{'fraction_non_alphanumeric': 0.01834862385321101, 'fraction_numerical': 0.002117148906139732, 'mean_word_length': 5.950980392156863, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
[Repeated vertebrobasilar ischemic stroke caused by an intracranial vertebral artery dissection not detected on the initial angiogram: a case report].

Spontaneous dissection of the intracranial vertebral artery has been increasingly recognized as a cause of vertebrobasilar ischemic stroke. However, little is known about its natural history and clinical course. The authors report a young patient with repeated cerebral infarction in the posterior cerebral circulation caused by dissection of the vertebral artery, which was not detected on the first angiogram. The otherwise healthy 22-year-old male suddenly developed visual disturbance. Neuroradiological examination revealed right occipital infarction, but cerebral aniography revealed no caliber change or other pathological findings. He was treated with antiplatelet therapy. Two years later, he suffered vertigo, nausea, and dysarthria due to newly developed left cerebellar and medullary infarction. Cerebral angiography revealed left vertebral artery occlusion. T1-weighted MR image demonstrated Gadlinium-enhanced intramural hematoma in the occluded left vertebral artery, which was compatible to the arterial dissection. The present case argues serial neuroimaging studies especially in young patients with vertebrobasilar stroke in order to rule out the arterial dissection, even if initial angiography failed to demonstrate any radiographical evidence.