title: Evaluation of vertebral artery dominance, hypoplasia and variations in the origin: angiographic study in 254 patients.
abstract: BACKGROUND
  The aim of this study was to determine the dimensional characteristics and variations in the origin of vertebral arteries (VA).
  
  
  METHODS
  We retrospectively reviewed angiographic studies in 254 patients (133 males, 121 females) for the evaluation of diameter differences in VA. We examined different criteria from the literature (difference of ≥ 0.3 mm, ≥ 0.8 mm, ≥ 1 mm between the widths of two VA and diameter ratio more than 1.4) to find out the dominant VA, rate of co-dominance and hypoplasia. The differences among groups were analysed using the c2 and Kruskal-Wallis test. Also concordance analysis test was used to determine correspondence between the tests. We also noticed the variations in the origin of VA.
  
  
  RESULTS
  The average diameter of VA in 254 patients was 3.21 ± 0.7 mm on the right, and 3.16 ± 0.7 mm on the left. The average diameter difference was found 0.88 ± 0.7 mm. The rate of hypoplasia was found 7.1% on the right and 9.4% on the left. Among 254 patients according to the criterion of any diameter difference; right side was found wider in 126 (49.6%) patients and left side was found wider in 120 (47.2%) patients. The criterion of 0.3 mm or greater difference showed right VA dominance in 107 (42.1%) patients, left VA dominance in 99 (39%) patients. Co-dominance was mainly observed when we used the criteria of 0.8 mm and 1 mm or greater difference and diameter ratio more than 1.4. We found out harmony of two criterion of difference of ≥ 0.8 mm and ≥ 1 mm (concordance analysis test, 76.1%). There was no statistically significant relation between age, gender and any dominance criteria (p > 0.05). The majority of VA showed classical origin arising from both subclavian arteries with a rate of 94.9%.
  
  
  CONCLUSIONS
  The most striking result we have found is the dominance of the right VA in diameter by using all different criteria unlike with previous reports in the literature.
authors.affiliation: Department of Radiology, Ankara Diskapi Yildirim Beyazit Training and Research Hospital, Ankara, Turkey. onurergun@yahoo.com.
authors.forename: O
authors.initials: O
authors.lastname: Ergun
authors.forename: I
authors.initials: I
authors.lastname: Gunes Tatar
authors.forename: E
authors.initials: E
authors.lastname: Birgi
authors.forename: B
authors.initials: B
authors.lastname: Hekimoglu
mesh_terms: D000792:Angiography; D001013:Aorta, Thoracic; D005260:Female; D006801:Humans; D008297:Male; D013348:Subclavian Artery; D014711:Vertebral Artery
keywords: anatomic variation; angiography; vertebral artery