Vertebral Artery Hypoplasia is Associated With A Decrease in Net Vertebral Flow Volume

Yen Yu Chen, A. Ching Chao, Hung Yi Hsu, Chih Ping Chung, Han Hwa Hu

Research output: Contribution to journalArticlepeer-review

51 Citations (Scopus)


The definition and clinical significance of vertebral artery hypoplasia (VAH) remain inconclusive. VAH has been proposed as a predisposing factor of posterior circulation ischemic stroke. The aim of this study was to determine a best cut-off diameter of vertebral artery (VA) for VAH and to investigate if unilateral VAH is associated with a decrease in net vertebral flow volume. Retrospective data of 1000 presumably healthy subjects free of cerebrovascular disease or apparent carotid atherosclerosis were analysed. We found that a VA diameter ≤2.5 mm is an ideal value to define VAH. The flow volume of the identified hypoplastic VA was remarkably low and the contralateral VA had only a slightly increased compensatory flow volume. The net VA flow volumes remained significantly and markedly lower in subjects with unilateral VAH (140.7 ± 46.2 mL/min) than those in subjects without VAH (190.1 ± 54.5 mL/min, p < 0.001). Flow volume insufficiency of VA (defined as a net VA flow volume less than 100 mL/min) occurred more frequently in individuals with VAH than in those without VAH (22.1% vs. 2.4%, p < 0.001). Our study suggested that asymptomatic subjects with VAH had a significantly lower net VA flow volume and a higher frequency of VA flow insufficiency than the control group. (E-mail:

Original languageEnglish
Pages (from-to)38-43
Number of pages6
JournalUltrasound in Medicine and Biology
Issue number1
Publication statusPublished - Jan 1 2010
Externally publishedYes

ASJC Scopus subject areas

  • Radiological and Ultrasound Technology
  • Biophysics
  • Acoustics and Ultrasonics


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