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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  [3042 journals]
  • Effect of Carbon Dioxide on the Twinkling Artifact in Ultrasound Imaging
           of Kidney Stones: A Pilot Study
    • Authors: Julianna C. Simon; Yak-Nam Wang; Bryan W. Cunitz; Jeffrey Thiel; Frank Starr; Ziyue Liu; Michael R. Bailey
      Pages: 877 - 883
      Abstract: Publication date: May 2017
      Source:Ultrasound in Medicine & Biology, Volume 43, Issue 5
      Author(s): Julianna C. Simon, Yak-Nam Wang, Bryan W. Cunitz, Jeffrey Thiel, Frank Starr, Ziyue Liu, Michael R. Bailey
      Bone demineralization, dehydration and stasis put astronauts at increased risk of forming kidney stones in space. The color-Doppler ultrasound “twinkling artifact,” which highlights kidney stones with color, can make stones readily detectable with ultrasound; however, our previous results suggest twinkling is caused by microbubbles on the stone surface which could be affected by the elevated levels of carbon dioxide found on space vehicles. Four pigs were implanted with kidney stones and imaged with ultrasound while the anesthetic carrier gas oscillated between oxygen and air containing 0.8% carbon dioxide. On exposure of the pigs to 0.8% carbon dioxide, twinkling was significantly reduced after 9–25 min and recovered when the carrier gas returned to oxygen. These trends repeated when pigs were again exposed to 0.8% carbon dioxide followed by oxygen. The reduction of twinkling caused by exposure to elevated carbon dioxide may make kidney stone detection with twinkling difficult in current space vehicles.

      PubDate: 2017-05-08T10:27:27Z
      DOI: 10.1016/j.ultrasmedbio.2016.12.010
       
  • Value of Shear Wave Elastography in the Diagnosis of Gouty and Non-Gouty
           Arthritis
    • Authors: Yuanjiao Tang; Feng Yan; Yujia Yang; Xi Xiang; Liyun Wang; Lingyan Zhang; Li Qiu
      Pages: 884 - 892
      Abstract: Publication date: May 2017
      Source:Ultrasound in Medicine & Biology, Volume 43, Issue 5
      Author(s): Yuanjiao Tang, Feng Yan, Yujia Yang, Xi Xiang, Liyun Wang, Lingyan Zhang, Li Qiu
      Our aim was to analyze the diagnostic performance of shear wave elastography (SWE) in the diagnosis of gouty arthritis (GA) and non-gouty arthritis (non-GA). Thirty-nine patients in the GA group and 55 patients in the non-GA group were included in the study. Based on the echo intensity of the joint lesions, the GA group was subdivided into hypo-echoic GA, slightly hyper-echoic GA and hyper-echoic GA subgroups. Quantitative SWE features were evaluated and receiver operating characteristic analysis was performed. On the basis of the study, the elastic modulus (E max), mean elastic modulus (E mean), minimum elastic modulus (E min) and elastic modulus standard deviation (E SD) were significantly higher in the GA group than in the non-GA group and were highest in the hyper-echoic GA subgroup (p < 0.01 for all). E min, E mean and E max were significantly higher in the hyper-echoic GA subgroup than in the hypo-echoic GA subgroup and non-GA group (p < 0.001 for all), and E SD was significantly higher in the hyper-echoic GA subgroup than in the non-GA group (p = 0.001). E min, E mean, E max and E SD were higher in the hypo-echoic GA subgroup than in the non-GA group, and the differences were significant (p < 0.001 for all). Based on the hypo-echoic GA subgroup and non-GA group, areas under the receiver operating characteristic curves for the prediction of GA were 0.749 for E min, 0.877 for E mean, 0.896 for E max and 0.886 for E SD, with optimal cutoff values of 29.40 kPa for E min, 45.35 kPa for E mean, 67.54 kPa for E max and 7.85 kPa for E SD. Our results indicate that SWE can differentially diagnose GA and non-GA, especially when the ultrasound manifestations are not typical.

      PubDate: 2017-05-08T10:27:27Z
      DOI: 10.1016/j.ultrasmedbio.2016.12.012
       
  • Evaluation of Coronary Artery Disease Using Myocardial Elastography with
           Diverging Wave Imaging: Validation against Myocardial Perfusion Imaging
           and Coronary Angiography
    • Authors: Julien Grondin; Marc Waase; Alok Gambhir; Ethan Bunting; Vincent Sayseng; Elisa E. Konofagou
      Pages: 893 - 902
      Abstract: Publication date: May 2017
      Source:Ultrasound in Medicine & Biology, Volume 43, Issue 5
      Author(s): Julien Grondin, Marc Waase, Alok Gambhir, Ethan Bunting, Vincent Sayseng, Elisa E. Konofagou
      Myocardial elastography (ME) is an ultrasound-based technique that can image 2-D myocardial strains. The objectives of this study were to illustrate that 2-D myocardial strains can be imaged with diverging wave imaging and differ, on average, between normal and coronary artery disease (CAD) patients. In this study, 66 patients with symptoms of CAD were imaged with myocardial elastography before a nuclear stress test or an invasive coronary angiography. Radial cumulative strains were estimated in all patients. The end-systolic radial strain in the total cross section of the myocardium was significantly higher in normal patients (17.9 ± 8.7%) than in patients with reversible perfusion defect (6.2 ± 9.3%, p < 0.001) and patients with significant (−0.9 ± 7.4%, p < 0.001) and non-significant (3.7 ± 5.7%, p < 0.01) lesions. End-systolic radial strain in the left anterior descending, left circumflex and right coronary artery territory was found to be significantly higher in normal patients than in CAD patients. These preliminary findings indicate that end-systolic radial strain measured with ME is higher on average in healthy persons than in CAD patients and that ME has the potential to be used for non-invasive, radiation-free early detection of CAD.

      PubDate: 2017-05-08T10:27:27Z
      DOI: 10.1016/j.ultrasmedbio.2017.01.001
       
  • What Help Could Ultrasound Elastography Give to the Diagnosis of Breast
           Papillary Lesions'
    • Authors: Lu-Jing Li; Ji-Yi Yao; Xin-Chuan Zhou; Xin-Bao Zhao; Wen-Jing Zhong; Bing Ou; Bao-Ming Luo; Shao-Yun Hao; Hui Zhi
      Pages: 903 - 910
      Abstract: Publication date: May 2017
      Source:Ultrasound in Medicine & Biology, Volume 43, Issue 5
      Author(s): Lu-Jing Li, Ji-Yi Yao, Xin-Chuan Zhou, Xin-Bao Zhao, Wen-Jing Zhong, Bing Ou, Bao-Ming Luo, Shao-Yun Hao, Hui Zhi
      On the basis of results of our previous studies and the findings of other scholars, the most common histologic type of false-positive diagnosis with strain elastography (SE) was papilloma. The objectives of our study were to evaluate whether SE could contribute to conventional ultrasound differentiation between benign and malignant papillary lesions and between papillary lesions and other common benign breast lesions. Data on 89 papillary lesions at our hospital, including 74 benign and 15 malignant papillary lesions, were included in our study. In addition, 198 non-papillary benign tumors were selected as the control group, including 126 fibroadenomas and 72 cases of fibrocystic mastopathy. All patients gave written informed consent. All patients with breast lesions underwent conventional ultrasound and SE examination. Breast Imaging Recording and Data System (BI-RADS) category and SE score were compared with respect to sensitivity, specificity and accuracy in differentiating between benign and malignant papillary lesions. We then explored the possibility of using BI-RADS combined with SE to differentiate papillary lesions from non-papillary benign tumors. For differentiating between benign and malignant papillary lesions, the area under the receiver operating characteristic curve (AUC) of BI-RADS was 0.568, whereas the AUC values of SE score, strain ratio and BI-RADS combined with SE were 0.517, 0.584 and 0.509, respectively (p > 0.05). For differentiating between papillary lesions and non-papillary benign lesions, the AUC of BI-RADS combined with SE was 0.835, which was higher than the values for BI-RADS (0.775) and SE (SE score: 0.648, strain ratio: 0.661) (p < 0.001). The specificity and accuracy of BI-RADS combined with SE were significantly higher than those for BI-RADS alone without a decrease in sensitivity (p < 0.05). SE could not improve the diagnostic efficiency of BI-RADS in differentiating between benign and malignant papillary lesions. However, BI-RADS combined with SE could improve the specificity of BI-RADS without decrease in sensitivity for differentiating breast papillary lesions from non-papillary benign lesions.

      PubDate: 2017-05-08T10:27:27Z
      DOI: 10.1016/j.ultrasmedbio.2017.01.004
       
  • Semi-Quantitative Strain Ratio Determined Using Different Measurement
           Methods: Comparison of Strain Ratio Values and Diagnostic Performance
           Using One- versus Two-Region-of-Interest Measurement
    • Authors: Jung Hyun Yoon; Mi Kyung Song; Eun-Kyung Kim
      Pages: 911 - 917
      Abstract: Publication date: May 2017
      Source:Ultrasound in Medicine & Biology, Volume 43, Issue 5
      Author(s): Jung Hyun Yoon, Mi Kyung Song, Eun-Kyung Kim
      We evaluated the agreement and diagnostic performance of strain ratio values using measurements made with one and two user-defined regions of interest (ROIs) on breast elastography. Two hundred forty-three breast masses of 226 women (mean age: 48.2 y) were included. Ultrasonography (US) and elastography images of the masses were recorded. Strain ratio was measured twice on the same elastography image; strain ratio 1, applying one ROI at the target mass for measurement, and strain ratio 2, applying one ROI at the target mass and another ROI as reference strain. The two strain ratio measurements were in substantial agreement, with an intra-class correlation coefficient of 0.655 (95% confidence interval: 0.577–0.722). Specificity, positive predictive value and accuracy (cutoffs: 2.66 and 2.35) were significantly improved for US combined with the two strain ratio measurements (all p values < 0.05). Strain ratios measured using one or two user-defined ROIs were in substantial agreement, both contributing to the improved diagnostic performance of breast US.

