title: Tracking delivery of a drug surrogate in the porcine heart using photoacoustic imaging and spectroscopy.
abstract: Although the drug-eluting stent (DES) has dramatically reduced the rate of coronary restenosis, it still occurs in up to 20% of patients with a DES. Monitoring drug delivery could be one way to decrease restenosis rates. We demonstrate real-time photoacoustic imaging and spectroscopy (PAIS) using a wavelength-tunable visible laser and clinical ultrasound scanner to track cardiac drug delivery. The photoacoustic signal was initially calibrated using porcine myocardial samples soaked with a known concentration of a drug surrogate (DiI). Next, an in situ coronary artery was perfused with DiI for 20 min and imaged to monitor dye transport in the tissue. Finally, a partially DiI-coated stent was inserted into the porcine brachiocephalic trunk for imaging. The photoacoustic signal was proportional to the DiI concentration between 2.4 and 120 ?? ? g / ml , and the dye was detected over 1.5 mm from the targeted coronary vessel. Photoacoustic imaging was also able to differentiate the DiI-coated portion of the stent from the uncoated region. These results suggest that PAIS can track drug delivery to cardiac tissue and detect drugs loaded onto a stent with sub-mm precision. Future work using PAIS may help improve DES design and reduce the probability of restenosis.
authors.affiliation: University of Pittsburgh, Department of Bioengineering, Pittsburgh, Pennsylvania, United States.
authors.forename: Kenneth J
authors.initials: KJ
authors.lastname: Furdella
authors.affiliation: University of Arizona, Department of Medical Imaging, Tucson, Arizona, United States.
authors.forename: Russell S
authors.initials: RS
authors.lastname: Witte
authors.affiliation: University of Pittsburgh, Department of Bioengineering, Pittsburgh, Pennsylvania, United States.
authors.forename: Jonathan P
authors.initials: JP
authors.lastname: Vande Geest
mesh_terms: D000818:Animals; D023903:Coronary Restenosis / Q000628:therapy; D054855:Drug-Eluting Stents / Q000592:standards; D006321:Heart / Q000000981:diagnostic imaging*; D006801:Humans; D061088:Photoacoustic Techniques; D013057:Spectrum Analysis; D013552:Swine