Synthetic aperture-based reconstruction of intravascular ultrasound images in the time domain and frequency domain

Intravascular ultrasound images are limited by a poor lateral resolution and elevated grating lobes. In this paper, two reconstruction algorithms are presented which succeed in improving the lateral resolution and reducing the grating lobes by means of the synthetic aperture focusing technique (SAFT). For the time domain reconstruction, appropriately time-delayed and weighted signals are summed up. The frequency domain reconstruction is based on the similarity of the recorded signals with chirp signals. The reconstruction results experimentally confirm that the frequency domain reconstruction creates a better lateral resolution and requires less computation time. However, the time domain reconstruction produces lower grating lobes and hence results in a better overall image quality.