title: 3.0-T MR imaging of intracoronary local delivery of motexafin gadolinium into coronary artery walls.
abstract: OBJECTIVE
  To develop a technique with clinical 3.0-T magnetic resonance (MR) imaging to delineate local contrast agent distribution in coronary artery walls for potential molecular MR imaging-guided local gene or drug therapy of atherosclerotic coronary artery disease.
  
  
  METHODS
  This animal protocol was approved by the institutional animal care and use committee and was in compliance with the Guide for the Care and Use of Laboratory Animals. For in vitro confirmation, human arterial smooth muscle cells (SMCs) were used to determine capability of SMCs in uptake of motexafin gadolinium (MGd) and its optimal dose. For ex vivo evaluation, a 2-mL mixture of MGd and trypan blue was locally infused into coronary artery walls of six cadaveric pig hearts with MR monitoring and an MR imaging guidewire, surface coils, or both. For in vivo validation, the balloon catheter was placed into coronary arteries of seven living pigs, and the MGd and trypan blue mixture was infused into arterial walls with MR guidance. Signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) of coronary artery walls were recorded by using different coils between pre- and postcontrast infusion, with subsequent histologic confirmation. Paired Student t tests were used to compare average SNRs and CNRs of arterial walls before and after contrast agent infusion with different coils.
  
  
  RESULTS
  SMCs could take up MGd with the optimal concentration at 150 µmol/L. Average SNR with the MR imaging guidewire and surface coil combination was significantly higher than that with the MR imaging guidewire only or with surface coils only (P < .05), and average SNR and CNR of postinfusion MR imaging was significantly higher than that of preinfusion MR imaging (P < .05). Histologic analysis was used to confirm successful intracoronary infiltration of MGd and trypan blue within coronary artery walls.
  
  
  CONCLUSIONS
  MR imaging can be used to delineate locally infused contrast agent distribution in coronary artery walls. This establishes groundwork for development of molecular MR imaging-guided intracoronary therapy.
authors.affiliation: Image-Guided Bio-Molecular Interventions Research, Department of Radiology, University of Washington School of Medicine, 815 Mercer St, Seattle, WA 98109, USA.
authors.forename: Yanfeng
authors.initials: Y
authors.lastname: Meng
authors.forename: Jinnan
authors.initials: J
authors.lastname: Wang
authors.forename: Jihong
authors.initials: J
authors.lastname: Sun
authors.forename: Feng
authors.initials: F
authors.lastname: Zhang
authors.forename: Patrick
authors.initials: P
authors.lastname: Willis
authors.forename: Jiakai
authors.initials: J
authors.lastname: Li
authors.forename: Han
authors.initials: H
authors.lastname: Wang
authors.forename: Tong
authors.initials: T
authors.lastname: Zhang
authors.forename: Stephanie
authors.initials: S
authors.lastname: Soriano
authors.forename: Bensheng
authors.initials: B
authors.lastname: Qiu
authors.forename: Xiaoming
authors.initials: X
authors.lastname: Yang
mesh_terms: D000818:Animals; D003287:Contrast Media / Q000493:pharmacokinetics*; D003331:Coronary Vessels / Q000378:metabolism*; D066298:In Vitro Techniques; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008665:Metalloporphyrins / Q000493:pharmacokinetics*; D018613:Microscopy, Confocal; D059629:Signal-To-Noise Ratio; D013552:Swine; D014364:Tryptophan / Q000493:pharmacokinetics
chemical_list: D003287:Contrast Media; D008665:Metalloporphyrins; C437683:motexafin gadolinium; D014364:Tryptophan