Three-dimensional ultrasound is a powerful imaging technique, but it requires thousands of sensors and complex hardware. Very recently, the discovery of compressive sensing has shown that the signal structure can be exploited to reduce the burden posed by traditional sensing requirements. In this spirit, we have designed a simple ultrasound imaging device that can perform three-dimensional imaging using just a single ultrasound sensor. Our device makes a compressed measurement of the spatial ultrasound field using a plastic aperture mask placed in front of the ultrasound sensor. The aperture mask ensures that every pixel in the image is uniquely identifiable in the compressed measurement. We demonstrate that this device can successfully image two structured objects placed in water. The need for just one sensor instead of thousands paves the way for cheaper, faster, simpler, and smaller sensing devices and possible new clinical applications.@en

In the field of vascular interventions, forward-looking intravascular ultrasound transducers (FL-IVUS) are needed for better visualization of complex lesions, such as chronic total occlusions. In this work, we propose a strategy for 3D imaging using a single-element transducer and an optical shape sensing fiber (OSS) in a steerable catheter tip. We evaluate the performance of the integrated device by imaging a six-wire phantom submerged in water. While steering the catheter tip across the wires, ultrasound and OSS data are acquired continuously. We combine the distance information obtained from the ultrasound data with the tip position and direction obtained from the OSS data to reconstruct the wires in 3D space. We quantify the accuracy of the imaging technique by the distance between the wires, and find a mean relative error of 36%. We discuss how this estimate can be further improved by modifications of the probe. This proof-of-principle test demonstrates the feasibility of FL-IVUS imaging using a single-element transducer integrated in a steerable catheter together with an OSS fiber.

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upture of vulnerable plaques in coronary arteries is the major cause of acute coronary syndromes. Most vulnerable plaques consist of a thin fibrous cap covering an atheromous core. These plaques can be identified using intravascular ultrasound (IVUS) palpography, which measures radial strain by cross-correlating RF signals at different intraluminal pressures. Multiple strain images (i.e., partial palpograms) are averaged per heart cycle to produce a more robust compounded palpogram. However, catheter motion due to cardiac activity causes misalignment of the RF signals and thus of the partial palpograms, resulting in less valid strain estimates. To compensate for in-plane catheter rotation and translation, we devised four methods based on block matching. The global rotation block matching (GRBM) and contour mapping (CMAP) methods measure catheter rotation, and local block matching (LBM) and catheter rotation and translation (CRT) estimate displacements of local tissue regions. These methods were applied to nine in vivo pullback acquisitions, made with a 20 MHz phased-array transducer. We found that all these methods significantly increase the number of valid strain estimates in the partial and compounded palpograms (P < 0.008). The best method, LBM, attained an average increase of 17% and 15%, respectively. Implementation of this method should improve the information coming from IVUS palpography, leading to better vulnerable plaque detection. @en