for Journals by Title or ISSN
for Articles by Keywords
help
  Subjects -> PHYSICS (Total: 800 journals)
    - ELECTRICITY AND MAGNETISM (9 journals)
    - MECHANICS (20 journals)
    - NUCLEAR PHYSICS (48 journals)
    - OPTICS (89 journals)
    - PHYSICS (580 journals)
    - SOUND (23 journals)
    - THERMODYNAMICS (31 journals)

PHYSICS (580 journals)

The end of the list has been reached or no journals were found for your choice.
Journal Cover Ultrasound in Medicine & Biology
  [SJR: 0.939]   [H-I: 91]   [7 followers]  Follow
    
   Full-text available via subscription Subscription journal
   ISSN (Print) 0301-5629
   Published by Elsevier Homepage  [2969 journals]
  • Correlation of Breast Ultrasound Classifications with Breast Cancer in
           Chinese Women
    • Abstract: Publication date: Available online 21 August 2016
      Source:Ultrasound in Medicine & Biology
      Author(s): Xin-Yan Hou, Hai-Yan Niu, Xiao-Ling Huang, Yu Gao
      The aim of this study was to identify potential links between ultrasonographic breast parenchymal patterns and the risk of breast cancer in Chinese women. The population of Chinese women at high risk for breast cancer was explored using the ultrasonographic classification. Ultrasonographic parenchymal patterns were classified into four types: heterogeneous type, ductal type, mixed type and fibrous type. A total of 5879 Chinese women underwent breast ultrasound examination from May 2010 to April 2014. Of the 5879 women, 256 women had pathology-confirmed breast cancer. Among the remaining 5623 women, 512 randomly selected, age-matched women were recruited into the present study. The correlation between ultrasonographic type and breast cancer revealed that the odds ratio (OR) was highest for the heterogeneous type (odds ratio = 4.11, 95% confidence interval: 2.01–8.41, p < 0.001), followed by the fibrous type (odds ratio = 2.05, 95% confidence interval: 1.51–2.78, p < 0.001). The odds ratios of the ductal and mixed types were both less than 1 (p < 0.05). This study indicates that the heterogeneous and fibrous types in the ultrasonographic classification are associated with an increased risk of breast cancer and, therefore, can be used as a marker of breast cancer risk in the female population of China.


      PubDate: 2016-08-23T02:20:50Z
       
  • Microvascular Injury and Perfusion Changes Induced by Ultrasound and
           Microbubbles in a Machine-Perfused Pig Liver
    • Abstract: Publication date: Available online 20 August 2016
      Source:Ultrasound in Medicine & Biology
      Author(s): Christina P. Keravnou, Ine De Cock, Ine Lentacker, Maria-Louisa Izamis, Michalakis A. Averkiou
      Localized drug delivery and uptake can benefit from the combined action of ultrasound and microbubbles at a specific site. Some of the possible mechanisms suggested are vessel poration and/or cell poration, but the exact acoustic parameters that trigger those phenomena remain unknown. Ex vivo machine perfusion of human-sized organs is a technique that provides an ideal environment for pre-clinical investigations with high physiologic relevance not possible with in vitro experiments. In this work, ex vivo machine-perfused pig livers were combined with an image-guided therapy system to investigate microvascular flow changes caused by the interaction of ultrasound-driven microbubbles with the vasculature. The effects of acoustic pressure (1.7–4 MPa peak negative pressures) and number of cycles (1000 or 20 cycles) were examined. Perfusion changes caused by the action of ultrasound on microbubbles in the microcirculation were qualitatively and quantitatively assessed with contrast-enhanced ultrasound and used as a metric of the extent of vessel perforation, thus, extravasation. Areas that were exposed to peak negative pressures above 1.7 MPa underwent a detectable and irreversible perfusion change. Complete devascularization of the area exposed to ultrasound was observed at much larger acoustic pressures (∼4 MPa). Shorter acoustic pulses (20 cycles) produced markedly fewer perfusion changes than longer pulses (1000 cycles) under the same acoustic amplitude exposure.


      PubDate: 2016-08-23T02:20:50Z
       
  • Ultrasound and Contrast-Enhanced Ultrasound for Evaluation of Irreversible
           Electroporation Ablation: In Vivo Proof of Concept in Normal Porcine
           Liver
    • Abstract: Publication date: Available online 18 August 2016
      Source:Ultrasound in Medicine & Biology
      Author(s): Man-Xia Lin, Ming Kuang, Ming Xu, Bo-Wen Zhuang, Wen-Shuo Tian, Jie-Yi Ye, Xiao-Hua Xie, Xiao-Yan Xie
      The objective of this study was to describe the performance of ultrasound (US) and contrast-enhanced ultrasound (CEUS) within 2 h after irreversible electroporation (IRE) ablation of porcine liver. Six IRE ablations were performed on porcine liver in vivo; ultrasound assessments were performed within 2 h after IRE ablation. On US images, the ablation zone appeared as a hypo-echoic area within 10 min after the ablation, and then the echo of the ablation zone gradually increased. On CEUS images, the ablation zone appeared as a non-enhanced area within 10 min after ablation and then was gradually centripetally filled by microbubbles. A hyper-echoic rim on US images and a hyper-enhanced rim on CEUS images appeared in the periphery of the ablation zone 60 min after the ablation. Characteristic and dynamic ultrasound images of the IRE ablation zone were obtained within 2 h after IRE ablation of in vivo porcine liver.


      PubDate: 2016-08-23T02:20:50Z
       
  • High-Resolution Ultrasound of Schwannomas of the Limbs: Analysis of 72
           Cases
    • Abstract: Publication date: Available online 21 August 2016
      Source:Ultrasound in Medicine & Biology
      Author(s): Haixian Zhang, Yiming Li, Jie Shao, Weimin Chen, Yi Wang
      Schwannomas are common benign tumors that develop in peripheral nerves. High-resolution ultrasound (HRUS) is an effective imaging modality in clinics. The aim of this study was to define the value of HRUS in diagnosing schwannomas that originate from different nerves in limbs. We reviewed the ultrasound and surgical records of 72 pathologically confirmed schwannomas in the limbs of 60 patients. Results revealed that 44 (61.1%) of 72 cases, 44 (75.9%) of 58 cases and 0 (0%) of 14 cases received an overall correct pre-operative diagnosis, a correct pre-operative diagnosis in nerve trunks and a correct pre-operative diagnosis in small branches, respectively. Identification of the nerve of origin of schwannomas through HRUS likely increased confidence in diagnosing these benign tumors.


      PubDate: 2016-08-23T02:20:50Z
       
  • Diagnostic Utility of Acoustic Structure Quantification for Evaluation of
           Radiation Sialadenitis after Radioactive Iodine Therapy
    • Abstract: Publication date: Available online 16 August 2016
      Source:Ultrasound in Medicine & Biology
      Author(s): Sun Hye Jeong, Hyun Sook Hong, Eun Hye Lee
      Acoustic structure quantification (ASQ) software was used to analyze statistical information on acquired echo signals, to determine the ability of ASQ to distinguish normal salivary glands of asymptomatic patients from glands of patients with radiation sialadenitis (RS) after radioactive iodine therapy. The ASQ values of 192 salivary glands were compared by multinomial logistic regression analysis, and receiver operating characteristic curves were constructed. Between-observer agreement was assessed by calculating the intra-class correlation coefficient. The mean ASQ values of patients with chronic RS or asymptomatic patients who had undergone radioactive iodine therapy were greater than those of patients with normal glands (p < 0.001). The ratio was associated with the highest odds ratio in patients with chronic RS compared with normal patients. Diagnostic performance was moderate; the intra-class correlation coefficient between observers was very good. ASQ can objectively differentiate RS-affected tissue from normal salivary tissue and is thus valuable for clinically diagnosing RS after radioactive iodine therapy.


      PubDate: 2016-08-18T01:45:42Z
       
  • Effect of Hypoxemia with or without Increased Placental Vascular
           Resistance on Fetal Left and Right Ventricular Myocardial Performance
           Index in Chronically Instrumented Sheep
    • Abstract: Publication date: Available online 17 August 2016
      Source:Ultrasound in Medicine & Biology
      Author(s): Amar Bhide, Olli Vuolteenaho, Mervi Haapsamo, Tiina Erkinaro, Juha Rasanen, Ganesh Acharya
      Myocardial performance index (MPI) is increased in growth-restricted fetuses with placental insufficiency, but it is unknown if this is due to fetal hypoxemia or increased placental vascular resistance (R plac). We used chronically instrumented sheep fetuses (n = 24). In 12 fetuses, placental embolization was performed 24 h before experiments. On the day of the experiment, left (LV) and right (RV) ventricular MPIs were obtained by pulsed Doppler at baseline and in the hypoxemia and recovery phases. At baseline, R plac was greater and fetal pO2 lower in the placental embolization group, but RV and LV MPIs were comparable to those of the control group. During hypoxemia, mean LV MPI increased significantly only in fetuses with an intact placenta (0.34 vs. 0.46), returning to baseline during the recovery phase. Right ventricular MPI was unaffected. We conclude that fetal LV function is sensitive to acute hypoxemia. Exposure to chronic hypoxemia could pre-condition the fetal heart and protect its function with worsening hypoxemia.


