A framework for accurate determination of the T2 distribution from multiple echo magnitude MRI image

Bai R, Koay CG, Hutchinson E, and Basser PJ. (2014) A framework for accurate determination of the T2distribution from multiple echo magnitude MRI images. J Magn Reson. 244:53-63.

Simultaneous calcium fluorescence imaging and MR of ex vivo organotypic cortical cultures: a new tes

Recently, several new functional MRI contrast mechanisms including diffusion, phase imaging, proton density, etc.have been proposed to measure neuronal activity more directly and accurately than blood-oxygen-level dependent (BOLD) fMRI. However, these approaches have proved difficult to reproduce, mainly because of the dearth of reliable and robust test systems to vet and validate them. Here we describe the development and testing of such a test bed for non-BOLD fMRI. Organotypic cortical cultures were used as a stable and reproducible biological model of neuronal activity that shows spontaneous activity similar to that of in vivo brain cortex without any hemodynamic confounds. An open-access, single-sided magnetic resonance (MR) “profiler” consisting of four permanent magnets with magnetic field of 0.32 T was used in this study to perform MR acquisition. A fluorescence microscope with long
working distance objective was mounted on the top of a custom-designed chamber that keeps the organotypic culture vital, and the MR system was mounted on the bottom of the chamber to achieve real-time simultaneous calcium fluorescence optical imaging and MR acquisition on the same specimen. In this study, the reliability and performance of the proposed test bed were demonstrated by a conventional CPMG MR sequence acquired simultaneously with calcium imaging, which is a well-characterized measurement of neuronal activity. This experimental design will make it possible to correlate directly the other candidate functional MR signals to the optical indicia of neuronal activity in the future

Bai R, Klaus A, Bellay T, Stewart C, Pajevic S, Nevo U, Merkle H, Plenz D, and Basser PJ. 2015. Simultaneous calcium fluorescence imaging and MR of ex vivo organotypic cortical cultures: a new test bed for functional MRI. NMR Biomed 28(12):1726-38.

Efficient 2D MRI relaxometry using compressed sensing

Bai R, Cloninger A, Czaja W, Basser PJ. 2015. Efficient 2D MRI relaxometry using compressed sensing. J Magn Reson. 255:88-99. PubMed

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