نتایج جستجو برای: ultrasound scanner
تعداد نتایج: 127783 فیلتر نتایج به سال:
Ductal carcinoma in situ: magnetic resonance and ultrasound imaging in mouse models of breast cancer
The earliest stage of breast cancer, ductal carcinoma in situ (DCIS), is a remarkably heterogeneous disease with diverse molecular and prognostic subtypes. Mouse models of breast cancer offer an effective experimental framework in which to investigate DCIS, and biomedical imaging can provide potential insights into the biology of these models. In this study, we develop a high resolution, multi-...
Methods The respiratory liver motion simulator consists of a physical ovine liver, agar-gelatine block surrounding the liver, a medical air balloon which is connected to a lung ventilator, and two water balloons which are used to move the phantom back to its original position. The whole setup was MR compatible, including the ventilator which is used to provide simulation of respiratory motion. ...
BACKGROUND The purpose of this study was to assess the advantages and disadvantages of 3D gray-scale and power Doppler ultrasound, including thin slice volume rendering (TSVR), applied for evaluation of thyroid nodules. METHODS The retrospective evaluation by two observers of volumes of 71 thyroid nodules (55 benign, 16 cancers) was performed using a new TSVR technique. Dedicated 4D ultrasoun...
Accurate calibration is a requirement of many array signal processing techniques. We investigate the calibration of a transducer array using time delays. We derive a strategy based on the mean square error criterion and discuss how time delays that are not available can be interpolated from existing ones. The proposed method is made robust to noise and model mismatch by means of a novel iterati...
A new approach is proposed to estimate the spatial distribution of shear modulus of tissues in-vivo. An image sequence is acquired using a standard medical ultrasound scanner while varying the force applied to the handle. The elastic properties are then recovered simultaneously with the inter-frame displacement fields using a computational procedure based on finite element modeling and trust re...
We present herein 4D ultrafast ultrasound flow imaging, a novel ultrasound-based volumetric imaging technique for the quantitative mapping of blood flow. Complete volumetric blood flow distribution imaging was achieved through 2D tilted plane-wave insonification, 2D multi-angle cross-beam beamforming, and 3D vector Doppler velocity components estimation by least-squares fitting. 4D ultrafast ul...
Diagnostic ultrasound can cause hazardous temperature rises under certain imaging conditions. Thermocouples have been used to measure temperature, but they are invasive and it is difficult to localise the peak value. This paper examines the potential and limitations of using ultrasonic thermography to measure the temperature distribution due to a diagnostic ultrasound field. The technique explo...
Ten preterm infants were each studied by three observers using a commercial duplex Doppler ultrasound scanner, in order to determine the intra-observer and inter-observer variability in the measurement of pulsatility index (PI) of the anterior cerebral artery. There was considerable difference in estimates of PI, with a mean range of 0.11 between the three observers for each infant. Intra-obser...
One hundred and eleven high risk neonates were subjected to (cranial ultrasound (CR-USG) Caranial sonography was performed by 2D realtime scanner with 5 MHz transducer through anterior and posterior fontanelle and temporo-squamal suture. One quarter of these neonates developed intracranial hemorrhage (ICH) within 120 hours of birth. Of them 42.8% neonates recovered completely, 21.4% developed v...
background and aims. digital radiographs have some advantages over conventional ones. application of digital receptors is not routine yet. therefore, there is a need for digitizing conventional radiographs. the aim of the present study was to compare the diagnostic accuracy of digitized conventional radiographs by scanner and camera in detection of proximal caries. material and methods. three h...
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