NOrmalized MAgnetization Ratio (NOMAR) filtering for creation of tissue selective contrast maps |
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| Authors: | Guanshu Liu Kannie W. Y. Chan Xiaolei Song Jiangyang Zhang Assaf A. Gilad Jeff W. M. Bulte Peter C. M. van Zijl Michael T. McMahon |
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| Affiliation: | 1. F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA;2. The Russell H. Morgan Department of Radiology and Radiological Sciences, Division of MR Research, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA;3. Cellular Imaging Section and Vascular Biology Program, Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA;4. Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA;5. Department of Chemical and Biomolecular Engineering, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA |
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| Abstract: | An MRI segmentation technique based on collecting two additional saturation transfer images is proposed as an aid for improved detection of chemical exchange saturation transfer agents. In this approach, the additional images are acquired at saturation frequencies of ?12.5 and ?50 ppm. Use of the ratio of these images allows differentiation of voxels with low magnetization transfer contrast (such as fat, cerebrospinal fluid, edema, or blood) from target tissue voxels using a global threshold determined by histogram analysis. We demonstrate that this technique can reduce artifacts, in vitro, in a phantom containing tubes with chemical exchange saturation transfer contrast agent embedded in either crosslinked bovine serum albumin or buffer, and in vivo for detecting diamagnetic CEST (DIACEST) liposomes injected into mice. Magn Reson Med, 2013. © 2012 Wiley Periodicals, Inc. |
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| Keywords: | MRI segmentation magnetization transfer (MT) chemical exchange saturation transfer (CEST) |
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