Ultrasound in medicine & biology
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Ultrasound Med Biol · Jan 2003
Doppler colour flow imaging and flow quantification with a novel forward-viewing intravascular ultrasound system.
The aim of this work was to investigate the potential of a novel forward-viewing intravascular ultrasound (IVUS) system for flow quantification and colour flow imaging combined with B-mode imaging. A stiff 3.8-mm diameter catheter was used to scan a 72 degrees sector ahead of its tip. Operating at 30 MHz, the catheter was integrated with an IVUS scanner and a radiofrequency (RF) data-acquisition system. ⋯ Steady flow in the range of 45 to 146 mL/min toward the catheter, was used in wall-less tissue-mimicking phantoms simulating healthy lumen (8-mm diameter), 30% diameter symmetrical stenosis and 37% diameter eccentric stenosis. The system provided colour flow images and good estimation of peak velocity and volumetric flows (within 1% to 9% and 16% to 48%, respectively, of calculated values) at 5 to 7 mm distal to the catheter. A sector forward-viewing IVUS imaging/Doppler system is suitable for combined anatomical and functional assessment of stenosed vessels.
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Ultrasound Med Biol · Nov 2002
The ability of quantitative ultrasound at the calcaneus to identify postmenopausal women with different types of nontraumatic fractures.
The aim of the cross-sectional study was to determine if ultrasound (US) measurements of the calcaneus have the ability to predict the risk for fractures and to discriminate between postmenopausal women with and without different types of nontraumatic fractures. All women (n = 1,129, age range 40 to 87 years) were divided into group 1, created by 656 women with 956 nontraumatic past fractures, and group 2, consisting of 473 women without fractures. Group 1 was divided into subgroups: with hip fractures, with vertebral (nonhip) fractures, with wrist (nonhip and nonspine) fractures and with other (nonhip, nonspine and nonwrist) fractures. ⋯ The present study demonstrates the ability of calcaneal QUS to discriminate between healthy individuals and subjects with different types of nontraumatic fractures. Calcaneal US parameters show the best sensitivity and specificity in discriminating the hip fracture patients from the controls. Generally, the SOS parameter is a better discriminator than SI and BUA and estimates the highest OR for fractures.
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Ultrasound Med Biol · Apr 2002
Comparative StudyComparison of breast mammography, sonography and physical examination for screening women at high risk of breast cancer in taiwan.
Recommended surveillance for screening breast cancer, which includes regular mammography and clinical breast examination, has long been established in Western countries. This strategy may be too costly and unnecessary for countries with low incidences of breast cancer. The purpose of the present study is to compare breast mammography, sonography and physical examination in screening female relatives of breast cancer index cases from the hospital, and their relative efficiency. ⋯ This indicates that sonography is a more accurate screening tool for breast cancer in the high-risk group. Although breast sonography has not yet been recommended as a routine screening tool for breast cancer in Western countries, it may be superior to mammography and physical examination for the screening of Taiwanese high-risk female relatives of breast cancer index cases. If it should also be considered as a routine adjunct screening modality for Taiwanese women with lower rates of breast cancer will need further study.
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Ultrasound Med Biol · Jun 2000
Comparative StudyIntervertebral disc structure: observation by a novel use of ultrasound imaging.
The internal structure of intervertebral discs is clinically important in the management of back pain. No current routine imaging modality is able to image disc structure satisfactorily. The aim of this work was to investigate and validate ultrasound imaging so that it might be applied to assessment of structural integrity and degree of degeneration. ⋯ The optimum disc imaging technique was found to be a posterolateral approach, 1 to 2 cm lateral of the dorsal midline, that revealed structure within the disc not apparent using other approaches. It was demonstrated that posterolateral imaging introduces a smaller reproducibility error in measurements of linear dimensions close to the disc. It is possible to observe internal structure within the disc between T11 and L3 in at least 54% of individuals.
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Ultrasound Med Biol · May 2000
Comparative StudyDetection of stenoses in the anterior circulation using frequency-based transcranial color-coded sonography.
Atherosclerotic stenoses of the intracranial vessels are less frequent than those of the extracranial vessels, but they are associated with a considerable annual stroke rate. The aim of the present study was to investigate the usefulness of frequency-based transcranial color-coded sonography (TCCS), transcranial Doppler sonography (TCD) and digital subtraction angiography (DSA) in patients with middle cerebral artery (MCA) and intracranial internal carotid artery (ICA) stenosis. Forty patients presenting with 48 intracranial stenoses of the anterior circulation were involved in the study. ⋯ MCA branch stenosis in 4 patients, but TCD failed in these two subgroups. The agreement between DSA and TCCS to evaluate semiquantitatively 18 intracranial stenoses resulted in a weighted-kappa value of 0.764. The major clinically relevant advantages of TCCS over TCD in MCA stenosis are its ability to differentiate MCA trunk stenosis from terminal ICA or MCA branch stenosis reliably and to perform angle-corrected flow velocity measurements.