title: Accuracy of a novel risk index combining degree of stenosis of the carotid artery and plaque surface echogenicity.
abstract: OBJECTIVE
  The purpose of this study was to determine the accuracy of a risk index in symptomatic or asymptomatic carotid stenoses.
  
  
  METHODS
  Consecutive patients presenting 50% to 99% carotid stenoses were included. A semiautomated gray scale-based color mapping (red, yellow, and green) of the whole plaque and of its surface was achieved. Surface was defined as the region located between the lumen (Level 0) and, respectively, 0.5, 1, 1.5, and 2 mm. Risk index was based on a combination of degree of stenosis and the proportion of the red color (reflecting low echogenicity) on the surface or on the whole plaque.
  
  
  RESULTS
  There were 67 (36%) symptomatic and 117 (64%) asymptomatic carotid stenoses. Risk index values were higher among symptomatic stenoses (0.46 mean versus 0.29; P<0.0001); on receiver operating characteristic curves, risk index presented a stronger predictive power compared with degree of stenosis or surface echogenicity alone. Also, in a regression model including age, gender, degree of stenosis, surface echogenicity, gray median scale of the whole plaque, and risk index, risk index measured within the surface region located at 0.5 mm from the lumen was the only parameter significantly associated with the presence of symptoms (OR, 4.89; 95% CI, 2.7-8.7; P=0.0000002). The best criterion to differentiate between symptomatic and asymptomatic stenoses was a risk index value >0.36 (sensitivity and specificity of 78% and 65%, respectively).
  
  
  CONCLUSIONS
  Risk index was significantly higher in the presence of symptoms and could therefore be a valuable tool to assess the clinical risk of a carotid plaque.
authors.affiliation: Department of Neurology, UniversityHospital Geneva and Medical School, Geneva, Switzerland.
authors.forename: Isabelle
authors.initials: I
authors.lastname: Momjian-Mayor
authors.forename: Igor
authors.initials: I
authors.lastname: Kuzmanovic
authors.forename: Shahan
authors.initials: S
authors.lastname: Momjian
authors.forename: Christophe
authors.initials: C
authors.lastname: Bonvin
authors.forename: Stefane
authors.initials: S
authors.lastname: Albanese
authors.forename: Denis
authors.initials: D
authors.lastname: Bichsel
authors.forename: Mario
authors.initials: M
authors.lastname: Comelli
authors.forename: Vitor Mendez
authors.initials: VM
authors.lastname: Pereira
authors.forename: Karl O
authors.initials: KO
authors.lastname: Lovblad
authors.forename: Roman F
authors.initials: RF
authors.lastname: Sztajzel
mesh_terms: D000367:Age Factors; D000368:Aged; D016893:Carotid Stenosis / Q000150:complications / Q000000981:diagnostic imaging* / Q000473:pathology*; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D012044:Regression Analysis; D012189:Retrospective Studies; D012307:Risk Factors; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D012737:Sex Factors; D020521:Stroke / Q000453:epidemiology*; D018608:Ultrasonography, Doppler