IEEE Trans Ultrason Ferroelectr Freq Control. 2014 Feb;61(2):239-50. doi: 10.1109/TUFFC.2014.6722610.
Intravascular ultrasound (IVUS) and intracardiac echography (ICE) catheters with real-time volumetric ultrasound imaging capability can provide unique benefits to many interventional procedures used in the diagnosis and treatment of coronary and structural heart diseases. Integration of capacitive micromachined ultrasonic transducer (CMUT) arrays with front-end electronics in single-chip configuration allows for implementation of such catheter probes with reduced interconnect complexity, miniaturization, and high mechanical flexibility. We implemented a single-chip forward-looking (FL) ultrasound imaging system by fabricating a 1.4-mm-diameter dual-ring CMUT array using CMUT-on-CMOS technology on a front-end IC implemented in 0.35-μm CMOS process. The dual-ring array has 56 transmit elements and 48 receive elements on two separate concentric annular rings. The IC incorporates a 25-V pulser for each transmitter and a low-noise capacitive transimpedance amplifier (TIA) for each receiver, along with digital control and smart power management. The final shape of the silicon chip is a 1.5-mm-diameter donut with a 430-μm center hole for a guide wire. The overall front-end system requires only 13 external connections and provides 4 parallel RF outputs while consuming an average power of 20 mW. We measured RF A-scans from the integrated single- chip array which show full functionality at 20.1 MHz with 43% fractional bandwidth. We also tested and demonstrated the image quality of the system on a wire phantom and an ex vivo chicken heart sample. The measured axial and lateral point resolutions are 92 μm and 251 μm, respectively. We successfully acquired volumetric imaging data from the ex vivo chicken heart at 60 frames per second without any signal averaging. These demonstrative results indicate that single-chip CMUT-on-CMOS systems have the potential to produce realtime volumetric images with image quality and speed suitable for catheter-based clinical applications.
血管内超声（IVUS）和心内超声（ICE）导管具有实时容积超声成像能力，可为诊断和治疗冠状动脉和结构性心脏病的许多介入程序提供独特的优势。将电容式微机械超声换能器（CMUT）阵列与前端电子器件集成到单个芯片配置中，可以实现这种导管探头的互连复杂性降低、小型化和高机械灵活性。我们使用 CMUT-on-CMOS 技术在前端 IC 上制造了一个 1.4 毫米直径的双环 CMUT 阵列，在 0.35 微米 CMOS 工艺中实现的前端 IC 上实现了一个单芯片前向（FL）超声成像系统。双环阵列在两个单独的同心环形环上具有 56 个发射元件和 48 个接收元件。该 IC 为每个发射器包含一个 25V 脉冲发生器，为每个接收器包含一个低噪声电容跨阻放大器（TIA），以及数字控制和智能电源管理。硅芯片的最终形状是一个 1.5 毫米直径的圆环，中心有一个 430 微米的孔，用于穿入导丝。整个前端系统仅需要 13 个外部连接，并提供 4 个并行 RF 输出，同时平均功耗为 20 毫瓦。我们从集成的单芯片阵列测量了 RF A 扫描，结果显示在 20.1MHz 时具有 43%的分数带宽，具有全功能。我们还在金属丝仿体和离体鸡心样本上测试和演示了系统的图像质量。测量的轴向和侧向点分辨率分别为 92μm 和 251μm。我们成功地以每秒 60 帧的速度从离体鸡心获取了容积成像数据，无需进行任何信号平均。这些示范结果表明，单芯片 CMUT-on-CMOS 系统具有实时生成容积图像的潜力，其图像质量和速度适合基于导管的临床应用。
