for Journals by Title or ISSN
for Articles by Keywords
help
  Subjects -> PHYSICS (Total: 798 journals)
    - ELECTRICITY AND MAGNETISM (9 journals)
    - MECHANICS (19 journals)
    - NUCLEAR PHYSICS (49 journals)
    - OPTICS (85 journals)
    - PHYSICS (581 journals)
    - SOUND (23 journals)
    - THERMODYNAMICS (32 journals)

PHYSICS (581 journals)

The end of the list has been reached or no journals were found for your choice.
Journal Cover Ultrasound in Medicine & Biology
  [SJR: 0.885]   [H-I: 106]   [8 followers]  Follow
    
   Full-text available via subscription Subscription journal
   ISSN (Print) 0301-5629
   Published by Elsevier Homepage  [3038 journals]
  • Calendar
    • Abstract: Publication date: November 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 11


      PubDate: 2016-11-03T22:14:49Z
       
  • Effect of Low-Intensity Pulsed Ultrasound on a Rat Model of
           Dentin–Dental Pulp Injury and Repair
    • Authors: Fei Wang; Yueheng Zhengyan Yang Keke Jing Zuo Zhi Zhou
      Abstract: Publication date: Available online 1 November 2016
      Source:Ultrasound in Medicine & Biology
      Author(s): Fei Wang, Yueheng Li, Zhengyan Yang, Keke Lu, Jing Zuo, Zhi Zhou
      This study investigated histopathologic changes in dental pulp after treatment with low-intensity pulsed ultrasound (LIPUS). Fifty rats were randomly divided into an experimental group (n = 25) and a blank control group (n = 25). In the experimental group, a cavity was prepared in the bilateral maxillary first molars. The upper right first molars were stimulated with LIPUS (30 mW/cm2, 1.5 MHz) for 20 min/d. The cavities prepared in the left teeth were used as experimental controls (i.e., no LIPUS). Five rats in each group were sacrificed at days 1, 3, 5, 7 and 14. Inflammatory response was visible at different time points after cavity preparation, peaking at day 3, after which it gradually weakened. More reparative dentin was found on the LIPUS treatment side. transforming growth factor-β1 expression increased after treatment, peaking at day 5 and returning to normal at day 14 on both sides, but was stronger with LIPUS treatment. SMAD2 and SMAD3 expressions in the dental pulp gradually increased after cavity preparation, especially in the experimental group. LIPUS promoted the repair of dentin–pulp complex injury, to a certain extent and should be investigated further as a potential therapy.

      PubDate: 2016-11-03T22:14:49Z
       
  • Microvascular Injury and Perfusion Changes Induced by Ultrasound and
           Microbubbles in a Machine-Perfused Pig Liver
    • Authors: Christina Keravnou; Ine Cock Ine Lentacker Maria-Louisa Izamis Michalakis Averkiou
      Abstract: Publication date: November 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 11
      Author(s): Christina P. Keravnou, Ine De Cock, Ine Lentacker, Maria-Louisa Izamis, Michalakis A. Averkiou
      Localized drug delivery and uptake can benefit from the combined action of ultrasound and microbubbles at a specific site. Some of the possible mechanisms suggested are vessel poration and/or cell poration, but the exact acoustic parameters that trigger those phenomena remain unknown. Ex vivo machine perfusion of human-sized organs is a technique that provides an ideal environment for pre-clinical investigations with high physiologic relevance not possible with in vitro experiments. In this work, ex vivo machine-perfused pig livers were combined with an image-guided therapy system to investigate microvascular flow changes caused by the interaction of ultrasound-driven microbubbles with the vasculature. The effects of acoustic pressure (1.7–4 MPa peak negative pressures) and number of cycles (1000 or 20 cycles) were examined. Perfusion changes caused by the action of ultrasound on microbubbles in the microcirculation were qualitatively and quantitatively assessed with contrast-enhanced ultrasound and used as a metric of the extent of vessel perforation, thus, extravasation. Areas that were exposed to peak negative pressures above 1.7 MPa underwent a detectable and irreversible perfusion change. Complete devascularization of the area exposed to ultrasound was observed at much larger acoustic pressures (∼4 MPa). Shorter acoustic pulses (20 cycles) produced markedly fewer perfusion changes than longer pulses (1000 cycles) under the same acoustic amplitude exposure.

      PubDate: 2016-11-03T22:14:49Z
       
  • Retrospective Analysis of Ultrasound-Detected Bleeding Complications after
           Ultrasound-Guided Transcutaneous Kidney Biopsies
    • Authors: Stephanie Preuss; Claudius Kuechle Stefan Wagenpfeil Christoph Schmaderer Lutz Renders
      Abstract: Publication date: Available online 13 October 2016
      Source:Ultrasound in Medicine & Biology
      Author(s): Stephanie Preuss, Claudius Kuechle, Stefan Wagenpfeil, Christoph Schmaderer, Lutz Renders, Uwe Heemann, Konrad Stock
      The aim of this retrospective single-center study was to examine ultrasound-detected complications after diagnostic parenchymal renal biopsies. After 471 ultrasound-guided kidney biopsies (225 native kidneys and 246 renal allografts), ultrasound revealed hematomas (21.9%), arterio-venous fistulas (8.9%), active bleeding (1.1%) and hematuria (0.4%). Only 0.8% of all patients required invasive intervention such as coiling (n = 3) and surgical procedures (n = 1). Three episodes of bleeding (0.6%) were solved with manual compression. One patient (0.2%) needed an irrigation catheter because of hematuria. Furthermore, six patients (1.3%) received blood transfusion. Ultrasound-guided biopsies are safe. With modern ultrasound machines using multi-frequency transducers with high resolution and harmonic imaging, even marginal bleeding after renal biopsy is detected.

      PubDate: 2016-11-03T22:14:49Z
       
  • Transthoracic Ultrasound Elastography in Pulmonary Lesions and Diseases
    • Authors: Chor-Kuan Lim; Che-Liang Chung Yen-Ting Lin Chia-Hao Chang Yi-Chun Lai
      Abstract: Publication date: Available online 12 October 2016
      Source:Ultrasound in Medicine & Biology
      Author(s): Chor-Kuan Lim, Che-Liang Chung, Yen-Ting Lin, Chia-Hao Chang, Yi-Chun Lai, Hao-Chien Wang, Chong-Jen Yu
      Ultrasound elastography has shown promising result in the diagnosis of various diseases; however, its application for pulmonary diseases has yet to be clarified. This study aimed to assess the application and feasibility of ultrasound elastography in various pulmonary lesions and diseases. We enrolled 45 patients with radiographic evidence of pneumonia, tumors or obstructive pneumonitis, and 70 ultrasonic lesions were identified (eight necrosis, 17 atelectasis, seven consolidation and 38 tumors). Ultrasound elastography was performed and the strain ratio, which is the ratio of strain of the reference tissue to an equally measuring region of interest of a lesion, was measured. The strain ratio was significantly different among lesions with different ultrasound morphologies (1.03 ± 0.71 [necrosis] vs. 2.51 ± 1.14 [atelectasis] vs. 19.98 ± 15.59 [consolidation] vs. 36.19 ± 20.18 [tumor]; p < 0.05). The strain ratio of primary lung cancer was also significantly different from pneumonia (p = 0.023) and metastatic lung cancer (p = 0.015). In conclusion, transthoracic ultrasound elastography can differentiate pulmonary lesions with different ultrasound morphologies. ClinicalTrials.gov Identifier: NCT02636985.

      PubDate: 2016-11-03T22:14:49Z
       
  • Automated Registration of Freehand B-Mode Ultrasound and Magnetic
           Resonance Imaging of the Carotid Arteries Based on Geometric Features
    • Authors: Diego D.B.; Carvalho Andres Mauricio Arias Lorza Wiro Niessen Marleen
      Abstract: Publication date: Available online 13 October 2016
      Source:Ultrasound in Medicine & Biology
      Author(s): Diego D.B. Carvalho, Andres Mauricio Arias Lorza, Wiro J. Niessen, Marleen de Bruijne, Stefan Klein
      An automated method for registering B-mode ultrasound (US) and magnetic resonance imaging (MRI) of the carotid arteries is proposed. The registration uses geometric features, namely, lumen centerlines and lumen segmentations, which are extracted fully automatically from the images after manual annotation of three seed points in US and MRI. The registration procedure starts with alignment of the lumen centerlines using a point-based registration algorithm. The resulting rigid transformation is used to initialize a rigid and subsequent non-rigid registration procedure that jointly aligns centerlines and segmentations by minimizing a weighted sum of the Euclidean distance between centerlines and the dissimilarity between segmentations. The method was evaluated in 28 carotid arteries from eight patients and six healthy volunteers. First, the automated US lumen segmentation method was validated and optimized in a cross-validation experiment. Next, the effect of the weighting parameter of the proposed registration dissimilarity metric and the control point spacing in the non-rigid registration was evaluated. Finally, the proposed registration method was evaluated in comparison to an existing intensity-and-point-based method, a registration using only the centerlines and a registration using manual US lumen segmentations. Registration accuracy was measured in terms of the mean surface distance between manual US segmentations and the registered MRI segmentations. The average mean surface distance was 0.78 ± 0.34 mm for all subjects, 0.65 ± 0.09 mm for healthy volunteers and 0.87 ± 0.42 mm for patients. The results for the complete set were significantly better (Wilcoxon test, p < 0.01) than the results for the intensity-and-point-based method and the centerline-based registration method. We conclude that the proposed method can robustly and accurately register US and MR images of the carotid artery, allowing multimodal analysis of the carotid plaque to improve plaque assessment.

