A study on multiple array method of birdcage coils to improve the signal intensity and homogeneity in small‐animal whole‐body magnetic resonance imaging at 7 T

Heo, Pilwon; Kim, Han‐Joong; Han, Sang-Doc; Kim, Donghyuk; Im, Geun Ho; Kim, Soobum; Kim, Kyoung Nam

doi:10.1002/ima.22383

Cited by 5 publications

(4 citation statements)

References 34 publications

(68 reference statements)

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“…Dynamic contrast-enhanced (DCE) MR imaging 51 , 52 and susceptibility-weighted imaging (SWI) 53 , 54 , which extracts susceptibility maps from information of magnitude and phase in MR images, are techniques that can provide highly sensitive MR images from stroke and it-derived cerebral lesions, and the application of these imaging sequences can obtain more detailed information on the occurrence and recovery of brain damage. The employment of coils designed and manufactured tailored to middle animals is also a method to improve MR signal acquisition sensitivity 55 , 56 .…”

Section: Resultsmentioning

confidence: 99%

Development of a photochemical thrombosis investigation system to obtain a rabbit ischemic stroke model

Kim

Lee

Bae

et al. 2021

Sci Rep

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Photochemical thrombosis is a method for the induction of ischemic stroke in the cerebral cortex. It can generate localized ischemic infarcts in the desired region; therefore, it has been actively employed in establishing an ischemic stroke animal model and in vivo assays of diagnostic and therapeutic techniques for stroke. To establish a rabbit ischemic stroke model and overcome the shortcoming of previous studies that were difficult to build a standardized photothrombotic rabbit model, we developed a photochemical thrombosis induction system that can produce consistent brain damage on a specific area. To verify the generation of photothrombotic brain damage using the system, longitudinal magnetic resonance imaging, 2,3,5-triphenyltetrazolium chloride staining, and histological staining were applied. These analytical methods have a high correlation for ischemic infarction and are appropriate for analyzing photothrombotic brain damage in the rabbit brain. The results indicated that the photothrombosis induction system has a main advantage of being accurately controlled a targeted region of photothrombosis and can produce cerebral hemisphere lesions on the target region of the rabbit brain. In conjugation with brain atlas, it can induce photochemical ischemic stroke locally in the part of the brain that is responsible for a particular brain function and the system can be used to develop animal models with degraded specific functions. Also, the photochemical thrombosis induction system and a standardized rabbit ischemic stroke model that uses this system have the potential to be used for verifications of biomedical techniques for ischemic stroke at a preclinical stage in parallel with further performance improvements.

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Section: Resultsmentioning

confidence: 99%

Development of a photochemical thrombosis investigation system to obtain a rabbit ischemic stroke model

Kim

Lee

Bae

et al. 2021

Sci Rep

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“…The design concept of a modified birdcage coil for imaging chick embryos has been successfully demonstrated on a 7 T MRI scanner and has been proven to outperform the standard birdcage coil used for comparison. Whereas the SNR and \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{upgreek} \usepackage{mathrsfs} \setlength{\oddsidemargin}{-69pt} \begin{document} ${{B}_1}^ + $\end{document} homogeneity of the standard birdcage coil was shown to significantly be degraded in the area close to the end-rings [12] , [27] , [28] , the proposed coil design incorporates a curved feature which tapers down towards the end-rings in both directions, thus enhancing the transmit efficiency, the filling factor and the SNR. Here, the higher SNR was achieved with the modified coil, which has a higher filling factor and is more sample dominant (i.e., 20% higher Q-ratio shown in Table I ), despite possessing slightly higher intrinsic loss (i.e., lower unloaded Q-factor, less than a 5% difference in Table I ).…”

Section: Discussionmentioning

confidence: 99%

“…Furthermore, SNR may diminish in areas of the embryo that are located close to the end-rings of the standard coils. While this can simply be compensated for by increasing the length of the birdcage coil, due to the filling factor the quality of the enlarged coil decreases as a function of the increased length and diameter of the coil when the size of the object is identical [12] , [26] , [27] , [28] , [29] . Moreover, maintaining consistent imaging orientations is further complicated as the position of the chick embryo changes over time.…”

Section: Introductionmentioning

confidence: 99%

A Modified Quadrature Birdcage Coil Incorporated With a Curved Feature for In Ovo MR Imaging

Choi,

Bruch,

Hong

et al. 2024

IEEE Open J. Eng. Med. Biol.

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Goal: This study presents a novel MRI coil design approach explicitly tailored for chick embryo measurements, with the primary objective of improving sensitivity and coverage. Methods: The limitations posed by conventional birdcage coils were addressed by introducing a curvature feature into a standard coil. The performance of the modified coil was assessed using EM simulations and experimental evaluations, which were subsequently validated using a 7 T MRI scanner. A comparative analysis was conducted against a standard quadrature low-pass birdcage coil to evaluate key factors. Results: The proposed coil demonstrated improved SNR and uniformity, particularly in the proximity of the end-rings. These results were consistent with the findings obtained from the simulations. Conclusions: The use of our innovative birdcage coil design holds promise and offers practical potential for in ovo studies.

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“…In a study, Nabetani et al revealed that the utilization of the shorter legs can enhance the performance of the birdcage coil for ultra-high field MRI applications [117]. Heo et al used the idea of shorter legs and devised a method for using an array of the birdcage coils in combination in order to improve the signal intensity and B1 magnetic field homogeneity at 7T [107].…”

Section: Modified Birdcage Coilsmentioning

confidence: 99%

Recent Progress in Birdcage RF Coil Technology for MRI System

et al. 2020

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The radio frequency (RF) coil is one of the key components of the magnetic resonance imaging (MRI) system. It has a significant impact on the performance of the nuclear magnetic resonance (NMR) detection. Among numerous practical designs of RF coils for NMR imaging, the birdcage RF coil is the most popular choice from low field to ultra-high field MRI systems. In the transmission mode, it can establish a strong and homogeneous transverse magnetic field B1 for any element at its Larmor frequency. Similarly, in the reception mode, it exhibits extremely high sensitivity for the detection of even faint NMR signals from the volume of interest. Despite the sophisticated 3D structure of the birdcage coil, the developments in the design, analysis, and implementation technologies during the past decade have rendered the development of the birdcage coils quite reasonable. This article provides a detailed review of the recent progress in the birdcage RF coil technology for the MRI system.

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A study on multiple array method of birdcage coils to improve the signal intensity and homogeneity in small‐animal whole‐body magnetic resonance imaging at 7 T

Cited by 5 publications

References 34 publications

Development of a photochemical thrombosis investigation system to obtain a rabbit ischemic stroke model

Development of a photochemical thrombosis investigation system to obtain a rabbit ischemic stroke model

A Modified Quadrature Birdcage Coil Incorporated With a Curved Feature for In Ovo MR Imaging

Recent Progress in Birdcage RF Coil Technology for MRI System

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