title: Magnetization transfer and adiabatic T1ρ MRI reveal abnormalities in normal-appearing white matter of subjects with multiple sclerosis.
abstract: Diffuse abnormalities are known to occur within the brain tissue of multiple sclerosis (MS) patients that is "normal appearing" on T1-weighted and T2-weighted magnetic resonance images.
  
  
  
  With the goal of exploring the sensitivity of novel MRI parameters to detect such abnormalities, we implemented an inversion-prepared magnetization transfer (MT) protocol and adiabatic T1ρ and T2ρ rotating frame relaxation methods.
  
  
  
  Nine relapsing-remitting MS patients and seven healthy controls were recruited. Relaxation parameters were measured in a single slice just above the lateral ventricles and approximately parallel to the AC-PC line.
  
  
  
  The MT ratio of regions encompassing the normal-appearing white matter (NAWM) was different in MS patients as compared with controls (p = 0.043); however, the T1 measured during off-resonance irradiation (T1sat) was substantially more sensitive than the MT ratio for detecting differences between groups (p = 0.0006). Adiabatic T1ρ was significantly prolonged in the NAWM of MS patents as compared to controls (by 6%, p = 0.026), while no differences were found among groups for T2ρ. No differences among groups were observed in the cortical gray matter for any relaxation parameter.
  
  
  
  The results suggest degenerative processes occurring in the NAWM of MS, likely not accompanied by significant abnormalities in iron content.
authors: Center for Magnetic Resonance Research (CMRR), Department of Radiology, University of Minnesota, USA mangia@umn.edu.
authors: Silvia
authors: S
authors: Mangia
authors: Department of Neurology, University of Minnesota, USA Brain Sciences Center, VA Medical Center, USA.
authors: Adam F
authors: AF
authors: Carpenter
authors: Department of Neurology, University of Minnesota, USA.
authors: Andy E
authors: AE
authors: Tyan
authors: Division of Biostatistics, School of Public Health, University of Minnesota, USA.
authors: Lynn E
authors: LE
authors: Eberly
authors: Center for Magnetic Resonance Research (CMRR), Department of Radiology, University of Minnesota, USA.
authors: Michael
authors: M
authors: Garwood
authors: Center for Magnetic Resonance Research (CMRR), Department of Radiology, University of Minnesota, USA.
authors: Shalom
authors: S
authors: Michaeli
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D056784:Leukoencephalopathies / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D020529:Multiple Sclerosis, Relapsing-Remitting / Q000000981:diagnostic imaging*; D009410:Nerve Degeneration; D011237:Predictive Value of Tests; D066127:White Matter / Q000000981:diagnostic imaging*
keywords: MRI; adiabatic pulses; inversion-prepared MT; multiple sclerosis; relapsing–remitting; rotating frame relaxation