Eight-Channel Monopole Array Using ICE Decoupling for Human Head MR Imaging at 7 T

Abstract

Due to the unique structure of radiative coil elements, traditional decoupling methods face technical challenges in reducing the electromagnetic coupling of the radiative arrays. In this study, we aim to investigate the possibility of using the recently introduced induced current elimination (ICE) decoupling technique for cylindrical shaped radiative coil array designs. To evaluate the method, an eight-channel transmit/receive monopole array with the ICE decoupling, suitable for human head imaging at 7 T, was built and comparatively investigated. In vivo human head images were acquired and geometry factor maps were measured and calculated to evaluate the performance of the ICE-decoupled monopole array. Compared with the monopole array without decoupling methods, the ICE-decoupled monopole array had a higher signal-to-noise ratio and demonstrated improved parallel imaging ability. The experimental results indicate that the ICE decoupling method is a promising solution to addressing the coupling issue of radiative array at ultrahigh fields.

Optimizing the ICE decoupling element distance to improve monopole antenna arrays for 7 Tesla MRI

“…These simulation results were also validated by experimental results. This finding is also in agreement with our previous work [16]. For D d =0, the monopole elements have high Q values ( Q unlaod / Q load =110/33) [16] and high signal intensity at the peripheral areas.…”

“…This finding is also in agreement with our previous work [16]. For D d =0, the monopole elements have high Q values ( Q unlaod / Q load =110/33) [16] and high signal intensity at the peripheral areas. When no decoupling methods was applied, which can be assumed as D d =∞, the monopole array has a very low Q value ( Q unload / Q load =9.3/3.1) [3] and high signal intensity in the middle of the brain.…”

“…For the ICE-decoupled monopole array, however, the decoupling element is also a kind of radiative antenna and thus has a more significant shielding effect. That effect significantly decreases the B 1 field of the ICE-decoupled monopole array near the decoupling elements, ultimately resulting in dark spots in the MR images [16]. …”

Sensitivity enhancement of traveling wave MRI using free local resonators: an experimental demonstration

“…Unlike the element layout shown in Figure 6 where the two elements were placed orthogonally and thus intrinsically decoupled, when more resonant elements are involved, electromagnetic coupling among elements may become an issue. This coupling issue can be possibly addressed by using the magnetic wall or ICE decoupling technology reported in literatures (24)(25)(26)(27)(28)(29)(30)(31)(32)(33)(34)(35). i.e.…”

A Dedicated 36-Channel Receive Array for Fetal MRI at 3T

“…Due to the need for high signal-to-noise ratio (SNR) in the fast imaging acquisition, the utilization of the phased array receive coils with parallel imaging technology [7]-[12] would be essential for the application of ultrafast MRI sequences. In fetal MRI today, the commercially available torso or abdomen coil array combined with a spine array is used in clinical settings [5].…”