title: Branching patterns determine the size of single subcortical infarctions.
abstract: OBJECTIVE
  The size variation of single subcortical infarcts (SSIs) may be because of differences in stroke mechanisms or branching patterns of perforators. We aim to investigate this issue using high-resolution MRI.
  
  
  METHODS
  Patients with high-resolution MRI-identified SSI without significant (≥50%) middle cerebral artery stenosis were enrolled. Perforator stems were defined as perforators originating from the middle cerebral artery and perforator branches as linear structures inside the infarcted area, traceable from >2 adjacent slices. The branching index was calculated as the number of perforator branches divided by the number of perforator stems. Clinical and imaging characteristics were compared between large (≥20 mm in diameter) and small SSI groups.
  
  
  RESULTS
  Forty-one patients (10 large and 31 small SSIs) were enrolled. Larger SSIs were more closely associated with diabetes mellitus and severe neurological dysfunction but not with the presence of middle cerebral artery plaque. Although there was no difference in the number of perforator stems, the number of perforator branches (4.8±2.2 versus 2.3±1.4; P=0.005) and branching index (2.9±1.0 versus 1.2±0.8; P<0.001) was higher in the large SSI group. SSI diameter showed a significant correlation with the number of perforator branches (r=0.630; P<0.001) and branching index (r=0.750; P<0.001).
  
  
  CONCLUSIONS
  SSI diameter seems to be associated with anatomic branching variation rather than the mechanism of stroke. Definition of small vessel disease with lesion diameter criteria may not be appropriate.
authors.affiliation: From the Departments of Neurology (B.J.K., D.-W.K., S.U.K., J.S.K.) and Neuroradiology (D.H.L.), University of Ulsan, Asan Medical Center, Seoul, Korea.
authors.forename: Bum Joon
authors.initials: BJ
authors.lastname: Kim
authors.forename: Deok Hee
authors.initials: DH
authors.lastname: Lee
authors.forename: Dong-Wha
authors.initials: DW
authors.lastname: Kang
authors.forename: Sun U
authors.initials: SU
authors.lastname: Kwon
authors.forename: Jong S
authors.initials: JS
authors.lastname: Kim
mesh_terms: D000368:Aged; D002544:Cerebral Infarction / Q000145:classification / Q000473:pathology* / Q000503:physiopathology; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D020768:Middle Cerebral Artery / Q000473:pathology* / Q000503:physiopathology; D056910:Republic of Korea; D014057:Tomography, X-Ray Computed
keywords: magnetic resonance imaging