title: Computer-aided detection and evaluation of lipid-rich plaque on noncontrast cardiac CT.
abstract: OBJECTIVE
  Noncontrast electron beam CT (EBCT) and MDCT are established for the assessment of calcified plaque, but not lipid-rich plaque. We developed software to identify lipid-rich plaque with noncontrast electron beam tomography (EBT) and MDCT.
  
  
  METHODS
  A computer algorithm was developed to automatically find contiguous lipid-rich lesions with voxel intensities below a calculated patient-specific lipid threshold. Lipid density and lipid inhomogeneity in Hounsfield units were calculated in the proximal left coronaries of three populations: 34 low-risk patients (low-risk group < 6% Framingham risk score, no calcium), 31 high-risk patients (high-risk group > 20% Framingham risk score, no calcium), and 37 patients with calcified plaque (calcium group).
  
  
  RESULTS
  The mean lipid density was -19.6 +/- 3.0 (SD) H in the low-risk group, -25.3 +/- 8.2 H in the high-risk group, and -34.3 +/- 13.0 H in the calcium group (p < 0.05). The mean lipid inhomogeneity was 17.7 +/- 3.6 H in the low-risk group, 21.5 +/- 5.5 H in the high-risk group, and 29.0 +/- 7.6 H in the calcium group (p < 0.05). The mean interscan variability in lipid density and lipid inhomogeneity were 2.0 +/- 3.3 H and 2.1 +/- 3.6 H, respectively. In five patients, the locations of lipid-rich plaque correlated well with available intravascular sonography findings.
  
  
  CONCLUSIONS
  Our method may be able to identify lipid-rich plaque on noncontrast cardiac CT.
authors.affiliation: Department of Imaging, Cedars-Sinai Medical Center, 8700 Beverly Blvd., Rm. 1258, Los Angeles, CA 90048, USA.
authors.forename: Damini
authors.initials: D
authors.lastname: Dey
authors.forename: Tracy
authors.initials: T
authors.lastname: Callister
authors.forename: Piotr
authors.initials: P
authors.lastname: Slomka
authors.forename: Fatma
authors.initials: F
authors.lastname: Aboul-Enein
authors.forename: Hidetaka
authors.initials: H
authors.lastname: Nishina
authors.forename: Xingping
authors.initials: X
authors.lastname: Kang
authors.forename: Heidi
authors.initials: H
authors.lastname: Gransar
authors.forename: Nathan D
authors.initials: ND
authors.lastname: Wong
authors.forename: Romalisa
authors.initials: R
authors.lastname: Miranda-Peats
authors.forename: Sean
authors.initials: S
authors.lastname: Hayes
authors.forename: John D
authors.initials: JD
authors.lastname: Friedman
authors.forename: Daniel S
authors.initials: DS
authors.lastname: Berman
mesh_terms: D000328:Adult; D000368:Aged; D003327:Coronary Disease / Q000000981:diagnostic imaging*; D003936:Diagnosis, Computer-Assisted; D005260:Female; D006801:Humans; D008055:Lipids; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012984:Software; D014057:Tomography, X-Ray Computed
chemical_list: D008055:Lipids