      PubDate: 2016-11-03T22:14:49Z
       
  • Examination of Effects of Low-Frequency Ultrasound on Scleral Permeability
           and Collagen Network
    • Authors: Wai-Leung Langston; Suen Jun Jiang Hoi Sang Wong Jianan Ying
      Abstract: Publication date: November 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 11
      Author(s): Wai-Leung Langston Suen, Jun Jiang, Hoi Sang Wong, Jianan Qu, Ying Chau
      Delivery of therapeutics to the intraocular space or to targeted tissues in the posterior segment is challenging because of the structural and dynamic barriers surrounding the eye. Previously, we reported the feasibility of using ultrasound (US) irradiation to deliver macromolecules to the posterior segment of the eye via the transscleral route, which consists of sclera as the outermost anatomic barrier. In this study, we found that although ultrasound increases scleral permeability for macromolecules, the scleral collagen arrangement remains undisturbed. In an ex vivo experiment, protein permeation across the sclera was significantly enhanced by ultrasound in the stable cavitation regime. The scleral collagen network was further examined by second harmonic generation imaging. Quantitative image analysis techniques were adopted to examine the density, anisotropy and interlacing pattern of collagen fibers before and after ultrasound irradiation. Repeated ultrasound applications did not induce significant changes in the arrangement of collagen fibrils at 40 kHz with a spatial average temporal average intensity (I SATA) <1.8 W/cm2. These parameters correspond to a mechanical index (MI) below 0.8 in our setting. These data suggested that enhanced permeation of macromolecules across the sclera was achieved without disturbing the collagen network of the sclera. This evidence supports that low-frequency, low-intensity ultrasound is a tolerable approach to transscleral drug delivery.

      PubDate: 2016-11-03T22:14:49Z
       
  • Effects of Stone Size on the Comminution Process and Efficiency in Shock
           Wave Lithotripsy
    • Authors: Ying Zhang; Isaac Nault Sorin Mitran Edwin Iversen Pei Zhong
      Abstract: Publication date: November 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 11
      Author(s): Ying Zhang, Isaac Nault, Sorin Mitran, Edwin S. Iversen, Pei Zhong
      The effects of stone size on the process and comminution efficiency of shock wave lithotripsy (SWL) were investigated in experiments, numerical simulations and scale analysis. Cylindrical BegoStone phantoms with approximately equal height and diameter of either 4, 7 or 10 mm, in a total aggregated mass of about 1.5 g, were treated in an electromagnetic shock wave lithotripter field. The resultant stone comminution was found to correlate closely with the average peak pressure, P +(avg), incident on the stones. The P +(avg) threshold necessary to initiate stone fragmentation in water increased from 7.9 to 8.8 to 12.7 MPa, respectively, as stone size decreased from 10 to 7 to 4 mm. Similar changes in the P +(avg) threshold were observed for the 7- and 10-mm stones treated in 1,3-butanediol, in which cavitation is suppressed, suggesting that the observed size dependency is due to changes in stress distribution within stones of different size. Moreover, the slope of the correlation curve between stone comminution and ln ( P ¯ + ( avg ) ) in water increased with decreasing stone size, whereas the opposite trend was observed in 1,3-butanediol. The progression of stone comminution in SWL exhibited size-dependence: the 7- and 10-mm stones fragmented into progressively smaller pieces, whereas a significant portion (>30%) of the 4-mm stones reached a stalemate within the size range of 2.8 ∼ 4 mm, even after 1000 shocks. Analytical scaling considerations suggest size-dependent fragmentation behavior, a hypothesis further supported by numerical model calculations that reveal changing patterns of constructive and destructive wave interference and, thus, variations in the maximum tensile stress or stress integral produced in cylindrical and spherical stone of different sizes.

      PubDate: 2016-11-03T22:14:49Z
       
  • Contrast-Enhanced Ultrasound in the Assessment of Patients with
           Indeterminate Abdominal Findings at Positron Emission Tomography Imaging
    • Authors: Orlando Catalano; Fabio Sandomenico Paolo Vallone Sergio Venanzio Setola Vincenza
      Abstract: Publication date: November 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 11
      Author(s): Orlando Catalano, Fabio Sandomenico, Paolo Vallone, Sergio Venanzio Setola, Vincenza Granata, Roberta Fusco, Secondo Lastoria, Luigi Mansi, Antonella Petrillo
      Widespread use of fluorodeoxyglucose-positron emission tomography (PET) in cancer imaging may result in a number of indeterminate and false-positive findings. We investigated the role of contrast-enhanced ultrasound (CEUS) as a second-level option after inconclusive PET. We reviewed CEUS images acquired over 4 y, selecting the examinations performed specifically to better assess an unclear PET image. Final diagnosis was confirmed by biopsy, surgery, further imaging or follow-up. Seventy CEUS examinations were performed after a PET scan (44 PET examinations, 19 PET-computer tomography [CT] examinations and 7 PET-CECT examinations). The target organ was the liver in 54 cases, spleen in 12, gallbladder in 2 and pancreas and kidney in one each. In 6 of 70 cases, CEUS was performed because of a negative PET (no uptake) despite an abnormal finding on the CT images of the PET-CT study; CEUS allowed a correct diagnosis in all of these. In 20 of 70 cases, the PET findings were categorized as indeterminate and non-specific (non-specific fluorodeoxyglucose uptake in PET report with no standardized uptake value given); CEUS reached a correct diagnosis in 19 of the 20 cases with one false negative. In 34 of 70 cases, PET was indeterminate, but specific (fluorodeoxyglucose uptake with a standardized uptake value provided); CEUS reached a correct diagnosis in 30 of these 34 cases. In 10 of 70 cases, PET was categorized as determinate but to be investigated because of discrepancy with clinical or imaging findings; CEUS a definitive diagnosis in 9 of 10 cases. CEUS proved to be effective option in the assessment of cancer patients with indeterminate PET findings.

      PubDate: 2016-11-03T22:14:49Z
       
  • Two-Dimensional Time-Harmonic Elastography of the Human Liver and Spleen
    • Authors: Heiko Manh; Nguyen Trong Tobias Scheuermann Selcan Ipek-Ugay Thomas Fischer
      Abstract: Publication date: November 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 11
      Author(s): Heiko Tzschätzsch, Manh Nguyen Trong, Tobias Scheuermann, Selcan Ipek-Ugay, Thomas Fischer, Michael Schultz, Jürgen Braun, Ingolf Sack
      Measurement of shear wave speed of the liver and spleen by elastography is an established diagnostic procedure for the detection of hepatic fibrosis, portal hypertension and esophageal varices. However, current elastography systems are limited by the size and penetration depth of elastographic windows. In this study, 2D time-harmonic elastography is proposed for generating full field-of-view shear wave speed maps in great depth. Two-dimensional time-harmonic elastography uses external harmonic stimulation at multiple frequencies to create compound shear wave speed maps. The method is tested in a phantom with soft and stiff inclusions and used for elastography of the liver and spleen in 13 asymptomatic volunteers. Each volunteer was scanned twice to determine the sensitivity of the method to physiologic variations: first, after 2 h of fasting, and a second time, 15 min after drinking 1 L of water. The wave speed maps of the phantom clearly identified the soft and stiff inclusions, yielding values that were consistent with those from magnetic resonance elastography. In vivo wave speed values were 1.49 ± 0.11 m/s for the liver and 2.03 ± 0.15 m/s for the spleen in a lower-frequency band centered at 40 Hz and 3.15 ± 0.30 m/s for the spleen in a higher-frequency band centered at 120 Hz. After water intake, wave speed values increased by 6% in the liver (p = 0.002) and decreased in the spleen by 4% (p = 0.021, low-frequency band) and 6% (p = 0.0002, high-frequency band), suggesting the high sensitivity of the method to altered blood flow and perfusion pressure. Two-dimensional time-harmonic elastography of the liver and spleen is a promising method for measuring tissue stiffness at different states of blood flow and perfusion in a large tissue window and at great penetration depth.

      PubDate: 2016-11-03T22:14:49Z
       
  • Quantitative Differences Between the First and Second Injection of
           Contrast Agent in Contrast-Enhanced Ultrasonography of Feline Kidneys and
           Spleen
    • Authors: Emmelie Stock; Katrien Vanderperren Hendrik Haers Luc Duchateau Myriam Hesta
      Abstract: Publication date: Available online 14 October 2016
      Source:Ultrasound in Medicine & Biology
      Author(s): Emmelie Stock, Katrien Vanderperren, Hendrik Haers, Luc Duchateau, Myriam Hesta, Jimmy H. Saunders
      Contrast-enhanced ultrasound is a valuable and safe technique for the evaluation of organ perfusion. Repeated injections of ultrasound contrast agent are often administered during the same imaging session. However, it remains unclear if quantitative differences are present between the consecutive microbubble injections. Therefore, the first and second injection of contrast agent for the left renal cortex, renal medulla and the splenic parenchyma in healthy cats were compared. A lower peak intensity and area under the curve were observed for the first injection of contrast agent in the feline kidney, both for the renal cortex and medulla, and spleen. Moreover, for the renal cortex, the time-intensity curve was steeper after the second injection. Findings from the present study demonstrate that a second injection of contrast agent provides stronger enhancement. The exact mechanism behind our findings remains unclear; however, saturation of the lung macrophages is believed to play an important role.

