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Sri Lankan Journal of Physics     Open Access  
Strain     Hybrid Journal   (Followers: 2)
Strength of Materials     Hybrid Journal   (Followers: 4)
Strength, Fracture and Complexity     Hybrid Journal   (Followers: 1)
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Ultrasound in Medicine & Biology     Full-text available via subscription   (Followers: 6)
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Women in Engineering Magazine, IEEE     Full-text available via subscription   (Followers: 8)
World Journal of Condensed Matter Physics     Open Access  
Zeitschrift für angewandte Mathematik und Physik     Hybrid Journal   (Followers: 1)

  First | 1 2 3 4 5 6 | Last

Journal Cover Ultrasound in Medicine & Biology
   [8 followers]  Follow    
   Full-text available via subscription Subscription journal
     ISSN (Print) 0301-5629
     Published by Elsevier Homepage  [2575 journals]   [SJR: 0.864]   [H-I: 85]
  • High-Frequency Ultrasound as an Option for Scanning of Prepared
           Teeth: An in Vitro Study
    • Abstract: Publication date: January 2015
      Source:Ultrasound in Medicine & Biology, Volume 41, Issue 1
      Author(s): Fabrice Chuembou Pekam , Juliana Marotti , Stefan Wolfart , Joachim Tinschert , Klaus Radermacher , Stefan Heger
      Because of its ability to non-invasively capture hard structures behind soft tissue, high-frequency ultrasound (HFUS)-assisted microscanning could be a patient-friendly and promising alternative for digitization of prepared teeth. However, intra-oral HFUS microscanners for taking digital impressions of prepared teeth are still not available in the clinical setting. Because working range, scanner size, scanning time, surface reconstruction accuracy and costs are major factors in such a system, our overall objective is to minimize hardware efforts and costs while maintaining the accuracy of the surface-reconstructed tooth model in the range 50 μm. In the work described here, we investigated the accuracy of tooth impression taking using a single-element HFUS microscanner with only three translational degrees of freedom under the restriction that only one occlusal scan is performed per tooth. As in favor of time and scanning efforts the data density is expected to be low, the surface reconstruction process is linked to a model-based surface reconstruction approach using a thin spline robust point matching algorithm to fill data gaps. A priori knowledge for the model is generated based on the original HFUS measurement data. Three artificial teeth and one human molar were prepared and scanned using an extra-oral HFUS laboratory microscanner that was built to test and evaluate different scanning setups. A scanner with three translational degrees of freedom was used to scan the teeth from an occlusal direction. After application of the proposed thin-spline robust point matching algorithm-based reconstruction approach, reconstruction accuracy was assessed by comparing the casts with a control group scanned with an extra-oral laser-scanning system. The mean difference between the reconstructed casts and the optical control group was in the range 14–53 μm. The standard deviation was between 21 and 52 μm. This let us assume that the suggested approach can help to decrease hardware efforts while maintaining the robustness of the 3-D surface reconstruction process for future HFUS-based intra-oral scanners.


      PubDate: 2014-12-16T19:46:08Z
       
  • In Vitro Enamel Thickness Measurements with Ultrasound
    • Abstract: Publication date: January 2015
      Source:Ultrasound in Medicine & Biology, Volume 41, Issue 1
      Author(s): Khalid Hussain Sindi , Nigel Lawrence Bubb , Diana Lynn Gutteridge , Joseph Anthony Evans
      In the work described here, agreement between ultrasound and histologic measurements of enamel thickness in vitro was investigated. Fifteen extracted human premolars were sectioned coronally to produce 30 sections. The enamel thickness of each specimen was measured with a 15-MHz hand-held ultrasound probe and verified with histology. The speed of sound in enamel was established. Bland–Altman analysis, intra-class correlation coefficient and Wilcoxon sign rank test were used to assess agreement. The mean speed of sound in enamel was 6191 ± 199 m s−1. Bland–Altman limits of agreement were −0.16 to 0.18 mm when the speed of sound for each specimen was used, and −0.17 to 0.21 mm when the mean speed of sound was used. Intra-class correlation coefficient agreement was 0.97, and the Wilcoxon sign rank test yielded a p-value of 0.55. Using the speed of sound for each specimen results in more accurate measurement of enamel thickness. Ultrasound measurements were in good agreement with histology, which highlights its potential for monitoring the progressive loss of enamel thickness in erosive tooth surface loss.


      PubDate: 2014-12-16T19:46:08Z
       
  • A Novel Ultrasound Methodology for Estimating Spine Mineral Density
    • Abstract: Publication date: January 2015
      Source:Ultrasound in Medicine & Biology, Volume 41, Issue 1
      Author(s): Francesco Conversano , Roberto Franchini , Antonio Greco , Giulia Soloperto , Fernanda Chiriacò , Ernesto Casciaro , Matteo Aventaggiato , Maria Daniela Renna , Paola Pisani , Marco Di Paola , Antonella Grimaldi , Laura Quarta , Eugenio Quarta , Maurizio Muratore , Pascal Laugier , Sergio Casciaro
      We investigated the possible clinical feasibility and accuracy of an innovative ultrasound (US) method for diagnosis of osteoporosis of the spine. A total of 342 female patients (aged 51–60 y) underwent spinal dual X-ray absorptiometry and abdominal echographic scanning of the lumbar spine. Recruited patients were subdivided into a reference database used for US spectral model construction and a study population for repeatability and accuracy evaluation. US images and radiofrequency signals were analyzed via a new fully automatic algorithm that performed a series of spectral and statistical analyses, providing a novel diagnostic parameter called the osteoporosis score (O.S.). If dual X-ray absorptiometry is assumed to be the gold standard reference, the accuracy of O.S.-based diagnoses was 91.1%, with k = 0.859 (p < 0.0001). Significant correlations were also found between O.S.-estimated bone mineral densities and corresponding dual X-ray absorptiometry values, with r 2 values up to 0.73 and a root mean square error of 6.3%–9.3%. The results obtained suggest that the proposed method has the potential for future routine application in US-based diagnosis of osteoporosis.


      PubDate: 2014-12-16T19:46:08Z
       
  • Statistics of Boundaries in Ultrasonic B-Scan Images
    • Abstract: Publication date: January 2015
      Source:Ultrasound in Medicine & Biology, Volume 41, Issue 1
      Author(s): P. Mohana Shankar
      The existence of edges and boundaries in regions of interest (ROIs) in B-scan images alters the statistics of the backscattered echo from the ROI. Boundaries are the result of at least two different types of scattering scenarios in tissue, and the Nakagami model, which is being used extensively in ultrasound, is unlikely to fit the statistics of the backscattered echo under these conditions. Furthermore, there are very few other statistical models exist that describe the statistics of the backscattered echo from regions containing boundaries. In this work, the gamma mixture density and the recently proposed McKay density are explored as two viable models to fill this void. Justifications of these models are presented along with methods for estimating their parameters. Random number simulations and studies on tissue-mimicking phantoms indicate that the McKay and gamma mixture densities are the best for the modeling of the backscattered echo intensity when boundaries are present in the regions of interest.


      PubDate: 2014-12-16T19:46:08Z
       
  • Semi-automated Segmentation and Quantification of Mitral Annulus and
           Leaflets from Transesophageal 3-D Echocardiographic Images
    • Abstract: Publication date: January 2015
      Source:Ultrasound in Medicine & Biology, Volume 41, Issue 1
      Author(s): Miguel Sotaquira , Mauro Pepi , Laura Fusini , Francesco Maffessanti , Roberto M. Lang , Enrico G. Caiani
      Quantification of three-dimensional (3-D) morphology of the mitral valve (MV) using real-time 3-D transesophageal echocardiography (RT3-D TEE) has proved to be a valuable tool for the assessment of MV pathologies, but of limited use in clinical practice because it relies on user-intensive approaches. This study presents a new algorithm for the segmentation and morphologic quantification of the mitral annulus (MA) and mitral leaflets (ML) in closed valve configuration from RT3-D TEE volumes. Following initialization, the MA and the ML and the coaptation line (CL) are automatically obtained in 3-D. Validation with manual tracings was performed on 33 patients, resulting in segmentation errors in the order of 0.7 mm and 0.6 mm for the MA and ML segmentation, in addition to good intra- and inter-observer reproducibility (coefficients of variation below 12% and 15%, respectively). The ability of the algorithm to assess different MV pathologies as well as repaired valves with implanted annular rings was also explored. The reported performance of the proposed fast, semi-automated MA and ML quantification makes it promising for future applications in clinical settings such as the operating room, where obtaining results in short time is important.


      PubDate: 2014-12-16T19:46:08Z
       
  • Computed Ultrasound Tomography in Echo Mode for Imaging Speed of Sound
           Using Pulse-Echo Sonography: Proof of Principle
    • Abstract: Publication date: January 2015
      Source:Ultrasound in Medicine & Biology, Volume 41, Issue 1
      Author(s): Michael Jaeger , Gerrit Held , Sara Peeters , Stefan Preisser , Michael Grünig , Martin Frenz
      The limitations of diagnostic echo ultrasound have motivated research into novel modalities that complement ultrasound in a multimodal device. One promising candidate is speed of sound imaging, which has been found to reveal structural changes in diseased tissue. Transmission ultrasound tomography shows speed of sound spatially resolved, but is limited to the acoustically transparent breast. We present a novel method by which speed-of-sound imaging is possible using classic pulse-echo equipment, facilitating new clinical applications and the combination with state-of-the art diagnostic ultrasound. Pulse-echo images are reconstructed while scanning the tissue under various angles using transmit beam steering. Differences in average sound speed along different transmit directions are reflected in the local echo phase, which allows a 2-D reconstruction of the sound speed. In the present proof-of-principle study, we describe a contrast resolution of 0.6% of average sound speed and a spatial resolution of 1 mm (laterally) × 3 mm (axially), suitable for diagnostic applications.


