Ultrasonics
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The concept of high frame rate ultrasound imaging (typically greater than 1000 frames per second) has inspired new fields of clinical applications for ultrasound imaging such as fast cardiovascular imaging, fast Doppler imaging and real-time 3D imaging. Coherent plane-wave compounding is a promising beamforming technique to achieve high frame rate imaging. By combining echoes from plane waves with different angles, dynamic transmit focusing is efficiently accomplished at all points in the image field. ⋯ The image quality of different beamforming methods was quantified in terms of contrast-to-noise ratio (CNR). Our results show that the new SMF based plane-wave compounding method provides better contrast than DAS based compounding method. Also CSMF can obtain a similar contrast level to dynamic transmit-receive focusing with only 21 transmit events.
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Ultrasonic phantoms are objects that mimic some features of biological tissues, allowing the study of their interactions with ultrasound (US). In the diagnostic-imaging field, breast phantoms are an important tool for testing performance and optimizing US systems, as well as for training medical professionals. This paper describes the design and manufacture of breast lesions by using polyvinyl chloride plastisol (PVCP) as the base material. ⋯ A single layer of carnauba wax was added to the lesion surface in order to evaluate its applicability for imaging. The images of the phantoms were acquired using commercial ultrasound equipment; a specialist rated the images, elaborating diagnoses representative of both benign and malignant lesions. The results indicated that it was possible to easily create a phantom by using low-cost materials, readily available in the market and stable at room temperature, as the basis of ultrasonic phantoms that reproduce the image characteristics of fatty breast tissue and typical lesions of the breast.
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Clear needle visualisation is recognised as an unmet need for ultrasound guided percutaneous needle procedures including regional anaesthesia and tissue biopsy. With inadequate needle visibility, these procedures may result in serious complications or a failed operation. This paper reports analysis of the modal behaviour of a previously proposed ultrasound-actuated needle configuration, which may overcome this problem by improving needle visibility in colour Doppler imaging. ⋯ Moreover, the needle tip is highlighted by strong coloured artefacts around the actuated needle generated by its flexural vibration. A limitation of the technique is that the transducer mode requires needles of specific lengths so that the needle's resonance frequency matches the transducer. This may restrict the choice of needle lengths in clinical applications.
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To investigate the value of microbubble contrast-enhanced ultrasound (CEUS) in evaluating the treatment response of uterine fibroids to HIFU ablation. ⋯ CEUS clearly showed the size of fibroids and the non-perfused areas of the fibroid. Results from CEUS correlated well with results obtained from MRI.
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Bone fracture induces moderate inflammatory responses that are regulated by cyclooxygenase-2 (COX-2) or 5-lipoxygenase (5-LO) for initiating tissue repair and bone formation. Only a handful of non-invasive techniques focus on monitoring acute inflammation of injured bone currently exists. In the current study, we monitored in vivo inflammation levels during the initial 2 weeks of the inflammatory stage after mouse bone fracture utilizing 50 MHz ultrasound. ⋯ In contrast, treatment with IND or SC-236 did not reduce the hyperechogenicity, as confirmed by cell death (TUNEL) and expression levels of COX-2 or BLT1. Taken together, the current study reports the feasibility of a non-invasive ultrasound method capable of monitoring post-fracture tissue inflammation that positively correlates with histological findings. Results of this study also suggest that this approach may be further applied to elucidate the underlying mechanisms of inflammatory processes and to develop therapeutic strategies for facilitating fracture healing.