title: A1 segment hypoplasia accompanied by AcomA aneurysms assessed with magnetic resonance angiography.
abstract: OBJECTIVE
  This study is to evaluate the use of three-dimensional time-of-flight magnetic resonance angiography (3D-TOF MRA) at 3.0 T for the detection and classification of A1 segment hypoplasia based on a large case series and investigates the potential links with AcomA aneurysm occurrence.
  
  
  METHODS
  Between January 2009 and June 2012, 8,013 patients underwent MRA examination at 3.0 T in our hospital. MRA was performed using 3D-TOF with volume rendering technique. The presence and location of A1 segment hypoplasia and AcomA aneurysm was reviewed.
  
  
  RESULTS
  Among the 8,013 patients examined, 138 patients were identified with AcomA aneurysms. 425 patients were defined with A1 segment hypoplasia, among whom 303 right-sided A1 hypoplasia and 122 left-sided A1 hypoplasia. 60 of these 425 patients were confirmed with AcomA aneurysms, among them were 49 right-sided A1 hypoplasia. The prevalence of AcomA aneurysm with A1 segment hypoplasia was 14.1 %, which was much higher compared with that (1.0 %) of AcomA aneurysm without A1 segment hypoplasia (P < 0.001).
  
  
  CONCLUSIONS
  The incidence of right-sided A1 segment hypoplasia either accompanied with AcomA aneurysm or not was much greater than that of left-sided. Intracranial AcomA aneurysm development appeared to be associated with A1 segment hypoplasia.
authors.affiliation: Institute of Diagnostic and Interventional Radiology, The Shanghai Sixth People's Hospital, Shanghai Jiao Tong University, 600 Yi Shan Road, 200233, ShangHai, China, stevnish@gmail.com.
authors.forename: Hao
authors.initials: H
authors.lastname: Chen
authors.forename: Ming-Hua
authors.initials: MH
authors.lastname: Li
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002941:Circle of Willis / Q000002:abnormalities*; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D021621:Imaging, Three-Dimensional; D002532:Intracranial Aneurysm / Q000175:diagnosis* / Q000453:epidemiology; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015995:Prevalence
references.citation: N Engl J Med. 1994 Jun 2;330(22):1565-70
references.pmid: 8177246
references.citation: AJNR Am J Neuroradiol. 1996 Aug;17(7):1295-301
references.pmid: 8871715
references.citation: Tohoku J Exp Med. 1980 Sep;132(1):69-73
references.pmid: 7209970
references.citation: Surg Radiol Anat. 2012 Oct;34(8):777-80
references.pmid: 22271161
references.citation: Stroke. 1999 Jul;30(7):1432-9
references.pmid: 10390319
references.citation: Neurology. 2011 Aug 16;77(7):667-76
references.pmid: 21775735
references.citation: Surg Radiol Anat. 2011 Aug;33(6):531-8
references.pmid: 21328075
references.citation: Magn Reson Med Sci. 2008;7(4):169-78
references.pmid: 19110511
references.citation: J Biomech. 2010 Aug 10;43(11):2189-95
references.pmid: 20447636
references.citation: Stroke. 1984 Sep-Oct;15(5):846-50
references.pmid: 6474536
references.citation: Neurology. 2008 Feb 26;70(9):700-5
references.pmid: 18299521
references.citation: Eur Radiol. 2005 Mar;15(3):441-7
references.pmid: 15678323
references.citation: Clin Neuropathol. 1991 Jul-Aug;10(4):187-9
references.pmid: 1884526
references.citation: Neuroradiology. 2006 Sep;48(9):647-52
references.pmid: 16786350
references.citation: J Neurosurg. 1991 Dec;75(6):950-3
references.pmid: 1823542
references.citation: AJNR Am J Neuroradiol. 2009 Feb;30(2):297-302
references.pmid: 19131411
references.citation: AJNR Am J Neuroradiol. 2010 Aug;31(7):1186-91
references.pmid: 20360345
references.citation: Neurol Res. 1991 Dec;13(4):253-6
references.pmid: 1687336