      PubDate: 2014-12-16T19:46:08Z
       
  • Loss of Echogenicity and Onset of Cavitation from Echogenic Liposomes:
           Pulse Repetition Frequency Independence
    • Abstract: Publication date: January 2015
      Source:Ultrasound in Medicine & Biology, Volume 41, Issue 1
      Author(s): Kirthi Radhakrishnan , Kevin J. Haworth , Tao Peng , David D. McPherson , Christy K. Holland
      Echogenic liposomes (ELIP) are being developed for the early detection and treatment of atherosclerotic lesions. An 80% loss of echogenicity of ELIP has been found to be concomitant with the onset of stable and inertial cavitation. The ultrasound pressure amplitude at which this occurs is weakly dependent on pulse duration. It has been reported that the rapid fragmentation threshold of ELIP (based on changes in echogenicity) is dependent on the insonation pulse repetition frequency (PRF). The study described here evaluates the relationship between loss of echogenicity and cavitation emissions from ELIP insonified by duplex Doppler pulses at four PRFs (1.25, 2.5, 5 and 8.33 kHz). Loss of echogenicity was evaluated on B-mode images of ELIP. Cavitation emissions from ELIP were recorded passively on a focused single-element transducer and a linear array. Emissions recorded by the linear array were beamformed, and the spatial widths of stable and inertial cavitation emissions were compared with the calibrated azimuthal beamwidth of the Doppler pulse exceeding the stable and inertial cavitation thresholds. The inertial cavitation thresholds had a very weak dependence on PRF, and stable cavitation thresholds were independent of PRF. The spatial widths of the cavitation emissions recorded by the passive cavitation imaging system agreed with the calibrated Doppler beamwidths. The results also indicate that 64%–79% loss of echogenicity can be used to classify the presence or absence of cavitation emissions with greater than 80% accuracy.


      PubDate: 2014-12-16T19:46:08Z
       
  • Shaken and Stirred: Mechanisms of Ultrasound-Enhanced Thrombolysis
    • Abstract: Publication date: January 2015
      Source:Ultrasound in Medicine & Biology, Volume 41, Issue 1
      Author(s): Kenneth B. Bader , Matthew J. Gruber , Christy K. Holland
      The use of ultrasound and microbubbles as an effective adjuvant to thrombolytics has been reported in vitro, ex vivo and in vivo. However, the specific mechanisms underlying ultrasound-enhanced thrombolysis have yet to be elucidated. We present visual observations illustrating two mechanisms of ultrasound-enhanced thrombolysis: acoustic cavitation and radiation force. An in vitro flow model was developed to observe human whole blood clots exposed to human fresh-frozen plasma, recombinant tissue-type plasminogen activator (0, 0.32, 1.58 or 3.15 μg/mL) and the ultrasound contrast agent Definity (2 μL/mL). Intermittent, continuous-wave ultrasound (120 kHz, 0.44 MPa peak-to-peak pressure) was used to insonify the perfusate. Ultraharmonic emissions indicative of stable cavitation were monitored with a passive cavitation detector. The clot was observed with an inverted microscope, and images were recorded with a charge-coupled device camera. The images were post-processed to determine the time-dependent clot diameter and root-mean-square velocity of the clot position. Clot lysis occurred preferentially surrounding large, resonant-sized bubbles undergoing stable oscillations. Ultraharmonic emissions from stable cavitation were found to correlate with the lytic rate. Clots were observed to translate synchronously with the initiation and cessation of the ultrasound exposure. The root-mean-square velocity of the clot correlated with the lytic rate. These data provide visual documentation of stable cavitation activity and radiation force during sub-megahertz sonothrombolysis. The observations of this study suggest that the process of clot lysis is complex, and both stable cavitation and radiation force are mechanistically responsible for this beneficial bio-effect in this in vitro model.


      PubDate: 2014-12-16T19:46:08Z
       
  • Contents
    • Abstract: Publication date: January 2015
      Source:Ultrasound in Medicine & Biology, Volume 41, Issue 1




      PubDate: 2014-12-16T19:46:08Z
       
  • Factors that Influence Kidney Shear Wave Speed Assessed by Acoustic
           
    • Abstract: Publication date: January 2015
      Source:Ultrasound in Medicine & Biology, Volume 41, Issue 1
      Author(s): Simona Bota , Flaviu Bob , Ioan Sporea , Roxana Şirli , Alina Popescu
      Our aim was to assess kidney shear wave speed by means of acoustic radiation force impulse (ARFI) elastography in patients without kidney pathology (“normal” patients) and to identify the factors that influence it. We analyzed 91 “normal” patients in whom kidney shear wave speed was assessed by means of ARFI elastography. Five valid ARFI elastographic measurements were obtained in all “normal” patients in both kidneys. In univariate analysis, age (r = −0.370, p = 0.003), gender (female vs. male, r = −0.305, p = 0.003) and measurement depth (r = −0.285, p = 0.01) were significantly correlated with kidney shear wave speed values assessed by ARFI elastography, whereas body mass index, kidney length and renal parenchyma thickness were not correlated. In multivariate analysis, only age (p = 0.006) and gender (p = 0.03) were significantly correlated with kidney shear wave speed values. In conclusion, kidney shear wave speed values assessed by ARFI elastography in “normal” patients are influenced mainly by age and gender and less by measurement depth.


      PubDate: 2014-12-16T19:46:08Z
       
  • Microbubble Injection Enhances Inhibition of Low-Intensity Pulsed
           Ultrasound on Debris-Induced Periprosthetic Osteolysis in Rabbit Model
    • Abstract: Publication date: January 2015
      Source:Ultrasound in Medicine & Biology, Volume 41, Issue 1
      Author(s): Bin Hu , Xun-Zi Cai , Zhong-Li Shi , Yun-Lin Chen , Xiang Zhao , Han-Xiao Zhu , Shi-Gui Yan
      We determined whether the addition of microbubbles enhances the effect of low-intensity pulsed ultrasound (LIPUS) on bone–implant integration in an early-stage osteolysis model. The bone canals were injected with titanium particles before implantation to establish the periprosthetic osteolysis model. Before ultrasonic therapy, the microbubble-enhanced LIPUS group (GTi-Us-Mb) received an intra-articular injection of microbubbles. Biomechanical testing revealed that GTi-Us-Mb had significantly greater fixation strength than the LIPUS group (GTi-Us). Distal periprosthetic bone mineral density was also higher in GTi-Us than in the Ti group (GTi), but no significant increase was detected after administration of microbubbles. Histomorphometric analyses revealed that bone formation around the implant in GTi-Us was enhanced by the addition of microbubbles in GTi-Us-Mb. Taken together, our data indicate that microbubble injection enhances the inhibitory effect of LIPUS on debris-induced osteolysis and further strengthens the mechanical fixation of implants in an early-stage osteolysis model in vivo.


      PubDate: 2014-12-16T19:46:08Z
       
  • Ultrasound and Microbubble-Induced Local Delivery of MicroRNA-Based
           Therapeutics
    • Abstract: Publication date: January 2015
      Source:Ultrasound in Medicine & Biology, Volume 41, Issue 1
      Author(s): Rick F.J. Kwekkeboom , Zhiyong Lei , Sylvia J.P. Bogaards , Eric Aiazian , Otto Kamp , Walter J. Paulus , Joost P.G. Sluijter , René J.P. Musters
      MicroRNAs are involved in many pathologic processes and are a promising target for therapeutic intervention. However, successful, localized delivery of microRNA-based therapeutics is lacking. In this study, cationic ultrasound-responsive microbubbles (MBs) were used to deliver microRNA blockers and mimics in vitro and in vivo. Cationic MBs successfully delivered microRNA blockers to human endothelial cells on ultrasound (US) exposure in vitro. This in vitro US protocol did not successfully deliver microRNA mimics to skeletal muscle of mice, whereas an US protocol that is routinely used for contrast imaging did. Additionally, we used cationic MBs and US to locally deliver antimiR and antagomiR molecules with US causing inertial cavitation. Delivery of antimiR to the extracellular compartments of the muscle was only slightly increased, whereas delivery of antagomiR to the capillaries, myocytes and extracellular space was significantly increased. AntagomiR seems to be a more suitable microRNA blocker than antimiR for use in combination with MBs and US for local delivery.