      PubDate: 2016-11-03T22:14:49Z
       
  • Effect of Transmural Extent of the Simulated Infarction in a Left
           Ventricular Model on Displacement and Strain Distribution Estimated from
           Synthetic Ultrasonic Data
    • Authors: Jakub Szymon; Cygan Beata Kowalski Krzysztof
      Abstract: Publication date: Available online 13 October 2016
      Source:Ultrasound in Medicine & Biology
      Author(s): Jakub Żmigrodzki, Szymon Cygan, Beata Leśniak-Plewińska, MirosŁaw Kowalski, Krzysztof KaŁużyński
      The identification of a sub-endocardial infarction is of major interest in cardiology. This study evaluates the sensitivity of selected measures to the thickness of such an infarction. Synthetic ultrasonic data (long-axis view) of left ventricular models with inclusions were generated using Field II and meshes obtained from finite-element simulations, which also provided the reference for the estimates obtained from ultrasonic data. The displacements, the first and second component of the principal strain (ε1 and ε2), and several measures derived from these quantities were estimated. All estimates, except for the poorly estimated ε2, exhibited sensitivity to the presence and transmurality of the inclusion. The most sensitive was the gradient of the averaged transmural profiles of ε1, and ε1 averaged over the area corresponding to the transmural inclusion. The inflection point of the ε1 profile shifted toward the outer wall with increasing thickness of the non-transmural inclusion.

      PubDate: 2016-11-03T22:14:49Z
       
  • Breast Lesion Elastography Region of Interest Selection and Quantitative
           Heterogeneity: A Systematic Review and Meta-Analysis
    • Authors: Molly A.B.; Blank James Antaki
      Abstract: Publication date: Available online 14 October 2016
      Source:Ultrasound in Medicine & Biology
      Author(s): Molly A.B. Blank, James F. Antaki
      In this systematic review and meta-analysis, we report measured elasticities of benign and malignant breast pathologies from shear wave elastography (SWE), quantitatively confirm the effect of the selected region of interest (ROI) on these measures and test the hypothesis that a metric of heterogeneity based on the mean and maximum elasticity can improve specificity of diagnosis. The elasticities of benign, malignant and specific pathologic states are reported from 22 publications encompassing 2989 patients, identified from a structured search of the literature from May to September 2015. Twelve articles were included in a meta-analysis that grouped results by the method of ROI selection to discriminate between different pathologies. We observe a significant correlation between the method of selection of ROI for malignant mean (p < 0.001) and maximum (p = 0.027) elasticities, but no correlation with benign measures. We define a quantitative heterogeneity parameter, the “stiffness gradient,” computed from the mean and maximum measured elasticities. The stiffness gradient out-performed the current standard maximum elasticity metric in stratifying malignancy risk by a margin of 15% for the partial ROI, and 42% for the maximized ROI. An anecdotal example of improved differentiation using the stiffness gradient on pathology-specific lesions is also provided. These results quantitatively indicate that the method of ROI selection in SWE not only has a significant impact on the resulting mean reported elasticity of a lesion, but may provide some insight into lesion heterogeneity. Our results suggest that further exploration of quantitative heterogeneity is warranted to improve the specificity of diagnosis.

      PubDate: 2016-11-03T22:14:49Z
       
  • Metrological Validation of a Measurement Procedure for the
           Characterization of a Biological Ultrasound Tissue-Mimicking Material
    • Authors: Taynara Santos; Alvarenga Oliveira Rodrigo P.B. Costa-Felix
      Abstract: Publication date: Available online 15 October 2016
      Source:Ultrasound in Medicine & Biology
      Author(s): Taynara Q. Santos, André V. Alvarenga, Débora P. Oliveira, Rodrigo P.B. Costa-Felix
      The speed of sound and attenuation are important properties for characterizing reference materials such as biological phantoms used in ultrasound applications. There are many publications on the manufacture of ultrasonic phantoms and the characterization of their properties. However, few studies have applied the principles of metrology, such as the expression of the uncertainty of measurement. The objective of this study is to validate a method for characterizing the speed of sound and the attenuation coefficient of tissue-mimicking material (TMM) based on the expression of the measurement of uncertainty. Six 60-mm-diameter TMMs were fabricated, three 10 mm thick and three 20 mm thick. The experimental setup comprised two ultrasonic transducers, acting as transmitter or receiver depending on the stage of the measurement protocol, both with a nominal center frequency of 5 MHz and an element diameter of 12.7 mm. A sine burst of 20 cycles and 20-V peak-to-peak amplitude at 5 MHz excited the transmitter transducer, producing a maximum pressure of 0.06 MPa. The measurement method was based on the through-transmission substitution immersion technique. The speed of sound measurement system was validated using a calibrated stainless-steel cylinder as reference material, and normalized errors were <0.8. The attenuation coefficient measurement method was validated using replicated measurements under repeatability conditions. The normalized error between the two measurement sets was <1. The proposed uncertainty models for the measurements of the speed of sound and the attenuation coefficient can help other laboratories develop their own uncertainty models. These validated measurement methods can be used to certify a TMM as a reference material for biotechnological applications.

      PubDate: 2016-11-03T22:14:49Z
       
  • A Meta-analysis for the Diagnostic Performance of Transient Elastography
           for Clinically Significant Portal Hypertension
    • Authors: Myung-Won Kyung; Won Kim Junhee Pyo Jimi Huh Hyoung Jung
      Abstract: Publication date: Available online 15 October 2016
      Source:Ultrasound in Medicine & Biology
      Author(s): Myung-Won You, Kyung Won Kim, Junhee Pyo, Jimi Huh, Hyoung Jung Kim, So Jung Lee, Seong Ho Park
      We aimed to evaluate the correlation between liver stiffness measurement using transient elastography (TE-LSM) and hepatic venous pressure gradient and the diagnostic performance of TE-LSM in assessing clinically significant portal hypertension through meta-analysis. Eleven studies were included from thorough literature research and selection processes. The summary correlation coefficient was 0.783 (95% confidence interval [CI], 0.737–0.823). Summary sensitivity, specificity and area under the hierarchical summary receiver operating characteristic curve (AUC) were 87.5% (95% CI, 75.8–93.9%), 85.3 % (95% CI, 76.9–90.9%) and 0.9, respectively. The subgroup with low cut-off values of 13.6–18 kPa had better summary estimates (sensitivity 91.2%, specificity 81.3% and partial AUC 0.921) than the subgroup with high cut-off values of 21–25 kPa (sensitivity 71.2%, specificity 90.9% and partial AUC 0.769). In summary, TE-LSM correlated well with hepatic venous pressure gradient and represented good diagnostic performance in diagnosing clinically significant portal hypertension. For use as a sensitive screening tool, we propose using low cut-off values of 13.6–18 kPa in TE-LSM.

      PubDate: 2016-11-03T22:14:49Z
       
  • Polymer-Based Materials in Cancer Treatment: From Therapeutic Carrier and
           Ultrasound Contrast Agent to Theranostic Applications
    • Authors: Boriphat Methachan; Kamolrat Thanapprapasr
      Abstract: Publication date: Available online 15 October 2016
      Source:Ultrasound in Medicine & Biology
      Author(s): Boriphat Methachan, Kamolrat Thanapprapasr
      The emergence of theranostics with ultrasound technology is a promising development, as it opens pathways to providing more effective treatments for cancer. Advancements in ultrasound imaging would give a more detailed and accurate image for better diagnosis and treatment planning. Polymeric ultrasound contrast agents (UCAs) are appealing because they are stable and easily modified for active targeting. In addition, a better therapy could be achieved in conjunction with advancements in UCAs. The active targeting not only makes the precise imaging possible, but also leads to targeted delivery of active components to specific local treatment sites. A polymeric nanocarrier with surface bioconjugation is the key to prolonging the bioavailability of the encapsulated drugs or genes and the capacity to target the specific tumor site. Using ultrasound with other imaging modalities will open more precise and better ways for diagnosis and therapy and bring us a step closer to personalized medicine. This review focuses on polymer-based materials of UCAs, multimodal imaging agents and therapeutic carriers that have been currently explored for their theranostic applications involving ultrasound for cancer diagnosis and treatment.

