INTRODUCTION: Vascular pathology in the extracranial vertebral arteries remains among the possible causes in cryptogenic stroke. However, the diagnosis is challenged by the great variety in the anatomy of the vertebral arteries, clinical symptoms and difficulties in the radiological assessments. The aim of this study was to assess the prevalence of CT angiography (CTA)-detected pathological findings in the extracranial vertebral arteries in an acute stroke population and secondly to determine the frequency of posterior pathology as probable cause in patients with otherwise cryptogenic stroke. METHOD: The analysis was based on 657 consecutive patients with symptoms of acute stroke and a final diagnosis of ischemic stroke or transient ischemic attack. On admission, a noncontrast CT cerebrum and CTA were performed. A senior consultant neuroradiologist, blinded to clinical data, reviewed all CTA scans systematically, assessing the four segments of the extracranial vertebral arteries. First, the frequency of pathological findings including stenosis, plaques, dissection, kinked artery and coiling was assessed. Subsequently, we explored the extent of the pathological findings that were the most plausible causes of stroke, namely either a possible dissection or a kinked artery. RESULTS: Findings in the extracranial vertebral arteries included significant stenosis (0.8%), atherosclerotic plaque types (3.8%), possible dissections (2.6%), kinked arteries (2.6%) and coiling (32.0%). Eighteen patients (2.8%) with pathological findings had an unknown cause of stroke, likely posterior symptoms and no clinical stroke symptoms from the anterior circuit. Of these, 3 cases were kinked arteries (0.5%) and 15 cases (2.3%) were possible dissections. CONCLUSION: We found that in approximately 3% of the study population, the most plausible cause of the cryptogenic strokes was due to a pathological finding in the posterior extracranial vertebral arteries, being either a possible dissection or a kinked artery. In general, posterior vascular pathology is not uncommon, and CTA is a useful modality in the detection of changes based on characteristics and locations of findings in the extracranial vertebral arteries. Ultrasound examination can be a useful supplementary tool in deciding the consequence of vascular findings on CTA.