Vertebral Artery Hypoplasia

Abstract

Background and Purpose-Vertebral artery hypoplasia (VAH) is supposed to be a risk factor for posterior circulation ischemia (PCI), particularly in the territory of the posterior inferior cerebellar artery (PICA). The aim of our study was to determine whether VAH impedes perfusion in the dependent PICA territory even in the absence of manifest PCI. Methods-VA diameter was retrospectively measured in 934 consecutive patients who underwent whole-brain multimodal computed tomography because of suspected stroke. VAH was defined by a diameter of ≤2 mm and an asymmetry ratio of ≤1:1.7 of both VAs. We performed blinded computed tomography perfusion reading in patients with VAH without PCI (MRI-confirmed) and in control patients (ratio 1:2) with normal VAs. Four different perfusion maps were evaluated for a relative hypoperfusion in the PICA territory. Results-VAH was found in 146 of 934 patients (15.6%). It was more frequent on the right side (66.1%). Of 146 patients, 59without PCI qualified for computed tomography perfusion analysis. Depending on the perfusion map, ≤42.4% (25/59) of patients with VAH, but only 7.6% (9/118) without VAH, showed an ipsilateral PICA hypoperfusion (P<0.001). Sensitivities in patients with VAH were as follows: time to drain 42.4% (25/59)>mean transit time 39.0% (23/59)>cerebral blood flow 25.4% (15/59). Cerebral blood volume was never affected. Conclusions-VAH is a frequent vascular variant that can lead to a relative regional hypoperfusion in the PICA territory.Additional research should clarify the pathophysiological role of VAH in PCI.

Cerebellar Hypoperfusion in Migraine Attack: Incidence and Significance

“…Fifty-two percent of patients with oligemia presented with abnormal cerebellar perfusion, and 39.1% fulfilled the criteria for CCD, rendering it a frequent consequence of cortical spreading depression unrelated to vertebral artery hypoplasia. 25 Cerebellar hypoperfusion in patients with stroke is associated with a worse clinical outcome than if it was not present, related to deafferentation and transneural metabolic depression. 26 In seizure-related CCD, the outcome is variable, ranging from complete neurologic recovery to permanent disability depending on the duration of prolonged excitatory synaptic activity affecting cortico-ponto-cerebellar pathways.…”

Evaluating the morphological changes of intracranial arteries and whole-brain perfusion in undetermined isolated vertigo

“…VA hypoplasia (VAH) was defined as a V4 diameter of ≤ 2.0 mm [20], [21]. In this study, VAH was considered as a synonym of contralateral VAD.…”

“…The territories of PCA were the occipitotemporal lobe and the thalamus. The definition of VA blood flow distribution was the cerebellum derives from branches arising from posterior inferior cerebellar artery (PICA), and the main territory of BA was the brainstem [16], [21].…”

Cerebellar Cortical Infarct Cavities

“…Nevertheless, most cerebellar cortical cavities occur in the posterior lobe of the cerebellum, 15 which is largely perfused by the posterior inferior cerebellar arteries arising from the vertebral arteries, the flow of which was not assessed in this study. 37,38 A final interesting observation of this study was the significant association between cerebellar cortical cavities and brain atrophy, which persisted after correction for supratentorial infarcts. We hypothesize that this association could be mediated by concomitant supratentorial cerebrovascular lesions below the detection limit of 1.5-Tesla MRI, such as cerebral microinfarcts.…”