title: Comparison of carotid plaque ulcer detection using contrast-enhanced and time-of-flight MRA techniques.
abstract: OBJECTIVE
  Ulceration in carotid plaque is a risk indicator for ischemic stroke. Our aim was to compare plaque ulcer detection by standard TOF and CE-MRA techniques and to identify factors that influence its detection.
  
  
  METHODS
  Carotid MR imaging scans were acquired on 2066 participants in the ARIC study. We studied the 600 thickest plaques. TOF-MRA, CE-MRA, and black-blood MR images were analyzed together to define ulcer presence (plaque surface niche ≥2 mm in depth). Sixty ulcerated arteries were detected. These arteries were randomly assigned, along with 40 nonulcerated plaques from the remaining 540, for evaluation of ulcer presence by 2 neuroradiologists. Associations between ulcer detection and ulcer characteristics, including orientation, location, and size, were determined and explored by CFD modeling.
  
  
  RESULTS
  One CE-MRA and 3 TOF-MRAs were noninterpretable and excluded. Of 71 ulcers in 56 arteries, readers detected an average of 39 (55%) on both TOF-MRA and CE-MRA, 26.5 (37.5%) only on CE-MRA, and 1 (1.5%) only on TOF-MRA, missing 4.5 (6%) ulcers by both methods. Ulcer detection by TOF-MRA was associated with its orientation (distally pointing versus perpendicular: OR = 5.57 [95% CI, 1.08-28.65]; proximally pointing versus perpendicular: OR = 0.21 [95% CI, 0.14-0.29]); location relative to point of maximum stenosis (distal versus isolevel: OR = 5.17 [95% CI, 2.10-12.70]); and neck-to-depth ratio (OR = 1.96 [95% CI, 1.11-3.45]) after controlling for stenosis and ulcer volume.
  
  
  CONCLUSIONS
  CE-MRA detects more ulcers than TOF-MRA in carotid plaques. Missed ulcers on TOF-MRA are influenced by ulcer orientation, location relative to point of maximum stenosis, and neck-to-depth ratio.
authors.affiliation: Russell H. Morgan Department of Radiology and Radiological Sciences, The Johns Hopkins Hospital, Baltimore, Maryland 21287, USA.
authors.forename: M
authors.initials: M
authors.lastname: Etesami
authors.forename: Y
authors.initials: Y
authors.lastname: Hoi
authors.forename: D A
authors.initials: DA
authors.lastname: Steinman
authors.forename: S K
authors.initials: SK
authors.lastname: Gujar
authors.forename: A E
authors.initials: AE
authors.lastname: Nidecker
authors.forename: B C
authors.initials: BC
authors.lastname: Astor
authors.forename: A
authors.initials: A
authors.lastname: Portanova
authors.forename: Y
authors.initials: Y
authors.lastname: Qiao
authors.forename: W M A
authors.initials: WM
authors.lastname: Abdalla
authors.forename: B A
authors.initials: BA
authors.lastname: Wasserman
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D016893:Carotid Stenosis / Q000175:diagnosis*; D003287:Contrast Media; D005260:Female; D019786:Gadolinium DTPA; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods*; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D015588:Observer Variation; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D003287:Contrast Media; C064925:gadodiamide; D019786:Gadolinium DTPA