title: Aneurysms in twig-like middle cerebral artery.
abstract: BACKGROUND
  We report a vascular abnormality of the middle cerebral artery (MCA) that has not been described in the literature before.
  
  
  METHODS
  Two patients (1 male and 1 female; age 44 and 67 years, respectively) were found to have a vascular abnormality in which the main trunk of the MCA had a twig-like form. Both patients presented with intracranial hemorrhage.
  
  
  RESULTS
  In these 2 patients, the abnormality was seen before the genu of the MCA. They had an intracranial hemorrhage due to an associated aneurysm inside the twigs. The twig appeared to be a network between the bifurcation of internal carotid artery and insular segment of MCA, and it was different from the collateral circulation due to acquired occlusion or moyamoya disease.
  
  
  CONCLUSIONS
  This new type of vascular lesion of the MCA is not benign. It appears to be associated with the occurrence of an aneurysm, an important clinical aspect.
authors.affiliation: Department of Radiology, Division of Neurosurgery, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan. hml@ha.mc.ntu.edu.tw
authors.forename: Hon-Man
authors.initials: HM
authors.lastname: Liu
authors.forename: Dar-Ming
authors.initials: DM
authors.lastname: Lai
authors.forename: Yong-Kwang
authors.initials: YK
authors.lastname: Tu
authors.forename: Yao-Hung
authors.initials: YH
authors.lastname: Wang
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D002532:Intracranial Aneurysm / Q000000981:diagnostic imaging* / Q000601:surgery; D018810:Magnetic Resonance Angiography; D008297:Male; D020768:Middle Cerebral Artery / Q000002:abnormalities*; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome