title: 2D phase-sensitive inversion recovery imaging to measure in vivo spinal cord gray and white matter areas in clinically feasible acquisition times.
abstract: OBJECTIVE
  To present and assess a procedure for measurement of spinal cord total cross-sectional areas (TCA) and gray matter (GM) areas based on phase-sensitive inversion recovery imaging (PSIR). In vivo assessment of spinal cord GM and white matter (WM) could become pivotal to study various neurological diseases, but it is challenging because of insufficient GM/WM contrast provided by conventional magnetic resonance imaging (MRI).
  
  
  METHODS
  We acquired 2D PSIR images at 3T at each disc level of the spinal axis in 10 healthy subjects and measured TCA, cord diameters, WM and GM areas, and GM area/TCA ratios. Second, we investigated 32 healthy subjects at four selected levels (C2-C3, C3-C4, T8-T9, T9-T10, total acquisition time <8 min) and generated normative reference values of TCA and GM areas. We assessed test-retest, intra- and interoperator reliability of the acquisition strategy, and measurement steps.
  
  
  RESULTS
  The measurement procedure based on 2D PSIR imaging allowed TCA and GM area assessments along the entire spinal cord axis. The tests we performed revealed high test-retest/intraoperator reliability (mean coefficient of variation [COV] at C2-C3: TCA = 0.41%, GM area = 2.75%) and interoperator reliability of the measurements (mean COV on the 4 levels: TCA = 0.44%, GM area = 4.20%; mean intraclass correlation coefficient: TCA = 0.998, GM area = 0.906).
  
  
  CONCLUSIONS
  2D PSIR allows reliable in vivo assessment of spinal cord TCA, GM, and WM areas in clinically feasible acquisition times. The area measurements presented here are in agreement with previous MRI and postmortem studies.
authors.affiliation: Department of Neurology, University of California San Francisco, San Francisco, California, USA.
authors.forename: Nico
authors.initials: N
authors.lastname: Papinutto
authors.affiliation: Department of Neurology, University of California San Francisco, San Francisco, California, USA.|Department of Neurology, University of Basel, Basel, Switzerland.
authors.forename: Regina
authors.initials: R
authors.lastname: Schlaeger
authors.affiliation: ITAB - Institute of Advanced Biomedical Technologies, University "G. D'Annunzio,", Chieti, Italy.
authors.forename: Valentina
authors.initials: V
authors.lastname: Panara
authors.affiliation: Department of Neurology, University of California San Francisco, San Francisco, California, USA.
authors.forename: Eduardo
authors.initials: E
authors.lastname: Caverzasi
authors.affiliation: Siemens Healthcare USA, San Francisco, California, USA.
authors.forename: Sinyeob
authors.initials: S
authors.lastname: Ahn
authors.affiliation: Siemens Healthcare USA, San Francisco, California, USA.
authors.forename: Kevin J
authors.initials: KJ
authors.lastname: Johnson
authors.affiliation: Department of Neurology, University of California San Francisco, San Francisco, California, USA.
authors.forename: Alyssa H
authors.initials: AH
authors.lastname: Zhu
authors.affiliation: Department of Neurology, University of California San Francisco, San Francisco, California, USA.
authors.forename: William A
authors.initials: WA
authors.lastname: Stern
authors.affiliation: Siemens Healthcare USA, San Francisco, California, USA.
authors.forename: Gerhard
authors.initials: G
authors.lastname: Laub
authors.affiliation: Department of Neurology, University of California San Francisco, San Francisco, California, USA.
authors.forename: Stephen L
authors.initials: SL
authors.lastname: Hauser
authors.affiliation: Department of Neurology, University of California San Francisco, San Francisco, California, USA.|Bioengineering Graduate Group, University of California San Francisco, San Francisco and University of California Berkeley, Berkeley, California, USA.|Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, California, USA.
authors.forename: Roland G
authors.initials: RG
authors.lastname: Henry
mesh_terms: D000328:Adult; D000368:Aged; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D005260:Female; D066128:Gray Matter / Q000473:pathology*; D064368:Healthy Volunteers; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009422:Nervous System Diseases / Q000503:physiopathology; D012016:Reference Values; D015203:Reproducibility of Results; D059629:Signal-To-Noise Ratio; D013116:Spinal Cord / Q000473:pathology*; D013997:Time Factors; D066127:White Matter / Q000473:pathology*; D051598:Whole Body Imaging
keywords: anatomy; gray matter; magnetic resonance imaging; morphometry; spinal cord; white matter