Development of an intravascular ultrasound elastography based on a dual-element transducer

Figures

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  Figure 1.. Scanning scheme of the ARF-IVUS elasticity imaging system. Photograph of the dual-frequency IVUS transducer (a). Scanning method of the transducer inside the artery (b).

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  Figure 2.. Block diagram of the experimental system.

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  Figure 3.. Representative timing diagram for the experiments. Pushing pulses produced by the 8.5 MHz element were synchronized (with a 2 ms delay) with the initial imaging pulses of the 31 MHz element.

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  Figure 4.. Sketches of the two types of gelatin phantom: type I, containing the softer rod (3% gelatin) (a); and type II, containing the harder rod (7% gelatin) (b).

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  Figure 5.. Acoustic intensities (ISPTA values) generated by the 8.5 MHz element measured by a hydrophone for different excitation voltages (85, 130, 145, 160 and 170 V) and for excitation durations from 0.2 to 1.0 ms with a step of 0.2 ms.

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  Figure 6.. Dynamic displacement curves measured in a 3%-gelatin phantom for excitation voltages from 85 to 170 V at a fixed excitation duration of 1 ms (a) and for excitation durations from 0.2 to 1 ms at a fixed excitation voltage of 170 V (b).

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  Figure 7.. Peak displacement (a) and velocity (b) of the shear wave propagation in the 3%- and 7%-gelatin phantoms for excitation durations from 0.2 to 1 ms at a fixed excitation voltage of 170 V. Data are mean and s.d. values.

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  Figure 8.. B-mode image (a), wave-amplitude image (b) and wave-velocity image (c) for phantom type I. B-mode image (d), wave-amplitude image (e) and wave-velocity image (f) for phantom type II.

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  Figure 9.. Ex vivo experiments for a rabbit aorta with a lipid-diet-induced plaque. B-mode image (a), wave-amplitude image (b) and wave-velocity image (c).