      PubDate: 2014-12-16T19:46:08Z
       
  • High-Intensity Focused Ultrasound Attenuates Neural Responses of Sciatic
           Nerves Isolated from Normal or Neuropathic Rats
    • Abstract: Publication date: January 2015
      Source:Ultrasound in Medicine & Biology, Volume 41, Issue 1
      Author(s): Yee-Fun Lee , Chou-Ching Lin , Jung-Sung Cheng , Gin-Shin Chen
      Patients with diabetic neuropathy often have neuropathic pain. The purpose of our work was to investigate the effects of high-intensity focused ultrasound (HIFU) on the conduction block of normal and neuropathic nerves for soothing pain. Adult male Sprague–Dawley rats were used, and diabetes was induced by streptozotocin injection. Diabetic neuropathy was evaluated with animal behavior tests. Sciatic nerves of both control and neuropathic rats were dissected from the starting point of the sciatic nerve to the point where the sural nerve ends near the ankle. The nerves were stored in Ringer's solution. The in vitro nerve was placed on a self-developed experimental platform for HIFU exposure. Stimulation and recording of the compound action potentials (CAPs) and sensory action potentials (SAPs) were performed. Control and neuropathic nerves exposed or not exposed to HIFU were submitted to histologic analysis. For the control and neuropathic nerves, suppression of CAPs and SAPs started 2 min post-HIFU treatment. Maximum suppression of SAPs was 34.4 ± 3.2% for the control rats and 11.6 ± 2.0% and 9.8 ± 3.0% for rats 4 wk post-injection and 8 wk post-injection, respectively. Time to full recovery was 25, 70 and 80 min, respectively. Histologic analysis revealed that the nerves in which CAPs and SAPs did not fully recover were damaged thermally or mechanically by HIFU. It is feasible to reversibly block nerves with appropriate HIFU treatment. Diabetic nerves were less suppressed by HIFU and were more vulnerable to permanent damage.


      PubDate: 2014-12-16T19:46:08Z
       
  • Therapeutic Ultrasound Suppresses Neuropathic Pain and Upregulation of
           Substance P and Neurokinin-1 Receptor in Rats after Peripheral Nerve
           Injury
    • Abstract: Publication date: January 2015
      Source:Ultrasound in Medicine & Biology, Volume 41, Issue 1
      Author(s): Yu-Wen Chen , Jann-Inn Tzeng , Po-Ching Huang , Ching-Hsia Hung , Dong-Zi Shao , Jhi-Joung Wang
      We studied the mechanisms and impact of therapeutic ultrasound (TU) for pain caused by nerve injury. TU began on post-operative day 5 (POD5) and then continued daily for the next 22 d. Sensitivity to thermal and mechanical stimuli and levels of neurokinin-1 receptor, substance P, tumor necrosis factor-α and interleukin-6 in the sciatic nerve were examined. On POD7, chronic constriction injury rats undergoing TU at an intensity of 1 W/cm2, but not 0.25 or 0.5 W/cm2, had increases in both the mechanical withdrawal threshold and the thermal withdrawal latency compared with the chronic constriction injury group. Moreover, chronic constriction injury rats exhibited upregulation of neurokinin-1 receptor, substance P, tumor necrosis factor-α and interleukin-6 in the sciatic nerve on PODs 14 and 28, whereas TU inhibited their increased expression. We suggest that the efficacy of TU is dependent on its ability to limit the upregulation of neurokinin-1 receptor, substance P, tumor necrosis factor-α and interleukin-6 around the injured sciatic nerve.


      PubDate: 2014-12-16T19:46:08Z
       
  • Effects of Phonophoresis and Gold Nanoparticles in Experimental Model of
           Muscle Overuse: Role of Oxidative Stress
    • Abstract: Publication date: January 2015
      Source:Ultrasound in Medicine & Biology, Volume 41, Issue 1
      Author(s): Diogo Zortéa , Paulo C.L. Silveira , Priscila S. Souza , Giulia S.P. Fidelis , Carla S. Paganini , Bruna G. Pozzi , Talita Tuon , Claudio T. De Souza , Marcos M.S. Paula , Ricardo A. Pinho
      The aim of the study described here was to investigate the effects of pulsed ultrasound and gold nanoparticles (AuNPs) on behavioral, inflammatory and oxidative stress parameters in an experimental model of overuse. Wistar rats performed 21 d of exercise on a treadmill at different intensities and were exposed to ultrasound in the presence or absence of AuNPs. The overuse model promoted behavioral changes and increased creatine kinase, superoxide dismutase and glutathione peroxidase activity, as well as the levels of superoxide, nitrotyrosine, nitric oxide, thiobarbituric acid reactive substance, carbonyl, tumor necrosis factor α and interleukin-6. These values were significantly decreased by AuNPs and by AuNPs plus ultrasound. Catalase activity remained unchanged and the glutathione level increased significantly after exposure to AuNPs plus ultrasound. These results suggest a susceptibility to anxiety as well as elevated levels of oxidative stress. However, therapeutic interventions with AuNPs plus ultrasound reduced the production of oxidants and oxidative damage and improved the anti-oxidant defense system.


      PubDate: 2014-12-16T19:46:08Z
       
  • Neurophysiologic Correlates of Sonication Treatment in Patients with
           Essential Tremor
    • Abstract: Publication date: January 2015
      Source:Ultrasound in Medicine & Biology, Volume 41, Issue 1
      Author(s): Jin Woo Chang , Byoung-Kyong Min , Bong-Soo Kim , Won Seok Chang , Yong-Ho Lee
      Transcranial magnetic resonance imaging-guided high-intensity focused ultrasound (MRgHIFU) is gaining attention as a potent substitute for surgical intervention in the treatment of neurologic disorders. To discern the neurophysiologic correlates of its therapeutic effects, we applied MRgHIFU to an intractable neurologic disorder, essential tremor, while measuring magnetoencephalogram mu rhythms from the motor cortex. Focused ultrasound sonication destroyed tissues by focusing a high-energy beam on the ventralis intermedius nucleus of the thalamus. The post-treatment effectiveness was also evaluated using the clinical rating scale for tremors. Thalamic MRgHIFU had substantial therapeutic effects on patients, based on MRgHIFU-mediated improvements in movement control and significant changes in brain mu rhythms. Ultrasonic thalamotomy may reduce hyper-excitable activity in the motor cortex, resulting in normalized behavioral activity after sonication treatment. Thus, non-invasive and spatially accurate MRgHIFU technology can serve as a potent therapeutic tool with broad clinical applications.


      PubDate: 2014-12-16T19:46:08Z
       
  • Usefulness of Real-Time Elastography Strain Ratio in the Assessment of
           Bile Duct Ligation-Induced Liver Injury and the Hepatoprotective Effect of
           Chitosan: An Experimental Animal Study
    • Abstract: Publication date: January 2015
      Source:Ultrasound in Medicine & Biology, Volume 41, Issue 1
      Author(s): Marina Dudea , Simona Clichici , Diana Elena Olteanu , Andras Nagy , Maria Cucoş , Sorin Dudea
      The purpose of the study described here was to evaluate the usefulness of the elastographic strain ratio in the assessment of liver changes in an experimental animal setting and the hepatoprotective effects of chitosan. Ultrasonography and Strain Ratio calculation were performed before and after bile duct ligation (BDL) in three groups of Wistar albino rats (n = 10 animals per group): (i) rats subjected to bile duct ligation only; (ii) rats subjected to bile duct ligation and administered chitosan for 14 d; (iii) rats subjected to bile duct ligation and administered chitosan for 7 d. The results were compared with the laboratory data and pathologic findings. Strain ratios revealed an increase in liver stiffness after bile duct ligation (p < 0.05), except in the group with chitosan administered for 7 d, and agreed with laboratory and pathology data. In conclusion, strain ratio can be used as an experimental research instrument in the assessment of liver response to injury. To the best of our knowledge, this is the first study reporting on the usefulness of the sonoelastographic liver-to-kidney strain ratio in assessing the effects of experimentally induced liver lesions.


      PubDate: 2014-12-16T19:46:08Z
       
  • 2-D Left Ventricular Flow Estimation by Combining Speckle Tracking With
           Navier–Stokes-Based Regularization: An In Silico, In Vitro and In
           Vivo Study
    • Abstract: Publication date: January 2015
      Source:Ultrasound in Medicine & Biology, Volume 41, Issue 1
      Author(s): Hang Gao , Nathalie Bijnens , Damien Coisne , Mathieu Lugiez , Marcel Rutten , Jan D'hooge
      Despite the availability of multiple ultrasound approaches to left ventricular (LV) flow characterization in two dimensions, this technique remains in its childhood and further developments seem warranted. This article describes a new methodology for tracking the 2-D LV flow field based on ultrasound data. Hereto, a standard speckle tracking algorithm was modified by using a dynamic kernel embedding Navier–Stokes-based regularization in an iterative manner. The performance of the proposed approach was first quantified in synthetic ultrasound data based on a computational fluid dynamics model of LV flow. Next, an experimental flow phantom setup mimicking the normal human heart was used for experimental validation by employing simultaneous optical particle image velocimetry as a standard reference technique. Finally, the applicability of the approach was tested in a clinical setting. On the basis of the simulated data, pointwise evaluation of the estimated velocity vectors correlated well (mean r = 0.84) with the computational fluid dynamics measurement. During the filling period of the left ventricle, the properties of the main vortex obtained from the proposed method were also measured, and their correlations with the reference measurement were also calculated (radius, r = 0.96; circulation, r = 0.85; weighted center, r = 0.81). In vitro results at 60 bpm during one cardiac cycle confirmed that the algorithm properly measures typical characteristics of the vortex (radius, r = 0.60; circulation, r = 0.81; weighted center, r = 0.92). Preliminary qualitative results on clinical data revealed physiologic flow fields.


