title: Proton magnetic resonance in myelin deficient brains of mutant mice.
abstract: The role of myelin in determining the magnetic resonance (MR) characterization of the central nervous system (CNS) was investigated in unmyelinated brains of normal fetal mice, as well as myelin-deficient adult mutant mice (shi, qk, mld) and their age-matched controls. In vitro NMR relaxation time measurements at 10 MHz for whole brains showed consistently longer T1 (range 558 +/- 8 to 580 +/- 27 msec) and T2 (range 81 +/- 3 to 89 +/- 3 msec) values for the adult myelin-deficient animals than the age-matched controls (T1 = 496 +/- 31, T2 = 79 +/- 4 msec). The fetal brains exhibited even more prolonged relaxation times (T1 = 976 +/- 60, T2 = 158 +/- 7 msec). MR images obtained at 81 MHz using spin echo (SE) sequences, which unlike the in vitro approach allowed discrimination between white and gray matter areas, revealed an absence of gray-white matter contrast in the brains of mutant mice, consistent with longer than normal relaxation of the myelin-deficient white matter. While larger tissue water components such as those present in the immature brain and edematous white matter contribute a greater effect, myelin and its associated bound water may still play an important role in the MR characterization of normal gray and white matter.
authors.affiliation: Department of Radiology, Harvard Medical School, Boston, MA.
authors.forename: F A
authors.initials: FA
authors.lastname: Jolesz
authors.forename: D A
authors.initials: DA
authors.lastname: Kirschner
authors.forename: P
authors.initials: P
authors.lastname: Jakab
authors.forename: A V
authors.initials: AV
authors.lastname: Lorenzo
mesh_terms: D000818:Animals; D001834:Body Water / Q000032:analysis; D001921:Brain / Q000473:pathology*; D004573:Electrolytes / Q000032:analysis; D006653:Histology; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D051379:Mice; D008817:Mice, Mutant Strains; D008821:Mice, Quaking; D009186:Myelin Sheath / Q000473:pathology*
chemical_list: D004573:Electrolytes