Image Quality Comparison of Three 3D Mobile X-Ray Imaging Guidance Devices Used in Spine Surgery: A Phantom Study.

An image-quality CT phantom was scanned with three different 3D X-ray imaging guidance devices in the operating theatre: O-Arm, Loop-X, and Airo TruCT. Default acquisition and reconstruction parameters for lumbar spine procedures were used on each device. The tube current was set to a dose level of around 27 mGy.

Microbubble shape oscillations excited through ultrasonic parametric driving.

An air bubble driven by ultrasound can become shape-unstable through a parametric instability. We report time-resolved optical observations of shape oscillations (mode n=2 to 6) of micron-sized single air bubbles. The observed mode number n was found to be linearly related to the ambient radius of the bubble.

Feasability of human endobronchial imaging with a linear-array ultrasound catheter.

Purpose: To explore the feasability of imaging lung masses with a novel endobronchial linear-array transducer.

Method: We used a linear-array transducer of 7 F (2.3 mm in diameter) operating at a center frequency of 10 MHz for endobronchial imaging.

[Sonopermeabilization: therapeutic alternative with ultrasound and microbubbles].

Future applications of ultrasound and microbubbles extend to more than imaging applications. Over the last few years, it was reported that sonographic contrast agent effects under ultrasound, modulate transiently cell membrane permeability. This process, named sonoporation and classified as a new physical method to transfer genes or drugs, consists of using a physical energy source to modulate membrane integrity.

Acoustical bubble trapper applied to hemodialysis.

Gaseous microemboli can arise in extracorporeal lines and devices such as dialysis machines. They are associated with severe pulmonary side effects in patients undergoing chronic hemodialysis sessions. The goal of this study was to develop a gaseous emboli trapper using ultrasound waves to remove any air bubble from the tubing system before they reach the patient.

Multifrequency transducer for microemboli classification and sizing.

The classification of circulating microemboli as gaseous or particulate matter is essential to establish the relevance of the detected embolic signals. Until now, Doppler techniques have failed to determine unambiguously the nature of circulating microemboli. Recently, a new approach based on the analysis of radio frequency (RF) signal and using the nonlinear characteristics of gaseous bubbles to classify emboli was investigated.

Optical observations of acoustical radiation force effects on individual air bubbles.

Previous studies dealing with contrast agent microbubbles have demonstrated that ultrasound (US) can significantly influence the movement of microbubbles. In this paper, we investigated the influence of the acoustic radiation force on individual air bubbles using high-speed photography. We emphasize the effects of the US parameters (pulse length, acoustic pressure) on different bubble patterns and their consequences on the translational motion of the bubbles.

Bladder volume measurements with a limited number of fixed ultrasound beams.

Over the past 30 years, various ultrasonic methods have been suggested to measure bladder volume. Ultrasound (US) represents a noninvasive and simple way to assess such volumes. Bladder volumes are usually estimated from cross-sectional planes obtained with instruments using full imaging capabilities, but their accuracy remains limited.

Emboli detection using a new transducer design.

We have presented, in a previous study, a new approach to detect, characterize and estimate the size of gaseous emboli, based on the nonlinear behavior of gaseous bubbles. In this study, a specific transducer design has been developed to be used for such a purpose. It is composed of two separate transmitting and receiving capabilities.

Subharmonic and ultraharmonic emissions for emboli detection and characterization.

Emboli detection and characterization is of importance for different patients, such as those undergoing carotid or cardiac surgery. The emboli occur as particulate or gaseous matters. To select the appropriate treatment and reduce the risk of embolism, it is essential to first detect and then classify and, ultimately, size the emboli.

New technique for emboli detection and discrimination based on nonlinear characteristics of gas bubbles.

Detection and characterization of emboli in the blood stream is of high clinical importance for making decisions after surgery. In this study, a new technique based on the nonlinear oscillations of gas bubbles was applied to gaseous emboli detection, characterization and sizing. To simulate gaseous emboli, an experimental system was developed to produce air bubbles of uniform diameters ranging from 19 microm up to 200 microm.