      PubDate: 2017-05-08T10:27:27Z
      DOI: 10.1016/j.ultrasmedbio.2017.01.005
       
  • Ultrasound Image Classification of Ductal Carcinoma In Situ (DCIS) of the
           Breast: Analysis of 705 DCIS Lesions1
    • Authors: Takanori Watanabe; Takuhiro Yamaguchi; Hiroko Tsunoda; Setsuko Kaoku; Eriko Tohno; Hidemitsu Yasuda; Kanako Ban; Koichi Hirokaga; Kumiko Tanaka; Takeshi Umemoto; Toshitaka Okuno; Yasuhisa Fujimoto; Shuichi Nakatani; Jun Ito; Ei Ueno
      Pages: 918 - 925
      Abstract: Publication date: May 2017
      Source:Ultrasound in Medicine & Biology, Volume 43, Issue 5
      Author(s): Takanori Watanabe, Takuhiro Yamaguchi, Hiroko Tsunoda, Setsuko Kaoku, Eriko Tohno, Hidemitsu Yasuda, Kanako Ban, Koichi Hirokaga, Kumiko Tanaka, Takeshi Umemoto, Toshitaka Okuno, Yasuhisa Fujimoto, Shuichi Nakatani, Jun Ito, Ei Ueno
      The Japan Association of Breast and Thyroid Sonology (JABTS) proposed, in 2003, a conceptual classification system for non-mass abnormalities to be applied in addition to the conventional concept of masses, to facilitate detecting ductal carcinoma in situ (DCIS) lesions. The aim of this study was to confirm the utility of this system and to clarify the distribution of these findings in DCIS lesions. Data on 705 surgically treated DCIS lesions from 16 institutions in Japan were retrospectively reviewed. All 705 DCIS lesions could be classified according to the JABTS classification system. The most frequent findings were hypo-echoic areas in the mammary gland (48.6%), followed by solid masses (28.0%) and duct abnormalities (10.2%) or mixed masses (8.1%). Distortion (1.3%), clustered microcysts (1.4%) and echogenic foci without a hypo-echoic area (2.5%) were uncommon. These results suggest that the concept of non-mass abnormalities is useful in detecting DCIS lesions.

      PubDate: 2017-05-08T10:27:27Z
      DOI: 10.1016/j.ultrasmedbio.2017.01.008
       
  • Common Carotid Artery Diameter, Blood Flow Velocity and Wave Intensity
           Responses at Rest and during Exercise in Young Healthy Humans: A
           Reproducibility Study
    • Authors: Nicola Pomella; Eurico Nestor Wilhelm; Christina Kolyva; José González-Alonso; Mark Rakobowchuk; Ashraf W. Khir
      Pages: 943 - 957
      Abstract: Publication date: May 2017
      Source:Ultrasound in Medicine & Biology, Volume 43, Issue 5
      Author(s): Nicola Pomella, Eurico Nestor Wilhelm, Christina Kolyva, José González-Alonso, Mark Rakobowchuk, Ashraf W. Khir
      The aim of this study was to assess the reproducibility of non-invasive, ultrasound-derived wave intensity (WI) in humans at the common carotid artery. Common carotid artery diameter and blood velocity of 12 healthy young participants were recorded at rest and during mild cycling, to assess peak diameter, change in diameter, peak velocity, change in velocity, time derivatives, non-invasive wave speed and WI. Diameter, velocity and WI parameters were fairly reproducible. Diameter variables exhibited higher reproducibility than corresponding velocity variables (intra-class correlation coefficient [ICC] = 0.79 vs. 0.73) and lower dispersion (coefficient of variation [CV] = 5% vs. 9%). Wave speed had fair reproducibility (ICC = 0.6, CV = 16%). WI energy variables exhibited higher reproducibility than corresponding peaks (ICC = 0.78 vs. 0.74) and lower dispersion (CV = 16% vs. 18%). The majority of variables had higher ICCs and lower CVs during exercise. We conclude that non-invasive WI analysis is reliable both at rest and during exercise.

      PubDate: 2017-05-08T10:27:27Z
      DOI: 10.1016/j.ultrasmedbio.2016.12.018
       
  • Usefulness of the Continuous-Wave Doppler-Derived Pulmonary
           Arterial–Right Ventricular Pressure Gradient Just before Atrial
           Contraction for the Estimation of Pulmonary Arterial Diastolic and Wedge
           Pressures
    • Authors: Michito Murayama; Taisei Mikami; Sanae Kaga; Kazunori Okada; Takuma Hioka; Nobuo Masauzi; Masahiro Nakabachi; Hisao Nishino; Shinobu Yokoyama; Mutsumi Nishida; Hiroyuki Iwano; Mamoru Sakakibara; Satoshi Yamada; Hiroyuki Tsutsui
      Pages: 958 - 966
      Abstract: Publication date: May 2017
      Source:Ultrasound in Medicine & Biology, Volume 43, Issue 5
      Author(s): Michito Murayama, Taisei Mikami, Sanae Kaga, Kazunori Okada, Takuma Hioka, Nobuo Masauzi, Masahiro Nakabachi, Hisao Nishino, Shinobu Yokoyama, Mutsumi Nishida, Hiroyuki Iwano, Mamoru Sakakibara, Satoshi Yamada, Hiroyuki Tsutsui
      In our new echocardiographic method, pulmonary regurgitant velocity immediately before right atrial (RA) contraction is used to estimate pulmonary artery diastolic pressure (PADP) and mean PA wedge pressure (MPAWP). Our aim here was to compare the usefulness of this new method with that of the conventional method, which uses pulmonary regurgitant velocity at end diastole. We studied 55 consecutive patients who underwent echocardiography and right-sided heart catheterization. The pulmonary regurgitant velocities just before RA contraction and at end diastole were measured to obtain echocardiographic estimates of PADP (EPADPpreA and EPADPED, respectively) by adding the pressure gradients to the echocardiographically estimated RA pressure. Compared with EPADPED, EPADPpreA correlated better with PADP (r = 0.87) and MPAWP (r = 0.80), and direct fixed biases were detected for EPADPED but not for EPADPpreA. The area under the receiver operating characteristic curve distinguishing patients with MPAWP ≥18 mm Hg was greater for EPADPpreA (0.97) than for E/e′ (0.94) and E/A (0.83). EPADPpreA is thus useful in estimating PADP and MPAWP in patients with heart disease.

      PubDate: 2017-05-08T10:27:27Z
      DOI: 10.1016/j.ultrasmedbio.2017.01.006
       
  • Transesophageal Echocardiography in Swine: Establishment of a Baseline
    • Authors: Katharina Huenges; Saskia Pokorny; Rouven Berndt; Jochen Cremer; Georg Lutter
      Pages: 974 - 980
      Abstract: Publication date: May 2017
      Source:Ultrasound in Medicine & Biology, Volume 43, Issue 5
      Author(s): Katharina Huenges, Saskia Pokorny, Rouven Berndt, Jochen Cremer, Georg Lutter
      The porcine model is a commonly used animal model in cardiovascular research. Along with new innovative operative techniques, choice of the optimal imaging technique is crucial. Transesophageal echocardiography (TEE) is a reliable imaging tool is highly important in a large number of experimental evaluations. But so far, TEE data for swine are limited, and few standard values have been established for the porcine model. The experience and baseline results for TEE in 45 swine are presented in this study. A full TEE examination was conducted in 45 German landrace or German large white swine, with an average body weight of 49 ± 3 kg, before experimental off-pump mitral valved stent implantation. Additionally hemodynamic measurements were evaluated. The valve implantation procedure was guided solely by real-time 3-D TEE. Baseline values of standard echocardiographic parameters are provided and, where appropriate, compared with human reference values. TEE proved to be an adequate imaging technique in this experimental porcine animal model. The baseline TEE and hemodynamic parameters established for the widely used porcine model can serve as a reference in future studies.

      PubDate: 2017-05-08T10:27:27Z
      DOI: 10.1016/j.ultrasmedbio.2016.12.011
       
  • Investigation of Ultrasound-Measured Flow Velocity, Flow Rate and Wall
           Shear Rate in Radial and Ulnar Arteries Using Simulation
    • Authors: Xiaowei Zhou; Chunming Xia; Gandy Stephen; Faisel Khan; George A. Corner; Peter R. Hoskins; Zhihong Huang
      Pages: 981 - 992
      Abstract: Publication date: May 2017
      Source:Ultrasound in Medicine & Biology, Volume 43, Issue 5
      Author(s): Xiaowei Zhou, Chunming Xia, Gandy Stephen, Faisel Khan, George A. Corner, Peter R. Hoskins, Zhihong Huang
      Parameters of blood flow measured by ultrasound in radial and ulnar arteries, such as flow velocity, flow rate and wall shear rate, are widely used in clinical practice and clinical research. Investigation of these measurements is useful for evaluating accuracy and providing knowledge of error sources. A method for simulating the spectral Doppler ultrasound measurement process was developed with computational fluid dynamics providing flow-field data. Specific scanning factors were adjusted to investigate their influence on estimation of the maximum velocity waveform, and flow rate and wall shear rate were derived using the Womersley equation. The overestimation in maximum velocity increases greatly (peak systolic from about 10% to 30%, time-averaged from about 30% to 50%) when the beam–vessel angle is changed from 30° to 70°. The Womersley equation was able to estimate flow rate in both arteries with less than 3% error, but performed better in the radial artery (2.3% overestimation) than the ulnar artery (15.4% underestimation) in estimating wall shear rate. It is concluded that measurements of flow parameters in the radial and ulnar arteries with clinical ultrasound scanners are prone to clinically significant errors.

      PubDate: 2017-05-08T10:27:27Z
      DOI: 10.1016/j.ultrasmedbio.2016.12.015
       
  • Impact of Filling Gas on Subharmonic Emissions of Phospholipid Ultrasound
           Contrast Agents
    • Authors: Emma Kanbar; Damien Fouan; Charles A. Sennoga; Alexander A. Doinikov; Ayache Bouakaz
      Pages: 1004 - 1015
      Abstract: Publication date: May 2017
      Source:Ultrasound in Medicine & Biology, Volume 43, Issue 5
      Author(s): Emma Kanbar, Damien Fouan, Charles A. Sennoga, Alexander A. Doinikov, Ayache Bouakaz
      Subharmonic signals backscattered from gas-filled lipid-shelled microbubbles have generated significant research interest because they can improve the detection and sensitivity of contrast-enhanced ultrasound imaging. However, the emission of subharmonic signals is strongly characterized by a temporal dependence, the origins of which have not been sufficiently elucidated. The features that influence subharmonic emissions need to be identified not only to better develop next-generation microbubble contrast agents, but also to develop more efficient subharmonic imaging (SHI) modes and therapeutic strategies. We examined the effect of microbubble filling gas on subharmonic emissions. Phospholipid shelled-microbubbles with different gaseous compositions such as sulfur hexafluoride (SF6), octafluoropropane (C3F8) or decafluorobutane (C4F10), nitrogen (N2)/C4F10 or air were insonated using a driving frequency of 10 MHz and peak negative pressure of 450 kPa, and their acoustic responses were tracked by monitoring both second harmonic and subharmonic emissions. Microbubbles were first acoustically characterized with their original gas and then re-characterized after substitution of the original gas with air, SF6 or C4F10. A measureable change in intensity of the subharmonic emissions with a 20- to 40-min delayed onset and increasing subharmonic emissions of the order 12–18 dB was recorded for microbubbles filled with C4F10. Substitution of C4F10 with air eliminated the earlier observed delay in subharmonic emissions. Significantly, substitution of SF6 for C4F10 successfully triggered a delay in the subharmonic emissions of the resultant agents, whereas substitution of C4F10 for SF6 eliminated the earlier observed suppression of subharmonic emissions, clearly suggesting that the type of filling gas contained in the microbubble agent influences subharmonic emissions in a time-dependent manner. Because our agents were dispersed in air-stabilized phosphate-buffered saline, these results suggest that the diffusivity of the gas from the agent to the surrounding medium is correlated with the time-dependent evolution of subharmonic emissions.

