (1–3 min) at standard image resolutions or to increase the resolution to obtain submillimeter isotropic images in scan times on the order of 5–6 minutes. The ability to perform 1 WIP, the product is currently under development and is not for sale in the US and in other countries. Its future availability cannot be ensured. Figure 1: 3D EPI sequence diagram and its corresponding k-space trajectory. 1