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SUMMARY:Intravascular polarization sensitive optical coherence tomography
DTSTART:20140328T120000
DTSTAMP:20260407T210913Z
UID:e7d706f22535f96f0d387feaea373519a3eb8434032b38b6a9b0a0b7
CATEGORIES:Conferences - Seminars
DESCRIPTION:Dr. Martin Villiger of the Wellman Center for Photomedicine\, 
 Massachusetts and the Harvard Medical School\nIn addition to structural im
 aging\, polarization sensitive optical coherence tomography (PS-OCT) quant
 ifies the polarization of the light scattered by a sample. Many tissues an
 d molecules intrinsically alter the polarization state of the probing ligh
 t\, and detecting these polarization signatures can offer valuable insight
  for diagnostic purposes and provides additional imaging contrast. PS-OCT 
 measurements through a catheter probe have been limited\, however\, by the
  presence of system induced polarization distortions. We have developed a 
 reconstruction strategy based on the Mueller-Stokes formalism that mitigat
 es the resulting artifacts and provides a measure of tissue birefringence 
 as well as depolarization. Although OCT is a coherent imaging technique th
 at by definition can only measure fully polarized light\, I will evidence 
 how spatial averaging is akin to making the imaging process partially cohe
 rent and enables the measure of depolarization effects.\nWe have performed
  catheter-based PS-OCT in human coronary arteries\, both in vivo and in ca
 daveric hearts\, for the assessment of atherosclerosis. The measure of bir
 efringence provides an estimation of the collagen content in the vessel wa
 ll and depolarization was found to be indicative of lipid pools and foam c
 ells. Plaques that rupture and potentially cause myocardial infarction typ
 ically have a thin fibrous cap devoid of collagen\, overlaying a large lip
 id pool. PS-OCT might help to identify these plaques and determine their v
 ulnerability. Collagen content is also modulated under the influence of in
 flammation and medication\, and PS-OCT could dramatically improve drug eva
 luation studies by providing early time points of drug efficacy.\nOur reco
 nstruction strategy reveals polarization features that complement well the
  structural OCT signal and offers a quantitative characterization of tissu
 e. Beyond intracoronary imaging\, this additional contrast shows great pro
 mise in several applications with clinical relevance.
LOCATION:BM 1130 https://plan.epfl.ch/?room==BM%201130
STATUS:CONFIRMED
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