      PubDate: 2016-08-18T01:45:42Z
       
  • Incorporating Contrast-Enhanced Ultrasound into the BI-RADS Scoring System
           
    • Abstract: Publication date: Available online 17 August 2016
      Source:Ultrasound in Medicine & Biology
      Author(s): Xiaoyun Xiao, Licong Dong, Qiongchao Jiang, Xiaofeng Guan, Huan Wu, Baoming Luo
      The aim of the study was to develop a scoring model incorporating the Breast Imaging Reporting and Data System (BI-RADS) and the contrast-enhanced ultrasound (CEUS) scoring system to differentiate between malignant and benign breast lesions. A total of 524 solid breast masses in 490 consecutive patients were evaluated with conventional US and CEUS in this prospective study. Each lesion was scored according to BI-RADS, CEUS, and CEUS-rerated BI-RADS. The diagnostic specificity, sensitivity and accuracy of BI-RADS were 77.9%, 88.9% and 84.0%, respectively, and the area under the receiver operating characteristic curve was 0.834. The corresponding values for rerated BI-RADS were 82.1%, 96.9%, 90.3% and 0.895. The area under the receiver operating characteristic curve of BI-RADS alone was significantly smaller than that of CEUS and the rerated BI-RADS (p = 0.008 compared with CEUS, p = 0.002 compared with rerated BI-RADS). This study indicates that rerating BI-RADS with the CEUS scoring system improves its diagnostic accuracy.


      PubDate: 2016-08-18T01:45:42Z
       
  • Maximum Value Measured by 2-D Shear Wave Elastography Helps in
           Differentiating Malignancy from Benign Focal Liver Lesions
    • Abstract: Publication date: September 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 9
      Author(s): Wen-Shuo Tian, Man-Xia Lin, Lu-Yao Zhou, Fu-Shun Pan, Guang-Liang Huang, Wei Wang, Ming-De Lu, Xiao-Yan Xie
      The goal of the work described here was to evaluate the diagnostic efficacy of 2-D shear wave elastography (2-D SWE) in differentiating malignancy from benign focal liver lesions (FLLs). The maxima, minima, means and the standard deviations of 2-D SWE measurements, expressed in kilopascals (E max, E min, E mean, E SD), were obtained for 221 patients with 229 FLLs. Receiver operating characteristic curve analysis was performed to evaluate the diagnostic performance of 2-D SWE. The Mann–Whitney U-test was used to assess inter-group differences. E max, E min, E mean and E SD were significantly higher in the 164 malignant lesions than in the 65 benign lesions (p < 0.001). For identification of malignant FLLs, the areas under receiver operating characteristic curves for E max, E min, E mean and E SD were 0.920, 0.710, 0.879 and 0.915, respectively. E max was 96.21 ± 35.40 for 19 intrahepatic cholangiocarcinomas and 90.32 ± 54.71 for 35 liver metastatic lesions, which were significantly higher than 61.83 ± 28.87 for 103 hepatocellular carcinomas (p < 0.0001 and p = 0.0237). E max was 38.72 ± 18.65 for 15 focal nodular hyperplasias, which was significantly higher than 20.56 ± 10.74 for 37 hemangiomas (p = 0.0009). The E max values for adjacent liver parenchyma of hepatocellular carcinomas and intrahepatic cholangiocarcinomas were significantly higher than those for the other three lesion types (p < 0.005). In conclusion, E max values of FLLs and adjacent liver parenchyma could help in differentiating malignant from benign FLLs.


      PubDate: 2016-08-14T00:54:53Z
       
  • Comparative Study of Three Regimens of Bowel Preparation Before
           Transabdominal Ultrasonography of the Colon
    • Abstract: Publication date: September 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 9
      Author(s): Xiu-ping Fan, Qiang Zhu, Ya-jing Zhou, Teng Ma, Chun-xia Xia, Hui-lian Huang
      The objective of the study was to compare the efficacy of three bowel preparation regimens for transabdominal colon ultrasonography. A total of 192 consecutive patients were given one of three regimens (senna, magnesium sulfate or polyethylene glycol electrolyte powder) before ultrasonographic examinations. The cleaning grade (I = emptying; II = filled or filled + empty; III = I or II with some retention; and IV = retention [grades I and II were termed “qualified”]) and cleaning range (A = all seven colon sections were qualified; B = four to six sections were qualified; C = three or less sections were qualified) were evaluated retrospectively. Senna was found more effective than polyethylene glycol in terms of cleaning grade (p < 0.001), qualified rate (p < 0.001) and cleaning range (p = 0.003). Senna was better than magnesium sulfate in cleaning grade (p < 0.001). Our results suggest that senna seems to be the preferred regimen for bowel preparation before transabdominal colonic ultrasonography.


      PubDate: 2016-08-14T00:54:53Z
       
  • Ultrasound and Point Shear Wave Elastography in Livers of Patients with
           Primary Sclerosing Cholangitis
    • Abstract: Publication date: September 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 9
      Author(s): Anders Batman Mjelle, Anesa Mulabecirovic, Trygve Hausken, Roald Flesland Havre, Odd Helge Gilja, Mette Vesterhus
      Point shear wave elastography (pSWE) is an ultrasound-based method for non-invasive quantification of liver fibrosis. The objective of this study was to explore liver pSWE in patients with primary sclerosing cholangitis (PSC) for assessment of fibrosis. Fifty-five non-transplant patients with PSC (38 males, 17 females; mean age: 46.4 y) were included and compared with 24 matched controls. Median (range) PSC duration was 8.1 (0–33) y. Ultrasonographic scanning followed by liver stiffness measurement by pSWE was performed using a conventional ultrasound system (Philips iU22). Signs of liver fibrosis on B-mode were identified in 21 patients (38%). Splenomegaly was found in 19 patients (35%) and ascites in two patients (4%). Successful pSWE measurements were achieved in the right liver lobe of all individuals and in the left liver lobe of 36 patients (65.5%). PSC patients had significantly higher median shear wave velocity (SWV) than controls in the right liver (median [range] SWV 1.26 [0.73–2.57] m/s vs. 1.09 [0.88–1.25] m/s, p < 0.001). SWV measured in the left liver lobe and spleen did not differ between PSC patients and controls. Our findings indicate that PSC patients have increased median SWV, indicating more fibrosis compared with controls; however, a wide range of SWV values were obtained among PSC patients, possibly reflecting the various stages in disease development.


      PubDate: 2016-08-14T00:54:53Z
       
  • Value of Virtual Touch Tissue Imaging Quantification for Evaluation of
           Ultrasound Breast Imaging-Reporting and Data System Category 4 Lesions
    • Abstract: Publication date: September 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 9
      Author(s): Xiao-Long Li, Hui-Xiong Xu, Xiao-Wan Bo, Bo-Ji Liu, Xian Huang, Dan-Dan Li, Le-Hang Guo, Jun-Mei Xu, Li-Ping Sun, Lin Fang, Xiao-Hong Xu
      The purpose of the study was to evaluate the value of 2-D shear wave elastography (SWE) of virtual touch tissue imaging quantification (VTIQ) for ultrasound (US) Breast Imaging-Reporting and Data System (BI-RADS) category 4 lesions. One hundred sixteen lesions were subject to conventional US, conventional strain elastography (SE) of elasticity imaging (EI), acoustic radiation force impulse (ARFI)-induced SE of virtual touch tissue imaging (VTI) and VTIQ before biopsies. Of the 116 lesions, 69 (59.5%) were benign and 47 (40.5%) were malignant. Significant differences were found between benign and malignant lesions in EI score, VTI score and shear wave speed (SWS) on VTIQ (both p < 0.05). The cut-off values were EI score ≥4, VTI score ≥4 and SWS ≥3.49 m/s, respectively. The diagnostic performance of VTIQ in terms of area under receiver operating characteristic curve (AUROC) were the highest (i.e., AUROC = 0.907), in comparison with EI, VTI alone or a combination of both. The associated sensitivity, specificity and accuracy were 87.2%, 82.6% and 84.5%, respectively. The combination of VTI and VTIQ, however, was similar with US BI-RADS (p = 0.475) in sensitivity in that only two (4.3%) of 47 malignant lesions were misdiagnosed as benign that were BI-RADS category 4b on US. VTIQ is valuable to differentiate benign from malignant BI-RADS category 4 lesions, and the combination of VTI and VTIQ might be useful for patient selection before biopsy.


