title: Definition of common carotid wall thickness affects risk classification in relation to degree of internal carotid artery stenosis: the Plaque At RISK (PARISK) study.
abstract: BACKGROUND
  Mean or maximal intima-media thickness (IMT) is commonly used as surrogate endpoint in intervention studies. However, the effect of normalization by surrounding or median IMT or by diameter is unknown. In addition, it is unclear whether IMT inhomogeneity is a useful predictor beyond common wall parameters like maximal wall thickness, either absolute or normalized to IMT or lumen size. We investigated the interrelationship of common carotid artery (CCA) thickness parameters and their association with the ipsilateral internal carotid artery (ICA) stenosis degree.
  
  
  METHODS
  CCA thickness parameters were extracted by edge detection applied to ultrasound B-mode recordings of 240 patients. Degree of ICA stenosis was determined from CT angiography.
  
  
  RESULTS
  Normalization of maximal CCA wall thickness to median IMT leads to large variations. Higher CCA thickness parameter values are associated with a higher degree of ipsilateral ICA stenosis (p < 0.001), though IMT inhomogeneity does not provide extra information. When the ratio of wall thickness and diameter instead of absolute maximal wall thickness is used as risk marker for having moderate ipsilateral ICA stenosis (>50%), 55 arteries (15%) are reclassified to another risk category.
  
  
  CONCLUSIONS
  It is more reasonable to normalize maximal wall thickness to end-diastolic diameter rather than to IMT, affecting risk classification and suggesting modification of the Mannheim criteria.
  
  
  BACKGROUND
  Clinical trials.gov NCT01208025 .
authors.affiliation: Biomedical Engineering, Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, The Netherlands.
authors.forename: J
authors.initials: J
authors.lastname: Steinbuch
authors.affiliation: Radiology, Erasmus Medical Center, Rotterdam, The Netherlands.|Neurology, Erasmus Medical Center, Rotterdam, The Netherlands.
authors.forename: A C
authors.initials: AC
authors.lastname: van Dijk
authors.affiliation: Radiology, Maastricht University Medical Center, Maastricht, The Netherlands.|Clinical Neurophysiology, Maastricht University Medical Center, PO Box 5800, 6202, Maastricht, AZ, The Netherlands.|Neurology, Maastricht University Medical Center, Maastricht, The Netherlands.
authors.forename: Fhbm
authors.initials: F
authors.lastname: Schreuder
authors.affiliation: Radiology, Maastricht University Medical Center, Maastricht, The Netherlands.|Clinical Neurophysiology, Maastricht University Medical Center, PO Box 5800, 6202, Maastricht, AZ, The Netherlands.|Neurology, Maastricht University Medical Center, Maastricht, The Netherlands.
authors.forename: Mtb
authors.initials: M
authors.lastname: Truijman
authors.affiliation: Radiology, University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: J
authors.initials: J
authors.lastname: Hendrikse
authors.affiliation: Neurology, Academic Medical Center, Amsterdam, The Netherlands.
authors.forename: P J
authors.initials: PJ
authors.lastname: Nederkoorn
authors.affiliation: Radiology, Erasmus Medical Center, Rotterdam, The Netherlands.
authors.forename: A
authors.initials: A
authors.lastname: van der Lugt
authors.affiliation: Radiology, Maastricht University Medical Center, Maastricht, The Netherlands.
authors.forename: E
authors.initials: E
authors.lastname: Hermeling
authors.affiliation: Biomedical Engineering, Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, The Netherlands.
authors.forename: Apg
authors.initials: A
authors.lastname: Hoeks
authors.affiliation: Clinical Neurophysiology, Maastricht University Medical Center, PO Box 5800, 6202, Maastricht, AZ, The Netherlands. werner.mess@mumc.nl.
authors.forename: W H
authors.initials: WH
authors.lastname: Mess
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D017536:Carotid Artery, Common / Q000000981:diagnostic imaging / Q000473:pathology*; D059168:Carotid Intima-Media Thickness; D016893:Carotid Stenosis / Q000145:classification / Q000000981:diagnostic imaging / Q000473:pathology*; D015331:Cohort Studies; D000072226:Computed Tomography Angiography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D014463:Ultrasonography
keywords: Atherosclerosis; Carotid IMT; Carotid artery imaging; Stenosis; Ultrasound