MRI Physics -
Center for Adaptive Imaging
Please visit us at http://splweb.bwh.harvard.edu:8000/pages/ppl/zientara/index.html
Principal Investigators:
Gary P Zientara, PhD
Lawrence P Panych, PhD
Co-Investigators:
Dimitris Mitsouras
Seung-Shik Yoo, PhD
Renxin Chu, PhD
Near-Optimal Non-Fourier Spatial Encoding
The development of near-optimal adaptive spatial encoding methods for efficient sub-second dynamic MRI acquisition in both 2D and 3D is the major area of ongoing research in this laboratory. Applications include interventional MRI, functional brain mapping, and cardiac MRI, but extend to all applications that require fast dynamic MRI. Research related to 2D spatial encoding emphasizes both wavelet encoding and the determination of reduced vector basis sets using linear algebraic techniques, particularly complete orthogonal decompositions and Krylov subspace methods. Also, non-orthogonal vector sets are being investigated for MRI spatial encoding. New spatially selective RF excitation methods using fast pulse sequences are investigated for implementation under the general topic of non-Fourier encoding (e.g., multiple excitation multi-echo pulse sequences). The goal in all studies is to use the information obtained to update, modify, or control the current and future data acquisition during fast real-time MRI. The current focus of our research is implementation of real-time non-Fourier 2D and 3D MRI and the design and setup of a specialized MR scanner console software suite that can facilitate the practical use of our adaptive encoding methods in clinical cases. Our studies also include the mathematics and physics required for spatial encoding.
Broadband MRI
An ongoing research topic is the design, development, and testing of a fully broadband MRI scanner. Broadband MRI specifically refers to a coherent, fully integrated system for fast, continuous, 3D, dynamic MR data acquisition, in which each system component transmits, receives, or processes a broad band of spatial / spectral frequency information, fully optimizing the flow rate of information in each component of the MRI acquisition pipeline. Broadband MRI, therefore, incorporates at its core: broadband sampling, broadband reception (which includes multiple receiver coils and multiple RF receiver channels now available with the multi-channel Parallel MRI commercial scanners), and multi-processor computer(s) integrated into the MR scanner.
Adaptive fMRI
Another area of research is adaptive functional MRI (fMRI), in which the tool of multi-resolution MR scanning is exploited to first locate, then zoom in on the multiple areas of activation occurring due to stimulation by complex tasks. In these patient studies, the imaging algorithm is modified dynamically dependent upon the observed BOLD response to optimize both temporal and spatial resolution during full brain data acquisition. This study emphasizes the dynamic adaptive processing of fMRI data. Primarily, this involves the elimination of non-stimulus-related physiological variation in the acquired MRI data using the latest mathematical approaches.
Our collaborators include faculty from MIT Department of Mathematics, MIT CSAIL (Computer Science and Artificial Intelligence Laboratory), Boston University Department of Bioengineering, and Northeastern University Department of Engineering, among others. The Center for Adaptive Imaging is located in the Thorn Research Building, rooms 328, 330.
For further information contact:
Gary P Zientara, PhD at zientara@bwh.harvard.edu
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