      PubDate: 2016-08-14T00:54:53Z
       
  • Assessment of Diagnostic Accuracy and Efficiency of Categories 4 and 5 of
           the Second Edition of the BI-RADS Ultrasound Lexicon in Diagnosing Breast
           Lesions
    • Abstract: Publication date: September 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 9
      Author(s): Xuebin Zou, Jianwei Wang, Xiaowen Lan, Qingguang Lin, Feng Han, Longzhong Liu, Anhua Li
      The purpose of this study was to evaluate the diagnostic accuracy and efficiency of categories 4 and 5 of the second edition of the Breast Imaging Reporting and Data System (BI-RADS) ultrasound (US) lexicon in diagnosing breast lesions. In our retrospective study, 579 lesions in 544 patients were assessed by US as the preliminary diagnosis and classified in subcategories 4a–4c and category 5 based on the second edition of the BI-RADS US lexicon with some obvious changes, such as the redefined margin, new calcification type, associated features and some special cases. Inter-observer agreement was determined. Ultrasound results were compared with the pathologic results for confirmation. Positive predictive values (PPVs) of subcategories 4a–4c were compared with theoretical values using the χ2 test; the binomial test was used for category 5 lesions. Of the 579 lesions, 212 were confirmed as benign (36.61%), and the remaining 367 lesions were confirmed as borderline/malignant (63.39%). Inter-observer agreement was moderate for subcategories 4a–4c (κ = 0.52), moderate for subcategories 4a–4c and category 5 (κ = 0.56) and substantial for categories 4 and 5 (κ = 0.67). The PPVs for subcategories 4a–4c were 23.74%, 70.67% and 81.25%, respectively. In addition, the total PPV for category 4 was 46.92% (183/390), and the total PPV for category 5 was 97.35% (184/189). Statistical results revealed that the PPVs of subcategories 4a and 4b differed significantly from the theoretical values (p < 0.05); the PPVs of subcategory 4c and category 5 were significantly correlated with the theoretical PPVs (p > 0.05). In conclusion, subcategories 4a and 4b have lower diagnostic efficiency than subcategory 4c and category 5. Inter-observer agreement for subcategories 4a–4c remains to be improved. The most common features of subcategories 4a–4c differ, but overlap. It is recommended that inexperienced doctors in primary hospitals not classify lesions into subcategories in clinical practice.


      PubDate: 2016-08-14T00:54:53Z
       
  • Better Overall Survival for Breast Cancer Patients by Adding Breast
           Ultrasound to Follow-Up Examinations for Early Detection of Locoregional
           Recurrence—A Survival Impact Study
    • Abstract: Publication date: September 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 9
      Author(s): Wan-Chen Tsai, Hung-Kuang Wei, Chen-Fang Hung, Christopher Kwang-Jane Lin, Skye Hung-Chun Cheng, Chii-Ming Chen, Yong Alison Wang
      We retrospectively reviewed patient records to evaluate the effectiveness of our 15 y of ultrasound (US) surveillance of recurrent breast disease in comparison with mammography (MM) and clinical examination. From 4796 stage 0–III breast cancer patients who had received surgical treatment, we identified locoregional recurrence (LRR) in 161 patients. The mean age of the 161 patients was 48 y (27–82 y), and the mean follow-up interval was 77.2 mo (11–167 mo). The methods of LRR detection, sites of LRR and overall survival (OS) were examined. Multivariate Cox survival analysis showed significantly better survival in groups detected by US (hazard ratio = 0.6, p = 0.042). The 10-y LRR OS by detection types for US (n = 69), clinical examination (n = 78) and MM (n = 8) were 58.5%, 33.1% and 100%, respectively (p = 0.0004). US was seen with better OS associated with the effective early detection of non-palpable LRR breast cancer, which is mostly not detectable on MM.


      PubDate: 2016-08-14T00:54:53Z
       
  • Contents
    • Abstract: Publication date: September 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 9




      PubDate: 2016-08-14T00:54:53Z
       
  • Sex- and Maturity-Related Differences in Cortical Bone at the Distal
           Radius and Midshaft Tibia Evaluated by Quantitative Ultrasonography
    • Abstract: Publication date: September 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 9
      Author(s): Fátima Baptista, Lurdes M. Rebocho, Graça Cardadeiro, Vera Zymbal, Nicoletta Rosati
      Boys usually have higher values of bone mineral density measured by dual-energy X-ray absorptiometry than girls, but contradictorily also have a greater incidence of fractures during growth. The purpose of this study was to investigate sex- and maturity-related differences in bone speed of sound (SoS) at the radius and tibia in a sample of 625 healthy children aged 10–14 y and to analyze the contributions of physical activity (PA) to possible dissimilarities. Radial and tibial SoS was evaluated by quantitative ultrasound, maturity was estimated as the years of distance from the peak height velocity age, and PA was assessed by accelerometry. Comparisons between sexes and maturity groups (low: below average [<−2.5 y], high: average or above [≥−2.5 y]) were made by two-sample t-tests with unequal variances. Girls in the high-maturity group had higher SoS at the radius and tibia compared with girls in the low-maturity group (p < 0.001). There were no SoS differences at the radius or tibia between the high- and low-maturity groups in boys. Within high-maturity children, girls had higher SoS than boys at the radius and tibia (p < 0.001). There were no differences at the radius and tibia between girls and boys with low maturity. The results were not modified after controlling for PA. Regardless of PA, the results provide insight into sex- and maturity-related differences in bone SoS at the distal radius and midshaft tibia from maturity less than 2.5 y from the peak height velocity age, with boys having lower SoS.


      PubDate: 2016-08-14T00:54:53Z
       
  • Sonoelastographic Modalities in the Evaluation of Salivary Gland
           Characteristics in Sjögren's Syndrome
    • Abstract: Publication date: September 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 9
      Author(s): Benedikt Hofauer, Naglaa Mansour, Clemens Heiser, Constanze Gahleitner, Klaus Thuermel, Murat Bas, Andreas Knopf
      The purpose of this study was to investigate salivary tissue assessment with various sonoelastographic modalities (real-time tissue elastography, Virtual Touch imaging and quantification) in patients with Sjögren's syndrome as compared with an appropriate control group. The sonoelastographic modalities were evaluated in 50 patients with primary Sjögren's syndrome (pSS). Patients underwent high-resolution ultrasonography of the submandibular and parotid glands. Results of B-mode, real-time tissue elastography, Virtual Touch imaging—each graded with the appropriate scoring system—and Virtual Touch quantification were compared with those for 50 patients with sicca symptoms who did not fulfill the American–European consensus group criteria. In B-mode, 34 of 50 parotid glands in patients with pSS and 8 of 50 in the control group had abnormal findings (p < 0.001). Compared with 9 of 50 control patients, 38 of 50 patients with pSS had abnormal findings in submandibular gland B-mode (p < 0.001). With real-time tissue elastography, there was a trend toward higher scores for parotid glands in the pSS group (p = 0.238), whereas scores for submandibular glands in the control group were higher (p = 0.107). Virtual Touch imaging did not indicate any difference (p = 0.647 and p = 0.658). In Virtual Touch quantification, values for parotid (mean: 2.99 m/s) and submandibular glands (mean: 2.54 m/s) in the pSS group were higher than those for parotid (mean: 2.16 m/s) and submandibular (mean: 2.04 m/s) glands in the control group (p < 0.001 and p = 0.008). Glandular stiffness, measured by Virtual Touch quantification, was significantly higher in patients with Sjögreńs syndrome than in patients with sicca symptoms.


      PubDate: 2016-08-14T00:54:53Z
       
  • Hyper-Echoic Rim in Thyroid Nodules: A New Ultrasonographic Feature for
           Malignancy Prediction
    • Abstract: Publication date: September 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 9
      Author(s): YiJie Dong, WeiWei Zhan, JianQiao Zhou, LinLin Song, XiaoFeng Ni, BenYan Zhang
      The goal of this study was to verify the ultrasound features of hyper-echoic rims in thyroid nodules and to evaluate their diagnostic value in predicting thyroid malignancies. We retrospectively analyzed 228 pathologically proven thyroid nodules (137 malignant and 91 benign nodules). Forty-eight thyroid nodules had a hyper echogenic rim. All malignant nodules (137) were papillary carcinomas, which were studied to identify the correlation between the hyper-echoic rim (detected by ultrasound) and other histologic features. Presence of a hyper-echoic rim had high specificity (94.51%), but low sensitivity (31.39%) in predicting malignancy (p < 0.05). Thirty-seven of 43 malignant nodules had boundary zones of mixed structure (apparent fibrous stroma bands or dense collagenous border with a mixed population of cancerous cells) under microscopic examination. In conclusion, the hyper-echogenic rim could be one additional ultrasound parameter in the diagnosis of thyroid lesions.


      PubDate: 2016-08-14T00:54:53Z
       
  • Carotid Atherosclerotic Plaque Alters the Direction of Longitudinal Motion
           in the Artery Wall
    • Abstract: Publication date: September 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 9
      Author(s): Jimmy Tat, Ioannis N. Psaromiligkos, Stella S. Daskalopoulou
      Longitudinal motion of the artery, a cyclical, bidirectional movement of the wall in the long axis of the artery, has recently gained interest in the characterization of artery function. The aim of this study was to evaluate longitudinal motion in patients with internal carotid atherosclerotic plaques. Speckle tracking ultrasound was used to assess common carotid artery wall motion in 12 patients with carotid plaque causing either moderate (50%–79%) or severe (80%–99%) stenosis based on the North American Carotid Endarterectomy Trial, and 23 healthy participants. Although healthy individuals were found to have a retrograde wall motion pattern, a distinct anterograde pattern was noted with plaque presence. Importantly, patients with severe plaque stenosis had greater anterograde motion (0.53 ± 0.36 mm) than those with moderate stenosis (0.17 ± 0.15 mm) (p < 0.05), likely owing to high wall shear stresses associated with greater peak systolic velocities at the site of stenosis (severe: 342.0 ± 99.4 cm/s, moderate: 177.5 ± 31.2 cm/s, p < 0.01). There were no differences in peak systolic velocities at plaque-free segments between plaque groups (severe: 80.2 ± 24.8 cm/s, moderate: 92.7 ± 23.0 cm/s). Blood flow at stenotic areas better predicted motion than plaque-free segments. We conclude that the presence of carotid plaque can have significant influence on longitudinal motion, with significantly greater anterograde displacements with increased stenosis. Future studies are needed to further investigate carotid artery wall mechanics.


