title: Chirp-Coded Ultraharmonic Imaging with a Modified Clinical Intravascular Ultrasound System.
abstract: Imaging plaque microvasculature with contrast-enhanced intravascular ultrasound (IVUS) could help clinicians evaluate atherosclerosis and guide therapeutic interventions. In this study, we evaluated the performance of chirp-coded ultraharmonic imaging using a modified IVUS system (iLab™, Boston Scientific/Scimed) equipped with clinically available peripheral and coronary imaging catheters. Flow phantoms perfused with a phospholipid-encapsulated contrast agent were visualized using ultraharmonic imaging at 12 MHz and 30 MHz transmit frequencies. Flow channels with diameters as small as 0.8 mm and 0.5 mm were visualized using the peripheral and coronary imaging catheters. Radio-frequency signals were acquired at standard IVUS rotation speed, which resulted in a frame rate of 30 frames/s. Contrast-to-tissue ratios up to 17.9 ± 1.11 dB and 10.7 ± 2.85 dB were attained by chirp-coded ultraharmonic imaging at 12 MHz and 30 MHz transmit frequencies, respectively. These results demonstrate the feasibility of performing ultraharmonic imaging at standard frame rates with clinically available IVUS catheters using chirp-coded excitation.
authors.affiliation: Department of Electrical and Computer Engineering, Hajim School of Engineering and Applied Sciences, University of Rochester, Rochester, NY, USA.
authors.forename: Himanshu
authors.initials: H
authors.lastname: Shekhar
authors.affiliation: Department of Electrical and Computer Engineering, Hajim School of Engineering and Applied Sciences, University of Rochester, Rochester, NY, USA.
authors.forename: Steven
authors.initials: S
authors.lastname: Huntzicker
authors.affiliation: Department of Electrical and Computer Engineering, Hajim School of Engineering and Applied Sciences, University of Rochester, Rochester, NY, USA.
authors.forename: Ivy
authors.initials: I
authors.lastname: Awuor
authors.affiliation: Department of Electrical and Computer Engineering, Hajim School of Engineering and Applied Sciences, University of Rochester, Rochester, NY, USA m.doyley@rochester.edu.
authors.forename: Marvin M
authors.initials: MM
authors.lastname: Doyley
mesh_terms: D003287:Contrast Media; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging*; D007089:Image Enhancement; D055806:Microvessels; D019047:Phantoms, Imaging; D058226:Plaque, Atherosclerotic / Q000000981:diagnostic imaging*; D018084:Ultrasonography, Interventional / Q000379:methods*
chemical_list: D003287:Contrast Media
keywords: chirp-coded excitation; intravascular ultrasound; ultraharmonic imaging; ultrasound contrast agents; vasa vasorum