title: NOrmalized MAgnetization Ratio (NOMAR) filtering for creation of tissue selective contrast maps.
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.
authors.affiliation: F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland 21231, USA.
authors.forename: Guanshu
authors.initials: G
authors.lastname: Liu
authors.forename: Kannie W Y
authors.initials: KW
authors.lastname: Chan
authors.forename: Xiaolei
authors.initials: X
authors.lastname: Song
authors.forename: Jiangyang
authors.initials: J
authors.lastname: Zhang
authors.forename: Assaf A
authors.initials: AA
authors.lastname: Gilad
authors.forename: Jeff W M
authors.initials: JW
authors.lastname: Bulte
authors.forename: Peter C M
authors.initials: PC
authors.lastname: van Zijl
authors.forename: Michael T
authors.initials: MT
authors.lastname: McMahon
mesh_terms: D000465:Algorithms; D000818:Animals; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008081:Liposomes / Q000032:analysis / Q000493:pharmacokinetics*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D051379:Mice; D008810:Mice, Inbred C57BL; D057054:Molecular Imaging / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D008081:Liposomes