Browsing by Author "Yu, Qianhuan"

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    High-sensitivity intravascular photoacoustic imaging of lipid-laden plaque with a collinear catheter design
    (SpringerNature, 2016-04-28) Cao, Yingchun; Hui, Jie; Kole, Ayeeshik; Wang, Pu; Yu, Qianhuan; Chen, Weibiao; Sturek, Michael; Cheng, Ji-Xin; Department of Cellular & Integrative Physiology, IU School of Medicine
    A highly sensitive catheter probe is critical to catheter-based intravascular photoacoustic imaging. Here, we present a photoacoustic catheter probe design on the basis of collinear alignment of the incident optical wave and the photoacoustically generated sound wave within a miniature catheter housing for the first time. Such collinear catheter design with an outer diameter of 1.6 mm provided highly efficient overlap between optical and acoustic waves over an imaging depth of >6 mm in D2O medium. Intravascular photoacoustic imaging of lipid-laden atherosclerotic plaque and perivascular fat was demonstrated, where a lab-built 500 Hz optical parametric oscillator outputting nanosecond optical pulses at a wavelength of 1.7 μm was used for overtone excitation of C-H bonds. In addition to intravascular imaging, the presented catheter design will benefit other photoacoustic applications such as needle-based intramuscular imaging.
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    High-speed intravascular photoacoustic imaging at 1.7 μm with a KTP-based OPO
    (The Optical Society, 2015-11-01) Hui, Jie; Yu, Qianhuan; Ma, Teng; Wang, Pu; Cao, Yingchun; Bruning, Rebecca S.; Qu, Yueqiao; Chen, Zhongping; Zhou, Qifa; Sturek, Michael; Cheng, Ji-Xin; Chen, Weibiao; Department of Cellular & Integrative Physiology, IU School of Medicine
    Lipid deposition inside the arterial wall is a hallmark of plaque vulnerability. Based on overtone absorption of C-H bonds, intravascular photoacoustic (IVPA) catheter is a promising technology for quantifying the amount of lipid and its spatial distribution inside the arterial wall. Thus far, the clinical translation of IVPA technology is limited by its slow imaging speed due to lack of a high-pulse-energy high-repetition-rate laser source for lipid-specific first overtone excitation at 1.7 μm. Here, we demonstrate a potassium titanyl phosphate (KTP)-based optical parametric oscillator with output pulse energy up to 2 mJ at a wavelength of 1724 nm and with a repetition rate of 500 Hz. Using this laser and a ring-shape transducer, IVPA imaging at speed of 1 frame per sec was demonstrated. Performance of the IVPA imaging system's resolution, sensitivity, and specificity were characterized by carbon fiber and a lipid-mimicking phantom. The clinical utility of this technology was further evaluated ex vivo in an excised atherosclerotic human femoral artery with comparison to histology.