      PubDate: 2017-05-08T10:27:27Z
      DOI: 10.1016/j.ultrasmedbio.2016.12.013
       
  • Acoustic Behavior of Halobacterium salinarum Gas Vesicles in the
           High-Frequency Range: Experiments and Modeling
    • Authors: Emmanuel Cherin; Johan M. Melis; Raymond W. Bourdeau; Melissa Yin; Dennis M. Kochmann; F. Stuart Foster; Mikhail G. Shapiro
      Pages: 1016 - 1030
      Abstract: Publication date: May 2017
      Source:Ultrasound in Medicine & Biology, Volume 43, Issue 5
      Author(s): Emmanuel Cherin, Johan M. Melis, Raymond W. Bourdeau, Melissa Yin, Dennis M. Kochmann, F. Stuart Foster, Mikhail G. Shapiro
      Gas vesicles (GVs) are a new and unique class of biologically derived ultrasound contrast agents with sub-micron size whose acoustic properties have not been fully elucidated. In this study, we investigated the acoustic collapse pressure and behavior of Halobacterium salinarum gas vesicles at transmit center frequencies ranging from 12.5 to 27.5 MHz. The acoustic collapse pressure was found to be above 550 kPa at all frequencies, nine-fold higher than the critical pressure observed under hydrostatic conditions. We illustrate that gas vesicles behave non-linearly when exposed to ultrasound at incident pressure ranging from 160 kPa to the collapse pressure and generate second harmonic amplitudes of −2 to −6 dB below the fundamental in media with viscosities ranging from 0.89 to 8 mPa·s. Simulations performed using a Rayleigh–Plesset-type model accounting for buckling and a dynamic finite-element analysis suggest that buckling is the mechanism behind the generation of harmonics. We found good agreement between the level of second harmonic relative to the fundamental measured at 20 MHz and the Rayleigh–Plesset model predictions. Finite-element simulations extended these findings to a non-spherical geometry, confirmed that the acoustic buckling pressure corresponds to the critical pressure under hydrostatic conditions and support the hypothesis of limited gas flow across the GV shell during the compression phase in the frequency range investigated. From simulations, estimates of GV bandwidth-limited scattering indicate that a single GV has a scattering cross section comparable to that of a red blood cell. These findings will inform the development of GV-based contrast agents and pulse sequences to optimize their detection with ultrasound.

      PubDate: 2017-05-08T10:27:27Z
      DOI: 10.1016/j.ultrasmedbio.2016.12.020
       
  • Effect of Low-Intensity Cavitation on the Isolated Human Thoracic Artery
           In Vitro
    • Authors: Algimantas Bubulis; Vida Garalienė; Vytautas Jurėnas; Jonas Navickas; Saulius Giedraitis
      Pages: 1040 - 1047
      Abstract: Publication date: May 2017
      Source:Ultrasound in Medicine & Biology, Volume 43, Issue 5
      Author(s): Algimantas Bubulis, Vida Garalienė, Vytautas Jurėnas, Jonas Navickas, Saulius Giedraitis
      Reported here are the results of an experimental study on the response to low-intensity cavitation induced by low-frequency (4–6 W/cm2, 20 kHz and 32.6 kHz) ultrasound of isolated human arterial samples taken during conventional myocardial revascularization operations. Studies have found that low-frequency ultrasound results in a significant (48%–54%) increase in isometric contraction force and does not depend on the number of exposures (10 or 20) or the time passed since the start of ultrasound (0, 10 and 20 min), but does depend on the frequency and location (internal or external) of the blood vessels for the application of ultrasound. Diltiazem (an inhibitor of slow calcium channels) and carbachol (an agonist of muscarinic receptors) used in a concentration-dependent manner did not modify the relaxation dynamics of smooth muscle affected by ultrasound. Thus, ultrasound conditioned to the augmentation of the isometric contraction force the smooth muscle of blood vessels and did not improve endothelial- and calcium channel blocker-dependent relaxation.

      PubDate: 2017-05-08T10:27:27Z
      DOI: 10.1016/j.ultrasmedbio.2016.12.007
       
  • Anatomical Regurgitant Orifice Detection and Quantification from 3-D
           Echocardiographic Images
    • Authors: Miguel Sotaquirá; Mauro Pepi; Gloria Tamborini; Enrico G. Caiani
      Pages: 1048 - 1057
      Abstract: Publication date: May 2017
      Source:Ultrasound in Medicine & Biology, Volume 43, Issue 5
      Author(s): Miguel Sotaquirá, Mauro Pepi, Gloria Tamborini, Enrico G. Caiani
      The vena contracta and effective regurgitant orifice area (EROA) are currently used for the clinical assessment of mitral regurgitation (MR) from 2-D color Doppler imaging. In addition to being highly user dependent and having low repeatability, these methods do not represent accurately the anatomic regurgitant orifice (ARO), which affects the adequate assessment of MR patients. We propose a novel method for semi-automatic detection and quantitative assessment of the 3-D ARO shape from 3-D transesophageal echocardiographic images. The algorithm was tested on a set of 25 patients with MR, and compared with EROA for validation. Results indicate the robustness of the proposed approach, with low variability in relation to different settings of user-defined segmentation parameters. Although EROA and ARO exhibited a good correlation (r = 0.8), relatively large biases were measured, indicating that EROA probably underestimates the real shape and size of the regurgitant orifice. Along with the higher reproducibility of the proposed approach, this highlights the limitations of current clinical approaches and underlines the importance of accurate assessment of the ARO shape for diagnosis and treatment in MR patients.

      PubDate: 2017-05-08T10:27:27Z
      DOI: 10.1016/j.ultrasmedbio.2016.12.017
       
  • Sonoelastomics for Breast Tumor Classification: A Radiomics Approach with
           Clustering-Based Feature Selection on Sonoelastography
    • Authors: Qi Zhang; Yang Xiao; Jingfeng Suo; Jun Shi; Jinhua Yu; Yi Guo; Yuanyuan Wang; Hairong Zheng
      Pages: 1058 - 1069
      Abstract: Publication date: May 2017
      Source:Ultrasound in Medicine & Biology, Volume 43, Issue 5
      Author(s): Qi Zhang, Yang Xiao, Jingfeng Suo, Jun Shi, Jinhua Yu, Yi Guo, Yuanyuan Wang, Hairong Zheng
      A radiomics approach to sonoelastography, called “sonoelastomics,” is proposed for classification of benign and malignant breast tumors. From sonoelastograms of breast tumors, a high-throughput 364-dimensional feature set was calculated consisting of shape features, intensity statistics, gray-level co-occurrence matrix texture features and contourlet texture features, which quantified the shape, hardness and hardness heterogeneity of a tumor. The high-throughput features were then selected for feature reduction using hierarchical clustering and three-feature selection metrics. For a data set containing 42 malignant and 75 benign tumors from 117 patients, seven selected sonoelastomic features achieved an area under the receiver operating characteristic curve of 0.917, an accuracy of 88.0%, a sensitivity of 85.7% and a specificity of 89.3% in a validation set via the leave-one-out cross-validation, revealing superiority over the principal component analysis, deep polynomial networks and manually selected features. The sonoelastomic features are valuable in breast tumor differentiation.

      PubDate: 2017-05-08T10:27:27Z
      DOI: 10.1016/j.ultrasmedbio.2016.12.016
       
  • Computer-Based Algorithmic Determination of Muscle Movement Onset Using
           M-Mode Ultrasonography
    • Authors: Andrew J. Tweedell; Courtney A. Haynes; Matthew S. Tenan
      Pages: 1070 - 1075
      Abstract: Publication date: May 2017
      Source:Ultrasound in Medicine & Biology, Volume 43, Issue 5
      Author(s): Andrew J. Tweedell, Courtney A. Haynes, Matthew S. Tenan
      The study purpose was to evaluate the use of computer-automated algorithms as a replacement for subjective, visual determination of muscle contraction onset using M-mode ultrasonography. Biceps and quadriceps contraction images were analyzed visually and with three different classes of algorithms: pixel standard deviation (SD), high-pass filter and Teager Kaiser energy operator transformation. Algorithmic parameters and muscle onset threshold criteria were systematically varied within each class of algorithm. Linear relationships and agreements between computed and visual muscle onset were calculated. The top algorithms were high-pass filtered with a 30 Hz cutoff frequency and 20 SD above baseline, Teager Kaiser energy operator transformation with a 1200 absolute SD above baseline and SD at 10% pixel deviation with intra-class correlation coefficients (mean difference) of 0.74 (37.7 ms), 0.80 (61.8 ms) and 0.72 (109.8 ms), respectively. The results suggest that computer automated determination using high-pass filtering is a potential objective alternative to visual determination in human movement science.

      PubDate: 2017-05-08T10:27:27Z
      DOI: 10.1016/j.ultrasmedbio.2016.12.019
       
  • Guidelines for Cleaning Transvaginal Ultrasound Transducers Between
           Patients
    • Authors: Jacques S. Abramowicz; David H. Evans; J. Brian Fowlkes; Karel Maršal; Gail terHaar
      Pages: 1076 - 1079
      Abstract: Publication date: May 2017
      Source:Ultrasound in Medicine & Biology, Volume 43, Issue 5
      Author(s): Jacques S. Abramowicz, David H. Evans, J. Brian Fowlkes, Karel Maršal, Gail terHaar
      The purpose of this article is to provide guidance regarding the cleaning and disinfection of transvaginal ultrasound probes. These recommendations are also applicable to transrectal probes.

