A high‐throughput eight‐channel probe head for murine MRI at 9.4 T

A 20-channel phased-array coil for MRI of mice has been designed, constructed, and validated with bench measurements and high-resolution accelerated imaging. The technical challenges of designing a small, high density array have been overcome using individual small-diameter coil elements arranged on a cylinder in a hexagonal overlapping design with adjacent low impedance preamplifiers to further decouple the array elements. Signal-to-noise ratio (SNR) and noise amplification in accelerated imaging were simulated and quantitatively evaluated in phantoms and in vivo mouse images. Comparison between the 20-channel mouse array and a length-matched quadrature driven small animal birdcage coil showed an SNR increase at the periphery and in the center of the phantom of 3-and 1.3-fold, respectively. Comparison with a shorter but SNR-optimized birdcage coil (aspect ratio 1:1 and only half mouse coverage) showed an SNR gain of twofold at the edge of the phantom and similar SNR in the center. G-factor measurements indicate that the coil is well suited to acquire highly accelerated images. Magn Reson Med 66:584-595,

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confidence: 99%

A 20‐channel receive‐only mouse array coil for a 3 T clinical MRI system

Keil

Wiggins

Triantafyllou

et al. 2011

“…This would result in an improved filling factor, and may provide additional scan time reduction from the application of parallel imaging. However, small array elements are prone to coil‐noise domination, which adversely affects coil array and SNR performance, particularly in center of the array .…”

Section: Discussionmentioning

confidence: 99%

Optimized radiofrequency coil setup for MR examination of living isolated rat hearts in a horizontal 9.4T magnet

Lohézic

Bollensdorff

Korn

et al. 2014

Self Cite

Purpose: (i) To optimize an MR-compatible organ perfusion setup for the nondestructive investigation of isolated rat hearts by placing the radiofrequency (RF) coil inside the perfusion chamber; (ii) to characterize the benefit of this system for diffusion tensor imaging and proton ( 1 H-) MR spectroscopy. Methods: Coil quality assessment was conducted both on the bench, and in the magnet. The benefit of the new RF-coil was quantified by measuring signal-to-noise ratio (SNR), accuracy, and precision of diffusion tensor imaging/error in metabolite amplitude estimation, and compared to an RF-coil placed externally to the perfusion chamber. Results: The new design provided a 59% gain in signal-to-noise ratio on a fixed rat heart compared to using an external resonator, which found reflection in an improvement of living heart data quality, compared to previous external resonator studies. This resulted in 14-29% improvement in accuracy and precision of diffusion tensor imaging. The Cramer-Rao lower bounds for metabolite amplitude estimations were up to 5-fold smaller. Conclusion: Optimization of MR-compatible perfusion equipment advances the study of rat hearts with improved signal-tonoise ratio performance, and thus improved accuracy/precision. Magn Reson Med 73:2398-2405,

“…For our experiments we used a volumetric coil array consisting of eight elements (id 35 mm, length 32.5 mm) arranged inside a linearly driven volume coil (id 67 mm, length 82 mm/od 115 mm) (see Ref. 23 for details). Comparative experiments were performed using a quadrature driven birdcage coil (id 35 mm, length 35 mm), optimized in geometry and loading for cardiac MR in mice.…”

Section: Methodsmentioning

confidence: 99%

“…We have designed and characterized an eight-channel volume receive array integrated into a linear driven volume transmit birdcage resonator ( 23 ). Following the evaluation of the array's SNR performance and its comparison to a quadrature-driven birdcage transmit/receive resonator with identical inner diameter, we hypothesized that the gain in SNR close to the coil array would facilitate accelerated cardiac MRI in mice.…”

mentioning

confidence: 99%

Accelerated cardiac magnetic resonance imaging in the mouse using an eight‐channel array at 9.4 Tesla

Schneider

Lanz

Barnes

et al. 2010

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MRI has become an important tool to noninvasively assess global and regional cardiac function, infarct size, or myocardial blood flow in surgically or genetically modified mouse models of human heart disease. Constraints on scan time due to sensitivity to general anesthesia in hemodynamically compromised mice frequently limit the number of parameters available in one imaging session. Parallel imaging techniques to reduce acquisition times require coil arrays, which are technically challenging to design at ultrahigh magnetic field strengths. This work validates the use of an eight-channel volume phased-array coil for cardiac MRI in mice at 9.4 T. Two- and three-dimensional sequences were combined with parallel imaging techniques and used to quantify global cardiac function, T1-relaxation times and infarct sizes. Furthermore, the rapid acquisition of functional cine-data allowed for the first time in mice measurement of left-ventricular peak filling and ejection rates under intravenous infusion of dobutamine. The results demonstrate that a threefold accelerated data acquisition is generally feasible without compromising the accuracy of the results. This strategy may eventually pave the way for routine, multiparametric phenotyping of mouse hearts in vivo within one imaging session of tolerable duration. Magn Reson Med, 2010. © 2010 Wiley-Liss, Inc.