      PubDate: 2014-12-16T19:46:08Z
       
  • Diagnostic Power of Longitudinal Strain at Rest for the Detection of
           Obstructive Coronary Artery Disease in Patients with Type 2 Diabetes
           Mellitus
    • Abstract: Publication date: January 2015
      Source:Ultrasound in Medicine & Biology, Volume 41, Issue 1
      Author(s): Houjuan Zuo , Jiangtao Yan , Hesong Zeng , Wenyu Li , Pengcheng Li , Zhengxiang Liu , Guanglin Cui , Jiagao Lv , Daowen Wang , Hong Wang
      Global longitudinal strain (GLS) measured by 2-D speckle-tracking echocardiography (2-D STE) at rest has been recognized as a sensitive parameter in the detection of significant coronary artery disease (CAD). However, the diagnostic power of 2-D STE in the detection of significant CAD in patients with diabetes mellitus is unknown. Two-dimensional STE features were studied in total of 143 consecutive patients who underwent echocardiography and coronary angiography. Left ventricular global and segmental peak systolic longitudinal strains (PSLSs) were quantified by speckle-tracking imaging. In the presence of obstructive CAD (defined as stenosis ≥75%), global PSLS was significantly lower in patients with diabetes mellitus than in patients without (16.65 ± 2.29% vs. 17.32 ± 2.27%, p < 0.05). Receiver operating characteristic analysis revealed that global PSLS could effectively detect obstructive CAD in patients without diabetes mellitus (cutoff value: –18.35%, sensitivity: 78.8%, specificity: 77.5%). However, global PSLS could detect obstructive CAD in diabetic patients at a lower cutoff value with inadequate sensitivity and specificity (cutoff value: –17.15%; sensitivity: 61.1%, specificity: 52.9%). In addition, the results for segmental PSLS were similar to those for global PSLS. In conclusion, global and segmental PSLSs at rest were significantly lower in patients with both obstructive CAD and diabetes mellitus than in patients with obstructive CAD only; thus, PSLSs at rest might not be a useful parameter in the detection of obstructive CAD in patients with diabetes mellitus.


      PubDate: 2014-12-16T19:46:08Z
       
  • Echo-Tracking Technology Assessment of Carotid Artery Stiffness in
           Patients with Coronary Slow Flow
    • Abstract: Publication date: January 2015
      Source:Ultrasound in Medicine & Biology, Volume 41, Issue 1
      Author(s): Song Yang , De-zhao Wang , Hong-xia Zhang , Wen He , Bu-xing Chen
      Coronary slow flow (CSF) in coronary angiography (CAG) is a well-recognized clinical entity. Previous studies have suggested that microvascular abnormalities and endothelial dysfunction are responsible for CSF. Accordingly, we hypothesized that the CSF phenomenon is a form of atherosclerosis including both small vessels and epicardial coronary arteries. The echo-tracking (ET) technique is a non-invasive detection method for early prediction of arterial atherosclerosis. Therefore, we investigated carotid elasticity with the ET technique in patients with CSF. Fifty patients with CSF and 50 patients with normal coronary artery blood flow, as determined by CAG, with a similar distribution of risk factors were recruited. The stiffness parameter (β), pressure–strain elastic modulus (E p), arterial compliance (AC), augmentation index (AIx) and local pulse-wave velocity (PWV) were determined at the level of the bilateral common carotid artery (CCA) with using the ET technique. Levels of serum high-sensitivity C-reactive protein (hs-HSCRP) were determined for the two groups. β, E p and PWV were significantly higher in the CSF group than in the control group (β: 11.4 ± 3.76 vs. 9.22 ± 3.28, p < 0.01; E p: 153.44 ± 47.85 vs. 126.40 ± 43.32, p < 0.01; PWV: 7.26 ± 1.10 vs. 6.55 ± 1.02, p < 0.01), but AC was lower in the CSF group than in the control group (0.62 ± 0.20 vs. 0.74 ± 0.24, p < 0.01). The elasticity parameters of the bilateral common carotid artery did not significantly differ. The level of hs-HSCRP was correlated positively with β (r = 0.306, p = 0.015), E p (r = 0.358, p = 0.005) and PWV (r = 0.306, p = 0.015), but negatively with AC (r = −0.236, p = 0.049). In conclusion, the ET technique is a simple practical method for evaluating carotid artery elasticity, and there is a significant correlation between carotid artery stiffness and level of hs-HSCRP in patients with CSF.


      PubDate: 2014-12-16T19:46:08Z
       
  • Preliminary in Vivo Breast Vibro-acoustography Results with
           a Quasi-2-D Array Transducer: A Step Forward Toward Clinical
           Applications
    • Abstract: Publication date: December 2014
      Source:Ultrasound in Medicine & Biology, Volume 40, Issue 12
      Author(s): Mohammad Mehrmohammadi , Robert T. Fazzio , Dana H. Whaley , Sandhya Pruthi , Randall R. Kinnick , Mostafa Fatemi , Azra Alizad
      We previously investigated the application of a novel imaging modality, vibro-acoustography (VA), using an annular confocal transducer (confocal VA) integrated into a clinical prone stereotactic mammography system, to detect various breast abnormalities. To shorten the scanning time and provide improved coverage of the breast, we have evolved our imaging system by implementing VA on a clinical ultrasound scanner equipped with a “quasi-2-D” array transducer. We call this technique “quasi-2-D vibro-acoustography” (Q2-DVA). A clinical ultrasound scanner (GE Vivid 7) was modified to perform both ultrasound imaging and VA using an array transducer consisting of a matrix of 12 rows by 70 columns of ultrasound elements. The newly designed system was used to perform VA on patients with either benign or cancerous lesions. Our results indicate that benign and malignant solid breast lesions were easily detected using our newly modified VA system. It was also possible to detect microcalcifications within the breast. Our results suggest that with further development, Q2-DVA could provide high-resolution diagnostic information in the clinical setting and may be used either as a stand-alone or as a complementary tool in support of other clinical imaging modalities.


      PubDate: 2014-12-16T19:46:08Z
       
  • Differential Diagnosis of Gallbladder Wall Thickening: The Usefulness
           of Contrast-Enhanced Ultrasound
    • Abstract: Publication date: December 2014
      Source:Ultrasound in Medicine & Biology, Volume 40, Issue 12
      Author(s): Jun-Mei Xu , Le-Hang Guo , Hui-Xiong Xu , Shu-Guang Zheng , Lin-Na Liu , Li-Ping Sun , Ming-De Lu , Xiao-Yan Xie , Wen-Ping Wang , Bing Hu , Kun Yan , Hong Ding , Shao-Shan Tang , Lin-Xue Qian , Bao-Ming Luo
      The purpose of this study was to evaluate the usefulness of contrast-enhanced ultrasound (CEUS) in the differential diagnosis of gallbladder wall (GBW) thickening and determine the predictors of malignant GBW thickening. One hundred fifty-nine patients with GBW thickening, including 76 men and 83 women, from eight institutions were enrolled. CEUS was performed after injection of a sulfur hexafluoride microbubble-based ultrasound contrast agent. Multiple logistic regression analysis was used to reveal independent predictors associated with malignant GBW thickening. The final diagnoses were 48 gallbladder carcinomas and 111 benign gallbladder diseases. Maximal thicknesses of the GBW in malignant and benign GBW thickening were 17.3 ± 5.2 (6–30) mm and 8.6 ± 5.1 (4–26) mm respectively (p < 0.001). CEUS revealed significant differences in intra-lesional vessels, enhancement homogeneity, time to hypo-enhancement, inner layer discontinuity, outer layer discontinuity and adjacent liver involvement (all p-values < 0.05) between malignant and benign GBW thickening. Patient age > 46.5 y, focal GBW thickening, inner layer discontinuity and outer layer discontinuity were found to be associated with malignancy by multiple logistic regression analysis (all p-values < 0.05). Receiver operating characteristic curve analysis revealed Az values for patient age, focal GBW thickening, inner wall discontinuity and outer wall discontinuity of 0.709 (95% confidence interval [CI]: 0.627–0.790), 0.714 (95% CI: 0.630–0.798), 0.860 (95% CI: 0.791–0.928) and 0.858 (95% CI: 0.783–0.933), respectively. CEUS is useful in the differential diagnosis between malignant and benign GBW thickening. Focal GBW thickening, inner wall discontinuity and outer wall discontinuity observed on CEUS are diagnostic clues for malignant GBW thickening.


      PubDate: 2014-12-16T19:46:08Z
       
  • Ultrasound Quantification of Acetabular Rounding in Hip Dysplasia:
           Reliability and Correlation to Treatment Decisions in a Retrospective
           Study
    • Abstract: Publication date: January 2015
      Source:Ultrasound in Medicine & Biology, Volume 41, Issue 1
      Author(s): Edwin Cheng , Myles Mabee , Vimarsha G. Swami , Yeli Pi , Richard Thompson , Sukhdeep Dulai , Jacob L. Jaremko
      Currently, acetabular rounding is only subjectively assessed on ultrasound for developmental dysplasia of the hip. We tested whether acetabular rounding can be quantified reliably and can distinguish between hips requiring and not requiring treatment. Consecutive infants (n = 90) suspected of having dysplasia of the hip, seen at a pediatric orthopedic clinic, were separated into four diagnostic categories (normal, borderline but resolved, treated by brace, treated surgically). Acetabular rounding was assessed by semi-quantitative grade (0 = nil, 1 = mild, 2 = moderate, 3 = severe) by three observers and by direct measurement of acetabular radius of curvature (AROC) by two observers. Inter-observer reliability of rounding grade was poor (κ = 0.30–0.37). AROC had an inter-observer intra-class correlation coefficient of 0.84 and coefficient of variation of 29%–34%. Mean AROC was significantly higher for hips requiring treatment than for those not requiring treatment (3.3 mm vs. 1.6 mm, p = 0.007). AROC reliably quantifies an observation currently being made subjectively by radiologists and surgeons, and may be useful as a supplementary ultrasound index of dysplasia of the hip in future prospective studies.


