title: Evaluation of coronary adventitial vasa vasorum using 3D optical coherence tomography--animal and human studies.
abstract: OBJECTIVE
  This study sought to evaluate adventitial vasa vasorum (VV) in vivo with novel imaging technique of optical coherence tomography (OCT).
  
  
  METHODS
  To verify OCT methods for quantification of VV, we first studied 2 swine carotid arteries in a model of focal angiogenesis by autologous blood injection, and compared microchannel volume (MCV) by OCT and VV by m-CT, and counts of those. In OCT images, adventitial MC was identified as signal-voiding areas which were located within 1 mm from the lumen-intima border. After manually tracing microchannel areas and the boundaries of lumen-intima and media-adventitial in all slices, we reconstructed 3D images. Moreover, we performed with OCT imaging in 8 recipients referred for evaluation of cardiac allograft vasculopathy at 1 year after heart transplantation. MCV and plaque volume (PV) were assessed with 3D images in each 10-mm-segment.
  
  
  RESULTS
  In the animal study, among the 16 corresponding 1-mm-segments, there were significant correlations of count and volume between both the modalities (count r(2) = 0.80, P < 0.01; volume r(2) = 0.50, P < 0.01) and a good agreement with a systemic bias toward underestimation with m-CT. In the human study, there was a significant positive correlation between MCV and PV (segment number = 24, r(2) = 0.63, P < 0.01).
  
  
  CONCLUSIONS
  Our results suggest that evaluation of MCV with 3D OCT imaging might be a novel method to estimate the amount of adventitial VV in vivo, and further has the potential to provide a pathophysiological insight into a role of the VV in allograft vasculopathy.
authors.affiliation: Division of Cardiovascular Diseases, Mayo Clinic, Rochester, MN, USA.
authors.forename: Tatsuo
authors.initials: T
authors.lastname: Aoki
authors.affiliation: Division of Cardiovascular Diseases, Mayo Clinic, Rochester, MN, USA.
authors.forename: Martin
authors.initials: M
authors.lastname: Rodriguez-Porcel
authors.affiliation: Division of Cardiovascular Diseases, Mayo Clinic, Rochester, MN, USA.
authors.forename: Yoshiki
authors.initials: Y
authors.lastname: Matsuo
authors.affiliation: Division of Cardiovascular Diseases, Mayo Clinic, Rochester, MN, USA.
authors.forename: Andrew
authors.initials: A
authors.lastname: Cassar
authors.affiliation: Division of Cardiovascular Diseases, Mayo Clinic, Rochester, MN, USA.
authors.forename: Teak-Geun
authors.initials: TG
authors.lastname: Kwon
authors.affiliation: Division of Cardiovascular Diseases, Mayo Clinic, Rochester, MN, USA.
authors.forename: Federico
authors.initials: F
authors.lastname: Franchi
authors.affiliation: Division of Cardiovascular Diseases, Mayo Clinic, Rochester, MN, USA.
authors.forename: Rajiv
authors.initials: R
authors.lastname: Gulati
authors.affiliation: Division of Cardiovascular Diseases, Mayo Clinic, Rochester, MN, USA.
authors.forename: Sudhir S
authors.initials: SS
authors.lastname: Kushwaha
authors.affiliation: Division of Biomedical Statistics and Informatics, Mayo Clinic, Rochester, MN, USA.
authors.forename: Ryan J
authors.initials: RJ
authors.lastname: Lennon
authors.affiliation: Division of Nephrology, Mayo Clinic, Rochester, MN, USA.
authors.forename: Lilach O
authors.initials: LO
authors.lastname: Lerman
authors.affiliation: Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN, USA.
authors.forename: Erik L
authors.initials: EL
authors.lastname: Ritman
authors.affiliation: Division of Cardiovascular Diseases, Mayo Clinic, Rochester, MN, USA. Electronic address: Lerman.Amir@mayo.edu.
authors.forename: Amir
authors.initials: A
authors.lastname: Lerman
mesh_terms: D063194:Adventitia / Q000473:pathology*; D064591:Allografts; D000818:Animals; D050197:Atherosclerosis / Q000473:pathology; D002339:Carotid Arteries / Q000473:pathology; D003331:Coronary Vessels / Q000473:pathology*; D005260:Female; D016027:Heart Transplantation; D006801:Humans; D007091:Image Processing, Computer-Assisted; D021621:Imaging, Three-Dimensional; D008297:Male; D008875:Middle Aged; D013552:Swine; D041623:Tomography, Optical Coherence; D014651:Vasa Vasorum / Q000473:pathology*; D055114:X-Ray Microtomography
keywords: Cardiac allograft vasculopathy; Microchannel; Microvessel; Optical coherence tomography