      PubDate: 2016-11-03T22:14:49Z
       
  • High-Intensity Focused Ultrasound– and Radiation Therapy–Induced
           Immuno-modulation: Comparison and Potential Opportunities
    • Authors: Roberta Cirincione; Federica Maria Maggio Giusi Irma Forte Luigi Minafra
      Abstract: Publication date: Available online 22 October 2016
      Source:Ultrasound in Medicine & Biology
      Author(s): Roberta Cirincione, Federica Maria Di Maggio, Giusi Irma Forte, Luigi Minafra, Valentina Bravatà, Laura Castiglia, Vincenzo Cavalieri, Giovanni Borasi, Giorgio Russo, Domenico Lio, Cristina Messa, Maria Carla Gilardi, Francesco Paolo Cammarata
      In recent years, high-intensity focused ultrasound (HIFU) has emerged as a new and promising non-invasive and non-ionizing ablative technique for the treatment of localized solid tumors. Extensive pre-clinical and clinical studies have evidenced that, in addition to direct destruction of the primary tumor, HIFU-thermoablation may elicit long-term systemic host anti-tumor immunity. In particular, an important consequence of HIFU treatment includes the release of tumor-associated antigens (TAAs), the secretion of immuno-suppressing factors by cancer cells and the induction of cytotoxic T lymphocyte (CTL) activity. Radiation therapy (RT) is the main treatment modality used for many types of tumors and about 50% of all cancer patients receive RT, often used in combination with surgery and chemotherapy. It is well known that RT can modulate anti-tumor immune responses, modifying micro-environment and stimulating inflammatory factors that can greatly affect cell invasion, bystander effects, radiation tissue complications (such as fibrosis), genomic instability and thus, intrinsic cellular radio-sensitivity. To date, various combined therapeutic strategies (such as immuno-therapy) have been performed in order to enhance RT success in treating locally advanced and recurrent tumors. Recent works suggested the combined use of HIFU and RT treatments to increase the tumor cell radio-sensitivity, in order to synergize the effects reaching the maximum results with minimal doses of ionizing radiation (IR). Here, we highlight the opposite immuno-modulation roles of RT and HIFU, providing scientific reasons to test, by experimental approaches, the use of HIFU immune-stimulatory capacity to improve tumor radio-sensitivity, to reduce the RT induced inflammatory response and to decrease the dose-correlated side effects in normal tissues.

      PubDate: 2016-11-03T22:14:49Z
       
  • Evaluating Affordable Cranial Ultrasonography in East African Neonatal
           Intensive Care Units
    • Authors: David Clay; Annika Linke Daniel Cameron Bobby Stojanoski Stephen Rulisa
      Abstract: Publication date: Available online 20 October 2016
      Source:Ultrasound in Medicine & Biology
      Author(s): David E. Clay, Annika C. Linke, Daniel J. Cameron, Bobby Stojanoski, Stephen Rulisa, Aggrey Wasunna, Sandrine de Ribaupierre, Rhodri Cusack
      Neuroimaging is a valuable diagnostic tool for the early detection of neonatal brain injury, but equipment and radiologic staff are expensive and unavailable to most hospitals in developing countries. We evaluated an affordable, portable ultrasound machine as a quantitative and qualitative diagnostic tool and to establish whether a novice sonographer could effectively operate the equipment and obtain clinically important information. Cranial ultrasonography was performed on term healthy, pre-term and term asphyxiated neonates in Rwandan and Kenyan hospitals. To evaluate the detection of ventriculomegaly and compression injuries, we measured the size of the lateral ventricles and corpus callosum. The images were also assessed for the presence of other cerebral abnormalities. Measurements were reliable across images, and cases of clinically relevant ventriculomegaly were detected. A novice sonographer had good-to-excellent agreement with an expert. This study demonstrates that affordable equipment and cranial ultrasound protocols can be used in low-resource settings to assess the newborn brain.

      PubDate: 2016-11-03T22:14:49Z
       
  • Ultrasound and Contrast-Enhanced Ultrasound for Evaluation of Irreversible
           Electroporation Ablation: In Vivo Proof of Concept in Normal Porcine
           Liver
    • Authors: Man-Xia Lin; Ming Kuang Ming Bo-Wen Zhuang Wen-Shuo Tian Jie-Yi
      Abstract: Publication date: November 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 11
      Author(s): Man-Xia Lin, Ming Kuang, Ming Xu, Bo-Wen Zhuang, Wen-Shuo Tian, Jie-Yi Ye, Xiao-Hua Xie, Xiao-Yan Xie
      The objective of this study was to describe the performance of ultrasound (US) and contrast-enhanced ultrasound (CEUS) within 2 h after irreversible electroporation (IRE) ablation of porcine liver. Six IRE ablations were performed on porcine liver in vivo; ultrasound assessments were performed within 2 h after IRE ablation. On US images, the ablation zone appeared as a hypo-echoic area within 10 min after the ablation, and then the echo of the ablation zone gradually increased. On CEUS images, the ablation zone appeared as a non-enhanced area within 10 min after ablation and then was gradually centripetally filled by microbubbles. A hyper-echoic rim on US images and a hyper-enhanced rim on CEUS images appeared in the periphery of the ablation zone 60 min after the ablation. Characteristic and dynamic ultrasound images of the IRE ablation zone were obtained within 2 h after IRE ablation of in vivo porcine liver.

      PubDate: 2016-11-03T22:14:49Z
       
  • Incorporating Contrast-Enhanced Ultrasound into the BI-RADS Scoring System
           
    • Authors: Xiaoyun Xiao; Licong Dong Qiongchao Jiang Xiaofeng Guan Huan Baoming
      Abstract: Publication date: November 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 11
      Author(s): Xiaoyun Xiao, Licong Dong, Qiongchao Jiang, Xiaofeng Guan, Huan Wu, Baoming Luo
      The aim of the study was to develop a scoring model incorporating the Breast Imaging Reporting and Data System (BI-RADS) and the contrast-enhanced ultrasound (CEUS) scoring system to differentiate between malignant and benign breast lesions. A total of 524 solid breast masses in 490 consecutive patients were evaluated with conventional US and CEUS in this prospective study. Each lesion was scored according to BI-RADS, CEUS, and CEUS-rerated BI-RADS. The diagnostic specificity, sensitivity and accuracy of BI-RADS were 77.9%, 88.9% and 84.0%, respectively, and the area under the receiver operating characteristic curve was 0.834. The corresponding values for rerated BI-RADS were 82.1%, 96.9%, 90.3% and 0.895. The area under the receiver operating characteristic curve of BI-RADS alone was significantly smaller than that of CEUS and the rerated BI-RADS (p = 0.008 compared with CEUS, p = 0.002 compared with rerated BI-RADS). This study indicates that rerating BI-RADS with the CEUS scoring system improves its diagnostic accuracy.

      PubDate: 2016-11-03T22:14:49Z
       
  • Contrast-Enhanced Ultrasound Imaging in Detection of Changes in Cerebral
           Perfusion
    • Authors: Federico Bilotta; Chiara Robba Antonio Santoro Roberto Delfini Giovanni Rosa
      Abstract: Publication date: November 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 11
      Author(s): Federico Bilotta, Chiara Robba, Antonio Santoro, Roberto Delfini, Giovanni Rosa, Luciano Agati
      Contrast-enhanced ultrasonography (CEU) is a non-invasive imaging technique that provides real-time, bedside information on changes in global and segmental organ perfusion. Currently, there is a lack of data concerning changes in the distribution of segmental brain perfusion in acute ischemic stroke treated by decompressive craniectomy. The aim of our case series was to assess the role of CEU after decompressive craniectomy in patients with acute ischemic stroke. CEU was performed in 12 patients at baseline and after any one of the following interventions was performed as dictated by the patient's clinical condition: vasoactive drug administration (in order to achieve cerebral perfusion pressure ≥70 mm Hg and mean arterial pressure <100 mm Hg for management of arterial blood pressure) and mild hyperventilation (carbon dioxide arterial pressure = 30–35 mm Hg). CEU was able to detect a significant variation in cerebral contrast distribution in both normal and pathologic hemispheres after induced hyperventilation (difference in time to peak [dTTP] = −38.4%), vasodilation (dTTP = −6.6%) and vasoconstriction (dTTP = +31.2%) (p < 0.05). CEU can be useful in assessing real-time cerebral perfusion changes in neurocritical care patients.

      PubDate: 2016-11-03T22:14:49Z
       
  • Calibrated Linear Array-Driven Photoacoustic/Ultrasound Tomography
    • Authors: Milan Oeri; Wolfgang Bost Steffen Tretbar Marc Fournelle
      Abstract: Publication date: November 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 11
      Author(s): Milan Oeri, Wolfgang Bost, Steffen Tretbar, Marc Fournelle
      The anisotropic resolution of linear arrays, tools that are widely used in diagnostics, can be overcome by compounding approaches. We investigated the ability of a recently developed calibration and a novel algorithm to determine the actual radial transducer array distance and its misalignment (tilt) with respect to the center of rotation in a 2-D and 3-D tomographic setup. By increasing the time-of-flight accuracy, we force in-phase summation during the reconstruction. Our setup is composed of a linear transducer and a rotation and translation axis enabling multidimensional imaging in ultrasound and photoacoustic mode. Our approach is validated on phantoms and young mice ex vivo. The results indicate that application of the proposed analytical calibration algorithms prevents image artifacts. The spatial resolution achieved was 160 and 250 μm in photoacoustic mode of 2-D and 3-D tomography, respectively.