      PubDate: 2017-05-08T10:27:27Z
      DOI: 10.1016/j.ultrasmedbio.2017.01.002
       
  • Investigation of Non-linear Chirp Coding for Improved Second Harmonic
           Pulse Compression
    • Authors: Muhammad Arif; Muhammad Asim Ali; Muhammad Mujtaba Shaikh; Steven Freear
      Abstract: Publication date: Available online 5 May 2017
      Source:Ultrasound in Medicine & Biology
      Author(s): Muhammad Arif, Muhammad Asim Ali, Muhammad Mujtaba Shaikh, Steven Freear
      Non-linear frequency-modulated (NLFM) chirp coding was investigated to improve the pulse compression of the second harmonic chirp signal by reducing the range side lobe level. The problem of spectral overlap between the fundamental component and second harmonic component (SHC) was also investigated. Therefore, two methods were proposed: method I for the non-overlap condition and method II with the pulse inversion technique for the overlap harmonic condition. In both methods, the performance of the NLFM chirp was compared with that of the reference LFM chirp signals. Experiments were performed using a 2.25 MHz transducer mounted coaxially at a distance of 5 cm with a 1 mm hydrophone in a water tank, and the peak negative pressure of 300 kPa was set at the receiver. Both simulations and experimental results revealed that the peak side lobe level (PSL) of the compressed SHC of the NLFM chirp was improved by at least 13 dB in method I and 5 dB in method II when compared with the PSL of LFM chirps. Similarly, the integrated side lobe level (ISL) of the compressed SHC of the NLFM chirp was improved by at least 8 dB when compared with the ISL of LFM chirps. In both methods, the axial main lobe width of the compressed NLFM chirp was comparable to that of the LFM signals. The signal-to-noise ratio of the SHC of NLFM was improved by as much as 0.8 dB, when compared with the SHC of the LFM signal having the same energy level. The results also revealed the robustness of the NLFM chirp under a frequency-dependent attenuation of 0.5 dB/cm·MHz up to a penetration depth of 5 cm and a Doppler shift up to 12 kHz.

      PubDate: 2017-05-08T10:27:27Z
      DOI: 10.1016/j.ultrasmedbio.2017.03.005
       
  • Comparison of 2-D Shear Wave Elastography and Transient Elastography for
           Assessing Liver Fibrosis in Chronic Hepatitis B
    • Authors: Jie Zeng; Jian Zheng; Zeping Huang; Shigao Chen; Jing Liu; Tao Wu; Rongqin Zheng; Mingde Lu
      Abstract: Publication date: Available online 5 May 2017
      Source:Ultrasound in Medicine & Biology
      Author(s): Jie Zeng, Jian Zheng, Zeping Huang, Shigao Chen, Jing Liu, Tao Wu, Rongqin Zheng, Mingde Lu
      This study compared 2-D shear wave elastography (SWE) and transient elastography (TE) for liver fibrosis staging in patients with chronic hepatitis B (CHB) infection using liver biopsy as the reference standard. Patients with CHB infection who underwent liver biopsy were consecutively included. After exclusions, 257 patients were analyzed. Two-dimensional SWE resulted in a significantly higher rate of reliable measurements (98.1%, 252/257) than TE (93.0%, 239/257) (p = 0.011). Liver stiffness measurements of the two examinations exhibited a strong correlation (r = 0.835, p < 0.001). In patients given a confirmed histologic diagnosis, Spearman's rank coefficients were 0.520 in stage F0 (p < 0.001), 0.684 in stage F1 (p < 0.001), 0.777 in stage F2 (p < 0.001), 0.672 in stage F3 (p < 0.001) and 0.755 in stage F4 (p < 0.001). There were no significant differences between the areas under the receiver operating characteristic (ROC) curves of 2-D SWE and TE for liver fibrosis staging (all p values > 0.05). Two-dimensional SWE had diagnostic accuracy comparable to that of TE for liver fibrosis staging. The measurements that the two techniques provide are not interchangeable.

      PubDate: 2017-05-08T10:27:27Z
      DOI: 10.1016/j.ultrasmedbio.2017.03.014
       
  • Ultrasound and Intra-clot Microbubbles Enhanced Catheter-Directed
           Thrombolysis in Vitro and in Vivo
    • Authors: Shunji Gao; Qiong Zhu; MengJiao Guo; Yuan Gao; Xiaoxiao Dong; Zhong Chen; Zheng Liu; Feng Xie
      Abstract: Publication date: Available online 4 May 2017
      Source:Ultrasound in Medicine & Biology
      Author(s): Shunji Gao, Qiong Zhu, MengJiao Guo, Yuan Gao, Xiaoxiao Dong, Zhong Chen, Zheng Liu, Feng Xie
      Insufficient penetration of microbubbles (MBs) into the vessel-obstructing thrombi significantly reduces the effectiveness of ultrasound thrombolysis (UT). The widely performed catheter-directed therapy (CDT) makes it possible to increase the local concentration of MBs in the clot. In an occluded vessel with a bypass, treatment of fresh human whole blood clots with CDT-based UT (intra-clot injection of MBs and urokinase, with ultrasound exposure) resulted in a significantly higher percentage of weight loss (35.32 ± 15.42%), compared with CDT alone (19.64 ± 4.71%), non-CDT-based UT (systemic administration of urokinase and MBs, with ultrasound exposure, 8.79 ± 3.02%) and systemic thrombolysis (7.90 ± 2.14). Ultrasound and intra-clot MB enhancement of CDT was further confirmed by a rabbit IVC thrombolysis study, where CDT-based UT resulted in significantly more effective thrombolysis compared with CDT alone. In summary, combining CDT with intra-clot MB-induced acoustic cavitation can improve thrombolysis.

      PubDate: 2017-05-08T10:27:27Z
      DOI: 10.1016/j.ultrasmedbio.2017.03.017
       
  • Transcranial Functional Ultrasound Imaging in Freely Moving Awake Mice and
           Anesthetized Young Rats without Contrast Agent
    • Authors: Elodie Tiran; Jérémy Ferrier; Thomas Deffieux; Jean-Luc Gennisson; Sophie Pezet; Zsolt Lenkei; Mickaël Tanter
      Abstract: Publication date: Available online 4 May 2017
      Source:Ultrasound in Medicine & Biology
      Author(s): Elodie Tiran, Jérémy Ferrier, Thomas Deffieux, Jean-Luc Gennisson, Sophie Pezet, Zsolt Lenkei, Mickaël Tanter
      Functional ultrasound (fUS) imaging by ultrasensitive Doppler detection of blood volume was previously reported to measure adult rat brain activation and functional connectivity with unmatched spatiotemporal sampling (100 μm, 1 ms), but skull-induced attenuation of ultrasonic waves imposed skull surgery or contrast agent use. Also, fUS feasibility remains to be validated in mice, a major pre-clinical model organism. In the study described here, we performed full-depth ultrasensitive Doppler imaging and 3-D Doppler tomography of the entire mouse brain under anesthesia, non-invasively through the intact skull and skin, without contrast agents. Similar results were obtained in anesthetized young rats up to postnatal day 35, thus enabling longitudinal studies on postnatal brain development. Using a newly developed ultralight ultrasonic probe and an optimized ultrasonic sequence, we also performed minimally invasive full-transcranial fUS imaging of brain vasculature and whisker stimulation-induced barrel cortex activation in awake and freely moving mice, validating transcranial fUS for brain imaging, without anesthesia-induced bias, for behavioral studies.

      PubDate: 2017-05-08T10:27:27Z
      DOI: 10.1016/j.ultrasmedbio.2017.03.011
       
  • Editorial Advisory Board
    • Abstract: Publication date: May 2017
      Source:Ultrasound in Medicine & Biology, Volume 43, Issue 5


      PubDate: 2017-05-08T10:27:27Z
       
  • Calendar
    • Abstract: Publication date: May 2017
      Source:Ultrasound in Medicine & Biology, Volume 43, Issue 5


      PubDate: 2017-05-08T10:27:27Z
       
  • Low-Intensity Pulsed Ultrasound Promotes Exercise-Induced Muscle
           Hypertrophy
    • Authors: Liang Tang; Jing Zhang; Xinjuan Zhao; Nan Li; Wenqi Jian; Shuxin Sun; Jianzhong Guo; Lijun Sun; Dean Ta
      Abstract: Publication date: Available online 29 April 2017
      Source:Ultrasound in Medicine & Biology
      Author(s): Liang Tang, Jing Zhang, Xinjuan Zhao, Nan Li, Wenqi Jian, Shuxin Sun, Jianzhong Guo, Lijun Sun, Dean Ta
      The purpose of this study was to investigate whether low-intensity pulsed ultrasound (LIPUS) promotes exercise-induced muscle hypertrophy. Twenty-four adult Sprague-Dawley (SD) rats were randomly assigned to three groups (n = 8 per group): normal control group (NC), treadmill exercise group (TE) and treadmill exercise + LIPUS group (TE + LIPUS). The TE + LIPUS group received a LIPUS treatment (1 MHz, 30 mW/cm2) at the gastrocnemius for 20 min/d after treadmill exercise. The TE group was sham-treated. Eight weeks of treadmill training successfully established the exercise-induced muscle hypertrophy model. Muscle strength, muscle mass and muscle fiber cross-sectional area were significantly increased in the TE + LIPUS group compared with the TE group. Moreover, LIPUS treatment significantly upregulated the expression of Akt, mTOR, p-Akt and p-mTOR and significantly downregulated the expression of MSTN, ActRIIB, FoxO1 and its phosphorylation. The results indicated that LIPUS promotes exercise-induced muscle hypertrophy by facilitating protein synthesis and inhibiting the protein catabolism pathway.

      PubDate: 2017-05-08T10:27:27Z
      DOI: 10.1016/j.ultrasmedbio.2017.02.017
       
  • Low-Intensity Pulsed Ultrasound-Induced Spinal Fusion is Coupled with
           Enhanced Calcitonin Gene-Related Peptide Expression in Rat Model
    • Authors: Xiao-Yi Zhou; Xi-Ming Xu; Sui-Yi Wu; Fei Wang; Zi-Cheng Zhang; Yi-Lin Yang; Ming Li; Xian-Zhao Wei
      Abstract: Publication date: Available online 28 April 2017
      Source:Ultrasound in Medicine & Biology
      Author(s): Xiao-Yi Zhou, Xi-Ming Xu, Sui-Yi Wu, Fei Wang, Zi-Cheng Zhang, Yi-Lin Yang, Ming Li, Xian-Zhao Wei
      Low-intensity pulsed ultrasound (LIPUS) has been found to accelerate fracture healing. In this study, we analyzed the role of calcitonin gene-related peptide (CGRP) in a rat spinal fusion model treated with LIPUS. The results revealed that LIPUS significantly increases bone formation, and the process was coupled with elevated CGRP innervation. CGRP was located in fibrous tissue, closely surrounding the allograft and newly formed cartilage. The density of CGRP peaked at week 3 after surgery in both the control (non-LIPUS-treated) and LIPUS-treated groups. These results suggest that LIPUS might accelerate spinal fusion by promoting sensory nerve fiber innervation.

