Closely Spaced Double-Row Microstrip RF Arrays for Parallel MR Imaging at Ultrahigh Fields

Yan, Xinqiang; Xue, Rong; Zhang, Xiaoliang

doi:10.1007/s00723-015-0712-1

Cited by 10 publications

(4 citation statements)

References 36 publications

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“…Such capability, however, is often hindered by the limited detection sensitivity, especially for regions deep lying inside the body. With the advent of higher magnetic fields 1 , array coils 2 , 3 , faster imaging sequences 4 , 5 and hyperpolarization schemes 6 , 7 , the detection sensitivity of MRI has continuously increased over the past few decades. Recently, a complementary strategy has been proposed to further enhance MRI detection sensitivity with a Wireless Amplified NMR Detector (WAND) 8 – 11 .…”

Section: Introductionmentioning

confidence: 99%

Wireless MRI Colonoscopy for Sensitive Imaging of Vascular Walls

Zeng

Chen

Wang

et al. 2017

Sci Rep

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A Wireless Amplified NMR Detector (WAND) with cylindrical symmetry has been fabricated and non-surgically inserted into a rodent lower digestive track to improve the imaging quality of deep-lying vessels inside the abdominal cavity. This symmetric detector has a compact design using two end-rings and two vertical legs to create two orthogonal resonance modes. Based on the principle of parametric amplification, the detector can harvest wireless pumping power with its end-rings and amplify Magnetic Resonance signals induced on its vertical legs. With good longitudinal and azimuthal homogeneity, the WAND can achieve up to 21-times sensitivity gain over a standard external detector for immediately adjacent regions, and at least 5-times sensitivity gain for regions separated by one diameter away from the detector’s cylindrical surface. The WAND can approach the region of interest through the lower digestive track, similar as a colonoscopy detector. But unlike an optical camera, the amplified MR detector can “see” across intestinal boundaries and clearly identify the walls of bifurcated vessels that are susceptible to atherosclerotic lesions. In addition to vascular wall imaging, this detector may also be used as a swallowable capsule to enhance the detection sensitivity of deep-lying organs near the digestive track.

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Section: Introductionmentioning

confidence: 99%

Wireless MRI Colonoscopy for Sensitive Imaging of Vascular Walls

Zeng

Chen

Wang

et al. 2017

Sci Rep

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“…Consequently, no decoupling treatments have been utilized to radiative array coils so far, which dramatically limits their imaging capability and performance. The induced current elimination (ICE) decoupling technique [28, 29] proposed recently has demonstrated its feasibility in designing microstrip transmission line (MTL) arrays [28, 30, 31] and traditional L/C loop arrays [32]. This decoupling method uses an independent decoupling element which forms a meta-material to eliminate the current induced by electromagnetic coupling.…”

Section: Introductionmentioning

confidence: 99%

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

et al. 2016

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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.

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“…This would be even more crucial and challenging when imaging deep lying tissues of interest. Although, there has been significant progress in improving the MRI sensitivity detection by increasing the field strengths [2], working with RF coil arrays [3], and parallel imaging acquisition [4]- [8], these techniques still have their own limitations to obtain sufficient signal sensitivity, especially in target regions that are deep inside the body. Recently, a complementary method is demonstrated to improve the detection sensitivity of the deep lying tissues using a Wireless Amplified Nuclear Magnetic Resonance (NMR) Detector (WAND) [9]- [12].…”

Section: Introductionmentioning

confidence: 99%

A Novel Expandable Catheter Wireless Amplified NMR Detector for MR Sensitivity Accessing the Kidney in Rodent Model

Timilsina

Cui

2019

IEEE Trans. Biomed. Circuits Syst.

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This article demonstrates the enlarged effective range for MRI sensitivity enhancement with a deformable catheter MRI coils integrated with a wirelessly powered amplifier. The expandable balloon Wireless Amplified Nuclear magnetic resonance Detector (WAND) is constructed on a copper-clad polyimide film to resonate at the first and second harmonics of the proton Larmor frequency at 7 Tesla. The WAND is then mounted on a balloon catheter system for easy delivery inside confined orifice. Upon reaching the region of interest, it is unfolded out of the sheath tube to increase its effective size. Magnetic Resonance (MR) imaging experiments with and without the WAND are performed both in a water phantom and in a live rat to evaluate the WAND's sensitivity advantage. Expanded from a 3 mm diameter in its folded state, this deformable WAND can change its width by > 100% in its inflated state to at least 6 mm, leading to a sensitive detection region extending to up to 20 mm in the transverse direction. When the deformable WAND is placed in an artery in the region of the kidney of a live rat, it could achieve at least a 10-fold SNR gain over images acquired by a standard external detector of 22 mm diameter, even though the region of interest is separated from the WAND's surface by a distance larger than the WAND's own width. The proposed expandable catheter WAND could significantly enlarge the effective range for MR sensitivity enhancement in-vivo, enabling versatile applications in interventional MRI.

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Closely Spaced Double-Row Microstrip RF Arrays for Parallel MR Imaging at Ultrahigh Fields

Cited by 10 publications

References 36 publications

Wireless MRI Colonoscopy for Sensitive Imaging of Vascular Walls

Wireless MRI Colonoscopy for Sensitive Imaging of Vascular Walls

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

A Novel Expandable Catheter Wireless Amplified NMR Detector for MR Sensitivity Accessing the Kidney in Rodent Model

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