      PubDate: 2016-11-03T22:14:49Z
       
  • Ultrasound Strain Measurements for Evaluating Local Pulmonary Ventilation
    • Authors: Jonathan Rubin; Jeffrey Horowitz Thomas Sisson Kang Kim Luis Ortiz
      Abstract: Publication date: November 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 11
      Author(s): Jonathan M. Rubin, Jeffrey C. Horowitz, Thomas H. Sisson, Kang Kim, Luis A. Ortiz, James D. Hamilton
      Local lung function is difficult to evaluate, because most lung function estimates are either global in nature (e.g., pulmonary function tests) or require equipment that cannot be used at a patient's bedside, such as computed tomography. Yet, local function measurements would be highly desirable for many reasons. Recently, we were able to track displacements of the lung surface during breathing. We have now extended these results to measuring lung strains during respiration as a means of assessing local lung ventilation. We studied two human volunteers and 14 mice with either normal lung function or experimentally induced pulmonary fibrosis. The differences in strains between the control, normal mice and those with pulmonary fibrosis were significant (p < 0.0001), whereas the strains measured in the human volunteers closely matched linear strains predicted from the literature. It may be possible to use ultrasonography to assess local lung ventilation in a clinical setting.

      PubDate: 2016-11-03T22:14:49Z
       
  • Optimization of a Pixel-to-Pixel Curve-Fitting Method for Poroelastography
           Imaging
    • Authors: Belfor Antonio; Galaz Rodrigo Hernan Acevedo
      Abstract: Publication date: Available online 17 October 2016
      Source:Ultrasound in Medicine & Biology
      Author(s): Belfor Antonio Galaz, Rodrigo Hernan Acevedo
      Ultrasound poroelastography is an imaging modality used to characterize the temporal behavior of soft tissue that can be modeled as a solid permeated by interconnected pores filled with liquid (poroelastic medium). It could be useful in the stage classification of lymphedema. Generally, time-constant models are applied to strain images, and precision of the fitting process, computational cost and versatility in response to changes in tissues properties are crucial aspects of clinical applications. In the work described here, we performed creep experiments on poroelastic phantoms and used rheologic models to visualize the changes in viscoelastic response associated with fluid mobility. We used the Levenberg–Marquardt algorithm as a fitting tool and performed parametric studies to improve its performance. On the basis of these studies, we proposed an optimization schema for the pixel-to-pixel curve-fitting process. We determined that the bimodal Kelvin–Voigt model describes efficiently the temporal evolution of the strain images in heterogeneous phantoms.

      PubDate: 2016-11-03T22:14:49Z
       
  • Diagnostic Utility of Acoustic Structure Quantification for Evaluation of
           Radiation Sialadenitis after Radioactive Iodine Therapy
    • Authors: Sun Hye; Jeong Hyun Sook Hong Eun Hye Lee
      Abstract: Publication date: November 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 11
      Author(s): Sun Hye Jeong, Hyun Sook Hong, Eun Hye Lee
      Acoustic structure quantification (ASQ) software was used to analyze statistical information on acquired echo signals, to determine the ability of ASQ to distinguish normal salivary glands of asymptomatic patients from glands of patients with radiation sialadenitis (RS) after radioactive iodine therapy. The ASQ values of 192 salivary glands were compared by multinomial logistic regression analysis, and receiver operating characteristic curves were constructed. Between-observer agreement was assessed by calculating the intra-class correlation coefficient. The mean ASQ values of patients with chronic RS or asymptomatic patients who had undergone radioactive iodine therapy were greater than those of patients with normal glands (p < 0.001). The ratio was associated with the highest odds ratio in patients with chronic RS compared with normal patients. Diagnostic performance was moderate; the intra-class correlation coefficient between observers was very good. ASQ can objectively differentiate RS-affected tissue from normal salivary tissue and is thus valuable for clinically diagnosing RS after radioactive iodine therapy.

      PubDate: 2016-11-03T22:14:49Z
       
  • Reproducibility of Acoustic Radiation Force Impulse Imaging in Thyroid and
           Salivary Glands with Experienced and Inexperienced Examiners
    • Authors: Benedikt Hofauer; Naglaa Mansour Clemens Heiser Markus Wirth Ulrich Denys
      Abstract: Publication date: November 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 11
      Author(s): Benedikt Hofauer, Naglaa Mansour, Clemens Heiser, Markus Wirth, Ulrich Straßen, Denys Loeffelbein, Murat Bas, Andreas Knopf
      Acoustic radiation force impulse (ARFI) imaging enables the sonographic measurement of tissue stiffness. The aim of this study was to evaluate if experience in ARFI imaging influences the reproducibility of ARFI imaging of the head and neck. Three experienced sonographers and three inexperienced sonographers performed ARFI imaging of thyroid, submandibular and parotid glands in 10 healthy volunteers. The examination was repeated after 2 wk. Ten single ARFI measurements were done in every gland. Inter-rater and intra-rater reliability was analyzed using the intra-class correlation coefficient (ICC). Moderate agreement was observed between experienced and inexperienced examiners (ICC = 0.46). In salivary glands, agreement was fair between the groups (ICC = 0.33), whereas in separate evaluations, inter-rater reliability in the submandibular glands was moderate (ICC = 0.52), and that in the parotid glands, only poor (ICC = 0.09). For ARFI imaging of the thyroid gland, there was moderate agreement between the groups (ICC = 0.50). The intra-rater reliability for the salivary and thyroid glands together and separately was strong in both groups. ARFI imaging of the thyroid and salivary glands did exhibit good reproducibility. ARFI imaging of the thyroid gland reached the highest levels of inter- and intra-observer agreement in both groups. ARFI imaging in salivary glands is only reproducible with experienced examiners.

      PubDate: 2016-11-03T22:14:49Z
       
  • The Effects of Oxygen on Ultrasound-Induced Blood–Brain Barrier
           Disruption in Mice
    • Authors: Nathan McDannold; Yongzhi Zhang Natalia Vykhodtseva
      Abstract: Publication date: Available online 24 October 2016
      Source:Ultrasound in Medicine & Biology
      Author(s): Nathan McDannold, Yongzhi Zhang, Natalia Vykhodtseva
      Numerous researchers are investigating the use of microbubble-enhanced ultrasound to disrupt the blood–brain barrier (BBB) and deliver drugs to the brain. This study investigated the impact of using oxygen as a carrier gas for anesthesia on microbubble activity and BBB disruption. Targets in mice were sonicated in combination with administration of Optison microbubbles (100 μL/kg) under isoflurane anesthesia with either oxygen or medical air. A 690-kHz focused ultrasound transducer applied 10-ms bursts at peak pressure amplitudes of 0.46–0.54 MPa (n = 2) or 0.34–0.36 MPa (n = 5). After sonication of two locations in one hemisphere, the carrier gas for the anesthesia was changed and the sonications were repeated in the contralateral hemisphere. The BBB disruption, measured via contrast-enhanced magnetic resonance imaging, was significantly greater (p < 0.001) with medical air than with oxygen. Harmonic emissions were also greater with air (p < 0.001), while the decay rate of the harmonic emissions was 1.5 times faster with oxygen. A good correlation (R2, 0.46) was observed between the harmonic emissions strength and magnetic resonance imaging signal enhancement. At 0.46–0.54 MPa, both the occurrence and strength of wideband emissions were greater with medical air. However, at lower peak pressure amplitudes of 0.34–0.36 MPa, the strength and probability for wideband emissions were higher with oxygen. Little or no effects were observed in histology at 0.34–0.36 MPa. These findings show that use of oxygen as a carrier gas can result in a substantial diminution of BBB disruption. These results should be taken into account when comparing studies from different researchers and in translating this method to humans.

      PubDate: 2016-11-03T22:14:49Z
       
  • Clinical Utility of Real-Time MR-Navigated Ultrasound with Supine Breast
           MRI for Suspicious Enhancing Lesions Not Identified on Second-Look
           Ultrasound
    • Authors: Doo Kyoung; Kang Yongsik Jung Sehwan Han Young Kim Tae
      Abstract: Publication date: Available online 22 October 2016
      Source:Ultrasound in Medicine & Biology
      Author(s): Doo Kyoung Kang, Yongsik Jung, Sehwan Han, Ji Young Kim, Tae Hee Kim
      This study evaluated the usefulness of magnetic resonance (MR)-navigated ultrasound (US) for evaluation of magnetic resonance imaging (MRI)-detected lesions not visible on second-look US and analyzed differences in lesion-to-nipple distance between supine and prone positions. Of the 831 consecutive patients who were diagnosed with breast cancer and examined with breast MRI from June 2013 to September 2015, 40 lesions in 37 patients who underwent MR-navigated US for MRI-detected lesions that were not visible on second-look US were included. First, MRI was performed in a prone position using a 1.5-T imager, and second, MRI was performed in a supine position for MR-navigated US. Of 40 lesions, 31 (78%) were identified with MR-navigated US, whereas 5 (13%) lesions disappeared on supine MRI and 4 (10%) exhibited no correlation on MR-navigated US. Of 31 lesions with pathologic confirmation, 7 (23%) were malignant, 2 (6%) were high-risk lesions and 22 (71%) were benign lesions. Comparison of the US findings of benign and malignant lesions revealed that orientation of the lesion differed significantly (p = 0.045), whereas lesion shape, margin and echo pattern did not significantly differ between the two groups (p = 0.088, p = 0.094 and p = 0.412, respectively). Median difference in lesion-to-nipple distance on supine and prone MRI was 8 mm (0–34 mm) in the horizontal direction and 5 mm (0–39.5 mm) in the vertical direction. Thirteen lesions exhibited a >1-cm difference in both horizontal and vertical directions. In conclusion, MR-navigated US was useful for the evaluation of MRI-detected lesions that were not visible on second-look US in breast cancer patients.