      PubDate: 2017-05-08T10:27:27Z
      DOI: 10.1016/j.ultrasmedbio.2017.03.012
       
  • Quantitative Assessment of Skin Stiffness in Localized Scleroderma Using
           Ultrasound Shear-Wave Elastography
    • Authors: Liyun Wang; Feng Yan; Yujia Yang; Xi Xiang; Li Qiu
      Abstract: Publication date: Available online 28 April 2017
      Source:Ultrasound in Medicine & Biology
      Author(s): Liyun Wang, Feng Yan, Yujia Yang, Xi Xiang, Li Qiu
      The purpose of this study was to evaluate the usefulness of ultrasound shear-wave elastography (US-SWE) in characterization of localized scleroderma (LS), as well as in the disease staging. A total of 21 patients with 37 LS lesions were enrolled in this study. The pathologic stage (edema, sclerosis or atrophy) of the lesions was characterized by pathologic examination. The skin elastic modulus (E-values including Emean, Emin, Emax and Esd) and thickness (h) was evaluated both in LS lesions and site-matched unaffected skin (normal controls) using US-SWE. The relative difference of E-values (ERD) was calculated between each pair of lesions and its normal control for comparison among different pathologic stages. Of the 37 LS lesions, 2 were in edema, 22 were in sclerosis and 13 were in atrophy. US-SWE results showed a significant increase of skin elastic modulus and thickness in all lesions (p < 0.001 in sclerosis and p < 0.05 in atrophy) compared with the normal controls. The measured skin elastic modulus and thickness were greater in sclerosis than in atrophy. However, once normalized by skin thickness, the atrophic lesions, which were on average thinner, appeared significantly stiffer than those of the sclerosis (normalized ERD: an increase of 316.3% in atrophy vs. 50.6% in sclerosis compared with the controls, p = 0.007). These findings suggest that US-SWE allows for quantitative evaluation of the skin stiffness of LS lesions in different stages; however, the E-values directly provided by the US-SWE system alone do not distinguish between the stages, and the normalization by skin thickness is necessary. This non-invasive, real-time imaging technique is an ideal tool for assessing and monitoring LS disease severity and progression.

      PubDate: 2017-05-08T10:27:27Z
      DOI: 10.1016/j.ultrasmedbio.2017.02.009
       
  • Non-invasive Thrombolysis Using Microtripsy in a Porcine Deep Vein
           Thrombosis Model
    • Authors: Xi Zhang; Jonathan J. Macoskey; Kimberly Ives; Gabe E. Owens; Hitinder S. Gurm; Jiaqi Shi; Matthew Pizzuto; Charles A. Cain; Zhen Xu
      Abstract: Publication date: Available online 28 April 2017
      Source:Ultrasound in Medicine & Biology
      Author(s): Xi Zhang, Jonathan J. Macoskey, Kimberly Ives, Gabe E. Owens, Hitinder S. Gurm, Jiaqi Shi, Matthew Pizzuto, Charles A. Cain, Zhen Xu
      Histotripsy is a non-invasive therapeutic technique that uses ultrasound generated from outside the body to create controlled cavitation in targeted tissue, and fractionates it into acellular debris. We have developed a new histotripsy approach, termed microtripsy, to improve targeting accuracy and to avoid collateral tissue damage. This in vivo study evaluates the safety and efficacy of microtripsy for non-invasive thrombolysis in a porcine deep vein thrombosis model. Acute thrombi were formed in left femoral veins of pigs (∼35 kg) by occluding the vessel using two balloon catheters and infusing with thrombin. Guided by real-time ultrasound imaging, microtripsy thrombolysis treatment was conducted in 14 pigs; 10 pigs were euthanized on the same day (acute) and 4 at 2 wk (subacute). To evaluate vessel damage, 30-min free-flow treatment in the right femoral vein (no thrombus) was also conducted in 8 acute pigs. Blood flow was successfully restored or significantly increased after treatment in 13 of the 14 pigs. The flow channels re-opened by microtripsy had a diameter up to 64% of the vessel diameter (∼6 mm). The average treatment time was 16 min per centimeter-long thrombus. Only mild intravascular hemolysis was induced during microtripsy thrombolysis. No damage was observed on vessel walls after 2 wk of recovery, venous valves were preserved, and there was no sign of pulmonary embolism. The results of this study indicate that microtripsy has the potential to be a safe and effective treatment for deep vein thrombosis in a porcine model.

      PubDate: 2017-05-08T10:27:27Z
      DOI: 10.1016/j.ultrasmedbio.2017.01.028
       
  • Evaluation of Transabdominal Ultrasound with Oral Cellulose-Based Contrast
           Agent in the Detection and Surveillance of Gastric Ulcer
    • Authors: Zhijun Liu; Jintao Guo; Shupeng Wang; Ying Zhao; Zhining Liu; Jing Li; Weidong Ren; Shaoshan Tang; Limei Xie; Ying Huang; Siyu Sun; Liping Huang
      Abstract: Publication date: Available online 28 April 2017
      Source:Ultrasound in Medicine & Biology
      Author(s): Zhijun Liu, Jintao Guo, Shupeng Wang, Ying Zhao, Zhining Liu, Jing Li, Weidong Ren, Shaoshan Tang, Limei Xie, Ying Huang, Siyu Sun, Liping Huang
      The aim of this study was to assess the role of transabdominal ultrasound with cellulose-based oral contrast agent (TUS-OCCA) in the detection and surveillance of gastric ulcer. The study was approved by the institutional review board at Shengjing Hospital of China Medical University. A total of 124 consecutive patients with benign gastric ulcer diagnosed by gastroscopy and biopsy were enrolled. Serial TUS-OCCA (approximately 1 exam every 2 wk) was performed to monitor the effects of treatment, and additional interventions were planned according to the results. TUS-OCCA detected gastric ulcer in 76% of patients (94 of 124). The detection rates for lesions of ≤5 mm, lesions of 5–10 mm, lesions of 10–15 mm and lesions >15 mm were 32% (10 of 31), 77% (27 of 35), 96% (25 of 26) and 100% (32 of 32), respectively. The detection rates for lesions located in the antrum, angle and body were 70%, 84% and 85%, respectively. Among 30 undetected lesions, which ranged 2–13 mm in size, 11 were at the antrum, 9 at the angle, 3 in the body, 6 at the cardia and 1 at the fundus. During the follow-up period, patients underwent a mean of 3.8 TUS-OCCA examinations (range 2–7), and ulcers were healed after 8 wk (range 2–12 wk) of standard therapy in 76 patients. Eighteen patients who did not show improvement after standard therapy underwent repeat gastroscopy with biopsy. Repeat biopsy was positive for gastric cancer in 4 of these: 2 of the remaining 14 were diagnosed with gastric cancer at gastrectomy, and 12 were diagnosed with chronic benign ulcer. These results indicate that serial TUS-OCCA can be used for close monitoring during routine treatment of gastric ulcers that are detectable by TUS-OCCA and that monitoring by TUS-OCCA can guide additional interventions. A non-invasive follow-up program based on TUS-OCCA can also help to detect gastric cancers that have been misdiagnosed as benign ulcers at the initial endoscopic biopsy.

      PubDate: 2017-05-08T10:27:27Z
      DOI: 10.1016/j.ultrasmedbio.2017.02.008
       
  • Monitoring Microwave Ablation of Ex Vivo Bovine Liver Using
           Ultrasonic Attenuation Imaging
    • Authors: Kayvan Samimi; James K. White; Christopher L. Brace; Tomy Varghese
      Abstract: Publication date: Available online 26 April 2017
      Source:Ultrasound in Medicine & Biology
      Author(s): Kayvan Samimi, James K. White, Christopher L. Brace, Tomy Varghese
      Thermal ablation of soft tissue changes the tissue microstructure and, consequently, induces changes in its acoustic properties. Although B-mode ultrasound provides high-resolution and high-frame-rate images of ablative therapeutic procedures, it is not particularly effective at delineating boundaries of ablated regions because of poor contrast in echogenicity between ablated and surrounding normal tissue. Quantitative ultrasound techniques can provide quantitative estimates of acoustic properties, such as backscatter and attenuation coefficients, and differentiate ablated and unablated regions more effectively, with the potential for monitoring minimally invasive thermal therapies. In this study, a previously introduced attenuation estimation method was used to create quantitative attenuation coefficient maps for 11 microwave ablation procedures performed on refrigerated ex vivo bovine liver. The attenuation images correlate well with the pathologic images of the ablated region. The mean attenuation coefficient for regions of interest drawn inside and outside the ablated zones were 0.9 (±0.2) and 0.45 (±0.15) dB/cm/MHz, respectively. These estimates agree with reported values in the literature and establish the usefulness of non-invasive attenuation imaging for monitoring therapeutic procedures in the liver.

      PubDate: 2017-05-08T10:27:27Z
      DOI: 10.1016/j.ultrasmedbio.2017.03.010
       
  • Inactivation of Planktonic Escherichia coli by Focused 2-MHz Ultrasound
    • Authors: Andrew A. Brayman; Brian E. MacConaghy; Yak-Nam Wang; Keith T. Chan; Wayne L. Monsky; Anna J. McClenny; Thomas J. Matula
      Abstract: Publication date: Available online 26 April 2017
      Source:Ultrasound in Medicine & Biology
      Author(s): Andrew A. Brayman, Brian E. MacConaghy, Yak-Nam Wang, Keith T. Chan, Wayne L. Monsky, Anna J. McClenny, Thomas J. Matula
      This study was motivated by the desire to develop a non-invasive means to treat abscesses, and represents the first steps toward that goal. Non-thermal, high-intensity focused ultrasound (HIFU) was used to inactivate Escherichia coli (∼1 × 109 cells/mL) in suspension. Cells were treated in 96-well culture plate wells using 1.95-MHz ultrasound and incident focal acoustic pressures as high as 16 MPa peak positive and 9.9 MPa peak negative (free field measurements). The surviving fraction was assessed by coliform culture and the alamarBlue assay. No biologically significant heating was associated with ultrasound exposure. Bacterial inactivation kinetics were well described by a half-life model, with a half-time of 1.2 min. At the highest exposure levels, a 2log inactivation was typically achieved within 10 min. The free field-equivalent peak negative acoustic pressure threshold for inactivation was ∼7 MPa. At the highest acoustic pressures used, inactivation efficacy was insensitive to reciprocal changes in pulse length and pulse repetition frequency at constant duty factor. Although treated volumes were very small, proof of principle was provided by these experiments.

