title: Quantification of intracranial internal carotid artery calcification on brain unenhanced CT: evaluation of its feasibility and assessment of the reliability of visual grading scales.
abstract: OBJECTIVE
  Previous studies have evaluated intracranial internal carotid artery calcifications (ICACs) qualitatively using different visual grading scales, which could lead to inconsistent results. The purpose of this study was to evaluate the feasibility of ICAC volume measurement and to correlate the volume with visual grading scales.
  
  
  METHODS
  We included 49 patients (>50 years) who underwent unenhanced cranial CT. Two observers evaluated four visual grading scales and measured ICAC volumes semi-automatically, and interobserver agreements were assessed. Differences in ICAC volume between visual grades of each scale were tested. The relationship between the visual grading and volume was assessed.
  
  
  RESULTS
  Interobserver agreements ranged from 0.841 to 0.901 for visual grading and 0.997 for volume measurement. Mean volumes were not significantly different between the visual grades (P > 0.05) except when comparing grade 4 with the other grades. The grades of each visual grading correlated well with ICAC volumes (Spearman's ρ = 0.849-0.881, P < 0.001). The relationship between the visual grades and volume was described by a quadratic model (R (2), 0.31-0.50, P < 0.01).
  
  
  CONCLUSIONS
  ICAC volume measurement is feasible and reproducible, whereas visual grades poorly reflect the actual volume; therefore, volume measurement may be warranted for future research.
authors: Department of Radiology and the Research Institute of Radiological Science, Yonsei University College of Medicine, Seoul, South Korea.
authors: Sung Soo
authors: SS
authors: Ahn
authors: Hyo Suk
authors: HS
authors: Nam
authors: Ji Hoe
authors: JH
authors: Heo
authors: Young Dae
authors: YD
authors: Kim
authors: Seung-Koo
authors: SK
authors: Lee
authors: Kyunghwa
authors: K
authors: Han
authors: Eung Yeop
authors: EY
authors: Kim
mesh_terms: D000368:Aged; D002114:Calcinosis / Q000000981:diagnostic imaging*; D002340:Carotid Artery Diseases / Q000000981:diagnostic imaging*; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011857:Radiographic Image Interpretation, Computer-Assisted; D015203:Reproducibility of Results; D014057:Tomography, X-Ray Computed / Q000379:methods*