title: Improved quantification of myocardial blood flow using highly constrained back projection reconstruction.
abstract: OBJECTIVE
  To improve quantification of myocardial blood flow using a fast T1 mapping technique using highly constrained back projection reconstruction (HYPR)-accelerated acquisition.
  
  
  METHODS
  A major source of error in the measurement of myocardial blood flow (MBF) using MRI is the nonlinear relationship between image signal intensity and contrast agent (CA) concentration. HYPR-accelerated radial acquisition was used to generate pixel-wise T1 maps with a temporal resolution of one heartbeat. HYPR produces images with a temporal footprint of 40 ms and four images within 188 ms. T1 values were converted into CA concentrations by the known linear relationship between CA concentration and T1 . The T1 mapping technique was used to quantify MBF in 10 healthy subjects and compared with MBF found using image signal intensity as well as MBF reported in the literature.
  
  
  RESULTS
  The MBF measured using the proposed method was more consistent with that previously reported in the literature and was significantly lower (P = 0.002) than that calculated using image signal intensity (1.11 ± 0.27 mL/min/g versus 1.88 ± 0.45 mL/min/g, respectively).
  
  
  CONCLUSIONS
  We developed a fast T1 mapping method for MBF quantification using radial sampling and HYPR. Further validation is required to determine its clinical value in assessing myocardial perfusion deficit in coronary artery disease.
authors.affiliation: Department of Biomedical Engineering, Northwestern University, Chicago, Illinois, USA; Biomedical Imaging Research Institute, Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, California, USA.
authors.forename: David
authors.initials: D
authors.lastname: Chen
authors.forename: Behzad
authors.initials: B
authors.lastname: Sharif
authors.forename: Rohan
authors.initials: R
authors.lastname: Dharmakumar
authors.forename: Louise E J
authors.initials: LE
authors.lastname: Thomson
authors.forename: C Noel
authors.initials: CN
authors.lastname: Bairey Merz
authors.forename: Daniel S
authors.initials: DS
authors.lastname: Berman
authors.forename: Debiao
authors.initials: D
authors.lastname: Li
mesh_terms: D055424:Cardiac-Gated Imaging Techniques; D003198:Computer Simulation; D003287:Contrast Media / Q000008:administration & dosage; D005260:Female; D006321:Heart / Q000033:anatomy & histology*; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D009942:Organometallic Compounds / Q000008:administration & dosage; D019047:Phantoms, Imaging; D013997:Time Factors
chemical_list: D003287:Contrast Media; D009942:Organometallic Compounds; C112666:gadoversetamide
keywords: MR studies; coronary artery disease; myocardial blood flow quantification; myocardial perfusion; radial acquisition