Ultrasound Processing and Computing: Review and Future Directions

Abstract

Since the introduction of medical ultrasound in the 1950s, modern diagnostic ultrasound has progressed to see many major diagnostic tools come into widespread clinical use, such as B-mode imaging, color-flow imaging, and spectral Doppler. New applications, such as panoramic imaging, three-dimensional imaging, and quantitative imaging, are now beginning to be offered on some commercial ultrasound machines and are expected to grow in popularity. In this review, we focus on the various algorithms, their processing requirements, and the challenges of these ultrasound modes. Whereas the older, mature B and color-flow modes could be systolically implemented using hardwired components and boards, new applications, such as three-dimensional imaging and image feature extraction, are being implemented more by using programmable processors. This trend toward programmable ultrasound machines will continue, because the programmable approach offers the advantages of quick implementation of new applications without any additional hardware and the flexibility to adapt to the changing requirements of these dynamic new applications.

Continuous real-time photoacoustic demodulation via field programmable gate array for dynamic imaging of zebrafish cardiac cycle

“…Since the PAM signal is oscillating in time, the morphological information of the axial dimension is distorted by the bi-polar nature of the signal. Other imaging techniques, including magnetic resonance imaging and ultrasound imaging, collect bi-polar signals; however, these techniques employ demodulation and signal enveloping to process the bi-polar signal into morphologically accurate information [18]. Conversely, PAM images are typically published as maximum amplitude projection (MAP) images or processed through Wiener deconvolution [19].…”

Doppler vortography - Detection and quantification of the vortices in the left ventricle

“…The received signal gives information on the blood flow in the area of interest. The flow velocity can be estimated from the phase shift between the echoes at a fixed depth during two or more subsequent pulses (refer to section 1.7) [26][27][28]. Given its wide availability, non-invasive, radiation-free and low-cost nature compared to other imaging methods such as CT and MRI, Doppler echography is currently the method of choice to evaluate cardiac diseases.…”

“…The transducer fires ultrasound pulses with the pulse repetition frequency (PRF), varying from 0.5 to 20 KHZ, based on the required time to reach the maximum depth of interest [28]. As it is mentioned before, the acoustic pulses travel through the tissue, a portion is scattered back to the transducer when any multiplies the sampled digital radio frequency data by the cosine and sine function to remove the carrier frequency and recover the received signal.…”

“…In-phase quadrature demodulation is an electronic process which after low pass filtering results in complex samples of the signal, referred to as IQ-signal, represented by I(t) + iQ(t), where I is the in-phase portion of the signal and Q is the quadrature component of the signal after demodulation [39]. There are two different steps to follow for blood flow estimation: wall filtering and velocity estimation [28,30].…”

Novel prospects for evaluation of follicle wall blood flow using color-Doppler ultrasonography

“…To successfully correlate the vascular profile in preovulatory and luteal phases with the subsequent outcome in fertility, methods of evaluating blood flow should reliably translate the physiological events (Fein et al, 1995;York and Kim, 1999). Currently, there are two methodologies to evaluate and score color-flow images in ultrasonographic examinations.…”