Inverse design of a phased‐array coil for breast magnetic resonance imaging

Abstract

Breast magnetic resonance imaging (MRI) is a very useful tool for human breast cancer detection and the advance of dedicated RF coil technology is essential for enhanced image quality. In this work, we propose an efficient, hybrid algorithm for the inverse design of a phased array coil for breast MRI. The design method starts with the specification of the desired RF (B 1 ) field within a predefined region, using the so-called target-field technique, followed by a streamline function method to find the initial coil winding by discretizing the calculated continuous current density. Then, a deformation approach is used to further optimize the coil shape by adjusting the coordinates of the selected control nodes on the coil contours; in this step, an iterative optimization algorithm is employed to minimize the cost functions that are mainly focused on the B 1 homogeneity and coil inductance. A two-element array breast coil has been designed using this method. The simulated and experimental results presented herein demonstrate the potential of the proposed design technique to produce low-inductance coil structures with improved RF field.

Inverse design of an organ-oriented RF coil for open, vertical-field, MR-guided, focused ultrasound surgery

“…The M and N in the series representations in Eq. (8) were set as M=N=9, which should be sufficient in terms of the accuracy of the solutions [11,20]. The coefficient λ was set as λ≈10 − 5 to keep the condition number of the matrix at the 10 9 level.…”

“…Fujita et al [7] directly gave the expressions according to their experiences with and to the principles of MRI [7]. Lawrence et al [8], While et al [9,10] and Li et al [11] all gave the expressions according to the requirements of their research. In the current study, the expressions were given according to a strictly analytical deduction from the stream function, which was related to the coil windings.…”

“…However, in engineering, it is impractical to construct an RF coil exactly according to the coil windings shown in Fig. 3 because of the high inductance of the structure [11,14]. The asteroid winding pattern (in red color in Fig.…”

“…Substituting (9), (10), (11), and (12) into (1), the solutions of F that were related to the coefficient matrix were obtained. Usually, Eq.…”

“…They developed the inverse methods to design an RF coil in a high field. Moreover, Li et al [11] reported a specialized phasedarray breast coil that was successfully designed with the inverse technique. All of these reports have shown the successful applications of the inverse technique in the RF coil design.…”