      PubDate: 2017-05-08T10:27:27Z
      DOI: 10.1016/j.ultrasmedbio.2017.03.009
       
  • Evaluation of Optic Nerve with Strain and Shear Wave Elastography in
           Patients with Behçet's Disease and Healthy Subjects
    • Authors: Mikail Inal; Sinan Tan; Serkan Demirkan; Veysel Burulday; Özgür Gündüz; Kemal Örnek
      Abstract: Publication date: Available online 24 April 2017
      Source:Ultrasound in Medicine & Biology
      Author(s): Mikail Inal, Sinan Tan, Serkan Demirkan, Veysel Burulday, Özgür Gündüz, Kemal Örnek
      The objective of this study was to investigate the elasticity characteristics of the optic nerve using strain and shear wave elastography in patients with Behçet's disease and to compare the results with those of healthy volunteers. Forty-six optic nerves from patients with Behçet's disease and 54 optic nerves from healthy volunteers were investigated prospectively in this study using strain and shear wave elastography. There was a statistically significant difference in terms of elasticity patterns between patients and healthy volunteers (p < 0.001). Elastographic images of healthy volunteers revealed most optic nerves to be type 3 (51.8%); however, type 2 (40.7%) and type 1 (7.5%) were also observed. Elastographic examination of Behçet's disease patients revealed type 2 in 52.2%, type 1 in 43.5% and type 3 in 4.3% of patients. Statistically significant differences were observed between patients and healthy volunteers in the analysis of shear wave elastography values (p < 0.001). Receiver operating characteristic curve analysis was perfect (0.933) (95% CI = 0.885–0.980), and a cutoff value of 16.5 kPa shear had very high sensitivity and specificity for the patient group. Strain and shear wave elastography findings for the optic nerves of patients with Behçet's disease were significantly different from those for healthy volunteers.

      PubDate: 2017-05-08T10:27:27Z
      DOI: 10.1016/j.ultrasmedbio.2017.03.008
       
  • Plaque Topographic Characterization: A New Element to Investigate Carotid
           Atherosclerosis
    • Authors: Agatino Manganaro; Roberta Manganaro; Domenico Buda; Giuseppe Andò
      Abstract: Publication date: Available online 24 April 2017
      Source:Ultrasound in Medicine & Biology
      Author(s): Agatino Manganaro, Roberta Manganaro, Domenico Buda, Giuseppe Andò


      PubDate: 2017-05-08T10:27:27Z
      DOI: 10.1016/j.ultrasmedbio.2017.03.007
       
  • Dynamic Enhancement of B-Mode Cardiac Ultrasound Image Sequences
    • Authors: Antonios Perperidis; David Cusack; Audrey White; Norman McDicken; Tom MacGillivray; Tom Anderson
      Abstract: Publication date: Available online 24 April 2017
      Source:Ultrasound in Medicine & Biology
      Author(s): Antonios Perperidis, David Cusack, Audrey White, Norman McDicken, Tom MacGillivray, Tom Anderson
      Limited contrast, along with speckle and acoustic noise, can reduce the diagnostic value of echocardiographic images. This study introduces dynamic histogram-based intensity mapping (DHBIM), a novel approach employing temporal variations in the cumulative histograms of cardiac ultrasound images to contrast enhance the imaged structures. DHBIM is then combined with spatial compounding to compensate for noise and speckle. The proposed techniques are quantitatively assessed (32 clinical data sets) employing (i) standard image quality measures and (ii) the repeatability of routine clinical measurements, such as chamber diameter and wall thickness. DHBIM introduces a mean increase of 120.9% in tissue/chamber detectability, improving the overall repeatability of clinical measurements by 17%. The integrated approach of DHBIM followed by spatial compounding provides the best overall enhancement of image quality and diagnostic value, consistently outperforming the individual approaches and achieving a 401.4% average increase in tissue/chamber detectability with an associated 24.3% improvement in the overall repeatability of clinical measurements.

      PubDate: 2017-05-08T10:27:27Z
      DOI: 10.1016/j.ultrasmedbio.2017.03.006
       
  • Microbubble Enzyme-Linked Immunosorbent Assay for the Detection of
           Targeted Microbubbles in in Vitro Static Binding Assays
    • Authors: Jennifer Wischhusen; Frederic Padilla
      Abstract: Publication date: Available online 24 April 2017
      Source:Ultrasound in Medicine & Biology
      Author(s): Jennifer Wischhusen, Frederic Padilla
      Targeted microbubbles (MBs) are ultrasound contrast agents that are functionalized with a ligand for ultrasound molecular imaging of endothelial markers. Novel targeted MBs are characterized in vitro by incubation in protein-coated wells, followed by binding quantification by microscopy or ultrasound imaging. Both methods provide operator-dependent results: Between 3 and 20 fields of view from a heterogeneous sample are typically selected for analysis by microscopy, and in ultrasound imaging, different acoustic settings affect signal intensities. This study proposes a new method to reproducibly quantify MB binding based on enzyme-linked immunosorbent assay (ELISA), in which bound MBs are revealed with an enzyme-linked antibody. MB-ELISA was adapted to in vitro static binding assays, incubating the MBs in inverted position or by agitation, and compared with microscopy. The specificity and sensitivity of MB-ELISA enable the reliable quantification of MB binding in a rapid, high-throughput and whole-well analysis, facilitating the characterization of new targeted contrast agents.

      PubDate: 2017-05-08T10:27:27Z
      DOI: 10.1016/j.ultrasmedbio.2017.03.004
       
  • Broadband Acoustic Measurement of an Agar-Based Tissue-Mimicking-Material:
           A Longitudinal Study
    • Authors: Adela Rabell Montiel; Jacinta E. Browne; Stephen D. Pye; Tom A. Anderson; Carmel M. Moran
      Abstract: Publication date: Available online 24 April 2017
      Source:Ultrasound in Medicine & Biology
      Author(s): Adela Rabell Montiel, Jacinta E. Browne, Stephen D. Pye, Tom A. Anderson, Carmel M. Moran
      Commercially available ultrasound quality assurance test phantoms rely on the long-term acoustic stability of the tissue-mimicking-material (TMM). Measurement of the acoustic properties of the TMM can be technically challenging, and it is important to ensure its stability. The standard technique is to film-wrap samples of TMM and to measure the acoustic properties in a water bath. In this study, a modified technique was proposed whereby the samples of TMM are measured in a preserving fluid that is intended to maintain their characteristics. The acoustic properties were evaluated using a broadband pulse-echo substitution technique over the frequency range 4.5–50 MHz at 0, 6 and 12 months using both techniques. For both techniques, the measured mean values for the speed of sound and attenuation were very similar and within the International Electrotechnical Commission-recommended value. However, the results obtained using the proposed modified technique exhibited greater stability over the 1-y period compared with the results acquired using the standard technique.

      PubDate: 2017-05-08T10:27:27Z
      DOI: 10.1016/j.ultrasmedbio.2017.02.019
       
  • Feasibility of Ultrasound-Based Computational Fluid Dynamics as a Mitral
           Valve Regurgitation Quantification Technique: Comparison with 2-D and 3-D
           Proximal Isovelocity Surface Area-Based Methods
    • Authors: Muhammad Jamil; Omar Ahmad; Kian Keong Poh; Choon Hwai Yap
      Abstract: Publication date: Available online 20 April 2017
      Source:Ultrasound in Medicine & Biology
      Author(s): Muhammad Jamil, Omar Ahmad, Kian Keong Poh, Choon Hwai Yap
      Current Doppler echocardiography quantification of mitral regurgitation (MR) severity has shortcomings. Proximal isovelocity surface area (PISA)-based methods, for example, are unable to account for the fact that ultrasound Doppler can measure only one velocity component: toward or away from the transducer. In the present study, we used ultrasound-based computational fluid dynamics (Ub-CFD) to quantify mitral regurgitation and study its advantages and disadvantages compared with 2-D and 3-D PISA methods. For Ub-CFD, patient-specific mitral valve geometry and velocity data were obtained from clinical ultrasound followed by 3-D CFD simulations at an assumed flow rate. We then obtained the average ratio of the ultrasound Doppler velocities to CFD velocities in the flow convergence region, and scaled CFD flow rate with this ratio as the final measured flow rate. We evaluated Ub-CFD, 2-D PISA and 3-D PISA with an in vitro flow loop, which featured regurgitation flow through (i) a simplified flat plate with round orifice and (ii) a 3-D printed realistic mitral valve and regurgitation orifice. The Ub-CFD and 3-D PISA methods had higher precision than the 2-D PISA method. Ub-CFD had consistent accuracy under all conditions tested, whereas 2-D PISA had the lowest overall accuracy. In vitro investigations indicated that the accuracy of 2-D and 3-D PISA depended significantly on the choice of aliasing velocity. Evaluation of these techniques was also performed for two clinical cases, and the dependency of PISA on aliasing velocity was similarly observed. Ub-CFD was robustly accurate and precise and has promise for future translation to clinical practice.

      PubDate: 2017-05-08T10:27:27Z
      DOI: 10.1016/j.ultrasmedbio.2017.02.012
       
  • Analgesic Effects of Transcutaneous Ultrasound Nerve Stimulation in a Rat
           Model of Oxaliplatin-Induced Mechanical Hyperalgesia and Cold Allodynia
    • Authors: Yueh-Ling Hsieh; Han-Yu Chen; Ching-Hsiang Yang; Chen-Chia Yang
      Abstract: Publication date: Available online 19 April 2017
      Source:Ultrasound in Medicine & Biology
      Author(s): Yueh-Ling Hsieh, Han-Yu Chen, Ching-Hsiang Yang, Chen-Chia Yang
      This study investigated the effects and underlying mechanisms of therapeutic ultrasound (TUS) in a rat model of oxaliplatin-induced peripheral neuropathy. Animals received a total of eight injections with oxaliplatin (4 mg/kg), administered at 3-d intervals. TUS intervention (1 MHz, 0.5 W/cm2) started on the fifth oxaliplatin administration and continued for 10 consecutive d. Sensory behavioral examinations, protein levels of transient receptor potential channels (TRPM8 and TRPV1) in dorsal root ganglia (DRG) and substance P (SP) in spinal dorsal horn were examined. Results indicated that TUS can reduce mechanical and cold hyper-responsive behaviors caused by repeated administration of oxaliplatin. Oxaliplatin-related increases in protein levels of TRPM8 in DRG and SP in the dorsal horn were also reduced after TUS. Taken together, the results revealed beneficial effects of TUS on oxaliplatin-induced mechanical hyperalgesia and cold allodynia and suggested involvement of TUS biochemicals in suppressing TRPM8 in DRG and SP in spinal cords.