      PubDate: 2016-11-03T22:14:49Z
       
  • In Vivo Endoluminal Ultrasound Biomicroscopy and Endoscopy of
           Inflamed Rat Esophagus
    • Authors: Rodrigo Gomes; Rossana Soletti Soldan Kalil Madi Stuart Foster Machado
      Abstract: Publication date: November 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 11
      Author(s): Rodrigo de Magalhães Gomes, Rossana C. Soletti, Mônica Soldan, Kalil Madi, F. Stuart Foster, João C. Machado
      The development of high-frequency endoscopic ultrasound for the investigation of models of esophageal disease may offer insights for future translation to human imaging. With respect to small animal models of esophageal diseases, ultrasound imaging instrumentation must employ frequencies scaled up to maintain the compromise between image resolution and inspected region. In this sense, a 40-MHz endoluminal ultrasound biomicroscopy (eUBM) system and an endoscope were tested as diagnostic methods of imaging rat esophageal lesions in the acute and chronic phases caused by sodium hydroxide. Although endoscopy allowed grading of the esophagus in accordance with a classification specific to the epithelial alterations and including hyperemia, edema, exudates, fibrin and superficial and deep ulcerations, the eUBM images yielded the detection of superficial and deep ulcerations, as well as wall alterations caused by edema and inflammatory infiltrate in the submucosa. Additionally, eUBM enabled wall thickness measurements, which were statistically significantly increased (p < 0.05) in the acute phase.

      PubDate: 2016-11-03T22:14:49Z
       
  • Characterisation of Liposome-Loaded Microbubble Populations for
           Subharmonic Imaging
    • Authors: James McLaughlan; Sevan Harput Radwa Abou-Saleh Sally Peyman Stephen Evans
      Abstract: Publication date: Available online 24 October 2016
      Source:Ultrasound in Medicine & Biology
      Author(s): James R. McLaughlan, Sevan Harput, Radwa H. Abou-Saleh, Sally A. Peyman, Stephen Evans, Steven Freear
      Therapeutic microbubbles could make an important contribution to the diagnosis and treatment of cancer. Acoustic characterisation was performed on microfluidic generated microbubble populations that either were bare or had liposomes attached. Through the use of broadband attenuation techniques (3–8 MHz), the shell stiffness was measured to be 0.72 ± 0.01 and 0.78 ± 0.05 N/m and shell friction was 0.37 ± 0.05 and 0.74 ± 0.05 × 10−6 kg/s for bare and liposome-loaded microbubbles, respectively. Acoustic scatter revealed that liposome-loaded microbubbles had a lower subharmonic threshold, occurring from a peak negative pressure of 50 kPa, compared with 200 kPa for equivalent bare microbubbles. It was found that liposome loading had a negligible effect on the destruction threshold for this microbubble type, because at a mechanical index >0.4 (570 kPa), 80% of both populations were destroyed.

      PubDate: 2016-11-03T22:14:49Z
       
  • An Artifact in Supersonic Shear Wave Elastography
    • Authors: Che-Yu Lin; Pei-Yu Chen Yio-Wha Shau Chung-Li Wang
      Abstract: Publication date: Available online 25 October 2016
      Source:Ultrasound in Medicine & Biology
      Author(s): Che-Yu Lin, Pei-Yu Chen, Yio-Wha Shau, Chung-Li Wang
      Supersonic shear wave elastography is a novel ultrasound technology that allows objective evaluation of soft tissue stiffness. The purpose of this study is to report an artifact in supersonic shear wave elastography that may strongly affect the accuracy and quality of the measurement of soft tissue stiffness, and to step-by-step describe how the artifact was found and how it was verified by a series of experiments under different conditions. There were a total of three longitudinal band-like artifacts, 1.3 cm apart from each other on the entire image along the length of the SuperLinear SL15-4 transducer surface, with the middle one at the center of the image. When using supersonic shear wave elastography, users should be keenly aware of the possible occurrence of the artifact and avoid it by choosing the quantification measurement regions of interest (ROIs) away from the artifact regions.

      PubDate: 2016-11-03T22:14:49Z
       
  • High-Resolution Ultrasound of Schwannomas of the Limbs: Analysis of 72
           Cases
    • Authors: Haixian Zhang; Yiming Jie Shao Weimin Chen Wang
      Abstract: Publication date: November 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 11
      Author(s): Haixian Zhang, Yiming Li, Jie Shao, Weimin Chen, Yi Wang
      Schwannomas are common benign tumors that develop in peripheral nerves. High-resolution ultrasound (HRUS) is an effective imaging modality in clinics. The aim of this study was to define the value of HRUS in diagnosing schwannomas that originate from different nerves in limbs. We reviewed the ultrasound and surgical records of 72 pathologically confirmed schwannomas in the limbs of 60 patients. Results revealed that 44 (61.1%) of 72 cases, 44 (75.9%) of 58 cases and 0 (0%) of 14 cases received an overall correct pre-operative diagnosis, a correct pre-operative diagnosis in nerve trunks and a correct pre-operative diagnosis in small branches, respectively. Identification of the nerve of origin of schwannomas through HRUS likely increased confidence in diagnosing these benign tumors.

      PubDate: 2016-11-03T22:14:49Z
       
  • Factors Predictive of Improved Abdominal Ultrasound Visualization after
           Oral Administration of Simethicone
    • Authors: Maria Marsico; Tommaso Gabbani Tommaso Casseri Maria Rosa Biagini
      Abstract: Publication date: November 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 11
      Author(s): Maria Marsico, Tommaso Gabbani, Tommaso Casseri, Maria Rosa Biagini
      Ultrasonography is a non-invasive, accurate and low-cost technique used to study the upper abdomen, but it has reduced reliability in the study of the pancreas and retroperitoneum. Simethicone is a well-known emulsifying agent that has been used to improve ultrasonographic visualization. The aim of this study was to identify anthropometric parameters that are able to predict a good response to simethicone in improving ultrasonographic visualization of abdominal structures. One hundred twenty-seven patients were recruited. After basal examination, their anthropometric parameters were collected. Patients with an incomplete upper abdominal examination because of gastrointestinal gas have greater body mass index, waist circumference and abdominal wall thickness. In our study, the best anthropometric parameter for identifying patients with poor visualization at abdominal ultrasound examination is waist circumference. Using a cutoff of 84 cm, we can identify patients with poor visibility at abdominal ultrasound examination (group B) with a sensitivity of 90%.

      PubDate: 2016-11-03T22:14:49Z
       
  • Potential Infection Control Risks Associated with Ultrasound Equipment –
           A Bacterial Perspective
    • Authors: Susan Campbell; Westerway Jocelyne Basseal Adam Brockway Jon Hyett Dee
      Abstract: Publication date: Available online 26 October 2016
      Source:Ultrasound in Medicine & Biology
      Author(s): Susan Campbell Westerway, Jocelyne M. Basseal, Adam Brockway, Jon A. Hyett, Dee A. Carter
      Ultrasound equipment used in trans-abdominal (TA) and trans-vaginal (TV) examination may carry bacterial contamination and pose risks to infection control during ultrasound examination. We aimed to describe the prevalence of bacterial contamination on ultrasound probes, gel, machine keyboard and cords and examined the effectiveness of low- and high-level disinfection techniques. This study was performed at a public hospital and a private practice. A total of 171 swabs were analyzed and bacterial species were identified using matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) analysis and polymerase chain reaction (PCR). Sixty percent of TA probes and 14% of TV probes had evidence of bacterial contamination after an ultrasound examination. Low-level disinfection was partially effective, but 4% of probes were still contaminated by spore-forming species. Some heated gel samples were highly contaminated with the environmental bacterium Brevundimonas aurantiaca, suggesting the gel was conducive to bacterial growth. Ultrasound machines, probe cords and gels were identified as potential sources of bacterial contamination and need to be cleaned and changed regularly to minimize risks of infection.

      PubDate: 2016-11-03T22:14:49Z
       
  • Is Grey Level a Suitable Alternative to Low-Contrast Penetration as a
           Serial Measure of Sensitivity in Computerised Ultrasound Quality
           Assurance'
    • Authors: Nicholas Dudley; Nicholas Gibson
      Abstract: Publication date: Available online 26 October 2016
      Source:Ultrasound in Medicine & Biology
      Author(s): Nicholas J. Dudley, Nicholas M. Gibson
      The aim of this study was to test the hypothesis that grey levels are a suitable alternative measure of sensitivity in ultrasound imaging quality assurance, as there are several caveats in the use of penetration depth. In a primary cohort of nine probes, where measurements had been made for 6 to 34 mo, both penetration depth and mean grey level fell below tolerance for six probes; both penetration depth and mean grey level remained within tolerance for three probes. In a secondary cohort where a measurement programme had been in place for a shorter period, grey level and/or penetration depth fell below tolerance in 15 of 66 probes; the sensitivity and specificity of at least 10% loss of grey level in predicting >5% loss in penetration depth were 91% and 93%, respectively. A loss of grey level accompanies a loss of penetration and provides a suitable alternative measure of sensitivity.