      PubDate: 2016-08-14T00:54:53Z
       
  • Three-Dimensional Assessment of Automated Breast Volume Scanner Compared
           with Handheld Ultrasound in Pre-Operative Breast Invasive Ductal
           Carcinomas: A Pilot Study of 51 Cases
    • Abstract: Publication date: September 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 9
      Author(s): Chaoli Xu, Shuping Wei, Yingdong Xie, Xiaoxiang Guan, Bin Yang
      The aim of the work described here was to compare the accuracy of conventional handheld ultrasound (HHUS) with that of an automated breast volume scanner (ABVS) in 3-D assessment of pre-operative invasive ductal carcinomas. HHUS and ABVS were used in 51 patients to obtain the largest tumor diameter, tumor volume and tumor surface area. The volumetric measurement was also obtained from ABVS data with medical software. With tumor size and volume on pathology as the gold standard, Bland–Altman analysis was used to compare variability. Correlation coefficients and receiver operating characteristic curves were established for all measurements for T2 classification. The correlation coefficients of all ABVS measurements were stronger than those of HHUS measurements, with the ABVS volumetric measurement significantly different with a higher accuracy of 88.24% (45/51) and predicting T-classification with higher area under the receiver operating characteristic curves (0.936). Therefore, 3-D measurements provide stronger correlations with pathology in tumor size measurement. However, more clinical trials are needed to confirm our findings.


      PubDate: 2016-08-14T00:54:53Z
       
  • Automated Breast Ultrasound: Dual-Sided Compared with Single-Sided Imaging
    • Abstract: Publication date: September 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 9
      Author(s): Eric D. Larson, Won-Mean Lee, Marilyn A. Roubidoux, Mitchel M. Goodsitt, Chris Lashbrook, Fouzaan Zafar, Oliver D. Kripfgans, Kai Thomenius, Paul L. Carson
      The design and performance of a mammographically configured, dual-sided, automated breast ultrasound (ABUS) 3-D imaging system are described. Dual-sided imaging (superior and inferior) is compared with single-sided imaging to aid decisions on clinical implementation of the more complex, but potentially higher-quality dual-sided imaging. Marked improvement in image quality and coverage of the breast is obtained in dual-sided ultrasound over single-sided ultrasound. Among hypo-echoic masses imaged, there are increases in the mean contrast-to-noise ratio of 57% and 79%, respectively, for spliced dual-sided versus superior or inferior single-sided imaging. The fractional breast volume coverage, defined as the percentage volume in the transducer field of view that is imaged with clinically acceptable quality, is improved from 59% in both superior and inferior single-sided imaging to 89% in dual-sided imaging. Applying acoustic coupling to the breast requires more effort or sophisticated methods in dual-sided imaging than in single-sided imaging.


      PubDate: 2016-08-14T00:54:53Z
       
  • Comparison of Inter-Observer Variability and Diagnostic Performance of the
           Fifth Edition of BI-RADS for Breast Ultrasound of Static versus Video
           Images
    • Abstract: Publication date: September 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 9
      Author(s): Ji Hyun Youk, Inkyung Jung, Jung Hyun Yoon, Sung Hun Kim, You Me Kim, Eun Hye Lee, Sun Hye Jeong, Min Jung Kim
      Our aim was to compare the inter-observer variability and diagnostic performance of the Breast Imaging Reporting and Data System (BI-RADS) lexicon for breast ultrasound of static and video images. Ninety-nine breast masses visible on ultrasound examination from 95 women 19–81 y of age at five institutions were enrolled in this study. They were scheduled to undergo biopsy or surgery or had been stable for at least 2 y of ultrasound follow-up after benign biopsy results or typically benign findings. For each mass, representative long- and short-axis static ultrasound images were acquired; real-time long- and short-axis B-mode video images through the mass area were separately saved as cine clips. Each image was reviewed independently by five radiologists who were asked to classify ultrasound features according to the fifth edition of the BI-RADS lexicon. Inter-observer variability was assessed using kappa (κ) statistics. Diagnostic performance on static and video images was compared using the area under the receiver operating characteristic curve. No significant difference was found in κ values between static and video images for all descriptors, although κ values of video images were higher than those of static images for shape, orientation, margin and calcifications. After receiver operating characteristic curve analysis, the video images (0.83, range: 0.77–0.87) had higher areas under the curve than the static images (0.80, range: 0.75–0.83; p = 0.08). Inter-observer variability and diagnostic performance of video images was similar to that of static images on breast ultrasonography according to the new edition of BI-RADS.


      PubDate: 2016-08-14T00:54:53Z
       
  • Application of a Novel Microvascular Imaging Technique in Breast Lesion
           Evaluation
    • Abstract: Publication date: September 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 9
      Author(s): Zhao Yongfeng, Zhou Ping, Liu Wengang, Shao Yang, Tian Shuangming
      Conventional power Doppler imaging (PDI) and the novel Superb Microvascular Imaging (SMI) technique were applied to observe the distribution of microvessels in 135 breast lesions, using semi-quantitative grading, penetrating vessel evaluation and flow distribution pattern to evaluate diagnostic efficacy. Compared with PDI, SMI detected more flow signals and details of microvessels. Further, when a centrally distributed branching or diffusing mode was used as a criterion for diagnosing malignancy, SMI improved diagnosis of breast masses. Sensitivity, specificity, positive predictive value and negative predictive value of SMI-assessed flow distribution were 85.4%, 92.6%, 83.3% and 93.5%, respectively, compared with 70.7%, 92.6%, 80.5% and 87.9% for PDI. We also found that flow distribution pattern analysis is superior to semi-quantitative grading and the penetrating vessel method in differentiating malignant breast lesions. Our work here further supports SMI as a novel and promising technique in visualizing microvasculature in breast lesions that may be of paramount use in initial diagnosis as well as follow-up assessment in various treatment regimes.


      PubDate: 2016-08-14T00:54:53Z
       
  • Color Doppler Ultrasound in Diagnosis and Assessment of Carotid Body
           Tumors: Comparison with Computed Tomography Angiography
    • Abstract: Publication date: September 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 9
      Author(s): Zhan-Qiang Jin, Wen He, Dong-Fang Wu, Mei-Ying Lin, Hua-Tang Jiang
      A carotid body tumor (CBT) is a rare, non-chromaffin paraganglioma, and its diagnosis mainly depends on imaging modalities. The aim of this study was to investigate the ability of color Doppler ultrasound (CDU) in the diagnosis and assessment of CBT based on computed tomography (CT). We retrospectively reviewed the CDU and CT features of 49 consecutive CBTs and 23 schwannomas from 67 patients and compared these findings with surgical resection specimens. The mean size of CBT lesions on ultrasound scans and CT angiography (CTA) was 3.24 cm ± 0.82 cm (range, 1.6–5.2 cm) and 3.84 cm ± 1.08 cm (range, 1.8–6.8 cm), respectively, which had statistically significant difference (t = 9.815, p = 0.000). The vascularity of CBT lesions was richer than that of schwannoma lesions (p < 0.05). Intra-lesional vascularities feeding CBT mostly arose from the external carotid artery and had spectrum characteristics including low velocity and resistance. Peak systolic velocity (PSV) and resistance index (RI) of the vasa vasorum were 39.8 cm/s ± 19.8 cm/s and 0.54 ± 0.06, respectively. There was the correlation between CTA and CDU in identifying Shamblin type I CBT lesions, while CTA technique was superior for CDU, identifying Shamblin type II and III CBT lesions. Accuracy, specificity and sensitivity of CDU in diagnosing CBTs were 87.5% (63 of 72), 82.6% (19 of 23) and 89.8% (44 of 49), respectively. Both accuracy and sensitivity of CTA in diagnosing CBTs were 100%. CDU can be useful for assessment of Shamblin's type and intra-lesional blood flow of CBTs before its metastases, while CT imaging can reveal the relationship between lesions and adjacent arteries, as well as the involvement of the skull base. CDU combined with CT imaging can be used as an optimal detection modality for the assessment and management of CBT.


      PubDate: 2016-08-14T00:54:53Z
       
  • Masthead
    • Abstract: Publication date: September 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 9




      PubDate: 2016-08-14T00:54:53Z
       
  • Editorial Advisory Board
    • Abstract: Publication date: September 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 9




      PubDate: 2016-08-14T00:54:53Z
       
  • Prediction of Renal Allograft Acute Rejection Using a Novel Non-Invasive
           Model Based on Acoustic Radiation Force Impulse
    • Abstract: Publication date: September 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 9
      Author(s): Cheng Yang, Yunjie Jin, Shengdi Wu, Long Li, Mushuang Hu, Ming Xu, Ruiming Rong, Tongyu Zhu, Wanyuan He
      Point shear wave elastography based on acoustic radiation force impulse is a novel technology used to quantify tissue stiffness by measuring shear wave speed. A total of 115 kidney transplantation recipients were consecutively enrolled in this prospective study. The patients were subdivided into two groups using 1 mo post-transplantation as the cutoff time for determining the development of acute rejection (AR). Shear wave speed was significantly higher in the AR group than in the non-AR group. We created a model called SEV, comprising shear wave speed, estimated glomerular filtration rate and kidney volume change, that could successfully discriminate patients with or without AR. The area under the receiver operating characteristic curve of SEV was 0.89, which was higher than values for other variables; it was even better in patients within 1 mo post-transplantation (0.954), but was lower than the estimated glomerular filtration rate in patients after 1 mo post-transplantation. Therefore, the SEV model may predict AR after renal transplantation with a high degree of accuracy, and it may be more useful in the early post-operative stage after renal transplantation.


