High resolution in vivo imaging at high frequencies with improved surface coils

The enhancement of the spatial resolution with an optimised surface coil design for MR imaging of small structures at high frequencies is presented. Surface coils provide high signal-to-noise ratios (SNR) which allow to improve the spatial resolution. However, their sensitivity is limited to the region adjacent to the coil where the B₁ field distribution is more homogeneous. The authors present an inductively coupled series-tuned circular coil prototype, optimised for ¹H MR imaging at 200 MHz. The inductively coupled scheme provides a good SNR by reducing the different losses mechanisms. Preliminary images, acquired on a Bruker BIOSPEC-BMT 47/40 working at 4.7 T, have been realised over a rabbit knee. Images depict a high spatial resolution, an excellent B₁ field homogeneity and no `hot spots´