title: SyMRI of the Brain: Rapid Quantification of Relaxation Rates and Proton Density, With Synthetic MRI, Automatic Brain Segmentation, and Myelin Measurement.
abstract: Conventional magnetic resonance images are usually evaluated using the image signal contrast between tissues and not based on their absolute signal intensities. Quantification of tissue parameters, such as relaxation rates and proton density, would provide an absolute scale; however, these methods have mainly been performed in a research setting. The development of rapid quantification, with scan times in the order of 6 minutes for full head coverage, has provided the prerequisites for clinical use. The aim of this review article was to introduce a specific quantification method and synthesis of contrast-weighted images based on the acquired absolute values, and to present automatic segmentation of brain tissues and measurement of myelin based on the quantitative values, along with application of these techniques to various brain diseases. The entire technique is referred to as "SyMRI" in this review. SyMRI has shown promising results in previous studies when used for multiple sclerosis, brain metastases, Sturge-Weber syndrome, idiopathic normal pressure hydrocephalus, meningitis, and postmortem imaging.
authors.affiliation: From the *Department of Radiology, Juntendo University School of Medicine; †Department of Radiology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan; ‡SyntheticMR AB; §Center for Medical Imaging Science and Visualization, Linköping, Sweden; and ∥Department of Radiological Sciences, Graduate School of Human Health Sciences, Tokyo Metropolitan University, Tokyo, Japan.
authors.forename: Akifumi
authors.initials: A
authors.lastname: Hagiwara
authors.forename: Marcel
authors.initials: M
authors.lastname: Warntjes
authors.forename: Masaaki
authors.initials: M
authors.lastname: Hori
authors.forename: Christina
authors.initials: C
authors.lastname: Andica
authors.forename: Misaki
authors.initials: M
authors.lastname: Nakazawa
authors.forename: Kanako Kunishima
authors.initials: KK
authors.lastname: Kumamaru
authors.forename: Osamu
authors.initials: O
authors.lastname: Abe
authors.forename: Shigeki
authors.initials: S
authors.lastname: Aoki
mesh_terms: D001921:Brain / Q000000981:diagnostic imaging / Q000473:pathology; D001927:Brain Diseases / Q000000981:diagnostic imaging* / Q000473:pathology; D001931:Brain Mapping / Q000379:methods*; D003287:Contrast Media; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D009186:Myelin Sheath; D011522:Protons
chemical_list: D003287:Contrast Media; D011522:Protons