Transmit/Receive Single Echo Acquisition MRI

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DESCRIPTION (provided by applicant): The objective of this EBRG proposal is to develop Transmit/Receive Single Echo Acquisition (SEA) magnetic resonance imaging to enable imaging and flow measurements at extremely high temporal resolutions and over arbitrarily curved planes (linear only in the frequency encoding direction). The use of a T/R array will remove the need for a phase compensation pulse, a limitation in our earlier results using receive-only arrays. Therefore this new technique will be far more robust, enabling conformable arrays and 3D imaging. To achieve this objective, we will build a 64 channel, 30 watt per channel transmitter. In parallel, we will evaluate five candidate array element designs for optimal combination of penetration depth and decoupling, and then construct 64 channel planar and cylindrical arrays. Finally, we will develop, test, and evaluate T/R SEA MRI of flow using phase contrast and spin-tagging methods on conventional and microfluidic phantoms with periodic and non-periodic flow. If successful, this study will have developed a new methodology capable of MR imaging at unprecedented frame rates (500 frames/second) over arbitrarily curved slices. The method will provide a true "snapshot" flow imaging method, capable of imaging one-time events such as transient waves being investigated for MR elastography or non-periodic flow such as in stenotic vessel models. The conformable arrays will be applicable in catheter based interventional MRI and detecting rapid responses in fMRI of the brain surface. Of particular interest in this study is the use of T/R SEA flow measurement for characterization of microfluidic lab-on-a-chip devices. Methods are being investigated to create chaotic flow patterns in these devices, which can decrease mixing times by several orders of magnitude, critical for molecular diagnostics and drug development. The methods proposed here could provide a new tool for characterization of chaotic flow in these devices relying purely on endogenous contrast, eliminating the need for optical windows or seeding for optical reflection.