      PubDate: 2014-12-16T19:46:08Z
       
  • Ultrasound Diagnosis of Carotid Artery Stiffness in Patients with Ischemic
           Leukoaraiosis
    • Abstract: Publication date: January 2015
      Source:Ultrasound in Medicine & Biology, Volume 41, Issue 1
      Author(s): Monika Turk , Janja Pretnar-Oblak , Matija Zupan , Bojana Zvan , Marjan Zaletel
      The pathophysiology of ischemic leukoaraiosis (ILA) is unknown. It was recently found that ILA patients have increased aortic stiffness. Carotid stiffness is a more specific parameter and could have value as a non-invasive diagnostic value for ILA. Therefore, using color-coded duplex sonography, we compared local carotid stiffness parameters of 59 patients with ILA with those of 45 well-matched controls. The diagnosis of ILA was based on exclusion of other causes of white matter changes seen on magnetic resonance imaging. Pulse wave velocity β (PWVβ, m/s), pressure–strain elasticity modulus (E p, kPa), β index and augmentation index (A ix, %) values were higher and arterial compliance (AC, mm2/kPa) values were lower in the ILA group; however, only E p and PWVβ reached statistical significance (p ≤ 0.05). β, E p and PWVβ exhibited an increasing trend with higher Fazekas score, though only E p reached significance (p = 0.05). The main conclusion was that E p and PWVβ could have a diagnostic role in patients with ILA.


      PubDate: 2014-12-16T19:46:08Z
       
  • Diagnostic Evaluation of Ductal Carcinoma in Situ of the Breast:
           Ultrasonographic, Mammographic and Histopathologic Correlations
    • Abstract: Publication date: January 2015
      Source:Ultrasound in Medicine & Biology, Volume 41, Issue 1
      Author(s): Zhan-Qiang Jin , Mei-Ying Lin , Wan-Qing Hao , Hua-Tang Jiang , Li Zhang , Wen-Hua Hu , Miao Zhang
      The aims of the study described here were to illustrate the spectrum of ultrasonographic features of ductal carcinoma in situ (DCIS) and to evaluate the ability of ultrasonography (US) to predict the grade and recurrence of DCIS on the basis of mammographic and histopathologic findings. We retrospectively evaluated the ultrasonographic features of 129 DCIS lesions from 127 consecutive women and compared these with their mammographic and histopathologic features. The mean size of DCISs on ultrasonography and mammography (MMG) was 3.67 ± 1.40 and 4.00 ± 1.74 cm, respectively, which do not differ statistically (p = 0.09). Despite the statistical difference in Breast Imaging Reporting and Data System (BI-RADS) classification on US and MMG (p = 0.000), the median BI-RADS classification is category 4c on both US and MMG (p = 0.01). There was no statistically significant difference in the distribution of microcalcification on MMG and US. Clusters <5 mm in greatest diameter are easily seen on MMG. At US, a scattered/linear distribution on MMG had a higher level of visibility than clustered distribution on MMG. The correlation between tumor size and DCIS with micro-invasion evaluated using US is higher than that obtained using MMG (p = 0.001 and 0.024, respectively). When US was used for the detection of DCIS, diagnostic accuracy was significantly associated with higher Van Nuys groups, the presence of micro-invasion and comedo carcinoma (p = 0.000, 0.022 and 0.011, respectively). However, mammographic diagnostic accuracy was found not to associate with higher Van Nuys groups, the presence of micro-invasion and comedo carcinoma (p = 0.054, 0.093 and 0.256, respectively). Ultrasonography may play an important role both in detecting DCIS and in evaluating its histopathologic features. Detection of DCIS using MMG alone may be suboptimal for patients with dense breasts, especially among Chinese women.


      PubDate: 2014-12-16T19:46:08Z
       
  • Evaluation of the Development of the Fetal Anal Sphincter with Tomography
           Ultrasonography Imaging
    • Abstract: Publication date: January 2015
      Source:Ultrasound in Medicine & Biology, Volume 41, Issue 1
      Author(s): Yang Guang , Xi Wang , Ai-Lu Cai , Li-Mei Xie , Hai-Long Ding , Xin-Yue Meng
      The aim of the study described here was to examine the potential of tomography ultrasonography imaging (TUI) in evaluation of the fetal anal sphincter. In this prospective cross-sectional study of the fetal anal sphincter with TUI, 326 singleton pregnancies (mean age = 28 y, range: 22–38 y) were scanned at 19–40 wk of gestation. The fetal anal region and ischium were revealed in 320 of 326 patients (98.2%). The normal fetal anal sphincter diameter and ischial space reached maximums of 15 and 39 mm, respectively. The normal fetal anal sphincter diameter and the ischial space were plotted as a function of gestational age (GA) on a linear curve, and the regression equations for normal fetal anal sphincter diameter and ischial space as a function of GA in weeks were obtained. A scatterplot was also created that revealed a significant positive relationship between normal fetal anal sphincter diameter and ischial space. On the basis of these criteria, imperforate anus was diagnosed in one fetus. Ultrasonographic assessment of the fetal anal sphincter and the ischium with TUI is feasible. The reference values reported in this article may be useful in prenatal diagnosis of fetal anal sphincter abnormalities.


      PubDate: 2014-12-16T19:46:08Z
       
  • Diagnostic Impact of Color Doppler Ultrasound-Guided Core Biopsy on
           Fine-Needle Aspiration of Anterior Mediastinal Masses
    • Abstract: Publication date: December 2014
      Source:Ultrasound in Medicine & Biology, Volume 40, Issue 12
      Author(s): Hung-Jen Chen , Wei-Chih Liao , Shinn-Jye Liang , Chia-Hsiang Li , Chih-Yen Tu , Wu-Huei Hsu
      Although lymphoma and thymoma are common etiologies of anterior mediastinal masses (AMMs), smaller percentages and numbers of patients with these diseases have been enrolled in previous ultrasound-guided biopsy studies. To date, there has been no study of color Doppler sonographic features to support the differentiation of AMMs. For this retrospective cohort study, a search of the database of the China Medical University Hospital using the clinical coding “ultrasound-guided biopsy” was conducted for the period December 2003 to February 2013. We selected patients diagnosed with AMMs (not cysts) using radiographic records. This search yielded a list of 80 cases. Real-time ultrasound-guided core needle biopsy (CNB) was performed in all but 5 patients without a sufficient safety range. In 89% (67/75) of these ultrasound-guided CNB cases, the diagnostic accuracy achieved subclassification. Fine-needle aspiration cytology achieved subclassification in only 10% of cases. On color Doppler sonography, 71% of lymphomas were characterized as “rich vascular with central/crisscross collocations” and 29% as “avascular or localized/scattered peripheral vessels.” However, decreased proportions of “rich vascular with central/crisscross collocations” were found in lung cancer (4% [1/23], odds ratio = 0.018, 95% confidence interval: 0.002–0.154, p < 0.001) and thymoma/thymic carcinoma (25% [4/16]; odds ratio = 0.133, 95% confidence interval: 0.035–0.514, p = 0.003) compared with the lymphoma group. We conclude that the vessels in lymphoma AMMs have specific patterns on color Doppler sonography. Ultrasound-guided CNB of AMMs had an accuracy of ≤89% in diagnosis and subclassification. Fine-needle aspiration cytology itself cannot aid in the diagnosis. Color Doppler sonographic evaluation of AMMs followed by real-time CNB is a more efficient method.


      PubDate: 2014-12-16T19:46:08Z
       
  • Acoustic Output Measured by Thermal and Mechanical Indices during Fetal
           Echocardiography at the Time of the First Trimester Scan
    • Abstract: Publication date: January 2015
      Source:Ultrasound in Medicine & Biology, Volume 41, Issue 1
      Author(s): Dragos Nemescu , Anca Berescu
      We measured acoustic output, expressed as the thermal index (TI) and mechanical index (MI), during fetal echocardiography at the time of the first trimester scan. TI and MI were retrieved from the saved displays during gray-mode, high-definition color flow Doppler and pulsed-wave Doppler (tricuspid flow) ultrasound examinations of the fetal heart and from the ductus venosus assessment. A total of 399 fetal cardiac examinations were evaluated. There was a significant increase in TI values from B-mode studies (0.07 ± 0.04 [mean ± SD]) to color flow mapping (0.2 ± 0.0) and pulsed-wave Doppler studies (0.36 ± 0.05). The TI from ductus venosus assessment (0.1 ± 0.01) was significantly lower than those from Doppler examinations of the heart. MI values from B-mode scans (0.65 ± 0.12) and color flow mapping (0.71 ± 0.11) were comparable, although different, and both values were higher than those from pulsed-wave Doppler tricuspid evaluation (0.39 ± 0.03). There were no differences in MI values from power Doppler assessment between the tricuspid flow and ductus venosus. Safety indices were remarkably stable and were largely constant, especially for color Doppler (TI), tricuspid flow (MI) and ductus venosus assessment (TI, MI). We acquired satisfactory Doppler images and/or signals at acoustic levels that were lower than the actual recommendations and never reached a TI of 0.5.