      PubDate: 2016-08-14T00:54:53Z
       
  • Feasibility and Usefulness of Intra-Cavitary Contrast-Enhanced Ultrasound
           in Percutaneous Nephrostomy
    • Abstract: Publication date: September 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 9
      Author(s): Xin-Wu Cui, Andre Ignee, Tiberius Maros, Bernd Straub, Jian-Guo Wen, Christoph F. Dietrich
      The aim of this study was to evaluate the feasibility and utility of intra-cavitary contrast enhanced ultrasound (ICCEUS) in guiding percutaneous nephrostomy (PCN) and assessing complications. Forty-five ultrasound-guided PCNs were performed in 35 patients with hydronephrosis resulting from urinary tract obstruction. Ultrasound contrast agent (0.1 mL diluted in 20–30 mL saline) was injected through the puncture needle and the drainage tube to precisely locate the device and obstruction, with the fluoroscopy results considered the gold standard. ICCEUS was performed again the next day to assess complications. All 45 PCNs were successfully performed under the guidance of ultrasound. With ICCEUS, we could confirm the correct insertion of needle and catheter and locate the obstruction in all 35 patients, with fluoroscopic results as the gold standard. Catheter dislodgement was diagnosed by administration of ultrasound contrast agent in 5 patients. Hematoma (1 patient) and urine leakage (1 patient) were also observed. With the advantages of lack of exposure to radiation, performance in real time and bedside availability, ICCEUS has the potential to become a new modality to guide PCN and assess catheter-related complications.


      PubDate: 2016-08-14T00:54:53Z
       
  • Usefulness of Microvascular Ultrasonography in Differentiating Metastatic
           Lymphadenopathy from Tuberculous Lymphadenitis
    • Abstract: Publication date: September 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 9
      Author(s): Inseon Ryoo, Sangil Suh, Sung-Hye You, Hae Young Seol
      This study was undertaken to evaluate the usefulness of vascular pattern analysis on microvascular ultrasonography in distinguishing metastatic lymphadenopathy from tuberculous lymphadenitis, compared with conventional power Doppler ultrasonography, and to evaluate inter-observer agreement for microvascular ultrasonography. Thirty-four patients with metastatic lymphadenopathy and 27 patients with tuberculous lymphadenitis were included. The level of inter-observer agreement was excellent or good for all aspects of vascular pattern analysis on both ultrasonographic examinations. Vascular distribution, internal vascularity and internal vascular features of lymph nodes on microvascular ultrasonography differed significantly different (p ≤ 0.002) between metastatic lymphadenopathy and tuberculous lymphadenitis. A central vascular pattern with displacement was prevalent in metastasis, and an avascular pattern was more frequent in tuberculosis. Internal vascularity of metastasis was higher than that of tuberculosis. Vascular patterns on power Doppler ultrasonography did not differ significantly. Vascular pattern analysis using microvascular ultrasonography can be helpful in differentiating metastatic lymphadenopathy from tuberculous lymphadenitis with good inter-observer agreement.


      PubDate: 2016-08-14T00:54:53Z
       
  • Prospective Evaluation of Ultrasound Accuracy in the Detection of Pelvic
           Carcinomatosis in Patients with Ovarian Cancer
    • Abstract: Publication date: September 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 9
      Author(s): Vit Weinberger, Daniela Fischerova, Ivana Semeradova, Jiri Slama, Pavel Dundr, Ladislav Dusek, David Cibula, Michal Zikan
      We analyzed the accuracy of transvaginal sonography in detection of pelvic carcinomatosis in ovarian cancer patients and factors (age, body mass index, performance status, ascites, stage, histotype, tumor grade) influencing the performance of ultrasound. In this prospective study, all 191 consecutively included patients underwent a pre-operative ultrasound staging examination according to institutional protocol. Peritoneal spread was assessed on the basis of peri-operative findings or histology. The area under the receiver operating characteristic curve for the detection of carcinomatosis was 0.90 (0.84–0.93); the sensitivity was 84% (95% confidence interval [CI]: 75%–%90), specificity 96% (95% CI: 89%–99%), positive predictive value 96% (95% CI: 89%–99%), negative predictive value 83% (95% CI: 74%–90%) and overall accuracy 89% (95% CI: 84%–93%). We report that transvaginal sonography is clinically useful in the detection of pelvic carcinomatosis.


      PubDate: 2016-08-14T00:54:53Z
       
  • Impact of Corticosteroid Injection Site on the Treatment Success Rate of
           Trigger Finger: A Prospective Study Comparing Ultrasound-Guided True
           Intra-Sheath and True Extra-Sheath Injections
    • Abstract: Publication date: September 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 9
      Author(s): Rikuo Shinomiya, Toru Sunagawa, Yuko Nakashima, Masaaki Yoshizuka, Nobuo Adachi
      The aim of this study was to investigate whether differences in corticosteroid injection site influence the therapeutic effect on trigger finger and thickness of local structures such as the A1 pulley and flexor tendons. Previously untreated trigger fingers were randomly assigned to receive either a true intra-sheath (group I) or an extra-sheath (group E) injection under ultrasonographic guidance. Symptom remission and recurrence rates and recurrence timing did not significantly differ between the groups. Ultrasonography revealed mean (standard deviation) pre-injection A1 pulley thicknesses of 1.1 (0.3) and 1.1 (0.2) mm in groups I and E, respectively. One month after injection, these decreased to 0.7 (0.2) and 0.8 (0.2) mm, respectively (p < 0.05). Furthermore, mean (standard) pre-injection flexor digitorum tendon thickness was 4.1 (0.4) and 4.0 (0.5) mm in groups I and E, respectively, and, 1 mo after injection, decreased to 3.9 (0.3) and 3.8 (0.5) mm, respectively (p < 0.05). However, the difference at each time point between the two groups was not statistically significant. True intra-sheath injection offers no apparent advantage over extra-sheath injection for treating trigger fingers because both have the same effect on local structures.


      PubDate: 2016-08-14T00:54:53Z
       
  • Design and Testing of a Single-Element Ultrasound Viscoelastography System
           for Point-of-Care Edema Quantification
    • Abstract: Publication date: September 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 9
      Author(s): John J. Pitre, Leo B. Koziol, Grant H. Kruger, Alan Vollmer, Jonathan Ophir, Jean-Jacques Ammann, William F. Weitzel, Joseph L. Bull
      Management of fluid overload in patients with end-stage renal disease represents a unique challenge to clinical practice because of the lack of accurate and objective measurement methods. Currently, peripheral edema is subjectively assessed by palpation of the patient's extremities, ostensibly a qualitative indication of tissue viscoelastic properties. New robust quantitative estimates of tissue fluid content would allow clinicians to better guide treatment, minimizing reactive treatment decision making. Ultrasound viscoelastography (UVE) can be used to estimate strain in viscoelastic tissue, deriving material properties that can help guide treatment. We are developing and testing a simple, low-cost UVE system using a single-element imaging transducer that is simpler and less computationally demanding than array-based systems. This benchtop validation study tested the feasibility of using the UVE system by measuring the mechanical properties of a tissue-mimicking material under large strains. We generated depth-dependent creep curves and viscoelastic parameter maps of time constants and elastic moduli for the Kelvin model of viscoelasticity. During testing, the UVE system performed well, with mean UVE-measured strain matching standard mechanical testing with maximum absolute errors ≤4%. Motion tracking revealed high correlation and signal-to-noise ratios, indicating that the system is reliable.


      PubDate: 2016-08-14T00:54:53Z
       
  • Effect of Thrombus Composition and Viscosity on Sonoreperfusion
           Efficacy in a Model of Micro-Vascular Obstruction
    • Abstract: Publication date: September 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 9
      Author(s): John J. Black, Francois T.H. Yu, Rick G. Schnatz, Xucai Chen, Flordeliza S. Villanueva, John J. Pacella
      Distal embolization of micro-thrombi during stenting for myocardial infarction causes micro-vascular obstruction (MVO). We have previously shown that sonoreperfusion (SRP), a microbubble (MB)-mediated ultrasound (US) therapy, resolves MVO from venous micro-thrombi in vitro in saline. However, blood is more viscous than saline, and arterial thrombi that embolize during stenting are mechanically distinct from venous clot. Therefore, we tested the hypothesis that MVO created with arterial micro-thrombi are more resistant to SRP therapy compared with venous micro-thrombi, and higher viscosity further increases the US requirement for effective SRP in an in vitro model of MVO. Lipid MBs suspended in plasma with adjusted viscosity (1.1 cP or 4.0 cP) were passed through tubing bearing a mesh with 40-μm pores to simulate a micro-vascular cross-section; upstream pressure reflected thrombus burden. To simulate MVO, the mesh was occluded with either arterial or venous micro-thrombi to increase upstream pressure to 40 mmHg ± 5 mmHg. Therapeutic long-tone-burst US was delivered to the occluded area for 20 min. MB activity was recorded with a passive cavitation detector. MVO caused by arterial micro-thrombi at either blood or plasma viscosity resulted in less effective SRP therapy compared to venous thrombi. Higher viscosity further reduced the effectiveness of SRP therapy. The passive cavitation detector showed a decrease in inertial cavitation when viscosity was increased, while stable cavitation was affected in a more complex manner. Overall, these data suggest that arterial thrombi may require higher acoustic pressure US than venous thrombi to achieve similar SRP efficacy; increased viscosity decreases SRP efficacy; and both inertial and stable cavitation are implicated in observed SRP efficacy.