      PubDate: 2017-05-08T10:27:27Z
      DOI: 10.1016/j.ultrasmedbio.2017.03.002
       
  • Subharmonic-Aided Pressure Estimation for Monitoring Interstitial Fluid
           Pressure in Tumors: Calibration and Treatment with Paclitaxel in Breast
           Cancer Xenografts
    • Authors: Valgerdur G. Halldorsdottir; Jaydev K. Dave; Andrew Marshall; Anya I. Forsberg; Traci B. Fox; John R. Eisenbrey; Priscilla Machado; Ji-Bin Liu; Daniel A. Merton; Flemming Forsberg
      Abstract: Publication date: Available online 19 April 2017
      Source:Ultrasound in Medicine & Biology
      Author(s): Valgerdur G. Halldorsdottir, Jaydev K. Dave, Andrew Marshall, Anya I. Forsberg, Traci B. Fox, John R. Eisenbrey, Priscilla Machado, Ji-Bin Liu, Daniel A. Merton, Flemming Forsberg
      Interstitial fluid pressure (IFP) in rats with breast cancer xenografts was non-invasively estimated using subharmonic-aided pressure estimation (SHAPE) versus an invasive pressure monitor. Moreover, monitoring of IFP changes after chemotherapy was assessed. Eighty-nine rats (calibration n = 25, treatment n = 64) were injected with 5 × 106 breast cancer cells (MDA-MB-231). Radiofrequency signals were acquired (39 rats successfully imaged) with a Sonix RP scanner (BK Ultrasound, Richmond, BC, Canada) using a linear array (L9-4, transmit/receive: 8/4 MHz) after administration of Definity (Lantheus Medical Imaging, North Billerica, MA, USA; 180 μL/kg) and compared with readings from an invasive pressure monitor (Stryker, Berkshire, UK). An inverse linear relationship was established between tumor IFP and SHAPE (y = −1.06x + 28.27, r = −0.69, p = 0.01) in the calibration group. Use of this relationship in the treatment group resulted in r = 0.74 (p < 0.05) between measured (pressure monitor) and SHAPE-estimated IFP (average error: 6.24 mmHg). No significant before/after differences were observed with respect to paclitaxel treatment (5 mg/kg, Mayne Pharma, Paramus, NJ, USA) with either method (p ≥ 0.15).

      PubDate: 2017-05-08T10:27:27Z
      DOI: 10.1016/j.ultrasmedbio.2017.02.011
       
  • Cardiac Amyloidosis Shows Decreased Diastolic Function as Assessed by
           Echocardiographic Parameterized Diastolic Filling
    • Authors: Katrin Salman; Peter A. Cain; Benjamin T. Fitzgerald; Martin G. Sundqvist; Martin Ugander
      Abstract: Publication date: Available online 19 April 2017
      Source:Ultrasound in Medicine & Biology
      Author(s): Katrin Salman, Peter A. Cain, Benjamin T. Fitzgerald, Martin G. Sundqvist, Martin Ugander
      Cardiac amyloidosis is a rare but serious condition with poor survival. One of the early findings by echocardiography is impaired diastolic function, even before the development of cardiac symptoms. Early diagnosis is important, permitting initiation of treatment aimed at improving survival. The parameterized diastolic filling (PDF) formalism entails describing the left ventricular filling pattern during early diastole using the mathematical equation for the motion of a damped harmonic oscillator. We hypothesized that echocardiographic PDF analysis could detect differences in diastolic function between patients with amyloidosis and controls. Pulsed-wave Doppler echocardiography of transmitral flow was measured in 13 patients with amyloid heart disease and 13 age- and gender matched controls. E- waves (2 to 3 per subject) were analyzed using in-house developed software. Nine PDF-derived parameters were obtained in addition to conventional echocardiographic parameters of diastolic function. Compared to controls, cardiac amyloidosis patients had a larger left atrial area (23.7 ± 7.5 cm2 vs. 18.5 ± 4.8 cm2, p = 0.04), greater interventricular septum wall thickness (14.4 ± 2.6 mm vs. 9.3 ± 1.3 mm, p < 0.001), lower e′ (0.06 ± 0.02 m/s vs. 0.09 ± 0.02 m/s, p < 0.001) and higher E/e′ (18.0 ± 12.9 vs. 7.7 ± 1.3, p = 0.001). The PDF parameter peak resistive force was greater in cardiac amyloidosis patients compared to controls (17.9 ± 5.7 mN vs. 13.1 ± 3.1 mN, p = 0.03), and other PDF parameters did not differ. PDF analysis revealed that patients with cardiac amyloidosis had a greater peak resistive force compared to controls, consistent with a greater degree of diastolic dysfunction. PDF analysis may be useful in characterizing diastolic function in amyloid heart disease.

      PubDate: 2017-05-08T10:27:27Z
      DOI: 10.1016/j.ultrasmedbio.2017.02.014
       
  • Optimal Ultrasound Exposure Conditions for Maximizing C2C12 Muscle Cell
           Proliferation and Differentiation
    • Authors: Alice Rita Salgarella; Andrea Cafarelli; Leonardo Ricotti; Lorenzo Capineri; Paolo Dario; Arianna Menciassi
      Abstract: Publication date: Available online 19 April 2017
      Source:Ultrasound in Medicine & Biology
      Author(s): Alice Rita Salgarella, Andrea Cafarelli, Leonardo Ricotti, Lorenzo Capineri, Paolo Dario, Arianna Menciassi
      Described here is an in vitro systematic investigation of the effects on C2C12 myoblasts of exposure to finely controlled and repeatable low-intensity pulsed ultrasound of different frequencies (500 kHz, 1 MHz, 3 MHz and 5 MHz) and different intensities (250, 500 and 1000 mW/cm2). An in-house stimulation system and an ultrasound-transparent cell culture well minimized reflections and attenuations, allowing precise control of ultrasound delivery. Results indicated that a 3 MHz stimulation at 1 W/cm2 intensity maximized cell proliferation in comparison with the other exposure conditions and untreated controls. In contrast, cell differentiation and the consequent formation of multinucleated myotubes were maximized by 1 MHz stimulation at 500 mW/cm2 intensity. The highly controlled exposure conditions employed allowed precise correlation of the ultrasound delivery to the bio-effects produced, thus overcoming the inconsistency of some results available in the literature and contributing to the potential of ultrasound treatment for muscle therapy and regeneration.

      PubDate: 2017-05-08T10:27:27Z
      DOI: 10.1016/j.ultrasmedbio.2017.03.003
       
  • Spatial Compounding Technique to Obtain Rotation Elastogram: A Feasibility
           Study
    • Authors: AliArshad Kothawala; Sowmiya Chandramoorthi; N. Ravi Kiran Reddy; Arun Kumar Thittai
      Abstract: Publication date: Available online 19 April 2017
      Source:Ultrasound in Medicine & Biology
      Author(s): AliArshad Kothawala, Sowmiya Chandramoorthi, N. Ravi Kiran Reddy, Arun Kumar Thittai
      The perception of stiffness and slipperiness of a breast mass on palpation is used by physicians to assess the level of suspicion of a lesion as being malignant or benign. However, most current ultrasound elastography imaging methods provide only stiffness-related information. There is no existing approach that provides information about the local rigid body rotation undergone by only a loosely bonded, asymmetrically oriented lesion subjected to a small quasi-static compression. The inherent poor lateral resolution in ultrasound imaging poses a limitation in estimating the local rigid body rotation. Several techniques have been reported in the literature to improve the lateral resolution in ultrasound imaging, and among them is spatial compounding. In this study, we explore the feasibility of obtaining better-quality rotation elastograms with spatial compounding through simulations using Field II and experiments on tissue-mimicking phantoms. The phantom was subjected to axial compression (∼1%–2%) from the top, and the angular axial and lateral displacement estimates were obtained using a multilevel 2-D displacement tracking algorithm at different insonification angles. A rotation elastogram (RE) was obtained by taking half of the difference between the lateral gradient of the axial displacement estimates and the axial gradient of the lateral displacement estimates. Contrast-to-noise ratio was used to quantify the improvements in quality of RE. Contrast-to-noise ratio values were calculated by varying the maximum steering angle and the incremental angle, and its effects on RE quality were evaluated. Both simulation and experimental results corroborated and indicated a significant improvement in the quality of RE using compounding technique.

      PubDate: 2017-05-08T10:27:27Z
      DOI: 10.1016/j.ultrasmedbio.2017.01.026
       
  • Role of Contrast-Enhanced Ultrasound in Diagnosis of Thyroid Nodules in
           Acoustic Radiation Force Impulse “Gray Zone”
    • Authors: Jia Zhan; Xue-Hong Diao; Lin Chen; Jia-Mei Jin; Yue Chen
      Abstract: Publication date: Available online 19 April 2017
      Source:Ultrasound in Medicine & Biology
      Author(s): Jia Zhan, Xue-Hong Diao, Lin Chen, Jia-Mei Jin, Yue Chen
      The aim of this study was to evaluate the clinical value of contrast-enhanced ultrasound (CEUS) in the diagnosis of thyroid nodules in the acoustic radiation force impulse (ARFI) “gray zone” (the shear wave velocity is in the range 2.5–3 m/s). ARFI was performed before thyroidectomy in 70 patients with 200 thyroid nodules, and then CEUS was performed in 40 thyroid nodules in the “gray zone.” The accuracy of ARFI for the 200 thyroid nodules was 82% (164/200). The accuracy of ARFI for the 40 “gray zone” thyroid nodules was 70% (28/40), whereas the accuracy of CEUS for the “gray zone” thyroid nodules was 90% (36/40). There was a significant difference in accuracy (p < 0.05). CEUS has better accuracy for thyroid nodules in the ARFI “gray zone.” CEUS supplemented ARFI in differential diagnosis of benign and malignant thyroid nodules.

      PubDate: 2017-05-08T10:27:27Z
      DOI: 10.1016/j.ultrasmedbio.2017.02.006
       
  • Shear Wave Liver Elastography with a Propagation Map: Diagnostic
           Performance and Inter-observer Correlation for Hepatic Fibrosis in Chronic
           Hepatitis
    • Authors: Eun Sun Lee; Jong Beum Lee; Hwi Ryong Park; Jeongin Yoo; Ji In Choi; Hyun Woong Lee; Hyung Joon Kim; Byung Ihn Choi; Hyun Jeong Park; Sung Bin Park
      Abstract: Publication date: Available online 18 April 2017
      Source:Ultrasound in Medicine & Biology
      Author(s): Eun Sun Lee, Jong Beum Lee, Hwi Ryong Park, Jeongin Yoo, Ji In Choi, Hyun Woong Lee, Hyung Joon Kim, Byung Ihn Choi, Hyun Jeong Park, Sung Bin Park
      The aim of this study was to determine the performance of shear wave elastography (SWE) with a propagation map in the diagnosis of hepatic fibrosis, and to assess its reliability with transient elastography (TE) as the reference standard. Our prospective study included 115 consecutive patients with suspected or alleged chronic hepatitis. Patients underwent SWE by two different operators and TE by sonographers on the same day. The correlation coefficient of the intra-class correlation test between an experienced radiologist and a third-year radiology resident was 0.878. There was a moderate correlation between SWE and TE (r = 0.511) in the diagnosis of hepatic fibrosis. The best cutoff values predicting significant hepatic fibrosis and liver cirrhosis by SWE were >1.78 m/s (area under the receiver operating characteristic curve [AUROC] = 0.777) and >2.24 m/s (AUROC = 0.935), respectively. SWE with a propagation map is a reliable method for predicting hepatic fibrosis regardless of operator experience.