      PubDate: 2014-12-16T19:46:08Z
       
  • Diagnostic Performance of Axial-Strain Sonoelastography in Confirming
           Clinically Diagnosed Achilles Tendinopathy: Comparison with B-Mode
           Ultrasound and Color Doppler Imaging
    • Abstract: Publication date: January 2015
      Source:Ultrasound in Medicine & Biology, Volume 41, Issue 1
      Author(s): Chin Chin Ooi , Michal Elisabeth Schneider , Peter Malliaras , Martine Chadwick , David Alister Connell
      This primary aim of this study was to evaluate the diagnostic performance of axial-strain sonoelastography (ASE), B-mode ultrasound (US) and color Doppler US in confirming clinically symptomatic Achilles tendinopathy. The secondary aim was to establish the relationship between the strain ratio during sonoelastography and Victorian Institute of Sport Assessment—Achilles (VISA-A) scores. The VISA-A questionnaire is a validated clinical rating scale that evaluates the symptoms and dysfunction of the Achilles tendon. One hundred twenty Achilles tendons of 120 consecutively registered patients with clinical symptoms of Achilles tendinopathy and another 120 gender- and age-matched, asymptomatic Achilles tendons of 120 healthy volunteers were assessed with B-mode US, ASE and color Doppler US. Symptomatic patients had significantly higher strain ratio scores and softer Achilles tendon properties compared with controls (p < 0.001). The strain ratio was moderately correlated with VISA-A scores (r = −0.62, p < 0.001). The diagnostic accuracy of B-mode US, ASE and color Doppler US in confirming clinically symptomatic Achilles tendinopathy was 94.7%, 97.8% and 82.5% respectively. There was excellent correlation between the clinical reference standard and the grade of tendon quality on ASE (κ = 0.91, p < 0.05), compared with B-mode US (κ = 0.74, p < 0.05) and color Doppler imaging (κ = 0.49, p < 0.05). ASE is an accurate clinical tool in the evaluation of Achilles tendinopathy, with results comparable to those of B-mode US and excellent correlation with clinical findings. The strain ratio may offer promise as a supplementary tool for the objective evaluation of Achilles tendon properties.


      PubDate: 2014-12-16T19:46:08Z
       
  • Editorial Advisory Board
    • Abstract: Publication date: January 2015
      Source:Ultrasound in Medicine & Biology, Volume 41, Issue 1




      PubDate: 2014-12-16T19:46:08Z
       
  • Masthead
    • Abstract: Publication date: January 2015
      Source:Ultrasound in Medicine & Biology, Volume 41, Issue 1




      PubDate: 2014-12-16T19:46:08Z
       
  • Masthead
    • Abstract: Publication date: December 2014
      Source:Ultrasound in Medicine & Biology, Volume 40, Issue 12




      PubDate: 2014-12-16T19:46:08Z
       
  • Editorial Advisory Board
    • Abstract: Publication date: December 2014
      Source:Ultrasound in Medicine & Biology, Volume 40, Issue 12




      PubDate: 2014-12-16T19:46:08Z
       
  • Contents
    • Abstract: Publication date: December 2014
      Source:Ultrasound in Medicine & Biology, Volume 40, Issue 12




      PubDate: 2014-12-16T19:46:08Z
       
  • Real-Time Sonoelastography of Salivary Glands for Diagnosis and Functional
           Assessment of Primary Sjögren’s Syndrome
    • Abstract: Publication date: December 2014
      Source:Ultrasound in Medicine & Biology, Volume 40, Issue 12
      Author(s): Christian Dejaco , Tobias De Zordo , Daniel Heber , Wolfgang Hartung , Rainer Lipp , Andre Lutfi , Marton Magyar , Dorothea Zauner , Angelika Lackner , Christina Duftner , Jutta Horwath-Winter , Winfried B. Graninger , Josef Hermann
      The purpose of this study was to investigate the value of real-time sonoelastography (RTS) of salivary glands for the diagnosis and assessment of glandular damage in primary Sjögren’s syndrome (pSS). After institutional review board approval, 45 pSS patients, 24 sicca patients and 11 healthy controls were investigated prospectively. Questionnaires were completed and Saxon and Schirmer tests and routine blood tests carried out in all patients. All patients underwent B-mode ultrasonography and RTS of parotid and submandibular glands. Abnormal findings were graded from 0 to 48 and from 0 to 16, respectively. Sialoscintigraphy was done according to a routine protocol; scoring ranged from 0 to 12. Statistical analysis comprised receiver operating characteristic curve and multivariate regression analysis. Patients with pSS had higher B-mode (median score = 25 [range: 2–44] vs. 9 [1–20], p < 0.001) and RTS (6.5 [2–13] versus 4 [1–9], p < 0.001) scores than controls with sicca syndrome, yielding areas under the curve of 0.83 and 0.85 (p < 0.05 each), respectively for pSS diagnosis. In cases with an inconclusive B-mode ultrasonography result, RTS (cutoff score: ≥6) led to a sensitive (66.7%) and specific (85.7%) classification of patients and sicca controls. In multivariate regression analysis, RTS (regression coefficient = –0.48, p = 0.005), but not B-mode ultrasonography, reflected impaired salivary gland function according to the Saxon test, whereas none of the subjective measures of dryness or discomfort were related to ultrasonography results. B-mode and RTS results were both associated with sialoscintigraphy scores (regression coefficient = 0.66, p < 0.001, and regression coefficient = 0.55, p = 0.001, respectively). Reproducibility of B-mode ultrasonography and RTS was good, with intra-class correlation coefficients of 0.93 (95% confidence interval: 0.57–0.98) and 0.93 (95% confidence interval: 0.79–0.98), respectively. In summary, RTS might be a useful adjunct to B-mode ultrasonography for diagnosis and assessment of salivary gland impairment in primary Sjögren’s syndrome.


      PubDate: 2014-12-16T19:46:08Z
       
  • Progressive Attenuation of the Longitudinal Kinetics in the Common Carotid
           Artery: Preliminary in Vivo Assessment
    • Abstract: Publication date: January 2015
      Source:Ultrasound in Medicine & Biology, Volume 41, Issue 1
      Author(s): Guillaume Zahnd , Simone Balocco , André Sérusclat , Philippe Moulin , Maciej Orkisz , Didier Vray
      Longitudinal kinetics (LOKI) of the arterial wall consists of the shearing motion of the intima–media complex over the adventitia layer in the direction parallel to the blood flow during the cardiac cycle. The aim of this study was to investigate the local variability of LOKI amplitude along the length of the vessel. By use of a previously validated motion-estimation framework, 35 in vivo longitudinal B-mode ultrasound cine loops of healthy common carotid arteries were analyzed. Results indicated that LOKI amplitude is progressively attenuated along the length of the artery, as it is larger in regions located on the proximal side of the image (i.e., toward the heart) and smaller in regions located on the distal side of the image (i.e., toward the head), with an average attenuation coefficient of −2.5 ± 2.0%/mm. Reported for the first time in this study, this phenomenon is likely to be of great importance in improving understanding of atherosclerosis mechanisms, and has the potential to be a novel index of arterial stiffness.


      PubDate: 2014-12-16T19:46:08Z
       
  • Calendar
    • Abstract: Publication date: January 2015
      Source:Ultrasound in Medicine & Biology, Volume 41, Issue 1




      PubDate: 2014-12-16T19:46:08Z
       
  • Electrophysiological Changes Correlated with Temperature Increases Induced
           by High-Intensity Focused Ultrasound Ablation
    • Abstract: Publication date: Available online 13 December 2014
      Source:Ultrasound in Medicine & Biology
      Author(s): Ziqi Wu , Ronald E. Kumon , Jacob I. Laughner , Igor R. Efimov , Cheri X. Deng
      To gain better understanding of the detailed mechanisms of high-intensity focused ultrasound (HIFU) ablation for cardiac arrhythmias, we investigated how the cellular electrophysiological (EP) changes were correlated with temperature increases and thermal dose (cumulative equivalent minutes [CEM 43 ]) during HIFU application using Langendorff-perfused rabbit hearts. Employing voltage-sensitive dye di-4-ANEPPS, we measured the EP and temperature during HIFU using simultaneous optical mapping and infrared imaging. Both action potential amplitude (APA) and action potential duration at 50% repolarization (APD50) decreased with temperature increases, and APD50 was more thermally sensitive than APA. EP and tissue changes were irreversible when HIFU-induced temperature increased above 52.3 ± 1.4°C and log10(CEM 43 ) above 2.16 ± 0.51 (n = 5), but were reversible when temperature was below 50.1 ± 0.8°C and log10(CEM 43 ) below –0.9 ± 0.3 (n = 9). EP and temperature/thermal dose changes were spatially correlated with HIFU-induced tissue necrosis surrounded by a transition zone.


      PubDate: 2014-12-16T19:46:08Z
       
  • Quantitative Bone Ultrasound at the Distal Radius in Adults with Cystic
           Fibrosis
    • Abstract: Publication date: January 2015
      Source:Ultrasound in Medicine & Biology, Volume 41, Issue 1
      Author(s): Inge Roggen , Olivia Louis , Stephanie Van Biervliet , Sabine Van Daele , Eddy Robberecht , Elke De Wachter , Anne Malfroot , Kathleen De Waele , Inge Gies , Jesse Vanbesien , Jean De Schepper
      It is of clinical importance to identify bone disease related to cystic fibrosis (CF) early in its course to allow therapeutic interventions that optimize bone health. To test the technical (precision) and clinical (percentage of abnormal results, correlation with clinical parameters) performance of a commercial quantitative ultrasound apparatus for radial measurements, speed of sound (SOS) was measured at the distal third of the left radius with the Omnisense 7000p apparatus (Sunlight Medical, Tel-Aviv, Israel) in a group of young adult CF patients with regular follow-up at the Brussels and Ghent University Hospital. Sixty-three (37 males) CF patients at a median (range) age of 23.5 y (18.1–39.9) were included. SOS, SOS z-score and SOS t-score were respectively 4017 ± 97 m/s, −0.31 ± 0.74 and −0.60 ± 0.78 in males and 4086 ± 97 m/s, −0.19 ± 0.75 and −0.51 ± 0.95 in females. Mean SOS t-score was significantly lower compared with the manufacturer's reference data for males (p < 0.0001) and females (p = 0.01). SOS z- and t-scores correlated with weight z-score and body mass index z-score in females. No significant correlation was found between SOS and forced expiratory volume in 1 s (%). Neither diabetes mellitus nor liver disease was found to influence SOS. Radial quantitative ultrasound has a precision of 0.55%. The SOS is in the low normal range in 14% of CF patients and is influenced by weight in female patients, but not by the severity of the lung disease.


