Shekhar Himanshu, Rowan Jeffrey S, Doyley Marvin M
Department of Electrical and Computer Engineering, University of Rochester, Rochester, NY, USA.
Department of Electrical and Computer Engineering, University of Rochester, Rochester, NY, USA.
Ultrasound Med Biol. 2017 Nov;43(11):2725-2732. doi: 10.1016/j.ultrasmedbio.2017.07.012. Epub 2017 Aug 26.
Contrast-enhanced intra-vascular ultrasound (CE-IVUS) imaging could provide clinicians a valuable tool to assess cardiovascular risk and guide the choice of therapeutic strategies. In this technical note, we evaluated the feasibility of combining subharmonic and ultraharmonic imaging to improve the performance of CE-IVUS. Vessel phantoms perfused with phospholipid-shelled ultrasound contrast agents were visualized using subharmonic, ultraharmonic and combined CE-IVUS modes with commercial peripheral and coronary imaging catheters. Flow channels as small as 0.8 mm and 0.5 mm were imaged at 12-MHz and 30-MHz transmit frequencies, respectively. Subharmonic and ultraharmonic imaging modes achieved a contrast-to-tissue ratio (CTR) up to 18.1 ± 1.8 dB and 19.6 ± 1.9 dB at 12-MHz, and 8.8 ± 1.8 and 12.5 ± 1.1 dB at 30-MHz transmit frequencies, respectively. Combining these modes improved the CTR to 32.5 ± 3.0 dB and 25.0 ± 1.6 dB at 12-MHz and 30-MHz transmit frequencies. These results underscore the potential of combined-mode CE-IVUS imaging. Furthermore, the demonstration of this approach with commercial catheters may serve as a first step toward the clinical translation of CE-IVUS.
对比增强血管内超声（CE-IVUS）成像可为临床医生提供一种评估心血管风险和指导治疗策略选择的宝贵工具。在本技术说明中，我们评估了结合次谐波和超谐波成像以提高CE-IVUS性能的可行性。使用商用外周和冠状动脉成像导管，通过次谐波、超谐波和联合CE-IVUS模式对灌注有磷脂壳超声造影剂的血管模型进行可视化。分别在12-MHz和30-MHz发射频率下对小至0.8毫米和0.5毫米的流动通道进行成像。次谐波和超谐波成像模式在12-MHz发射频率下的对比组织比（CTR）分别高达18.1±1.8 dB和19.6±1.9 dB，在30-MHz发射频率下分别为8.8±1.8和12.5±1.1 dB。在12-MHz和30-MHz发射频率下，将这些模式结合可使CTR分别提高到32.5±3.0 dB和25.0±1.6 dB。这些结果强调了联合模式CE-IVUS成像的潜力。此外，用商用导管演示这种方法可能是CE-IVUS临床转化的第一步。
