title: Computed Tomographic Distinction of Intimal and Medial Calcification in the Intracranial Internal Carotid Artery.
abstract: BACKGROUND
  Intracranial internal carotid artery (iICA) calcification is associated with stroke and is often seen as a proxy of atherosclerosis of the intima. However, it was recently shown that these calcifications are predominantly located in the tunica media and internal elastic lamina (medial calcification). Intimal and medial calcifications are thought to have a different pathogenesis and clinical consequences and can only be distinguished through ex vivo histological analysis. Therefore, our aim was to develop CT scoring method to distinguish intimal and medial iICA calcification in vivo.
  
  
  METHODS
  First, in both iICAs of 16 cerebral autopsy patients the intimal and/or medial calcification area was histologically assessed (142 slides). Brain CT images of these patients were matched to the corresponding histological slides to develop a CT score that determines intimal or medial calcification dominance. Second, performance of the CT score was assessed in these 16 patients. Third, reproducibility was tested in a separate cohort.
  
  
  RESULTS
  First, CT features of the score were circularity (absent, dot(s), <90°, 90-270° or 270-360°), thickness (absent, ≥1.5mm, or <1.5mm), and morphology (indistinguishable, irregular/patchy or continuous). A high sum of features represented medial and a lower sum intimal calcifications. Second, in the 16 patients the concordance between the CT score and the dominant calcification type was reasonable. Third, the score showed good reproducibility (kappa: 0.72 proportion of agreement: 0.82) between the categories intimal, medial or absent/indistinguishable.
  
  
  CONCLUSIONS
  The developed CT score shows good reproducibility and can differentiate reasonably well between intimal and medial calcification dominance in the iICA, allowing for further (epidemiological) studies on iICA calcification.
authors.affiliation: Department of Radiology, University Medical Center, Utrecht, Utrecht, The Netherlands.
authors.forename: Remko
authors.identifier: http://orcid.org/0000-0001-5208-5534
authors.initials: R
authors.lastname: Kockelkoren
authors.affiliation: Department of Pathology, University Medical Center, Utrecht, Utrecht, The Netherlands.
authors.forename: Annelotte
authors.initials: A
authors.lastname: Vos
authors.affiliation: Department of Pathology, University Medical Center, Utrecht, Utrecht, The Netherlands.
authors.forename: Wim
authors.initials: W
authors.lastname: Van Hecke
authors.affiliation: Department of Pathology, University Medical Center, Utrecht, Utrecht, The Netherlands.
authors.forename: Aryan
authors.initials: A
authors.lastname: Vink
authors.affiliation: Department of Anatomy, University Medical Center, Utrecht, Utrecht, The Netherlands.
authors.forename: Ronald L A W
authors.initials: RL
authors.lastname: Bleys
authors.affiliation: Department of Anatomy, University Medical Center, Utrecht, Utrecht, The Netherlands.
authors.forename: Daphne
authors.initials: D
authors.lastname: Verdoorn
authors.affiliation: Department of Radiology, University Medical Center, Utrecht, Utrecht, The Netherlands.
authors.forename: Willem P Th M
authors.initials: WP
authors.lastname: Mali
authors.affiliation: Department of Radiology, University Medical Center, Utrecht, Utrecht, The Netherlands.
authors.forename: Jeroen
authors.initials: J
authors.lastname: Hendrikse
authors.affiliation: Department of Geriatrics, University Medical Center, Utrecht, Utrecht, The Netherlands.
authors.forename: Huiberdina L
authors.initials: HL
authors.lastname: Koek
authors.affiliation: Department of Radiology, University Medical Center, Utrecht, Utrecht, The Netherlands.
authors.forename: Pim A
authors.initials: PA
authors.lastname: de Jong
authors.affiliation: Department of Radiology, University Medical Center, Utrecht, Utrecht, The Netherlands.
authors.forename: Jill B
authors.initials: JB
authors.lastname: De Vis
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002343:Carotid Artery, Internal / Q000000981:diagnostic imaging* / Q000473:pathology; D015331:Cohort Studies; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D014057:Tomography, X-Ray Computed; D017539:Tunica Intima / Q000000981:diagnostic imaging*; D017540:Tunica Media / Q000000981:diagnostic imaging* / Q000473:pathology; D061205:Vascular Calcification / Q000000981:diagnostic imaging* / Q000473:pathology