title: FLAIR2: A Combination of FLAIR and T2 for Improved MS Lesion Detection.
abstract: OBJECTIVE
  FLAIR and double inversion recovery are important MR imaging scans for MS. The suppression of signal from CSF in FLAIR and the additional suppression of WM signal in double inversion recovery improve contrast between lesions, WM and GM, albeit at a reduced SNR. However, whether the acquisition of double inversion recovery is necessary is still debated. Here, we present an approach that allows obtaining CSF-suppressed images with improved contrast between lesions, WM and GM without strongly penalizing SNR.
  
  
  METHODS
  3D T2-weighted and 3D-FLAIR data acquired from September 2014 to April 2015 in healthy volunteers (23.4 ± 2.4 years of age; female/male ratio, 3:2) and patients (44.1 ± 14.0 years of age; female/male ratio, 4:5) with MS were coregistered and multiplied (FLAIR(2)). SNR and contrast-to-noise measurements were performed for focal lesions and GM and WM. Furthermore, data from 24 subjects with relapsing-remitting and progressive MS were analyzed retrospectively (52.7 ± 8.1 years of age; female/male ratio, 14:10).
  
  
  RESULTS
  The GM-WM contrast-to-noise ratio was by 133% higher in FLAIR(2) than in FLAIR and improved between lesions and WM by 31%, 93%, and 158% compared with T2, DIR, and FLAIR, respectively. Cortical and juxtacortical lesions were more conspicuous in FLAIR(2). Furthermore, the 3D nature of FLAIR(2) allowed reliable visualization of callosal and infratentorial lesions.
  
  
  CONCLUSIONS
  We present a simple approach for obtaining CSF suppression with an improved contrast-to-noise ratio compared with conventional FLAIR and double inversion recovery without the acquisition of additional data. FLAIR(2) can be computed retrospectively if T2 and FLAIR scans are available.
authors.affiliation: From the Departments of Physics and Astronomy (V.W.) Pediatrics (V.W., E.H.T., A.R.) University of British Columbia MRI Research Centre (V.W., E.H.T., A.R.).
authors.forename: V
authors.identifier: http://orcid.org/0000-0001-5236-3039
authors.initials: V
authors.lastname: Wiggermann
authors.affiliation: Pediatrics (V.W., E.H.T., A.R.) University of British Columbia MRI Research Centre (V.W., E.H.T., A.R.).
authors.forename: E
authors.identifier: http://orcid.org/0000-0003-2873-5693
authors.initials: E
authors.lastname: Hernández-Torres
authors.affiliation: Medicine (Neurology) (A.T., D.K.B.L.).
authors.forename: A
authors.identifier: http://orcid.org/0000-0002-0351-9639
authors.initials: A
authors.lastname: Traboulsee
authors.affiliation: Medicine (Neurology) (A.T., D.K.B.L.) Radiology (D.K.B.L.) Centre for Brain Health (D.K.B.L., A.R.).
authors.forename: D K B
authors.identifier: http://orcid.org/0000-0002-1121-5571
authors.initials: DK
authors.lastname: Li
authors.affiliation: Pediatrics (V.W., E.H.T., A.R.) University of British Columbia MRI Research Centre (V.W., E.H.T., A.R.) Centre for Brain Health (D.K.B.L., A.R.) Child and Family Research Institute (A.R.), University of British Columbia, Vancouver, British Columbia, Canada. rauscher@physics.ubc.ca.
authors.forename: A
authors.identifier: http://orcid.org/0000-0002-1961-8252
authors.initials: A
authors.lastname: Rauscher
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D009103:Multiple Sclerosis / Q000473:pathology*; D012189:Retrospective Studies; D055815:Young Adult