title: Temporal characterization of the functional density of the vasa vasorum by contrast-enhanced ultrasonography maximum intensity projection imaging.
abstract: OBJECTIVE
  We sought to determine whether contrast-enhanced ultrasound (CEU) microangiography with maximum intensity projection (MIP) processing could temporally evaluate proliferation of the vasa vasorum (VV) in a model of mural hemorrhage.
  
  
  BACKGROUND
  Expansion of the VV and plaque neovascularization contributes to plaque growth and instability and may be triggered by a variety of stimuli, including vascular hemorrhage. However, quantitative in vivo methods for temporal assessment of VV remodeling are lacking.
  
  
  METHODS
  In 24 rabbits fed a high-fat diet, either autologous whole blood or saline was percutaneously injected into the media-adventitia of the femoral artery using ultrahigh-frequency ultrasound guidance. Functional VV density at the injection site and contralateral control artery was assessed 1, 2, and 6 weeks after injection with CEU imaging with MIP processing. In vitro studies with renathane microtubes were also performed to validate linear density measurement with CEU and MIP processing.
  
  
  RESULTS
  In vitro studies demonstrated that MIP processing of CEU data reflected the relative linear density of vessels in a manner that was relatively independent of contrast concentration or microtube flow rate. On CEU with MIP, there was a 3-fold increase in femoral artery VV microvascular density at 1 and 2 weeks after blood injection (p < 0.01 vs. contralateral control), whereas VV density increased minimally after saline injection. At 6 weeks, VV vascular density decreased in blood-treated vessels and was not different from saline-injected or contralateral control vessels.
  
  
  CONCLUSIONS
  CEU with MIP processing can provide quantitative data on temporal changes in the functional density of the VV. This method may be useful for evaluating high-risk features of plaque neovascularization or response to therapies aimed at plaque neovessels.
authors.affiliation: Division of Cardiovascular Medicine, Oregon Health & Science University, Portland, Oregon 97239, USA.
authors.forename: Sang Chol
authors.initials: SC
authors.lastname: Lee
authors.forename: Chad L
authors.initials: CL
authors.lastname: Carr
authors.forename: Brian P
authors.initials: BP
authors.lastname: Davidson
authors.forename: Dilantha
authors.initials: D
authors.lastname: Ellegala
authors.forename: Aris
authors.initials: A
authors.lastname: Xie
authors.forename: Azzdine
authors.initials: A
authors.lastname: Ammi
authors.forename: Todd
authors.initials: T
authors.lastname: Belcik
authors.forename: Jonathan R
authors.initials: JR
authors.lastname: Lindner
mesh_terms: D000818:Animals; D050197:Atherosclerosis / Q000000981:diagnostic imaging* / Q000473:pathology; D003287:Contrast Media; D004195:Disease Models, Animal; D018450:Disease Progression; D005263:Femoral Artery / Q000000981:diagnostic imaging* / Q000473:pathology; D007090:Image Interpretation, Computer-Assisted; D007150:Immunohistochemistry; D009389:Neovascularization, Pathologic / Q000000981:diagnostic imaging* / Q000473:pathology; D011817:Rabbits; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors; D018084:Ultrasonography, Interventional; D014651:Vasa Vasorum / Q000000981:diagnostic imaging* / Q000473:pathology
chemical_list: D003287:Contrast Media