      PubDate: 2016-08-14T00:54:53Z
       
  • Histotripsy Produced by Hundred-Microsecond-Long Focused Ultrasonic
           Pulses: A Preliminary Study
    • Abstract: Publication date: September 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 9
      Author(s): Yubo Guan, Mingzhu Lu, Yujiao Li, Fenfen Liu, Ya Gao, Tengju Dong, Mingxi Wan
      A new strategy is proposed in this study to rapidly generate mechanical homogenized lesions using hundred-microsecond-long pulses. The pulsing scheme was divided into two stages: generating sufficient bubble seed nuclei via acceleration by boiling bubbles and efficiently forming a mechanically homogenized and regularly shaped lesion with a homogenate inside via inertial cavitation. The duty cycle was set at 4.9%/3.9% in stage 1 and 1%/0.88% in stage 2 by changing the pulse duration (PD) and off-time independently. The pulse sequence was 500-μs/400-μs PD with a 100-Hz pulse repetition frequency (PRF) in stage 1, followed by 500-μs/400-μs PD with a 100-Hz PRF and 200-μs PD with a 200-Hz PRF in stage 2. Experiments were conducted on polyacrylamide phantoms with bovine serum albumin and on ex vivo porcine kidney tissues using a single-element 1.06-MHz transducer at an 8-MPa peak negative pressure with shock waves. The lesion evolution and dynamic elastic modulus variation in the phantoms and the histology in the tissue samples were investigated. The results indicate that the two-stage treatment using hundred-microsecond-long pulses can efficiently produce mechanically homogenized lesions with smooth borders, long tear shapes and the total homogenate inside. The time to generate a single mechanically homogenized lesion is shortened from >50 s to 17.1 s.


      PubDate: 2016-08-14T00:54:53Z
       
  • Increased Effects of Extracorporeal Shock Waves Combined with Gentamicin
           against Staphylococcus aureus Biofilms In Vitro and In Vivo
           
    • Abstract: Publication date: September 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 9
      Author(s): Xin Qi, Yaochao Zhao, Jieyuan Zhang, Dan Han, Chunyuan Chen, Yinjun Huang, Xiaofeng Chen, Xianlong Zhang, Ting Wang, Xiaolin Li
      An implant-associated bacterial infection is one of the most common and costly complications of orthopedic surgery. Once biofilms develop, it is extremely difficult to cure infections with antimicrobial agents. High-energy extracorporeal shock wave (ESW) treatment has been used for orthopedic-related diseases and has been found to be an effective bactericidal agent that is tolerable both in vitro and in vivo. The broad-spectrum antibiotic gentamicin exhibits bactericidal activity against Staphylococcus aureus, and bacterial resistance to gentamicin is lower. We tested the effectiveness of gentamicin in combination with ESW treatment against S. aureus biofilms in vivo and in vitro. The spread plate method, crystal violet staining, confocal laser scanning microscopy, scanning electron microscopy and microbiologic evaluation were used to compare the effects of combined treatment with those of either treatment alone. The results revealed statistically significant differences between the group treated with ESWs combined with gentamicin and all other groups. Our findings indicate that use of the combination of ESWs with gentamicin is more effective against S. aureus biofilms in vitro and in vivo.


      PubDate: 2016-08-14T00:54:53Z
       
  • Caveolin-1 Mediates Low-Intensity Ultrasound-Induced Apoptosis via
           Downregulation of Signal Transducer and Activator of Transcription 3
           Phosphorylation in Laryngeal Carcinoma Cells
    • Abstract: Publication date: September 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 9
      Author(s): Qingsheng Ye, Cuida Meng, Yannan Shen, Jianjun Ji, Xiaochun Wang, Sheng Zhou, Lili Jia, Yanqun Wang
      Low-intensity ultrasound therapy has been found to be a potential tool in the management of malignant tumors in recent years. However, the molecular mechanism underlying low-intensity ultrasound-induced apoptosis is still not clear. In this study, we investigated the effects of low-intensity ultrasound-induced apoptosis in HEp-2 cells. We found that low-intensity ultrasound significantly induced apoptosis, and the expression level of caveolin-1 (Cav-1) was dramatically increased after ultrasound treatment of HEp-2 cells. After inhibiting the expression level of Cav-1 using siRNA transfection, we found that the cellular apoptosis induced by low-intensity ultrasound was significantly suppressed. In addition, inhibition of Cav-1 expression promoted phosphorylation of signal transducer and activator of transcription 3 (STAT3), suggesting that the STAT3 signaling pathway was involved in low-intensity ultrasound-induced apoptosis via Cav-1 regulation. Our results indicate that Cav-1/STAT3 signaling pathway may mediate low-intensity ultrasound-induced apoptosis, and this technology could potentially be used clinically for the treatment of cancers.


      PubDate: 2016-08-14T00:54:53Z
       
  • Non-Invasive, Focal Disconnection of Brain Circuitry Using Magnetic
           Resonance-Guided Low-Intensity Focused Ultrasound to Deliver a
           Neurotoxin
    • Abstract: Publication date: September 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 9
      Author(s): Yanrong Zhang, Hongying Tan, Edward H. Bertram, Jean-François Aubry, Maria-Beatriz Lopes, Jack Roy, Erik Dumont, Mingxing Xie, Zhiyi Zuo, Alexander L. Klibanov, Kevin S. Lee, Max Wintermark
      Disturbances in the function of neuronal circuitry contribute to most neurologic disorders. As knowledge of the brain's connectome continues to improve, a more refined understanding of the role of specific circuits in pathologic states will also evolve. Tools capable of manipulating identified circuits in a targeted and restricted manner will be essential not only to expand our understanding of the functional roles of such circuits, but also to therapeutically disconnect critical pathways contributing to neurologic disease. This study took advantage of the ability of low-intensity focused ultrasound (FUS) to transiently disrupt the blood–brain barrier (BBB) to deliver a neurotoxin with poor BBB permeability (quinolinic acid [QA]) in a guided manner to a target region in the brain parenchyma. Ten male Sprague-Dawley rats were divided into two groups receiving the following treatments: (i) magnetic resonance-guided FUS + microbubbles + saline (n = 5), or (ii) magnetic resonance–guided FUS + microbubbles + QA (n = 5). Systemic administration of QA was well tolerated. However, when QA and microbubbles were systemically administered in conjunction with magnetic resonance-guided FUS, the BBB was disrupted and primary neurons were destroyed in the targeted subregion of the hippocampus in all QA-treated animals. Administration of vehicle (saline) together with microbubbles and FUS also disrupted the BBB but did not produce neuronal injury. These findings indicate the feasibility of non-invasively destroying a targeted region of the brain parenchyma using low-intensity FUS together with systemic administration of microbubbles and a neurotoxin. This approach could be of therapeutic value in various disorders in which disturbances of neural circuitry contribute to neurologic disease.


      PubDate: 2016-08-14T00:54:53Z
       
  • Longitudinal Motor and Behavioral Assessment of Blood–Brain Barrier
           Opening with Transcranial Focused Ultrasound
    • Abstract: Publication date: September 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 9
      Author(s): Oluyemi O. Olumolade, Shutao Wang, Gesthimani Samiotaki, Elisa E. Konofagou
      Focused ultrasound (FUS), in combination with microbubbles, has been found to open the blood–brain barrier (BBB) non-invasively. When this technique is used for drug delivery, repeated drug administration and BBB opening are likely required. Therefore, it is worth investigating the long-term effects of FUS-induced BBB opening. In this study, we focused on the assessment of potential behavior changes in mice that could be attributed to repeated BBB opening for up to 6 months. The striatum of animals was unilaterally sonicated either monthly or biweekly throughout the monitoring period. Behavioral assessments were conducted using open-field and rotarod performance tests. Upon completion of each sonication, mice underwent magnetic resonance imaging (MRI) to confirm and assess the volume of the BBB opening. No differences in locomotor activity between BBB-opened and control groups in both biweekly and monthly treated mice were evident up to 6 months. Similarly, there was no affinity for a particular turn angle in the sonicated mice compared with the control animals. However, the positive control group exhibited a significant decrease in locomotor activity, as well as rotation ipsilateral to the sonicated hemisphere. Our results based on the assessment using open-field and rotarod tests indicated that repeated opening of the BBB in the striatum using FUS in conjunction with microbubbles over a period of 6 mo and under the parameters used here did not cause motor impairment, behavioral changes or morphologic alterations. This reinforces the tolerability of repeated and long-term drug delivery using FUS-induced BBB opening.