      PubDate: 2014-12-16T19:46:08Z
       
  • Reference Characterisation of Sound Speed and Attenuation of the IEC
           Agar-Based Tissue-Mimicking Material Up to a Frequency of 60 MHz
    • Abstract: Publication date: January 2015
      Source:Ultrasound in Medicine & Biology, Volume 41, Issue 1
      Author(s): Srinath Rajagopal , Neelaksh Sadhoo , Bajram Zeqiri
      To support the development of clinical applications of high-frequency ultrasound, appropriate tissue-mimicking materials (TMMs) are required whose acoustic properties have been measured using validated techniques. This paper describes the characterisation of the sound speed (phase velocity) and attenuation coefficient of the International Electrotechnical Commission (IEC) agar-based TMM over the frequency range 1 to 60 MHz. Measurements implemented a broadband through-transmission substitution immersion technique over two overlapping frequency ranges, with co-axially aligned 50 MHz centre-frequency transducers employed for characterisation above 15 MHz. In keeping with usual practice employed within the technical literature, thin acoustic windows (membranes) made of 12-μm-thick Mylar protected the TMM from water damage. Various important sources of uncertainty that could compromise measurement accuracy have been identified and evaluated through a combination of experimental studies and modelling. These include TMM sample thickness, measured both manually and acoustically, and the influence of interfacial losses that, even for thin protective membranes, are significant at the frequencies of interest. In agreement with previous reports, the attenuation coefficient of the IEC TMM exhibited non-linear frequency dependence, particularly above 20 MHz, yielding a value of 0.93 ± 0.04 dB cm−1 MHz−1 at 60 MHz, derived at 21 ± 0.5°C. For the first time, phase velocity, measured with an estimated uncertainty of ±3.1 m s−1, has been found to be dispersive over this extended frequency range, increasing from 1541 m s−1 at 1 MHz to 1547 m s−1 at 60 MHz. This work will help standardise acoustic property measurements, and establishes a reference measurement capability for TMMs underpinning clinical applications at elevated frequencies.


      PubDate: 2014-12-16T19:46:08Z
       
  • Ultrasound-Based Measurement of Molecular Marker Concentration in Large
           Blood Vessels: A Feasibility Study
    • Abstract: Publication date: Available online 11 October 2014
      Source:Ultrasound in Medicine & Biology
      Author(s): Shiying Wang , F. William Mauldin Jr. , Alexander L. Klibanov , John A. Hossack
      Ultrasound molecular imaging has demonstrated efficacy in pre-clinical studies for cancer and cardiovascular inflammation. However, these techniques often require lengthy protocols because of waiting periods or additional control microbubble injections. Moreover, they are not capable of quantifying molecular marker concentration in human tissue environments that exhibit variable attenuation and propagation path lengths. Our group recently investigated a modulated acoustic radiation force-based imaging sequence, which was found to detect targeted adhesion independent of control measurements. In the present study, this sequence was tested against various experimental parameters to determine its feasibility for quantitative measurements of molecular marker concentration. Results indicated that measurements obtained from the sequence (residual-to-saturation ratio, Rresid) were independent of acoustic pressure and attenuation (p > 0.13, n = 10) when acoustic pressures were sufficiently low. The Rresid parameter exhibited a linear relationship with measured molecular marker concentration (R2 > 0.94). Consequently, feasibility was illustrated in vitro, for quantification of molecular marker concentration in large vessels using a modulated acoustic radiation force-based sequence. Moreover, these measurements were independent of absolute acoustic reflection amplitude and used short imaging protocols (3 min) without control measurements.


      PubDate: 2014-10-12T23:27:04Z
       
  • Acoustic Structure Quantification Ultrasound Software Proves Imprecise in
           Assessing Liver Fibrosis or Cirrhosis in Parenchymal Liver Diseases
    • Abstract: Publication date: Available online 11 October 2014
      Source:Ultrasound in Medicine & Biology
      Author(s): Christiane Krämer , Natalie Jaspers , Dirk Nierhoff , Kathrin Kuhr , Andrea Bowe , Tobias Goeser , Guido Michels
      The present study was conducted to assess the diagnostic accuracy of Acoustic Structure Quantification (ASQ) ultrasound software in liver biopsy of patients with liver fibrosis and cirrhosis. Eighty patients (47 ± 14 y, 41 men) with chronic liver diseases underwent ultrasound examination of the liver and liver biopsy. In addition to the standard-care ultrasound examination, three valid gray-scale images were obtained for each patient. With the ASQ software, the average and peak values ( C m 2 ) of each ultrasound gray-scale image were calculated and then compared with histologic fibrosis staging (F0–F4). No correlation was found between ASQ values and histologic fibrosis stage (p > 0.05). Areas under the curve for the diagnosis of no or mild fibrosis (F0 and F1), moderate/severe fibrosis (F2 and F3) and cirrhosis (F4) using average/peak C m 2 values of small regions of interest were 0.46/0.43, 0.62/0.68 and 0.38/0.33. Determination of liver fibrosis with ASQ in its present form as an alternative approach to liver biopsy is too imprecise.


      PubDate: 2014-10-12T23:27:04Z
       
  • Molecular Ultrasound Imaging Using Contrast Agents Targeting Endoglin,
           Vascular Endothelial Growth Factor Receptor 2 and Integrin
    • Abstract: Publication date: Available online 11 October 2014
      Source:Ultrasound in Medicine & Biology
      Author(s): Ingrid Leguerney , Jean-Yves Scoazec , Nicolas Gadot , Nina Robin , Frédérique Pénault-Llorca , Steeve Victorin , Nathalie Lassau
      Expression levels of endoglin, αv integrin and vascular endothelial growth factor receptor 2 (VEGFR2) were investigated using targeted, contrast-enhanced ultrasonography in murine melanoma tumor models. Microvasculature and expression levels of biomarkers were investigated using specific contrast agents conjugated with biotinylated monoclonal antibodies. Ultrasound signal intensity from bound contrast agents was evaluated in two groups of mice: control mice and mice treated with sorafenib. Expression levels were analyzed by immunohistochemistry. Endoglin biomarkers were more highly expressed than αv integrin and VEGFR2. Endoglin decreased in the sorafenib group, whereas it tended to increase with time in the control group. Targeted ultrasound contrast agents may be used for non-invasive longitudinal evaluation of tumor angiogenesis during tumor growth or therapeutic treatment in preclinical studies. Endoglin protein, which plays an important role in angiogenesis, seems to be a target of interest for detection of cancer and for prediction of therapeutic efficacy.


      PubDate: 2014-10-12T23:27:04Z
       
  • Comparison of Acoustic Radiation Force Impulse Imaging and Transient
           Elastography for Non-invasive Assessment of Liver Fibrosis in Patients
           with Chronic Hepatitis B
    • Abstract: Publication date: Available online 11 October 2014
      Source:Ultrasound in Medicine & Biology
      Author(s): Dakun Zhang , Min Chen , Ruifang Wang , Yang Liu , Dedong Zhang , Liping Liu , Guangde Zhou
      The aims of this study were to compare the performance of acoustic radiation force impulse (ARFI) elastography and transient elastography (TE) in the assessment of liver fibrosis in patients with chronic hepatitis B and to evaluate the impact of elevated alanine transaminase levels on liver stiffness assessment using ARFI elastography. One hundred eighty consecutive patients with chronic hepatitis B were enrolled in this study and evaluated with respect to histologic and biochemical features. All patients underwent ARFI elastography and TE. ARFI elastography and TE correlated significantly with histologically assessed fibrosis (r = 0.599, p < 0.001, for ARFI elastography; r = 0.628, p < 0.001, for TE) and necro-inflammatory activity (r = 0.591, p < 0.001, for ARFI elastography; r = 0.616, p < 0.001, for TE). Areas under the receiver operating characteristic curves for ARFI elastography and TE were 0.764 and 0.813 (p = 0.302, ≥stage 2), 0.852 and 0.852 (p = 1.000, ≥stage 3) and 0.825 and 0.799 (p = 0.655, S = 4), respectively. The optimum cutoff values for ARFI elastography were 1.63 m/s for stage ≥2, 1.74 m/s for stage ≥3 and 2.00 m/s for stage 4 in patients for whom alanine transaminase levels were evaluated. The cutoff values decreased to 1.24 m/s for ≥ stage 2, 1.32 m/s for ≥ stage 3 and 1.41 m/s for stage 4 in patients with normal alanine transaminase levels. ARFI elastography may be a reliable method for diagnosing the stage of liver fibrosis with diagnostic performance similar to that of TE in patients with chronic hepatitis B. In addition, liver stiffness values obtained with ARFI elastography, like those obtained with TE, may be influenced by alanine transaminase levels.


