title: Vertebral artery terminating in posterior inferior cerebellar artery: A normal variation with clinical significance.
abstract: A vertebral artery (VA) terminating in a posterior inferior cerebellar artery (PICA) is often considered to be a normal variation associated with VA hypoplasia. We aimed to investigate the clinical significance of this cerebrovascular variant. A total of 80 patients with clinically evident cerebrovascular events in posterior circulation were examined by duplex sonography and magnetic resonance angiography (MRA). Eighty healthy subjects who had MRA check-up were recruited as controls. PICA termination of the VA (PICA-VA) was identified as the VA not communicating with the basilar artery (BA) but ending into a PICA. We compared the prevalence of PICA-VA and associated hemodynamic parameters between the patients with and without PICA-VA, and investigated their relationships with VA hypoplasia. The prevalence of PICA-VA was higher in the patient group than in the controls (18.7% vs. 6.3%, p = 0.015). Most measurements (73.3%) of PICA-VA did not fit the criteria of VA hypoplasia. In comparison with the non-PICA-terminating group, the PICA-VA has a smaller diameter (3.7 ± 0.7 mm vs. 3.0 ± 0.5 mm, p < 0.001), lower mean velocity (241 ± 100 mm/sec vs. 164 ± 88 mm/sec, p < 0.01), and higher pulsatility index (1.3 ± 0.5 vs. 1.9 ± 0.6, p < 0.001). Moreover, a smaller diameter of the BA (3.2 ± 0.5 mm vs. 2.5 ± 0.9 mm, p = 0.004) and the posterior cerebral artery (PCA) (2.0 ± 0.1 mm vs. 1.6 ± 0.1 mm, p = 0.006) were also noted in the PICA-VA group. The higher prevalence of PICA-VA in the patient group with smaller diameter of VA, BA and PCA reflected its clinical significance, suggesting that PICA-VA may have a detrimental impact on cerebral hemodynamics. However, the sample is small, and further studies are needed with larger sample size for confirmation.
authors.affiliation: Department of Neurology, Taipei Veterans General Hospital, Taipei, Taiwan.
authors.forename: I-Wen
authors.initials: IW
authors.lastname: Liu
authors.affiliation: Department of Neurology, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan.|Department of Neurology, Kaohsiung Municipal Gangshan Hospital, Kaohsiung, Taiwan.
authors.forename: Bo-Lin
authors.initials: BL
authors.lastname: Ho
authors.affiliation: Department of Neurology, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan.
authors.forename: Chien-Fu
authors.initials: CF
authors.lastname: Chen
authors.affiliation: Department of Neurology and Neuroscience Center, First Hospital of Jilin University, Changchun, Jilin, China.
authors.forename: Ke
authors.initials: K
authors.lastname: Han
authors.affiliation: Department of Radiology, Taipei Veterans General Hospital, School of Medicine, National Yang Ming University, Taipei, Taiwan.
authors.forename: Chung-Jung
authors.initials: CJ
authors.lastname: Lin
authors.affiliation: Department of Neurology, Taipei Veterans General Hospital, Taipei, Taiwan.
authors.forename: Wen-Yung
authors.initials: WY
authors.lastname: Sheng
authors.affiliation: Department of Neurology, Taipei Veterans General Hospital, Taipei, Taiwan.|Graduate Institute of Clinical Medicine and Department of Neurology, College of Medicine, Taipei Medical University and Hospital, Taipei, Taiwan.
authors.forename: Han-Hwa
authors.initials: HH
authors.lastname: Hu
authors.affiliation: Department of Neurology, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan.|Department of Neurology, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan.
authors.forename: A-Ching
authors.identifier: http://orcid.org/0000-0003-1230-9622
authors.initials: AC
authors.lastname: Chao
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D063405:Anatomic Variation; D001158:Arteries / Q000033:anatomy & histology* / Q000000981:diagnostic imaging / Q000502:physiology / Q000503:physiopathology; D001488:Basilar Artery / Q000000981:diagnostic imaging; D002531:Cerebellum / Q000098:blood supply* / Q000000981:diagnostic imaging; D002533:Cerebral Angiography; D002561:Cerebrovascular Disorders / Q000000981:diagnostic imaging / Q000453:epidemiology / Q000503:physiopathology; D005260:Female; D006439:Hemodynamics; D006801:Humans; D018810:Magnetic Resonance Angiography; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D012307:Risk Factors; D018616:Ultrasonography, Doppler, Duplex; D014711:Vertebral Artery / Q000033:anatomy & histology* / Q000000981:diagnostic imaging / Q000502:physiology / Q000503:physiopathology