A 64-channel array coil for magnetic resonance imaging (MRI) has been designed and constructed. The coil was built to enable the testing of a new imaging method, single echo acquisition (SEA) MRI, in which an independent full image is acquired with every echo. This is accomplished by entirely eliminating phase encoding and instead using the spatial information obtained from an array of very narrow, long, parallel coils. The planar pair element design proved to be key in achieving welllocalized field sensitivity patterns and isolated elements, the crucial requirements for performing SEA. The matching and tuning of the array elements were accomplished on the coil array printed circuit board using varactor diodes biased over the RF lines. The array was successfully used to obtain SEA images as well as conventional partially parallel images at unprecedented acceleration factors. Magn Reson Med 54: 386 -392, 2005.

Objective: To demonstrate the effects of a very low-fat, vegan diet on patients with rheumatoid arthritis (RA).Design: Single-blind dietary intervention study. Subjects and study interventions:This study evaluated the influence of a 4-week, very lowfat (,10%), vegan diet on 24 free-living subjects with RA, average age, 56 6 11 years old.Outcome measurements: Prestudy and poststudy assessment of RA symptomatology was performed by a rheumatologist blind to the study design. Biochemical measures and 4-day diet data were also collected. Subjects met weekly for diet instruction, compliance monitoring, and progress assessments.Results: There were significant (p , 0.001) decreases in fat (69%), protein (24%), and energy (22%), and a significant increase in carbohydrate (55%) intake. All measures of RA symptomatology decreased significantly (p , 0.05), except for duration of morning stiffness (p . 0.05). Weight also decreased significantly (p , 0.001). At 4 weeks, C-reactive protein decreased 16% (ns, p . 0.05), RA factor decreased 10% (ns, p . 0.05), while erythrocyte sedimentation rate was unchanged (p . 0.05).Conclusion: This study showed that patients with moderate-to-severe RA, who switch to a very low-fat, vegan diet can experience significant reductions in RA symptoms. 71

Purpose To demonstrate the use of forced current excitation (FCE) to create homogeneous excitation of the breast at 7T, insensitive to the effects of asymmetries in the electrical environment. Materials and Methods FCE was implemented on two breast coils: one for quadrature 1H imaging and one for proton-decoupled 13C spectroscopy. Both were a Helmholtz-saddle combination, with the saddle tuned to 298 MHz for imaging and 75 MHz for spectroscopy. Bench measurements were acquired to demonstrate the ability to force equal currents on elements in the presence of asymmetric loading to improve homogeneity. Modeling and temperature measurements were conducted per safety protocol. B1 mapping, imaging, and proton decoupled 13C spectroscopy were demonstrated in vivo. Results Using FCE to ensure balanced currents on elements enabled straightforward tuning and maintaining of isolation between quadrature elements of the coil. Modeling and bench measurements confirmed homogeneity of the field, which resulted in images with excellent fat suppression and in broadband proton decoupled carbon-13 spectra. Conclusion FCE is a straightforward approach to ensure equal currents on multiple coil elements and a homogeneous excitation field, insensitive to the effects of asymmetries in the electrical environment. This enabled effective breast imaging and proton decoupled carbon-13 spectroscopy at 7T.

ABSTRACT:The application of nuclear magnetic resonance spectroscopy in metabolic studies usually includes concurrent operation at two different frequencies to enable excitation and detection of two different nuclei. When using separate radiofrequency coils for the multinuclear excitation, coupling between the two coils has been shown to be a problem, resulting in resonance frequency shifting and reduced sensitivity of the 1 H coil. Among the methods to reduce this coupling is the placement of an 1 H trap on the second-nuclei coil. This article presents the benefits of this method, specifically in this case for 31 P imaging/spectroscopy, through modeling results, bench measurements, imaging, and spectra acquisition. The use of a resonant trap in conjunction with a modular design permitted the insertion of the phosphorus coil as an ' 'add-on' ' into multiple existing proton coils, suggesting particular applicability in the high-field arena, where spectroscopy holds great promise, but where proton coil design complexity exists that is not easily re-engineered for dual-nuclei use.

Purpose To enable high spatial and temporal breast imaging resolution via combined use of high field MRI, array coils, and forced current excitation (FCE) multi channel transmit. Materials and Methods A unilateral 16-channel receive array insert was designed for use in a transmit volume coil optimized for quadrature operation with dual-transmit RF shimming at 7T. Signal-to-noise ratio (SNR) maps, g-factor maps, and high spatial and temporal resolution in vivo images were acquired to demonstrate the utility of the coil architecture. Results The dual-transmit FCE coil provided homogeneous excitation and the array provided an increase in average SNR of 3.3 times (max 10.8, min 1.5) compared to the volume coil in transmit/receive mode. High resolution accelerated in vivo breast imaging demonstrated the ability to achieve isotropic spatial resolution of 0.5 mm within clinically relevant 90 s scan times, as well as the ability to perform 1.0 mm isotropic resolution imaging, 7 s per dynamics, with the use of bidirectional SENSE acceleration of up to R = 9. Conclusion The FCE design of the transmit coil easily accommodates the addition of a sixteen channel array coil. The improved spatial and temporal resolution provided by the high-field array coil with FCE dual-channel transmit will ultimately be beneficial in lesion detection and characterization.