title: Post-stenotic Recirculating Flow May Cause Hemodynamic Perforator Infarction.
abstract: OBJECTIVE
  The primary mechanism underlying paramedian pontine infarction (PPI) is atheroma obliterating the perforators. Here, we encountered a patient with PPI in the post-stenotic area of basilar artery (BA) without a plaque, shown by high-resolution magnetic resonance imaging (HR-MRI). We performed an experiment using a 3D-printed BA model and a particle image velocimetry (PIV) to explore the hemodynamic property of the post-stenotic area and the mechanism of PPI.
  
  
  METHODS
  3D-model of a BA stenosis was reconstructed with silicone compound using a 3D-printer based on the source image of HR-MRI. Working fluid seeded with fluorescence particles was used and the velocity of those particles was measured horizontally and vertically. Furthermore, microtubules were inserted into the posterior aspect of the model to measure the flow rates of perforators (pre-and post-stenotic areas). The flow rates were compared between the microtubules.
  
  
  RESULTS
  A recirculating flow was observed from the post-stenotic area in both directions forming a spiral shape. The velocity of the flow in these regions of recirculation was about one-tenth that of the flow in other regions. The location of recirculating flow well corresponded with the area with low-signal intensity at the time-of-flight magnetic resonance angiography and the location of PPI. Finally, the flow rate through the microtubule inserted into the post-stenotic area was significantly decreased comparing to others (P<0.001).
  
  
  CONCLUSIONS
  Perforator infarction may be caused by a hemodynamic mechanism altered by stenosis that induces a recirculation flow. 3D-printed modeling and PIV are helpful understanding the hemodynamics of intracranial stenosis.
authors.affiliation: Department of Neurology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
authors.forename: Bum Joon
authors.initials: BJ
authors.lastname: Kim
authors.affiliation: Center for Biofluid and Biomimic Research, Department of Mechanical Engineering, Pohang University of Science and Technology, Pohang, Korea.
authors.forename: Hojin
authors.initials: H
authors.lastname: Ha
authors.affiliation: Center for Biofluid and Biomimic Research, Department of Mechanical Engineering, Pohang University of Science and Technology, Pohang, Korea.
authors.forename: Hyung Kyu
authors.initials: HK
authors.lastname: Huh
authors.affiliation: Asan Institute of Life Science, Asan Medical Center, Seoul, Korea.
authors.forename: Guk Bae
authors.initials: GB
authors.lastname: Kim
authors.affiliation: Department of Neurology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
authors.forename: Jong S
authors.initials: JS
authors.lastname: Kim
authors.affiliation: Department of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.|Department of Convergence Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
authors.forename: Namkug
authors.initials: N
authors.lastname: Kim
authors.affiliation: Center for Biofluid and Biomimic Research, Department of Mechanical Engineering, Pohang University of Science and Technology, Pohang, Korea.
authors.forename: Sang-Joon
authors.initials: SJ
authors.lastname: Lee
authors.affiliation: Department of Neurology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
authors.forename: Dong-Wha
authors.initials: DW
authors.lastname: Kang
authors.affiliation: Department of Neurology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
authors.forename: Sun U
authors.initials: SU
authors.lastname: Kwon
keywords: Cerebral blood flow; Experimental; Hemodynamics; Perforator infarcts