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Optical glass fiber shows great advantages over coaxial cables in terms of electromagnetic interference, thus, it should be considered a potential alternative for magnetic resonance imaging (MRI) receive coil interconnection, especially for a large number coil array at high field. In this paper, we propose a 4-channel analog direct modulation optical link for a 1.5-T MRI coil array interconnection. First, a general direct modulated optical link is compared to an external modulated optical link. And then the link performances of the proposed direct modulated optical link, including power gain, frequency response, and dynamic range, are analyzed and measured. Phantom and in vivo head images obtained using this optical link are demonstrated for comparison with those obtained by cable connections. The signal-to-noise (SNR) analysis shows that the optical link achieves 6%-8% SNR a improvement over coaxial cables by elimination of electrical interference between cables during MR signal transmission. Index Terms--Coil array, direct modulation, dynamic range, external modulation, signal-to-noise ratio (SNR).

Optical glass fiber shows great advantages over coaxial cables in terms of electromagnetic interference, thus, it should be considered a potential alternative for magnetic resonance imaging (MRI) receive coil interconnection, especially for a large number coil array at high field. In this paper, we propose a 4-channel analog direct modulation optical link for a 1.5-T MRI coil array interconnection. First, a general direct modulated optical link is compared to an external modulated optical link. And then the link performances of the proposed direct modulated optical link, including power gain, frequency response, and dynamic range, are analyzed and measured. Phantom and in vivo head images obtained using this optical link are demonstrated for comparison with those obtained by cable connections. The signal-to-noise (SNR) analysis shows that the optical link achieves 6%-8% SNR a improvement over coaxial cables by elimination of electrical interference between cables during MR signal transmission. [ABSTRACT FROM AUTHOR]

Abstract: Purpose: In a neonatal rat model of hypoxic–ischemic (HI) brain injury, using T2-weighted imaging (T2WI) and diffusion-weighted imaging (DWI), we aim to determine the best MRI method of lesion quantification that reflects infarct size. Materials and methods: Twenty 7-day-old rats underwent MRI 24h after HI brain injury was induced. Lesion size relative to whole brain was measured using T2WI and apparent diffusion coefficient (ADC) maps, applying thresholds of 60%, 70% and 80% contralateral control hemisphere mean ADC, and at day 10 post-HI on pathology with TTC staining. Multiple linear regression analysis was used to study the relationships between lesion size at MRI and pathology. Results: Lesion size measurement using all MRI methods significantly correlated with infarct size at pathology; using T2WI, r =0.808 (p <0.001), using 80% ADC, 70% ADC and 60% ADC thresholds, r =0.888 (p <0.001), 0.761, (p <0.001) and 0.569 (p =0.014), respectively. Eighty percent ADC threshold was found to be the only significant independent predictor of final infarct volume (adjusted R 2 =0.775). Conclusion: At 24h post-HI, lesion size on DWI, using 80% ADC threshold is the best predictor of final infarct volume. Although T2WI performed less well, it has the advantage of superior spatial resolution and is technically less demanding. These are important considerations for experiments which utilize MRI as a surrogate method for lesion quantification in the neonatal rat HI model. [Copyright &y& Elsevier]

Purpose To compare the performance of birdcage, transverse electromagnetic (TEM) and microstrip volume coils at 7T under the same geometric conditions. Materials and Methods Birdcage, TEM, and microstrip coils are modeled with the same dimensions. The finite difference time domain (FDTD) method is adopted to calculate the electromagnetic fields of the coils. Further, B1 field, specific absorption rate (SAR) and signal-to-noise ratio (SNR) are calculated for these coils. Results In the unloaded case, within the central axial plane, the variation of B1 field magnitude over 18-cm distance is about 15% for the birdcage coil, 23% for the TEM coil, and 38% for the microstrip coil. In the loaded case, the percentages of the samples on the central axial plane, which have B1 field magnitude within ±20% of the average B1 field magnitude, are about 57% for the birdcage, 72% for the TEM, and 59% for the microstrip coil. Average SAR levels are 11.4% and 42.9% higher in the birdcage than those in the TEM and microstrip coils, respectively. The average relative SNR on the central axial plane for the shielded birdcage, TEM, and microstrip coils are 1, 1.07, and 1.48, respectively. Conclusion The birdcage coil has the best unloaded B1 field homogeneity, and the TEM coil has the best loaded B1 field homogeneity and the lowest radiation loss; while the microstrip coil is better in SAR and SNR at 7T than the birdcage and TEM coils. J. Magn. Reson. Imaging 2006. © 2006 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

Proposes that statins downeregulate one or more isoprenoid-dependent steps in cell signaling following thrombin activation of protease activated receptor-1. Clinical relevance of statins;Functions of thrombin in thrombosis, thrombotic diseases, hemorrhage prevention and developmental and wound healing processes; Possible mechanisms for the induction of antithrombotic effects of statin drugs and dietary isoprenoids.

Presents a study demonstrating cholesterol ester transfer activity (CETA) in cultured hamster and rat adipose tissue. Data that supports the view that, in hamsters, adipose CETA has an in situ and intravascular functions, whereas in rats the role of adipose CETA is restricted to tissue-specific functions.