Volumetric Real-Time Tracking of Peripheral Human Vasculature With GPU-Accelerated Three-Dimensional Optoacoustic Tomography

Abstract

Optoacoustic tomography provides a unique possibility for ultra-high-speed 3-D imaging by acquiring complete volumetric datasets from interrogation of tissue by a single nanosecond-duration laser pulse. Yet, similarly to ultrasound, optoacoustics is a time-resolved imaging method, thus, fast 3-D imaging implies real-time acquisition and processing of high speed data from hundreds of detectors simultaneously, which presents significant technological challenges. Herein we present a highly efficient graphical processing unit (GPU) framework for real-time reconstruction and visualization of 3-D tomographic optoacoustic data. By utilizing a newly developed 3-D optoacoustic scanner, which simultaneously acquires signals with a handheld 256-element spherical ultrasonic array system, we further demonstrate tracking of deep tissue human vasculature rendered at a rate of 10 volumetric frames per second. The flexibility provided by the handheld hardware design, combined with the real-time operation, makes the developed platform highly usable for both clinical imaging practice and small animal research applications.

Universal Hand-held Three-dimensional Optoacoustic Imaging Probe for Deep Tissue Human Angiography and Functional Preclinical Studies in Real Time

“…During the course of this experiment, the probe was slowly scanned along the hand of a healthy human volunteer at a single wavelength of 800 nm with the laser operating at 10 pulses per sec 17 , so that real-time visualization of the blood vessels for all scanning positions is achieved. The representative maximum intensity projection (MIP) of the reconstructed images in all three directions are displayed in Figure 2.…”

“…The representative maximum intensity projection (MIP) of the reconstructed images in all three directions are displayed in Figure 2. Real-time visualization during the measurement is enabled with a GPU implementation of the filtered back-projection algorithm 17 .…”

“…An actual picture of the array of transducers along with the optical fiber bundle is shown in Figure 1B. The efficient excitation and simultaneous detection of signals allows deep-tissue imaging with single-shot excitation (one laser pulse), so that real-time imaging at a frame rate determined by the pulse repetition frequency of the laser is further enabled with a graphics-processing-unit (GPU) implementation of the reconstruction procedure 17 . A cylindrical casing with a transparent polyethylene membrane ( Figure 1C Start the hardware for data acquisition with the parameters described in 3.1 maintaining the execution of the preview software.…”

Mesoscopic and Macroscopic Optoacoustic Imaging of Cancer

“…28), and progress with fast tuning light sources (24) has led to breakthrough MSOT implementations that are capable of high-quality real-time imaging. Systems using multi-element ultrasound detector arrays have demonstrated not only 2D real-time imaging (29,30), but also 3D real-time imaging of tissue volumes (28,31), as also shown in Fig. 6A-E. Real-time handheld MSOT operation in a form similar to diagnostic ultrasound imaging can be considered a crucial step toward clinical applications (32-37), particularly when combined with fast wavelength tuning (24).…”

Correlation between volumetric oxygenation responses and electrophysiology identifies deep thalamocortical activity during epileptic seizures

“…The signals were subsequently bandpass filtered using a Butterworth frequency filter between 0.1 and 6 MHz to remove low frequency drifts as well as high frequency noise. Optoacoustic image reconstruction was then performed on a Cartesian grid by means of a GPU-based implementation of a filtered backprojection algorithm 23,24 for every wavelength using a volumetric image grid of 100 × 100 × 100 voxels. Intensity variations due to fluctuations in the laser energy were compensated by normalizing every reconstructed volume with the average optoacoustic signal recorded from a small rod-shaped absorber positioned between the fiber outlet and the mouse head.…”