• The Journal of the Acoustical Society of Korea
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• v.37 no.4
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• pp.215-222
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• 2018

This paper reports the development and performance evaluation of a backend system for real-time IVUS (Intravascular Ultrasound) imaging. The developed backend system was designed to minimize the amount of logic and memory usage by means of efficient LUTs (Look-up Tables), and it was implemented in a single FPGA (Field Programmable Gate Array) without using external memory. This makes it possible to implement the backend system that is less expensive, smaller, and lighter. The accuracy of the backend system implemented was evaluated by comparing the output of the FPGA with the result computed using a MATLAB program implemented in the same way as the VHDL (VHSIC Hardware Description Language) code. Based on the result of ex-vivo experiment using rabbit artery, the developed backend system was found to be suitable for real-time intravascular ultrasound imaging.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.23 no.12
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• pp.1514-1519
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• 2019

IVUS is an intra-operative imaging modality that facilitates observing and appraising the vessel wall structure of the human coronary arteries. IVUS is regularly used to locate the atherosclerosis lesions in the coronary arteries. Auto-segmentation of the vessel structure is important to detect the disorder of coronary artery. In this paper, we propose a simple strategy to extract Intima/Adventitia area effectively using fuzzy binarization from intravascular images. The proposed method apply fuzzy binarization to find the adventitia but apply average binarization to locate the intima since they have different homogeneity of pixel intensity comparing with the environment. In this paper, we demonstrate an effective auto-segmentation method for detecting the interior/exterior of the vessel walls by differentiating the fuzzy binarization result and average binarization result from IVUS image. Important statistics such as Intima-Media Thickness (IMT) or volume of a target area can be easily computed from result.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.3
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• pp.880-890
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• 2010

The intrasvascular ultrasound (IVUS) imaging technique is used to diagnose cerebrovascular diseases such as stroke. Recently, elasticity imaging methods have been investigated to diagnose blood clots attached to blood vessel intima. However, the IVUS imaging technique is an invasive method that requires a transducer to be inserted into blood vessel. In this paper, strain images are obtained of blood clots attached to blood vessel intima with data acquired from outside the blood vessel using a linear array transducer. In order to measure the displacement of blood vessel accurately, experimental data are acquired by steering ultrasound beams so that they can intersect the blood vessel wall at right angles. The acquired rf data are demodulated to the baseband. The resulting complex baseband signals are then processed by an autocorrelation algorithm to compute the blood vessel movement and thereby produce strain image. This proposed method is verified by experiments on a plastic blood vessel mimicking phantom. The efficacy of the proposed method was verified using a home-made blood vessel mimicking phantom. The blood vessel mimicking phantom was constructed by making a 6 mm diameter hollow cylinder inside it to simulate a blood vessel and adhering 2 mm thick soft plaque to the inner wall of the hollow cylinder. The RF data were acquired using a clinical ultrasound scanner (Accuvix XQ, Medison, Seoul. Korea) with a 7.5 MHz linear array transducer by steering ultrasound beams in steps of $1^{\circ}$ from $-40^{\circ}$ to $40^{\circ}$ for a total of 81 angles. Experimental results show that the plaque region near the blood vessel wall is softer than background tissue. Although the imaging region is restricted due to the limited range of angles for which scan lines are perpendicular to the wall, the feasibility of strain imaging is demonstrated.

• The Journal of the Acoustical Society of Korea
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• v.36 no.4
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• pp.238-246
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• 2017

High frequency ultrasound imaging typically suffers from low sensitivity due to the small aperture of high frequency transducers and shallow imaging depth due to the frequency-dependent attenuation of ultrasound. These limitations should be overcome to obtain high-frequency, high- resolution ultrasound images. One practical solution to the problems is a high-performance signal receiver capable of detecting a very small signal and amplifying the signal with minimal electronic noise addition. This paper reports a recently developed low-noise, wideband ultrasound receiver for high-frequency, high-resolution ultrasound imaging. The developed receiver has an amplification gain of up to 73 dB and a variable amplification gain range of 48 dB over an operating frequency of 80 MHz. Also, it has an amplification gain flatness of ${\pm}1dB$. Due to these high performances, the developed receiver has a signal-to-noise ratio of at least 8.4 dB and a contrast-to-noise ratio of at least 3.7 dB higher than commercial receivers.

• The Journal of the Acoustical Society of Korea
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• v.14 no.2E
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• pp.73-86
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• 1995

The transducer section of the forward-looking ultrasound imaging catheter (FLUIC) consists of a circular piezoelectric element as a vibrator and a conical acoustic mirror as a perfect reflector. A small diameter piezoelectric transducer element is mounted on the side of a catheter's rotating shaft. The unique design of FLUIC provides the capability to form a two-dimensional image of a cross-section of vessel in front of the catheter, which is lacking in the present generation of intravascular ultrasound (IVUS) transducers, as well as a conventional side view image. The mirror configuration for the transducer section of the FLUIC is designed using an approximated ray tracing techniques. The diffraction transfer function approach [1] developed for the field prediction from primary sources is generalized and extended to predict the secondary diffraction characterstics from an acoustic mirror. The extended model is verified by simulation and experiment through a simple plane reflector and employed to analyzed the field characteristics of a FLUIC.