ABSTRACT
The interest in wearable health systems (WHS) originates initially from the need to extend health services out of the hospital and monitor patients over extensive periods of time. Intelligent WIS are integrated systems in contact with or near the body able to sense, process and communicate biomedical,biochemical and physical parameters - and even carry out actions if necessary. Research and development (R&D) in WHS is mainly driven by two different, but complementary,approaches. The first one is "application-pull", stemming from an increased user demand for new solutions in healthcare. The second one is "technology-push", in which technological innovations lead to new systems and products for healthcare solutions. In both approaches, inter-disciplinarity is a key issue. Synergies across multiple domains like biomedical technologies,micro- and nano-technologies, materials engineering, and Information and Communication Technologies (ICT), enable new approaches to support personal health and well-being. These include, for example, unobtrusive personal health monitoring and point-of-care biochemical testing for disease prevention and early diagnosis, as well as follow-up of treatments. This article presents the state-of-the-art on wearable health systems, outlines current research achievements and indicates research trends and challenges in line with these two approaches.
Subject(s)
Clothing , Telemedicine/trends , Biomedical Technology/trends , HumansABSTRACT
The aim of this work was to investigate the suitability of a novel forward-viewing intravascular ultrasound (IVUS) technique for three-dimensional imaging of severely stenosed or totally occluded vessels, where the conventional side-viewing IVUS systems are of limited use. A stiff 3.8 mm diameter forward-viewing catheter was manufactured to scan a 72 degrees sector ahead of its tip. Conical volume data were acquired by rotating the catheter over 180 degrees by means of a motorised mechanical system. Operating at 30 MHz, the catheter was integrated with an IVUS scanner and a radiofrequency data acquisition system. Postmortem carotid and femoral arteries were scanned in vitro. Correlation of the reconstructed images with histology demonstrated the ability of this forward-viewing IVUS system to visualise healthy lumens, bifurcations, thickened atherosclerotic walls and, most importantly, severe and complete vessel occlusions. A rotating-sector forward-viewing IVUS system is suitable for anatomical assessment of severely diseased vessels in three dimensions.
Subject(s)
Imaging, Three-Dimensional/methods , Ultrasonography, Interventional/methods , Arterial Occlusive Diseases/diagnostic imaging , Carotid Arteries/diagnostic imaging , Femoral Artery/diagnostic imaging , Humans , In Vitro Techniques , Phantoms, Imaging , Ultrasonography, Interventional/instrumentationABSTRACT
An in vitro system for the investigation of the behaviour of contrast microbubbles in an ultrasound field, that provides a full diagnostic range of settings, is yet to be presented in the literature. The evaluation of a good compromise of such a system is presented in this paper. It is based on (a) an HD13000 ATL scanner (Bothell, WA, USA) externally controlled by a PC and (b) on the use of well-defined reference materials. The suspensions of the reference ultrasonic scattering material are placed in an anechoic tank. The pulse length ranges from 2 to 10 cycles, the acoustic pressure from 0.08 to 1.8 MPa, the transmit frequency from 1 to 4.3 MHz, and the receive frequency from 1 to 8 MHz. The collection of 256 samples of RF data, at an offset distance from the transducer face, was performed at 20 MHz digitization rate, which corresponds to approximately 1 cm depth in water. Two particle suspensions are also presented for use as reference scatterers for contrast studies: (a) a suspension of Orgasol (ELF Atochem, Paris, France) particles (approximately 5 microm mean diameter) and (b) a suspension of Eccosphere (New Metals & Chemicals Ltd, Essex, UK) particles (approximately 50 microm mean diameter). A preliminary experiment with the contrast agent Definity (DuPont Pharmaceutical Co, Waltham, MA) showed that the above two materials are suitable for use as a reference for contrast backscatter.
Subject(s)
Contrast Media/pharmacology , Ultrasonography/methods , Image Processing, Computer-Assisted/methods , In Vitro Techniques , Scattering, RadiationABSTRACT
Intravascular ultrasound (US) imaging is a useful tool for assessing arterial disease and aiding treatment procedures. Forward-viewing intravascular US imaging could be of particular use in severely stenosed or totally occluded arteries, where the current side-viewing intravascular US systems are limited by their inability to access the site of interest. In this study, five 3-D forward-viewing intravascular scanning patterns were investigated. The work was carried out using scaled-up vessel phantoms constructed from tissue-mimicking material and a PC-controlled scanning and acquisition system. The scanning patterns were examined and evaluated with regard to the image quality of dense and sparse data sets, the accuracy of quantitative measurements of lumen dimensions and the potential for clinical use. The relative merits and drawbacks of the different patterns are discussed and a preferred scanning pattern is recommended.
