title: In vivo quantitative measurement of intact fibrous cap and lipid-rich necrotic core size in atherosclerotic carotid plaque: comparison of high-resolution, contrast-enhanced magnetic resonance imaging and histology.
abstract: BACKGROUND
  Previous studies with contrast-enhanced magnetic resonance imaging (CEMRI) have shown that the fibrous cap (FC) in atherosclerotic carotid plaques enhances with gadolinium-based contrast agents. Conversely, the lipid-rich necrotic core (LR-NC), lacking both vasculature and matrix, shows no or only slight enhancement. The goal of this study was to assess whether CEMRI can be used to accurately measure the dimensions of the intact FC and LR-NC.
  
  
  RESULTS
  Twenty-one patients scheduled for carotid endarterectomy were imaged with a 1.5-T scanner. Precontrast images and CEMRI were obtained. One hundred eight locations with an intact FC were matched between MRI and the excised histology specimens. Quantitative measurements of FC length along the lumen circumference, FC area, and LR-NC area were collected from CEMRI images and histology sections. Blinded comparison of corresponding MR images and histology slices showed moderate to good correlation for length (r=0.73, P<0.001) and area (r=0.80, P<0.001) of the intact FC. The mean percentage LR-NC areas (LR-NC area/wall area) measured by CEMRI and histology were 30.1% and 32.7%, respectively, and were strongly correlated across locations (r=0.87, P<0.001).
  
  
  CONCLUSIONS
  In vivo high-resolution CEMRI is capable of quantitatively measuring the dimensions of the intact FC and LR-NC. These new parameters may be useful to evaluate plaque vulnerability and provide continuous variables for characterizing the intact FC and LR-NC in progression and regression studies.
authors.affiliation: Department of Radiology, University of Washington, Seattle, WA, USA.
authors.forename: Jianming
authors.initials: J
authors.lastname: Cai
authors.forename: Thomas S
authors.initials: TS
authors.lastname: Hatsukami
authors.forename: Marina S
authors.initials: MS
authors.lastname: Ferguson
authors.forename: William S
authors.initials: WS
authors.lastname: Kerwin
authors.forename: Tobias
authors.initials: T
authors.lastname: Saam
authors.forename: Baocheng
authors.initials: B
authors.lastname: Chu
authors.forename: Norihide
authors.initials: N
authors.lastname: Takaya
authors.forename: Nayak L
authors.initials: NL
authors.lastname: Polissar
authors.forename: Chun
authors.initials: C
authors.lastname: Yuan
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D050197:Atherosclerosis / Q000473:pathology*; D002340:Carotid Artery Diseases / Q000473:pathology*; D003287:Contrast Media; D005260:Female; D005682:Gadolinium; D006652:Histological Techniques; D006801:Humans; D008055:Lipids; D008279:Magnetic Resonance Imaging / Q000379:methods* / Q000592:standards; D008297:Male; D008875:Middle Aged; D009336:Necrosis; D015203:Reproducibility of Results
chemical_list: D003287:Contrast Media; D008055:Lipids; D005682:Gadolinium