title: Complex anomalies of type 1 proatlantal intersegmental artery and aortic arch variations.
abstract: OBJECTIVE
  We report a case of type 1 proatlantal intersegmental artery (PIA) associated with multiple anomalies of the aortic arch, and discuss the possible embryonic mechanism and clinical importance of the multiple cerebrovascular variants in this patient.
  
  
  METHODS
  A 65-year-old woman with dizziness underwent cerebral magnetic resonance (MR) imaging and head and neck MR angiography using a 3-tesla scanner and computed tomography (CT) angiography using a 64-slice multidetector CT scanner.
  
  
  RESULTS
  MR and CT angiography demonstrated an aneurysm of the distal end of the azygos anterior cerebral arteries and hypoplasia of the proximal right vertebral artery (VA) with an anastomotic artery, between the right internal carotid artery (ICA) and distal right VA that passed through the foramen magnum, indicating a type 1 PIA. She also demonstrated an aberrant right subclavian artery (ARSA) with hypoplasia of the right VA, and the left VA arose directly from the aortic arch.
  
  
  CONCLUSIONS
  To our knowledge, this is the first report of a type 1 PIA associated with multiple vascular anomalies of the aortic arch, such as ARSA and origin of the left VA from the arch. In cases of persistent anastomoses between the carotid and vertebrobasilar arteries, such as PIAs, imaging examination should include the aortic arch to identify associated vascular variations.
authors.affiliation: Department of Radiology, Saitama Medical University International Medical Center, 1397-1 Yamane, Hidaka, Saitama, 350-1298, Japan. naoko.saito.ns@gmail.com
authors.forename: Naoko
authors.initials: N
authors.lastname: Saito
authors.forename: Akira
authors.initials: A
authors.lastname: Uchino
authors.forename: Shoichiro
authors.initials: S
authors.lastname: Ishihara
mesh_terms: D000015:Abnormalities, Multiple; D000368:Aged; D000783:Aneurysm / Q000175:diagnosis; D001013:Aorta, Thoracic / Q000002:abnormalities* / Q000000981:diagnostic imaging / Q000473:pathology; D002343:Carotid Artery, Internal / Q000002:abnormalities* / Q000000981:diagnostic imaging / Q000473:pathology; D002536:Cerebral Arteries / Q000000981:diagnostic imaging / Q000473:pathology; D005260:Female; D006801:Humans; D018810:Magnetic Resonance Angiography / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods; D013348:Subclavian Artery / Q000002:abnormalities* / Q000000981:diagnostic imaging / Q000473:pathology; D014057:Tomography, X-Ray Computed / Q000379:methods; D054079:Vascular Malformations / Q000000981:diagnostic imaging* / Q000473:pathology*; D014711:Vertebral Artery / Q000002:abnormalities* / Q000000981:diagnostic imaging / Q000473:pathology