AN INVERSE METHOD TO DESIGN RF COILS WITH ARBITRARY CONDUCTOR PATTERNS FOR MRI SYSTEMS

Radio-frequency (RF) coils are used to pick up signals in the magnetic resonance imaging (MRI) systems. This paper presents an inverse design approach of RF coils with arbitrary conductor patterns to optimize the signal-to-noise ratio (SNR) at a point of interest. The source current is assumed to distribute in a specified plane area or a cylinder surface. Based on magnetic dipoles, it can be considered as a weighted current combination of an array of base coils. A single circular loop base coil is added in the array for the cylinder case to emulate the loop currents around cylinder. To achieve the best SNR at a given point in the object, the currents in the base coils are optimized and continuous current density distributions are then derived. By this method, the ultimate intrinsic SNR for various points inside a cylindrical object is estimated, and the method to evaluate the SNR performance of RF coils is discussed.