Algebraic Rreconstruction for Parallel Imaging with Radial Trajectory

A novel algebraic reconstruction method for parallel imaging with radial trajectory is proposed. Taking advantage of projection-slice theorem, the reconstruction can be performed by first carrying out a 1-D FFT and then iteratively solving a system of linear equations. Since the data in non-Cartesian coordinate are directly used, the bulk work of gridding is not required. The feasibility of this method was demonstrated by simulation.published_or_final_versio

A shielding-based decoupling technique for coil array design

A new decoupling technique which takes advantage of shielding for coil array design is proposed. A ground plane is used to reduce mutual inductance by reducing the effective coupling loop area of circuits; in addition, a "screen track" is placed between adjacent coils to minimize magnetic interferences. This technique requires no modification of circuit and doesnít cause loss of flexibility of coil geometry. Simulation and experiments show that a ground plane beneath surface coils can reduce mutual coupling by 10-20dB, and a "screen track" can further provide a 2-8dB more isolation.published_or_final_versio

Array with multiple loops for vertical field system

For vertical field MRI applications, the structure of the loop array is quite different from those in a horizontal-magnetic-field system. The conventional decoupling techniques are hard to be extended to vertical MRI system. Therefore, the loops for vertical MRI system are quite difficult to decouple. So far the coil array with up to two loop coils have been investigated on open low-field MRI, the array with more than three loop coils is sparsely reported. In this study, we present a decoupling technique using inductors for vertical-field loop coils. A four-channel array consisted of 3 loops and a saddle coil has been built for human knee at 0.5T vertical MRI system.published_or_final_versio

An optimized four-chanel microstrip array at 7T

The microstrip transmission-line (MTL) transmit/receive loop array has been recently developed for MR applications at ultrahigh fields (>4T). In this study, the geometry of transmission-line array, including the substrate thickness and gap between coil elements was investigated by simulation and the capacitive decoupling method was analyzed. Finally an optimized four-channel microstrip loop array was built for 7T.published_or_final_versio

Inductively Decoupled Microstrip Array at 9.4T

In this study, an inductive decoupling technique of microstrip array for ultra high fields has been discussed. The decoupling inductance is nearly independent of resonant frequency. Thus microstrip arrays can be tuned and work well at the magnetic fields higher than 7T. For the prototype of volume array, the introduced inductors can reduce the mutual coupling not only between adjacent elements, but also between non-adjacent elements.published_or_final_versio

Microstrip Loop Array (MLA) for Parallel Imaging

The microstrip loop array (MLA), an improved version of planar strip array, is proposed which take advantage of loop geometry. Without much loss of the well-decoupling benefit of strip line arrays, the proposed microstrip loop arrays have well-localized sensitivity profiles which are more suitable for parallel imaging. Simulation and experiment results show that microstrip loop coils have sensitivity profiles like conventional loop coils, while the mutual coupling is 10-20dB less at same distances. A sensitivity-encoded cardiac imaging was performed to demonstrate the suitability of MLA for parallel imaging.published_or_final_versio

LC decoupling circuit for arbitrarily placed coils

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Digital wireless Transmission for MRI

Analog wireless transmission has been reported for MRI application recently to reduce the interference among the array cables. In this work, we have designed and implemented a new transmission system based on digital wireless technique of WLAN IEEE 802.11b. Frequency Division Multiplexing (FDM) method also is proposed to expand possible more array channels for future MR applications.published_or_final_versio

Tunable loop microstrip (TLM) coil array with decoupling capacitors

The tunable loop microstrip (TLM) coil array with capacitive decoupling circuits can achieve more than -20dB element isolation. The decoupling circuit is quite simple and easy to be adjusted, so it is suitable for array with large number of elements. It is not only used for receive-only mode, but an excellent choice for transceiver as well for parallel MRI.published_or_final_versio

A novel RF coil: tunable loop microstrip (TLM) coil

A new tunable loop microstrip (TLM) RF coil for MRI is presented. It is a novel approach to use tuning capacitor on microstrip ring resonator. The resonant frequency and Q are analyzed based on microstrip theory. The experiment results show its advantages of higher Q and less frequency shift with loading effect than conventional microstrip coils terminated with open or short circuit. Because of its tunable characteristics, this new TLM coil can be easily applied to high and particularly to ultra-high filed MRI systems.published_or_final_versio