      PubDate: 2016-11-03T22:14:49Z
       
  • Editorial Advisory Board
    • Abstract: Publication date: November 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 11


      PubDate: 2016-11-03T22:14:49Z
       
  • Inter- and Intra-Observer Agreement in Ultrasound BI-RADS Classification
           and Real-Time Elastography Tsukuba Score Assessment of Breast Lesions
    • Authors: Fabienne Schwab; Katharina Redling Matthias Siebert Andy Cora-Ann Schoenenberger Rosanna
      Abstract: Publication date: November 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 11
      Author(s): Fabienne Schwab, Katharina Redling, Matthias Siebert, Andy Schötzau, Cora-Ann Schoenenberger, Rosanna Zanetti-Dällenbach
      Our aim was to prospectively evaluate inter- and intra-observer agreement between Breast Imaging Reporting and Data System (BI-RADS) classifications and Tsukuba elasticity scores (TSs) of breast lesions. The study included 164 breast lesions (63 malignant, 101 benign). The BI-RADS classification and TS of each breast lesion was assessed by the examiner and twice by three reviewers at an interval of 2 months. Weighted κ values for inter-observer agreement ranged from moderate to substantial for BI-RADS classification (κ = 0.585–0.738) and was substantial for TS (κ = 0.608–0.779). Intra-observer agreement was almost perfect for ultrasound (US) BI-RADS (κ = 0.847–0.872) and TS (κ = 0.879–0.914). Overall, individual reviewers are highly self-consistent (almost perfect intra-observer agreement) with respect to BI-RADS classification and TS, whereas inter-observer agreement was moderate to substantial. Comprehensive training is essential for achieving high agreement and minimizing the impact of subjectivity. Our results indicate that breast US and real-time elastography can achieve high diagnostic performance.

      PubDate: 2016-11-03T22:14:49Z
       
  • The Effectiveness of Radial Extracorporeal Shock Waves for Treatment of
           Carpal Tunnel Syndrome: A Randomized Clinical Trial
    • Authors: Gholam Reza; Raissi Fatemeh Ghazaei Bijan Forogh Seyed Pezhman Madani
      Abstract: Publication date: Available online 2 November 2016
      Source:Ultrasound in Medicine & Biology
      Author(s): Gholam Reza Raissi, Fatemeh Ghazaei, Bijan Forogh, Seyed Pezhman Madani, Abbas Daghaghzadeh, Tannaz Ahadi
      This study examined the effectiveness of radial extracorporeal shock wave therapy in the treatment of carpal tunnel syndrome (CTS). Forty patients with mild to moderate CTS were allocated to two groups: (i) shock wave + wrist splint and (ii) wrist splint. Patients used wrist splints followed by three sessions of low-energy shock wave therapy in the intervention group and wrist splints alone in the other group. The QuickDASH Questionnaire, visual analogue scale and nerve conduction studies were used to evaluate the patients before the study and at 3, 8 and 12 wk after the start of the treatment. At the end of the study, both groups saw the same clinical benefits. However, a significantly greater improvement in the median nerve distal sensory latency was noted in the shock wave group compared with the control group. We suggest that application of shock wave with alternative protocols may be effective in the treatment of CTS in future studies.

      PubDate: 2016-11-03T22:14:49Z
       
  • High-Frame-Rate Deformation Imaging in Two Dimensions Using Continuous
           Speckle-Feature Tracking
    • Authors: Martin Andersen; Cooper Moore Kristine Arges Peter Lasse Samuel Schmidt
      Abstract: Publication date: November 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 11
      Author(s): Martin V. Andersen, Cooper Moore, Kristine Arges, Peter Søgaard, Lasse R. Østergaard, Samuel E. Schmidt, Joseph Kisslo, Olaf T. Von Ramm
      The study describes a novel algorithm for deriving myocardial strain from an entire cardiac cycle using high-frame-rate ultrasound images. Validation of the tracking algorithm was conducted in vitro prior to the application to patient images. High-frame-rate ultrasound images were acquired in vivo from 10 patients, and strain curves were derived in six myocardial regions around the left ventricle from the apical four-chamber view. Strain curves derived from high-frame-rate images had a higher frequency content than those derived using conventional methods, reflecting improved temporal sampling.

      PubDate: 2016-11-03T22:14:49Z
       
  • Correlation of Breast Ultrasound Classifications with Breast Cancer in
           Chinese Women
    • Authors: Xin-Yan Hou; Hai-Yan Niu Xiao-Ling Huang Gao
      Abstract: Publication date: November 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 11
      Author(s): Xin-Yan Hou, Hai-Yan Niu, Xiao-Ling Huang, Yu Gao
      The aim of this study was to identify potential links between ultrasonographic breast parenchymal patterns and the risk of breast cancer in Chinese women. The population of Chinese women at high risk for breast cancer was explored using the ultrasonographic classification. Ultrasonographic parenchymal patterns were classified into four types: heterogeneous type, ductal type, mixed type and fibrous type. A total of 5879 Chinese women underwent breast ultrasound examination from May 2010 to April 2014. Of the 5879 women, 256 women had pathology-confirmed breast cancer. Among the remaining 5623 women, 512 randomly selected, age-matched women were recruited into the present study. The correlation between ultrasonographic type and breast cancer revealed that the odds ratio (OR) was highest for the heterogeneous type (odds ratio = 4.11, 95% confidence interval: 2.01–8.41, p < 0.001), followed by the fibrous type (odds ratio = 2.05, 95% confidence interval: 1.51–2.78, p < 0.001). The odds ratios of the ductal and mixed types were both less than 1 (p < 0.05). This study indicates that the heterogeneous and fibrous types in the ultrasonographic classification are associated with an increased risk of breast cancer and, therefore, can be used as a marker of breast cancer risk in the female population of China.

      PubDate: 2016-11-03T22:14:49Z
       
  • Reproducibility of Ultrasonographic Measurements of the Ulnar Nerve at the
           Cubital Tunnel
    • Authors: Alexandra Fink; Marlijn Teggeler Marc Schmitz Jaap Janssen Martijn Pisters
      Abstract: Publication date: Available online 27 October 2016
      Source:Ultrasound in Medicine & Biology
      Author(s): Alexandra Fink, Marlijn Teggeler, Marc Schmitz, Jaap Janssen, Martijn Pisters
      The cross-sectional area (CSA) of the ulnar nerve is thought to be indicative of ulnar nerve entrapment. The purpose of the study was to determine reproducibility of ultrasonographic measurements of CSA of the ulnar nerve at the cubital tunnel in healthy adults. Two sonographers tested 69 participants using a standardized protocol. The inter-rater reliability intra-class correlation coefficient was 0.63, and the intra-rater reliability intra-class correlation coefficient was 0.85 for sonographer 1 and 0.88 for sonographer 2. The smallest detectable changes were 2.47 and 2.63 mm2 (25% and 26% of the mean CSA). The mean difference and 95% limits of agreement for sonographers 1 and 2 were −0.13 (−2.56 to 2.29) and −0.38 (−2.93 to 2.18). Based on the fair to good inter-rater reliability, the excellent intra-rater reliability and the clinical applicable intra-rater agreement, ultrasonography seems to be a valuable tool with which to assess the CSA of the ulnar nerve for diagnostic and evaluative purposes.

      PubDate: 2016-11-03T22:14:49Z
       
  • Speckle Tracking Using Gray-Scale Information from Tissue Doppler
           Recordings versus Regular Gray-Scale Recordings in Term Neonates
    • Authors: Eirik Nestaas; Drude Fugelseth
      Abstract: Publication date: November 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 11
      Author(s): Eirik Nestaas, Asbjørn Støylen, Drude Fugelseth
      The use of 2-D strain speckle tracking echocardiography in B-mode images from tissue Doppler (TD) recordings was compared with its use in regular gray-scale (GS) recordings in healthy and asphyxiated neonates at days 1–3. Single-cycle and three-cycle longitudinal deformation indices were assessed. Median B-mode frame rates were 38/s (TD) and 77/s (GS). Systolic indices were similar for TD and GS recordings. Diastolic indices were lower for TD recordings. Single-cycle and three-cycle indices were equal. TD and GS recordings were similar in reproducibility, except for single-cycle inter-observer peak systolic strain rate and three-cycle intra-observer strain rate during atrial systole. Single-cycle reproducibility was lower than three-cycle reproducibility in all TD recording indices, GS recording inter-observer peak systolic strain and GS recording inter-observer early diastolic strain rate. Inter-observer reproducibility and intra-observer reproducibility were similar, except GS recording single-cycle peak systolic strain. In conclusion, use of TD and GS recordings interchangeably was feasible for systolic but not for diastolic indices. Three-cycle analyses improved reproducibility, especially in TD recordings.

