Search results for "sonography"
showing 10 items of 978 documents
Clinical and biochemical determinants of the extent of liver steatosis in type 2 diabetes mellitus
2015
Objective Nonalcoholic fatty liver disease is very frequent in both type 2 diabetes mellitus (T2DM) and the metabolic syndrome (MS), which share clinical and metabolic characteristics. Whether and to which extent these characteristics can predict the degree of liver steatosis are not entirely clear. Patients and methods We determined liver fat (divided into four classes) by standard sonographic images, and clinical and biochemical variables, in 60 consecutive patients with T2DM and with features of the MS. We examined both simple and multiple correlations between the degree of liver steatosis and the variables measured. Results Increased liver fat (defined as >5% of liver mass) was detec…
Sex reversal from functional disomy of Xp: Prenatal and post-mortem findings.
2008
Translocations involving the short arms of the X and Y chromosomes are uncommon and are often associated with anomalies in gonadal development. Segmental duplications of the X chromosome interfere with the formation of the testis in patients with a 46,XY karyotype. The gene products located within the duplicated segment, when present in double dose, may affect on male sex development. We report on a fetus with karyotype 46,XY,der (14)t(X;14) (p10;p10)dn. Attached to chromosome 14 is the entire short arm of the X chromosome. Therefore, the fetus is affected with a disomy of Xp, resulting in complete male to female sex reversal, as well as other structural defects. To the best of our knowledg…
Tibial Nerve Block: Supramalleolar or Retromalleolar Approach? A Randomized Trial in 110 Participants.
2020
Of the five nerves that innervate the foot, the one in which anesthetic blocking presents the greatest difficulty is the tibial nerve. The aim of this clinical trial was to establish a protocol for two tibial nerve block anesthetic techniques to later compare the anesthetic efficiency of retromalleolar blocking and supramalleolar blocking in order to ascertain whether the supramalleolar approach achieved a higher effective blocking rate. A total of 110 tibial nerve blocks were performed. Location of the injection site was based on a prior ultrasound assessment of the tibial nerve. The block administered was 3 mL of 2% mepivacaine. The two anesthetic techniques under study provided very simi…
Preoperative imaging findings in patients undergoing transcranial magnetic resonance imaging-guided focused ultrasound thalamotomy
2021
AbstractThe prevalence and impact of imaging findings detected during screening procedures in patients undergoing transcranial MR-guided Focused Ultrasound (tcMRgFUS) thalamotomy for functional neurological disorders has not been assessed yet. This study included 90 patients who fully completed clinical and neuroradiological screenings for tcMRgFUS in a single-center. The presence and location of preoperative imaging findings that could impact the treatment were recorded and classified in three different groups according to their relevance for the eligibility and treatment planning. Furthermore, tcMRgFUS treatments were reviewed to evaluate the number of transducer elements turned off after…
Numerical study for a new methodology of flaws detection in train axles
2013
Train loads and travel speeds have increased over time, requiring more efficient non-destructive inspection methods. Railway axles are critical elements; despite being designed to last more than 20 years several cases of premature failure have been recorded. Train axles are inspected regularly, but the limits associated to the traditional inspection technologies create a growing interest towards new solutions. Here a novel non-destructive inspection method of in-service axles based on non-contact data collection is presented. The propagation of surface waves, generated by a thermo-elastic laser source, is investigated using a finite element method based on dynamic explicit integration. Coup…
Assessment of the cortical bone thickness using ultrasonic guided waves: Modelling and in vitro study
2007
Determination of cortical bone thickness is warranted, e.g., for assessing the level of endosteal resorption in osteoporosis or other bone pathologies. We have shown previously that the velocity of the fundamental antisymmetric (or flexural) guided wave, measured for bone phantoms and bones in vitro, correlates with the cortical thickness significantly better than those by other axial ultrasound methods. In addition, we have introduced an inversion scheme based on guided wave theory, group velocity filtering and 2-D fast Fourier transform, for determination of cortical thickness from the measured velocity of guided waves. In this study, the method was validated for tubular structures by usi…
Thickness sensitivity of ultrasound velocity in long bone phantoms
2004
One approach to bone disease diagnosis such as osteoporosis is to measure the velocity of ultrasound propagating axially along long bones. In this study, the variation in velocity as a function of radial position was assessed using two polyvinyl chloride (PVC) bone phantoms with cross-sectional geometry similar to the human tibia but differing in medullary cavity diameter. Two ultrasonometers were used: these were a commercial device operating at a relatively high frequency (HF) of 1.25 MHz and a prototype low frequency (LF) device operating at approximately 200 kHz. The LF measurements showed a larger variation with radial position, with changes in velocity of up to 20% occurring around th…
Measuring guided waves in long bones: Modeling and experiments in free and immersed plates
2005
Guided waves, consistent with the A0 Lamb mode, have previously been observed in bone phantoms and human long bones. Reported velocity measurements relied on line fitting of the observed wave fronts. Such an approach has limited ability to assess dispersion and is affected by interference by other wave modes. For a more robust identification of modes and determination of phase velocities, signal processing techniques using the fast Fourier transform (FFT) were investigated. The limitations of FFT because of spatial resolution were addressed to improve the precision of the measured modes. An inversion scheme was developed for determining the plate thickness from the measured velocity. Experi…
Determination of Bubble Size Distribution Using Ultrasound Array Imaging
2020
In this article, ultrasonic phased arrays are deployed as an imaging tool for industrial process analysis. Such arrays are typically used for sonar, medical diagnosis, and nondestructive testing; however, they have not yet been applied to industrial process analysis. The precise positioning of array elements and high frequencies possible with this technology mean that highly focused images can be generated, which cannot currently be achieved using ultrasound tomography. This article aims to highlight the potential of this technology for the measurement of bubble size distribution (BSD) and to demonstrate its application to both intrusive and noninvasive process measurements. Ultrasound imag…
Coded excitation speeds up the detection of the fundamental flexural guided wave in coated tubes
2016
The fundamental flexural guided wave (FFGW) permits ultrasonic assessment of the wall thickness of solid waveguides, such as tubes or, e.g., long cortical bones. Recently, an optical non-contact method was proposed for ultrasound excitation and detection with the aim of facilitating the FFGW reception by suppressing the interfering modes from the soft coating. This technique suffers from low SNR and requires iterative physical scanning across the source-receiver distance for 2D-FFT analysis. This means that SNR improvement achieved by temporal averaging becomes time-consuming (several minutes) which reduces the applicability of the technique, especially in time-critical applications such as…