What you fail to grasp is that small Tesla coil is so much easier to smuggle into areas where Tesla coils are otherwise prohibited. Fitzsimmons et al reported using receive-only surface coils, designed to image the neck region, to provide high-quality MR images for low-field strength systems. Conceptually, we can put any kind of packaged food we want in there, said Keener, an associate professor in the coilsz. Department of Food Science. This is commonly called choke and is used to pass direct current while offering high opposition to alternating current. What some imaging systems are able to accomplish with the use of surface coils, others may achieve with selected pulse sequences or magnetic field gradients.