      PubDate: 2016-08-14T00:54:53Z
       
  • Quantification of Endothelial αvβ3 Expression with
           High-Frequency Ultrasound and Targeted Microbubbles:
           In Vitro and In Vivo Studies
    • Abstract: Publication date: September 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 9
      Author(s): Verya Daeichin, Klazina Kooiman, Ilya Skachkov, Johan G. Bosch, Thomas L. Theelen, Katja Steiger, Andrew Needles, Ben J. Janssen, Mat J.A.P. Daemen, Antonius F.W. van der Steen, Nico de Jong, Judith C. Sluimer
      Angiogenesis is a critical feature of plaque development in atherosclerosis and might play a key role in both the initiation and later rupture of plaques. The precursory molecular or cellular pro-angiogenic events that initiate plaque growth and that ultimately contribute to plaque instability, however, cannot be detected directly with any current diagnostic modality. This study was designed to investigate the feasibility of ultrasound molecular imaging of endothelial αvβ3 expression in vitro and in vivo using αvβ3-targeted ultrasound contrast agents (UCAs). In the in vitro study, αvβ3 expression was confirmed by immunofluorescence in a murine endothelial cell line and detected using the targeted UCA and ultrasound imaging at 18-MHz transmit frequency. In the in vivo study, expression of endothelial αvβ3 integrin in murine carotid artery vessels and microvessels of the salivary gland was quantified using targeted UCA and high-frequency ultrasound in seven animals. Our results indicated that endothelial αvβ3 expression was significantly higher in the carotid arterial wall containing atherosclerotic lesions than in arterial segments without any lesions. We also found that the salivary gland can be used as an internal positive control for successful binding of targeted UCA to αvβ3 integrin. In conclusion, αvβ3-targeted UCA allows non-invasive assessment of the expression levels of αvβ3 on the vascular endothelium and may provide potential insights into early atherosclerotic plaque detection and treatment monitoring.


      PubDate: 2016-08-14T00:54:53Z
       
  • Ex Vivo Porcine Arterial and Chorioallantoic Membrane Acoustic
           Angiography Using Dual-Frequency Intravascular Ultrasound Probes
    • Abstract: Publication date: September 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 9
      Author(s): K. Heath Martin, Brooks D. Lindsey, Jianguo Ma, Timothy C. Nichols, Xiaoning Jiang, Paul A. Dayton
      The presence of blood vessels within a developing atherosclerotic plaque has been found to be correlated with increased plaque vulnerability and ensuing cardiac events, however, detection of coronary intraplaque neovascularization poses a significant challenge in the clinic. We describe here a new in vivo intravascular ultrasound imaging method using a dual-frequency transducer to visualize contrast flow in microvessels with high specificity. This method uses a specialized transducer capable of exciting contrast agents at a low frequency (5.5 MHz) while detecting their nonlinear superhamonics at a much higher frequency (37 MHz). In vitro evaluation of the approach was performed in a microvascular phantom to produce 3-D renderings of simulated vessel patterns and to determine image quality metrics as a function of depth. Furthermore, we describe the ability of the system to detect microvessels both ex vivo using porcine arteries and in vivo using the chorioallantoic membrane of a developing chicken embryo with optical confirmation. Dual-frequency contrast-specific imaging was able to resolve vessels similar in size to those found in vulnerable atherosclerotic plaques at clinically relevant depths. The results of this study add to the support for further evaluation and translation of contrast-specific imaging in intravascular ultrasound for the detection of vulnerable plaques in atherosclerosis.


      PubDate: 2016-08-14T00:54:53Z
       
  • Cross-Modality Validation of Acetabular Surface Models Using 3-D
           Ultrasound Versus Magnetic Resonance Imaging in Normal and Dysplastic
           Infant Hips
    • Abstract: Publication date: September 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 9
      Author(s): Chad Diederichs, Alana Heath, Abhilash R. Hareendranathan, Dornoosh Zonoobi, Gregor Kuntze, Sukhdeep Dulai, Myles G. Mabee, Janet L. Ronsky, Jacob L. Jaremko
      Current imaging diagnosis of developmental dysplasia of the hip (DDH) in infancy relies on 2-D ultrasound (US), which is highly operator-dependent. 3-D US offers more complete, and potentially more reliable, imaging of infant hip geometry. We sought to validate the fidelity of acetabular surface models obtained by 3-D US against those obtained concurrently by magnetic resonance imaging (MRI). 3-D US and MRI scans were performed on the same d in 20 infants with normal to severely dysplastic hips (mean age, 57 d; range 13–181 d). 3-D US was performed by two observers using a Philips VL13-5 probe. Coronal 3-D multi-echo data image combination (MEDIC) magnetic resonance (MR) images (1-mm slice thickness) were obtained, usually without sedation, in a 1.5 T Siemens unit. Acetabular surface models were generated for 40 hips from 3-D US and MRI using semi-automated tracing software, separately by three observers. For each hip, the 3-D US and MRI models were co-registered to overlap as closely as possible using Amira software, and the root mean square (RMS) distances between points on the models were computed. 3-D US scans took 3.2 s each. Inter-modality variability was visually minimal. Mean RMS distance between corresponding points on the acetabular surface at 3-D US and MRI was 0.4 ± 0.3 mm, with 95% confidence interval <1 mm. Mean RMS errors for inter-observer and intra-observer comparisons were significantly less for 3-D US than for MRI, while inter-scan and inter-modality comparisons showed no significant difference. Acetabular geometry was reproduced by 3-D US surface models within 1 mm of the corresponding 3-D MRI surface model, and the 3-D US models were more reliable. This validates the fidelity of 3-D US modeling and encourages future use of 3-D US in assessing infant acetabulum anatomy, which may be useful to detect and monitor treatment of hip dysplasia.


      PubDate: 2016-08-14T00:54:53Z
       
  • Computer-Aided Diagnosis of Different Rotator Cuff Lesions Using Shoulder
           Musculoskeletal Ultrasound
    • Abstract: Publication date: September 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 9
      Author(s): Ruey-Feng Chang, Chung-Chien Lee, Chung-Ming Lo
      The lifetime prevalence of shoulder pain approaches 70%, which is mostly attributable to rotator cuff lesions such as inflammation, calcific tendinitis and tears. On clinical examination, shoulder ultrasound is recommended for the detection of lesions. However, there exists inter-operator variability in diagnostic accuracy because of differences in the experience and expertise of operators. In this study, a computer-aided diagnosis (CAD) system was developed to assist ultrasound operators in diagnosing rotator cuff lesions and to improve the practicality of ultrasound examination. The collected cases included 43 cases of inflammation, 30 cases of calcific tendinitis and 26 tears. For each case, the lesion area and texture features were extracted from the entire lesions and combined in a multinomial logistic regression classifier for lesion classification. The proposed CAD achieved an accuracy of 87.9%. The individual accuracy of this CAD system was 88.4% for inflammation, 83.3% for calcific tendinitis and 92.3% for tears. Cohen's k was 0.798. On the basis of its diagnostic performance, clinical use of this CAD technique has promise.


      PubDate: 2016-08-14T00:54:53Z
       
  • Complementary Detection of Multiple Electrical Sources in Tissue Using
           Acoustoelectric Effects
    • Abstract: Publication date: September 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 9
      Author(s): Zhaohui Wang, Rajab Challoo, Hu Peng, Chung S. Leung, Russell S. Witte
      Accurate 3-D mapping of multiple bioelectric sources in nerve fibers with high spatial resolution is challenging for the diagnosis and treatment of a variety of neural abnormalities. Ultrasound current source density imaging exploits the acoustoelectric (AE) effect, an interaction between electrical current and acoustic pressure waves propagating through a conducting material, and has distinct advantages over conventional electrophysiology (i.e., without ultrasound) for mapping electrical current flow in tissue. Ultrasound current source density imaging and two complementary Wheatstone bridge circuits were used to simultaneously detect two separate current flows induced in tissue phantoms. It has been found that the addition and subtraction of AE signals acquired by two circuits are independent components, regardless of whether the two sources are positioned at the same or different depths. In the ultrasound field, the AE signal from the bridge circuits is stronger, with a higher signal-to-noise ratio, than without a bridge circuit. Both experimental and simulated AE images depend on the magnitude and direction of the current, as well as the geometry (shape and thickness) and location of the current sources in the ultrasound field (2.25-MHz transducer). The experimental results are consistent with simulations consisting of multiple current sources. Real-time 3-D ultrasound current source density images of multiple current flows co-registered with convention pulse echo ultrasound potentially facilitate monitoring of neurologic disorders.


      PubDate: 2016-08-14T00:54:53Z
       
  • Role of Real-Time Elastography in the Evaluation of Cervical Lymph Nodes
           in Patients with Kikuchi Disease
    • Abstract: Publication date: September 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 9
      Author(s): Jiyeon Baik, Kwang Hwi Lee, JiHwa Ryu, OkHwa Kim, Jung-Hee Yoon, Seung Ho Kim, Hye Jin Baek
      The purpose of this study was to compare the use of conventional ultrasound (US) and real-time elastography (RTE) in Kikuchi disease (KD, n = 48) and malignant cervical lymphadenopathy (n = 100) and to evaluate the role of RTE in patients suspected of having KD. In univariate analysis, conventional US revealed each benign feature more frequently in KD than in malignant lymphadenopathy (p < 0.05). However, a considerable number of cases (29, 60.4%) of KD were assessed as malignant with US. KD was assessed as benign by RTE more frequently than malignant lymphadenopathy (37 [77.1%] vs. 37 [37.0%], p < 0.001). In multivariate analysis, perinodal hyper-echogenicity was predictive of KD (odds ratio: 67.25, confidence interval: 10.95–413.04, p < 0.001). There was a tendency for KD to be assessed as malignant with conventional US, but benign with RTE. RTE can help to avoid unnecessary biopsy in patients suspected of having KD on the basis of conventional US.