      PubDate: 2016-11-03T22:14:49Z
       
  • Automatic Detection of Standard Sagittal Plane in the First Trimester of
           Pregnancy Using 3-D Ultrasound Data
    • Authors: Siqing Nie; Jinhua Ping Chen Yuanyuan Wang Jian Qiu Zhang
      Abstract: Publication date: Available online 31 October 2016
      Source:Ultrasound in Medicine & Biology
      Author(s): Siqing Nie, Jinhua Yu, Ping Chen, Yuanyuan Wang, Jian Qiu Zhang
      Fetal nuchal translucency (NT) thickness is one of the most important parameters in prenatal screening. Locating the mid-sagittal plane is one of the key points to measure NT. In this paper, an automatic method for the sagittal plane detection using 3-D ultrasound data is proposed. To avoid unnecessary massive searching and the corresponding huge computation load, a model is proposed to turn the sagittal plane detection problem into a symmetry plane and axis searching problem. The deep belief network (DBN) and a modified circle detection method provide prior knowledge for the searching. The experiments show that in most cases, the result plane has small distance error and angle error at the same time—88.6% of the result planes have a distance error less than 4 mm and 71.0% have angle error less than 20°.

      PubDate: 2016-11-03T22:14:49Z
       
  • An Algorithm of Image Heterogeneity with Contrast-Enhanced Ultrasound in
           Differential Diagnosis of Solid Thyroid Nodules
    • Authors: Lifang Jin; Changsong Xueqian Xie Fan Xiuhong Lianfang
      Abstract: Publication date: Available online 28 October 2016
      Source:Ultrasound in Medicine & Biology
      Author(s): Lifang Jin, Changsong Xu, Xueqian Xie, Fan Li, Xiuhong Lv, Lianfang Du
      Enhancement heterogeneity on contrast-enhanced ultrasonography (CEUS) is used to differentiate between benign and malignant thyroid nodules. In this study, we used an algorithm to quantify enhancement heterogeneity of solid thyroid nodules on CEUS. The heterogeneity value (HV) is calculated as standard deviation/mean intensity × 100 (using Adobe Photoshop). The heterogeneity ratio (HR) is calculated as the ratio of the HV of the nodule to that of the surrounding parenchyma. Three phases—ascending, peak and descending phases—were studied. HV values at ascending (HVa) and peak (HVp) phases were significantly higher in malignant nodules than in benign nodules (95.57 ± 43.87 vs. 73.06 ± 44.04, p = 0.009, and 32.53 ± 10.73 vs. 26.44 ± 8.25, p = 0.002, respectively). HRa, HRp and HRd were significantly higher in malignant nodules than in benign nodules (1.93 ± 1.03 vs. 1.00 ± 0.47, p = 0.000, 1.43 ± 0.51 vs. 1.09 ± 0.28, p = 0.000, and 1.33 ± 0.40 vs. 1.08 ± 0.33, p = 0.001, respectively). HRa achieved optimal diagnostic performance on receiver operating characteristic curve analysis. The algorithm used for assessment of image heterogeneity on CEUS examination may be a useful adjunct to conventional ultrasound for differential diagnosis of solid thyroid nodules.

      PubDate: 2016-11-03T22:14:49Z
       
  • In Vitro Comparison of Five Different Elastography Systems for Clinical
           Applications, Using Strain and Shear Wave Technology
    • Authors: Anesa Mulabecirovic; Mette Vesterhus Odd Helge Gilja Roald Flesland Havre
      Abstract: Publication date: November 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 11
      Author(s): Anesa Mulabecirovic, Mette Vesterhus, Odd Helge Gilja, Roald Flesland Havre
      Several different platforms providing ultrasound elastography have emerged in recent years. In this in vitro study on a single tissue-mimicking phantom (CIRS Model 49), we aimed to compare the performance of quantitative elastography measurements from platforms running strain elastography and others running shear wave elastography. We evaluated five different elastography platforms using both linear and curvilinear probes. All measurements were performed in parallel by two independent investigators who recorded the elasticity quantitatively. We investigated intra- and inter-observer agreement by intra-class correlation analysis and coefficient of variation, by correlation and limits of agreement. The reproducibility of elasticity measurements was good to excellent for shear wave and strain elastography. All five elastography platforms had high intra-observer (intra-class correlation coefficient: 0.932–1.0) and inter-observer correlation (intra-class correlation coefficient: 0.845–0.996). All inclusions could be differentiated by quantitative elastography by all systems (p < 0.001). The use of a linear probe yielded more reproducible measurements compared with use of a convex probe in 3/4 platforms.

      PubDate: 2016-11-03T22:14:49Z
       
  • Effect of Hypoxemia with or without Increased Placental Vascular
           Resistance on Fetal Left and Right Ventricular Myocardial Performance
           Index in Chronically Instrumented Sheep
    • Authors: Amar Bhide; Olli Vuolteenaho Mervi Haapsamo Tiina Erkinaro Juha Rasanen
      Abstract: Publication date: November 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 11
      Author(s): Amar Bhide, Olli Vuolteenaho, Mervi Haapsamo, Tiina Erkinaro, Juha Rasanen, Ganesh Acharya
      Myocardial performance index (MPI) is increased in growth-restricted fetuses with placental insufficiency, but it is unknown if this is due to fetal hypoxemia or increased placental vascular resistance (R plac). We used chronically instrumented sheep fetuses (n = 24). In 12 fetuses, placental embolization was performed 24 h before experiments. On the day of the experiment, left (LV) and right (RV) ventricular MPIs were obtained by pulsed Doppler at baseline and in the hypoxemia and recovery phases. At baseline, R plac was greater and fetal pO2 lower in the placental embolization group, but RV and LV MPIs were comparable to those of the control group. During hypoxemia, mean LV MPI increased significantly only in fetuses with an intact placenta (0.34 vs. 0.46), returning to baseline during the recovery phase. Right ventricular MPI was unaffected. We conclude that fetal LV function is sensitive to acute hypoxemia. Exposure to chronic hypoxemia could pre-condition the fetal heart and protect its function with worsening hypoxemia.

      PubDate: 2016-11-03T22:14:49Z
       
  • The Effect of Low-Intensity Ultrasound on Brain-Derived Neurotropic Factor
           Expression in a Rat Sciatic Nerve Crushed Injury Model
    • Authors: Xue-Jun Xiao-Dong; Wang Ya-Hong Zhao Hua-Lin Sun Yu-Ming Jian Yao
      Abstract: Publication date: Available online 3 November 2016
      Source:Ultrasound in Medicine & Biology
      Author(s): Xue-Jun Ni, Xiao-Dong Wang, Ya-Hong Zhao, Hua-Lin Sun, Yu-Ming Hu, Jian Yao, Yi Wang
      Low-intensity ultrasound (LIU) can improve nerve regeneration and functional recovery after peripheral nerve crush injury, but the underlying mechanism is not clear. The objective of this study was to examine the effects of LIU on rat sciatic crush injury and to investigate a possible molecular mechanism. Adult male Sprague-Dawley rats underwent left sciatic nerve crush surgery and were then randomized into two groups: a treatment group that received LIU every other d, and a control group that received sham exposure. Compared with rats in the control group, rats in the treatment group had higher sciatic nerve function indexes, compound muscle action potentials, wet weight ratios of the target muscle and mRNA expression of brain-derived neurotropic factor (BDNF) in the crushed nerve and ipsilateral dorsal root ganglia. Our findings suggest that LIU might promote injured nerve regeneration by stimulating BDNF release.

      PubDate: 2016-11-03T22:14:49Z
       
  • Quantification of Temperature Rise within the Lens of the Porcine Eye
           Caused by Ultrasound Insonation
    • Authors: Randy King; Yunbo Liu Gerald Harris
      Abstract: Publication date: Available online 3 November 2016
      Source:Ultrasound in Medicine & Biology
      Author(s): Randy L. King, Yunbo Liu, Gerald R. Harris
      The soft tissue thermal index defined in the Output Display Standard is not applicable to eye exposures because of unique eye properties such as high ultrasound absorption in the lens and orbital fat. To address this potential safety issue, the U.S. Food and Drug Administration has recommended a maximum exposure level for ophthalmic exams of 50 mW/cm2 (derated spatial-peak temporal-average intensity, I SPTA.3) based on a model of ultrasound propagation in the eye. To gain a better understanding of actual temperature rise as a function of I SPTA.3, an ex vivo experimental study within the porcine lens was performed. Both temperature and acoustic pressure were measured simultaneously in the lens using a fiberoptic probe. At I SPTA.3 = 50 mW/cm2, the maximum and average temperature rises over 133 measurements were 0.23°C and 0.09°C, respectively. A 1.5°C temperature rise was not obtained until I SPTA.3 ≈ 435 mW/cm2. The data indicate that operating below the Food and Drug Administration guidance level should result in relatively low heating in ophthalmic exposures.

      PubDate: 2016-11-03T22:14:49Z
       
 
 
JournalTOCs
School of Mathematical and Computer Sciences
Heriot-Watt University
Edinburgh, EH14 4AS, UK
Email: journaltocs@hw.ac.uk
Tel: +00 44 (0)131 4513762
Fax: +00 44 (0)131 4513327
 
Home (Search)
Subjects A-Z
Publishers A-Z
Customise
APIs
Your IP address: 54.211.11.50
 
About JournalTOCs
API
Help
News (blog, publications)
JournalTOCs on Twitter   JournalTOCs on Facebook

JournalTOCs © 2009-2016