      PubDate: 2014-10-12T23:27:04Z
       
  • Reliability of Contrast-Enhanced Ultrasound for the Assessment of Muscle
           Perfusion in Health and Peripheral Arterial Disease
    • Abstract: Publication date: Available online 11 October 2014
      Source:Ultrasound in Medicine & Biology
      Author(s): Kate N. Thomas , James D. Cotter , Samuel J.E. Lucas , Brigid G. Hill , André M. van Rij
      We investigated the reliability of contrast-enhanced ultrasound (CEUS) in assessing calf muscle microvascular perfusion in health and disease. Response to a post-occlusive reactive hyperaemia test was repeated on two occasions >48 h apart in healthy young (28 ± 7 y) and elderly controls (70 ± 5 y), and in peripheral arterial disease patients (PAD, 69 ± 7 y; n = 10, 9 and 8 respectively). Overall, within-individual reliability was poor (coefficient of variation [CV] range: 15–87%); the most reliable parameter was time to peak (TTP, 15–48% CV). Nevertheless, TTP was twice as long in elderly controls and PAD compared to young (19.3 ± 10.4 and 22.0 ± 8.6 vs. 8.9 ± 6.2 s respectively; p < 0.01), and area under the curve for contrast intensity post-occlusion (a reflection of blood volume) was ∼50% lower in elderly controls (p < 0.01 versus PAD and young). Thus, CEUS assessment of muscle perfusion during reactive hyperaemia demonstrated poor reliability, yet still distinguished differences between PAD patients, elderly and young controls.


      PubDate: 2014-10-12T23:27:04Z
       
  • Duplex Ultrasound Findings Before and After Surgery in Children and
           Adolescents with Renovascular Hypertension
    • Abstract: Publication date: Available online 11 October 2014
      Source:Ultrasound in Medicine & Biology
      Author(s): Adina Voiculescu , Andreas Heusch , Philip Düppers , Siamak Pourhassan , Dirk Klee , Lars C. Rump , Wilhelm Sandmann
      We report our experience with duplex ultrasound in young patients with renal artery stenosis (RAS) or middle aortic syndrome (MAS) before and after surgery (1995 and 2009). Of 36 patients (mean age: 13 ± 7 y), 21 had RAS and 15 had MAS. For patients with RAS, the V max in the affected artery was 350 ± 111 cm/s before surgery and 145 ± 55 cm/s after surgery. The resistance index was 0.46 ± 0.1 in the post-stenotic kidney and increased to 0.60 ± 0.08 after revascularization. Determination of the flow profile in the iliac artery revealed triphasic flow. In individuals with MAS, V max in the aorta was 323 ± 98 and the resistance index in both kidneys was low, even in the absence of RAS. The flow profile in the iliac arteries was monophasic before surgery and became triphasic after surgery. Duplex ultrasound is useful for the evaluation of children and young adults both pre- and post-surgery. Duplex ultrasound criteria for RAS in adults appear to be applicable in children and young adults also. The diagnostic evaluation of suspected renal vascular disease should include assessment of the aorta and the flow profile in the iliac arteries, as this could help differentiate between aortic and isolated renal artery stenosis.


      PubDate: 2014-10-12T23:27:04Z
       
  • Ultrasound Speckle Tracking Strain Estimation of in Vivo Carotid
           Artery Plaque with in Vitro Sonomicrometry Validation
    • Abstract: Publication date: Available online 11 October 2014
      Source:Ultrasound in Medicine & Biology
      Author(s): Erik Widman , Kenneth Caidahl , Brecht Heyde , Jan D’hooge , Matilda Larsson
      Our objective was to validate a previously developed speckle tracking (ST) algorithm to assess strain in common carotid artery plaques. Radial and longitudinal strain was measured in common carotid artery gel phantoms with a plaque-mimicking inclusion using an in-house ST algorithm and sonomicrometry. Moreover, plaque strain by ST for seven patients (77 ± 6 y) with carotid atherosclerosis was compared with a quantitative visual assessment by two experienced physicians. In vitro, good correlation existed between ST and sonomicrometry peak strains, both radially (r = 0.96, p < 0.001) and longitudinally (r = 0.75, p < 0.01). In vivo, greater pulse pressure-adjusted radial and longitudinal strains were found in echolucent plaques than in echogenic plaques. This illustrates the feasibility of ultrasound ST strain estimation in plaques and the possibility of characterizing plaques using ST strain in vivo.


      PubDate: 2014-10-12T23:27:04Z
       
  • Ultrasound Tissue Characterization Does Not Differentiate Genotype, But
           Indexes Ejection Fraction Deterioration in Becker Muscular Dystrophy
    • Abstract: Publication date: Available online 11 October 2014
      Source:Ultrasound in Medicine & Biology
      Author(s): Vincenzo Giglio , Paolo Emilio Puddu , Mark R. Holland , Giovanni Camastra , Gerardo Ansalone , Enzo Ricci , Julia Mela , Federico Sciarra , Marco Di Gennaro
      The aims of the study were, first, to assess whether myocardial ultrasound tissue characterization (UTC) in Becker muscular dystrophy (BMD) can be used to differentiate between patients with deletions and those without deletions; and second, to determine whether UTC is helpful in diagnosing the evolution of left ventricular dysfunction, a precursor of dilated cardiomyopathy. Both cyclic variation of integrated backscatter and calibrated integrated backscatter (cIBS) were assessed in 87 patients with BMD and 70 controls. The average follow-up in BMD patients was 48 ± 12 mo. UTC analysis was repeated only in a subgroup of 40 BMD patients randomly selected from the larger overall group (15 with and 25 without left ventricular dysfunction). Discrimination between BMD patients with and without dystrophin gene deletion was not possible on the basis of UTC data: average cvIBS was 5.2 ± 1.2 and 5.5 ± 1.4 dB, and average cIBS was 29.9 ± 4.7 and 29.6 ± 5.8, respectively, significantly different (p < 0.001) only from controls (8.6 ± 0.5 and 24.6 ± 1.2 dB). In patients developing left ventricular dysfunction during follow-up, cIBS increased to 31.3 ± 5.4 dB, but not significantly (p = 0.08). The highest cIBS values (34.6 ± 5.3 dB, p < 0.09 vs. baseline, p < 0.01 vs BMD patients without left ventricular dysfunction) were seen in the presence of severe left ventricular dysfunction. Multivariate statistics indicated that an absolute change of 6 dB in cIBS is associated with a high probability of left ventricular dysfunction. UTC analysis does not differentiate BMD patients with or without dystrophin gene deletion, but may be useful in indexing left ventricular dysfunction during follow-up.


      PubDate: 2014-10-12T23:27:04Z
       
  • Pocket-Size Imaging Devices Allow for Reliable Bedside Screening for
           Femoral Artery Access Site Complications
    • Abstract: Publication date: Available online 11 October 2014
      Source:Ultrasound in Medicine & Biology
      Author(s): Dominika Filipiak-Strzecka , Błażej Michalski , Jarosław D. Kasprzak , Piotr Lipiec
      The aim of this study was to validate pocket-size imaging devices (PSIDs) as a fast screening tool for detecting complications after femoral artery puncture. Forty patients undergoing femoral artery puncture for arterial access related to percutaneous coronary intervention were enrolled. Twenty-four hours after percutaneous coronary intervention, the involved inguinal region was assessed with PSIDs enabling 2-D gray-scale and color Doppler imaging. Subsequently, examination with a stationary high-end ultrasound system was performed to verify the findings of bedside examination in all patients. In 37 patients, PSID imaging had good diagnostic quality. False aneurysms (one asymptomatic) occurred in four patients, and all were recognized during bedside screening with PSID. One case of femoral artery thrombosis was confirmed with PSID and during standard ultrasonographic examination. Physical examination augmented with the quick bedside PSID examination had a sensitivity of 100% and specificity of 91%. PSID facilitated rapid bedside detection of serious access site complications in the vast majority of patients, including asymptomatic cases.


      PubDate: 2014-10-12T23:27:04Z
       
  • Clinical Evaluation of Synthetic Aperture Sequential Beamforming
           Ultrasound in Patients with Liver Tumors
    • Abstract: Publication date: Available online 11 October 2014
      Source:Ultrasound in Medicine & Biology
      Author(s): Peter Møller Hansen , Martin Hemmsen , Andreas Brandt , Joachim Rasmussen , Theis Lange , Paul Suno Krohn , Lars Lönn , Jørgen Arendt Jensen , Michael Bachmann Nielsen
      Medical ultrasound imaging using synthetic aperture sequential beamforming (SASB) has for the first time been used for clinical patient scanning. Nineteen patients with cancer of the liver (hepatocellular carcinoma or colorectal liver metastases) were scanned simultaneously with conventional ultrasound and SASB using a commercial ultrasound scanner and abdominal transducer. SASB allows implementation of the synthetic aperture technique on systems with restricted data handling capabilities due to a reduction in the data rate in the scanner by a factor of 64. The image quality is potentially maintained despite the data reduction. A total of 117 sequences were recorded and evaluated blinded by five radiologists from a clinical perspective. Forty-eight percent of the evaluations were in favor of SASB, 33% in favor of conventional ultrasound and 19 % were equal, that is, a clear, but non-significant trend favoring SASB over conventional ultrasound (p = 0.18), despite the substantial data reduction.


      PubDate: 2014-10-12T23:27:04Z
       
 
 
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