      PubDate: 2016-08-14T00:54:53Z
       
  • Ultrasound-Derived Forearm Muscle Thickness Is a Powerful Predictor for
           Estimating DXA-Derived Appendicular Lean Mass in Japanese Older Adults
    • Abstract: Publication date: September 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 9
      Author(s): Takashi Abe, Eiji Fujita, Robert S. Thiebaud, Jeremy P. Loenneke, Takuya Akamine
      To test the validity of published equations, anterior forearm muscle thickness (MT-ulna) of 158 Japanese older adults (72 men and 86 women) aged 50–79 y was measured with ultrasound. Appendicular lean soft tissue mass (aLM) was estimated from MT-ulna using two equations (body height without [eqn 1] and with [eqn 2]) previously published in the literature. Appendicular lean mass was measured using dual-energy X-ray absorption (DXA), and this method served as the reference criterion. There was a strong correlation between DXA-derived and ultrasound-estimated aLM in both equations (r = 0.882 and r = 0.944). Total error was 2.60 kg for eqn (1) and 1.38 kg for eqn (2). A Bland–Altman plot revealed that there was no systematic bias between DXA-derived and ultrasound-estimated aLM; however, eqn (1) overestimated aLM compared with DXA-derived aLM. Our results suggest that an ultrasound MT-ulna equation that includes body height is appropriate and useful for estimating aLM in Japanese adults.


      PubDate: 2016-08-14T00:54:53Z
       
  • B-Flow Imaging in Lower Limb Peripheral Arterial Disease and Bypass Graft
           Ultrasonography
    • Abstract: Publication date: September 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 9
      Author(s): Fabrizio D'Abate, Veni Ramachandran, Mark A. Young, John Farrah, Mudasar H. Ahmed, Keith Jones, Robert J. Hinchliffe
      Doppler ultrasonography plays a key role in the diagnosis of peripheral arterial disease, but is often limited by pitfalls that may be overcome by B-flow imaging. Thus far, there is little information on B-flow imaging for the assessment of peripheral arterial disease and bypass grafts in lower limbs. This article describes the authors' early experience with B-flow in the lower extremities. Sixty patients were included among a large cohort of patients routinely referred to the vascular laboratory for peripheral arterial disease and bypass graft assessments. Two experienced vascular sonographers performed all scans, comparing color Doppler ultrasonography with B-flow imaging. All scans were performed using a combination of the 9 L linear and C2-9 curvilinear transducers with the LOGIQ E9 system (GE Healthcare, Waukesha, WI, USA). Our experience indicates that this relatively unexplored technology has the potential to significantly improve peripheral blood flow evaluation. Nevertheless, B-flow imaging is not exempt from limitations and should be considered complementary to color Doppler ultrasonography.


      PubDate: 2016-08-14T00:54:53Z
       
  • Calendar
    • Abstract: Publication date: September 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 9




      PubDate: 2016-08-14T00:54:53Z
       
  • In Vivo Endoluminal Ultrasound Biomicroscopy and Endoscopy of
           Inflamed Rat Esophagus
    • Abstract: Publication date: Available online 13 August 2016
      Source:Ultrasound in Medicine & Biology
      Author(s): Rodrigo de Magalhães Gomes, Rossana C. Soletti, Mônica Soldan, Kalil Madi, F. Stuart Foster, João C. Machado
      The development of high-frequency endoscopic ultrasound for the investigation of models of esophageal disease may offer insights for future translation to human imaging. With respect to small animal models of esophageal diseases, ultrasound imaging instrumentation must employ frequencies scaled up to maintain the compromise between image resolution and inspected region. In this sense, a 40-MHz endoluminal ultrasound biomicroscopy (eUBM) system and an endoscope were tested as diagnostic methods of imaging rat esophageal lesions in the acute and chronic phases caused by sodium hydroxide. Although endoscopy allowed grading of the esophagus in accordance with a classification specific to the epithelial alterations and including hyperemia, edema, exudates, fibrin and superficial and deep ulcerations, the eUBM images yielded the detection of superficial and deep ulcerations, as well as wall alterations caused by edema and inflammatory infiltrate in the submucosa. Additionally, eUBM enabled wall thickness measurements, which were statistically significantly increased (p < 0.05) in the acute phase.


      PubDate: 2016-08-14T00:54:53Z
       
  • Calibrated Linear Array-Driven Photoacoustic/Ultrasound Tomography
    • Abstract: Publication date: Available online 12 August 2016
      Source:Ultrasound in Medicine & Biology
      Author(s): Milan Oeri, Wolfgang Bost, Steffen Tretbar, Marc Fournelle
      The anisotropic resolution of linear arrays, tools that are widely used in diagnostics, can be overcome by compounding approaches. We investigated the ability of a recently developed calibration and a novel algorithm to determine the actual radial transducer array distance and its misalignment (tilt) with respect to the center of rotation in a 2-D and 3-D tomographic setup. By increasing the time-of-flight accuracy, we force in-phase summation during the reconstruction. Our setup is composed of a linear transducer and a rotation and translation axis enabling multidimensional imaging in ultrasound and photoacoustic mode. Our approach is validated on phantoms and young mice ex vivo. The results indicate that application of the proposed analytical calibration algorithms prevents image artifacts. The spatial resolution achieved was 160 and 250 μm in photoacoustic mode of 2-D and 3-D tomography, respectively.


      PubDate: 2016-08-14T00:54:53Z
       
  • Ultrasound Strain Measurements for Evaluating Local Pulmonary Ventilation
    • Abstract: Publication date: Available online 10 August 2016
      Source:Ultrasound in Medicine & Biology
      Author(s): Jonathan M. Rubin, Jeffrey C. Horowitz, Thomas H. Sisson, Kang Kim, Luis A. Ortiz, James D. Hamilton
      Local lung function is difficult to evaluate, because most lung function estimates are either global in nature (e.g., pulmonary function tests) or require equipment that cannot be used at a patient's bedside, such as computed tomography. Yet, local function measurements would be highly desirable for many reasons. Recently, we were able to track displacements of the lung surface during breathing. We have now extended these results to measuring lung strains during respiration as a means of assessing local lung ventilation. We studied two human volunteers and 14 mice with either normal lung function or experimentally induced pulmonary fibrosis. The differences in strains between the control, normal mice and those with pulmonary fibrosis were significant (p < 0.0001), whereas the strains measured in the human volunteers closely matched linear strains predicted from the literature. It may be possible to use ultrasonography to assess local lung ventilation in a clinical setting.


      PubDate: 2016-08-14T00:54:53Z
       
  • Effects of Stone Size on the Comminution Process and Efficiency in Shock
           Wave Lithotripsy
    • Abstract: Publication date: Available online 9 August 2016
      Source:Ultrasound in Medicine & Biology
      Author(s): Ying Zhang, Isaac Nault, Sorin Mitran, Edwin S. Iversen, Pei Zhong
      The effects of stone size on the process and comminution efficiency of shock wave lithotripsy (SWL) were investigated in experiments, numerical simulations and scale analysis. Cylindrical BegoStone phantoms with approximately equal height and diameter of either 4, 7 or 10 mm, in a total aggregated mass of about 1.5 g, were treated in an electromagnetic shock wave lithotripter field. The resultant stone comminution was found to correlate closely with the average peak pressure, P +(avg), incident on the stones. The P +(avg) threshold necessary to initiate stone fragmentation in water increased from 7.9 to 8.8 to 12.7 MPa, respectively, as stone size decreased from 10 to 7 to 4 mm. Similar changes in the P +(avg) threshold were observed for the 7- and 10-mm stones treated in 1,3-butanediol, in which cavitation is suppressed, suggesting that the observed size dependency is due to changes in stress distribution within stones of different size. Moreover, the slope of the correlation curve between stone comminution and ln ( P ¯ + ( avg ) ) in water increased with decreasing stone size, whereas the opposite trend was observed in 1,3-butanediol. The progression of stone comminution in SWL exhibited size-dependence: the 7- and 10-mm stones fragmented into progressively smaller pieces, whereas a significant portion (>30%) of the 4-mm stones reached a stalemate within the size range of 2.8 ∼ 4 mm, even after 1000 shocks. Analytical scaling considerations suggest size-dependent fragmentation behavior, a hypothesis further supported by numerical model calculations that reveal changing patterns of constructive and destructive wave interference and, thus, variations in the maximum tensile stress or stress integral produced in cylindrical and spherical stone of different sizes.


      PubDate: 2016-08-14T00:54:53Z
       
 
 
JournalTOCs
School of Mathematical and Computer Sciences
Heriot-Watt University
Edinburgh, EH14 4AS, UK
Email: journaltocs@hw.ac.uk
Tel: +00 44 (0)131 4513762
Fax: +00 44 (0)131 4513327
 
Home (Search)
Subjects A-Z
Publishers A-Z
Customise
APIs
Your IP address: 107.22.66.11
 
About JournalTOCs
API
Help
News (blog, publications)
JournalTOCs on Twitter   JournalTOCs on Facebook

JournalTOCs © 2009-2016