      PubDate: 2017-05-08T10:27:27Z
      DOI: 10.1016/j.ultrasmedbio.2017.02.010
       
  • Characterization of the Lung Parenchyma Using Ultrasound Multiple
           Scattering
    • Authors: Kaustav Mohanty; John Blackwell; Thomas Egan; Marie Muller
      Abstract: Publication date: Available online 16 March 2017
      Source:Ultrasound in Medicine & Biology
      Author(s): Kaustav Mohanty, John Blackwell, Thomas Egan, Marie Muller
      The purpose of the study described here was to showcase the application of ultrasound to quantitative characterization of the micro-architecture of the lung parenchyma to predict the extent of pulmonary edema. The lung parenchyma is a highly complex and diffusive medium for which ultrasound techniques have remained qualitative. The approach presented here is based on ultrasound multiple scattering and exploits the complexity of ultrasound propagation in the lung structure. The experimental setup consisted of a linear transducer array with an 8-MHz central frequency placed in contact with the lung surface. The diffusion constant D and transport mean free path L* of the lung parenchyma were estimated by separating the incoherent and coherent intensities in the near field and measuring the growth of the incoherent diffusive halo over time. Significant differences were observed between the L* values obtained in healthy and edematous rat lungs in vivo. In the control rat lung, L* was found to be 332 μm (±48.8 μm), whereas in the edematous lung, it was 1040 μm (±90 μm). The reproducibility of the measurements of L* and D was tested in vivo and in phantoms made of melamine sponge with varying air volume fractions. Two-dimensional finite difference time domain numerical simulations were carried out on rabbit lung histology images with varying degrees of lung collapse. Significant correlations were observed between air volume fraction and L* in simulation (r = −0.9542, p < 0.0117) and sponge phantom (r = −0.9932, p < 0.0068) experiments. Ex vivo measurements of a rat lung in which edema was simulated by adding phosphate-buffered saline revealed a linear relationship between the fluid volume fraction and L*. These results illustrate the potential of methods based on ultrasound multiple scattering for the quantitative characterization of the lung parenchyma.

      PubDate: 2017-03-27T16:57:48Z
      DOI: 10.1016/j.ultrasmedbio.2017.01.011
       
  • Whole-Breast Ultrasound for Breast Screening and Archiving
    • Authors: Chiun-Sheng Huang; Ya-Wen Yang; Rong-Tai Chen; Chung-Ming Lo; Chao Lo; Ching-Fen Cheng; Chao-Shuan Lee; Ruey-Feng Chang
      Abstract: Publication date: Available online 7 March 2017
      Source:Ultrasound in Medicine & Biology
      Author(s): Chiun-Sheng Huang, Ya-Wen Yang, Rong-Tai Chen, Chung-Ming Lo, Chao Lo, Ching-Fen Cheng, Chao-Shuan Lee, Ruey-Feng Chang
      The incidence of breast cancer is increasing worldwide, reinforcing the importance of breast screening. Conventional hand-held ultrasound (HHUS) for breast screening is efficient and relatively easy to perform; however, it lacks systematic recording and localization. This study investigated an electromagnetic tracking-based whole-breast ultrasound (WBUS) system to facilitate the use of HHUS for breast screening. One-hundred nine breast masses were collected, and the detection of suspicious breast lesions was compared between the WBUS system, HHUS and a commercial automated breast ultrasound (ABUS) system. The positioning error between WBUS and ABUS (1.39 ± 0.68 cm) was significantly smaller than that between HHUS and ABUS (1.62 ± 0.91 cm, p = 0.014) and HHUS and WBUS (1.63 ± 0.9 cm, p = 0.024). WBUS is a practical clinical tool for breast screening that can be used instead of the often unavailable and costly ABUS.

      PubDate: 2017-03-09T16:22:24Z
      DOI: 10.1016/j.ultrasmedbio.2017.01.009
       
  • Pharmacokinetics of Perfluorobutane after Intra-venous Bolus Injection of
           Sonazoid in Healthy Chinese Volunteers
    • Authors: Pengfei Li; Susan Hoppmann; Ping Du; Huiling Li; Paul M. Evans; Siver A. Moestue; Weiyue Yu; Fang Dong; Hongchuan Liu; Lihong Liu
      Abstract: Publication date: Available online 7 March 2017
      Source:Ultrasound in Medicine & Biology
      Author(s): Pengfei Li, Susan Hoppmann, Ping Du, Huiling Li, Paul M. Evans, Siver A. Moestue, Weiyue Yu, Fang Dong, Hongchuan Liu, Lihong Liu
      Sonazoid is an ultrasound contrast agent based on microbubbles (MB) containing perfluorobutane (PFB) gas. Sonazoid is approved in Japan, Korea and Norway for contrast-enhanced ultrasonography of focal liver lesions and focal breast lesions (Japan only). The objective of this study was to determine the pharmacokinetics (PKs) and safety of Sonazoid in Chinese healthy volunteers (HVs) and to evaluate the potential for ethnic differences in PKs between Chinese and Caucasian HVs. Sonazoid was administered as an intra-venous bolus injection at the clinical dose of 0.12 μL or 0.60 μL MB/kg body weight to two groups of eight Chinese HVs. Expired air and blood samples were collected and analyzed using a validated gas chromatographic tandem mass spectrometry method, and the main PK parameters were calculated. The highest PFB concentrations in blood were observed shortly after intra-venous administration of Sonazoid, and elimination of PFB was rapid. In the 0.12 μL MB/kg body weight cohort, PFB concentrations above the limit of quantification were observed for only 10 to 15 min post-injection. In the 0.60 μL MB/kg body weight cohort, PFB concentrations above the limit of quantification were observed for 60 min post-injection, and the shape of the elimination curve suggested a biphasic elimination profile. The maximum observed concentration (C max) values of PFB in blood were 2.3 ± 1.1 and 19.1 ± 9.2 ng/g for the 0.12 and 0.60 μL MB/kg body weight dose groups (mean ± standard deviation). Area under the curve values were 10.1 ± 2.7 and 90.1 ± 38.3 ng × min/g for the 0.12 and 0.60 μL MB/kg body weight dose groups. C max values of PFB in exhaled air were 0.35 ± 0.2 and 2.4 ± 0.7 ng/mL for the 0.12 and 0.60 μL MB/kg body weight dose groups. Assessment of laboratory parameters, vital signs, oxygen saturation and electrocardiograms revealed no changes indicative of a concern. The PK profile and safety data generated in the Chinese HVs were comparable to previous data for Caucasian HVs.

      PubDate: 2017-03-09T16:22:24Z
      DOI: 10.1016/j.ultrasmedbio.2017.01.003
       
  • Effect of Hypoxemia on Fetal Ventricular Deformation in a Chronically
           Instrumented Sheep Model
    • Authors: Amarnath Bhide; Juha Rasanen; Heikki Huhta; Juulia Junno; Tiina Erkinaro; Pasi Ohtonen; Mervi Haapsamo; Ganesh Acharya
      Abstract: Publication date: Available online 6 March 2017
      Source:Ultrasound in Medicine & Biology
      Author(s): Amarnath Bhide, Juha Rasanen, Heikki Huhta, Juulia Junno, Tiina Erkinaro, Pasi Ohtonen, Mervi Haapsamo, Ganesh Acharya
      We hypothesized that in near-term sheep fetuses, hypoxemia changes myocardial function as reflected in altered ventricular deformation on speckle-tracking echocardiography. Fetuses in 21 pregnant sheep were instrumented. After 4 d of recovery, fetal cardiac function was assessed by echocardiography at baseline, after 30 and 120 min of induced fetal hypoxemia and after its reversal. Left (LV) and right (RV) ventricular cardiac output and myocardial strain were measured. Baseline mean (standard deviation [SD]) LV and RV global longitudinal strains were −18.7% (3.8) and −14.3% (5.3). Baseline RV global longitudinal and circumferential deformations were less compared with those of the left ventricle (p = 0.016 and p < 0.005). LV, but not RV, global longitudinal strain was decreased (p = 0.003) compared with baseline with hypoxemia. Circumferential and radial strains did not exhibit significant changes. In the near-term sheep fetus, LV global longitudinal and circumferential strains are more negative than RV strains. Acute hypoxemia leads to LV rather than RV dysfunction as reflected by decreased deformation.

      PubDate: 2017-03-09T16:22:24Z
      DOI: 10.1016/j.ultrasmedbio.2017.01.010
       
  • Assessment of Curve Flexibility on Scoliotic Surgical Candidates Using
           Ultrasound Imaging Method
    • Authors: Rui Zheng; Doug Hill; Douglas Hedden; Marc Moreau; Lawrence H. Le; Jim Raso; Edmond Lou
      Abstract: Publication date: Available online 6 March 2017
      Source:Ultrasound in Medicine & Biology
      Author(s): Rui Zheng, Doug Hill, Douglas Hedden, Marc Moreau, Lawrence H. Le, Jim Raso, Edmond Lou
      The ultrasound imaging method was implemented to assess the spinal curve flexibility of scoliotic surgical candidates, or how much correction it can achieve while patients are bending or lying down. Fifteen participants were recruited. Pre-operative radiographs and ultrasound images in both standing and bending positions were acquired. The post-operative standing radiographs were obtained 1 wk after surgery. Two raters (RZ, EL) measured the ultrasound images twice, 1 wk apart. A curve correction index (C I ) was developed to estimate the curve flexibility. The C I from the pre-operative bending radiograph, ultrasound and post-operative radiograph were 0.51 ± 0.18; R1: 0.74 ± 0.08 vs R2: 0.72 ± 0.09 and 0.60 ± 0.10, respectively. The correlation of C I between ultrasound and post-operative radiography was slightly higher than the pre-operative bending and post-operative radiography. This pilot study demonstrated the bending ultrasound method is a promising supplemental tool to assess curve flexibility before surgical intervention for scoliotic surgical candidates.

      PubDate: 2017-03-09T16:22:24Z
      DOI: 10.1016/j.ultrasmedbio.2017.01.017
       
 
 
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