title: Detection of neuronal loss using T(1rho) MRI assessment of (1)H(2)O spin dynamics in the aphakia mouse.
abstract: The loss of dopaminergic (DA) neurons in the substantia nigra pars compacta (SNc) is well characterized in Parkinson's disease (PD). Recent developments in magnetic resonance imaging (MRI) techniques have provided the opportunity to evaluate for changes in cellular density. Longitudinal relaxation measurements in the rotating frame (T(1rho)) provide a unique magnetic resonance imaging contrast in vivo. Due to the specificity of T(1rho) to water-protein interactions, the T(1rho) MRI method has strong potential to be used as a non-invasive method for quantification of neuronal density in the brain. Recently introduced adiabatic T(1rho) magnetic resonance imaging mapping methods provide a tool to assess molecular motional regimes with high sensitivity due to utilization of an effective magnetic field sweep during adiabatic pulses. In this work, to investigate the sensitivity of T(1rho) to alterations in neuronal density, adiabatic T(1rho) MRI measurements were employed in vivo on Pitx3-homeobox gene-deficient aphakia mice in which the deficit of DA neurons in the SNc is well established. The theoretical analysis of T(1rho) maps in the different areas of the brain of aphakia mouse suggested variation of the (1)H(2)O rotational correlation times, tau(c). This suggests tau(c) to be a sensitive indicator for neuronal loss during neurological disorders. The results manifest significant dependencies of the T(1rho) relaxations on the cell densities in the SNc, suggesting T(1rho) MRI method as a candidate for detection of neuronal loss in neurological disorders.
authors.affiliation: Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota Medical School, Minneapolis, MN 55455, USA. shalom@cmrr.umn.edu
authors.forename: Shalom
authors.initials: S
authors.lastname: Michaeli
authors.forename: Terry C
authors.initials: TC
authors.lastname: Burns
authors.forename: Elina
authors.initials: E
authors.lastname: Kudishevich
authors.forename: Noam
authors.initials: N
authors.lastname: Harel
authors.forename: Tim
authors.initials: T
authors.lastname: Hanson
authors.forename: Dennis J
authors.initials: DJ
authors.lastname: Sorce
authors.forename: Michael
authors.initials: M
authors.lastname: Garwood
authors.forename: Walter C
authors.initials: WC
authors.lastname: Low
mesh_terms: D000818:Animals; D001035:Aphakia / Q000235:genetics / Q000473:pathology*; D001834:Body Water / Q000378:metabolism*; D001921:Brain / Q000473:pathology*; D001931:Brain Mapping; D018398:Homeodomain Proteins; D007089:Image Enhancement / Q000379:methods; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000379:methods*; D051379:Mice; D018345:Mice, Knockout; D009474:Neurons / Q000473:pathology*; D017711:Nonlinear Dynamics; D014157:Transcription Factors / Q000172:deficiency
chemical_list: D018398:Homeodomain Proteins; D014157:Transcription Factors; C433629:homeobox protein PITX3