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Spectroscopy Letters: An International Journal for Rapid Communication     Hybrid Journal   (Followers: 3)
Sri Lankan Journal of Physics     Open Access  
Strain     Hybrid Journal   (Followers: 2)
Strength of Materials     Hybrid Journal   (Followers: 3)
Strength, Fracture and Complexity     Hybrid Journal   (Followers: 1)
Structural Dynamics     Open Access  
Studies In Applied Mathematics     Hybrid Journal   (Followers: 1)
Superconductor Science and Technology     Hybrid Journal   (Followers: 1)
Surface Engineering     Hybrid Journal   (Followers: 3)
Surface Review and Letters     Hybrid Journal   (Followers: 1)
Surface Science Reports     Full-text available via subscription   (Followers: 10)
Surface Science Spectra     Hybrid Journal  
Surface Topography : Metrology and Properties     Full-text available via subscription  
Synchrotron Radiation News     Hybrid Journal   (Followers: 2)
Synthetic Metals     Hybrid Journal   (Followers: 3)
Technical Physics     Hybrid Journal  
Technical Physics Letters     Hybrid Journal  
Tectonics     Full-text available via subscription   (Followers: 7)
The Astronomy and Astrophysics Review     Hybrid Journal   (Followers: 2)
The Chemical Physics of Solid Surfaces     Full-text available via subscription  
The European Physical Journal H     Hybrid Journal   (Followers: 1)
The European Physical Journal Plus     Open Access  
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The Physics of Metals and Metallography     Hybrid Journal   (Followers: 1)
The Physics Teacher     Full-text available via subscription   (Followers: 4)
Theoretical and Computational Fluid Dynamics     Hybrid Journal   (Followers: 7)
Theoretical and Mathematical Physics     Hybrid Journal   (Followers: 4)
Transport Theory and Statistical Physics     Hybrid Journal   (Followers: 3)
Tribology International     Hybrid Journal   (Followers: 8)
Tribology Letters     Hybrid Journal   (Followers: 3)
Tribotest     Hybrid Journal   (Followers: 1)
Ultrasonics     Hybrid Journal   (Followers: 3)
Ultrasonics Sonochemistry     Hybrid Journal   (Followers: 2)
Ultrasound in Medicine & Biology     Full-text available via subscription   (Followers: 6)
Universal Journal of Physics and Application     Open Access  
Virtual Journal of Applications of Superconductivity     Hybrid Journal   (Followers: 1)
Virtual Journal of Biological Physics Research     Hybrid Journal   (Followers: 1)
Virtual Journal of Nanoscale Science & Technology     Hybrid Journal   (Followers: 1)
Virtual Journal of Ultrafast Science     Hybrid Journal   (Followers: 7)
Western Journal of Communication     Hybrid Journal   (Followers: 4)
Women & Performance: a journal of feminist theory     Hybrid Journal   (Followers: 2)
Women in Engineering Magazine, IEEE     Full-text available via subscription   (Followers: 8)
World Journal of Condensed Matter Physics     Open Access  
Zeitschrift für angewandte Mathematik und Physik     Hybrid Journal   (Followers: 1)

  First | 1 2 3 4 5 6 | Last

Journal Cover Ultrasound in Medicine & Biology
   [8 followers]  Follow    
   Full-text available via subscription Subscription journal
     ISSN (Print) 0301-5629
     Published by Elsevier Homepage  [2563 journals]   [SJR: 0.864]   [H-I: 85]
  • Efficacy of Therapeutic Ultrasound in Pain and Joint Mobility in Whiplash
           Traumatic Acute and Subacute Phases
    • Abstract: Publication date: Available online 9 July 2014
      Source:Ultrasound in Medicine & Biology
      Author(s): Carmen Ruiz-Molinero , Jose Jesus Jimenez-Rejano , Raquel Chillon-Martinez , Carmen Suarez-Serrano , Jesus Rebollo-Roldan , Veronica Perez-Cabezas
      To determine if ultrasound (US) is effective in reducing pain and mobility limitation in the treatment of traumatic cervical sprain, we performed an experimental study. The sample comprised 54 diagnosed subjects with a mean age of 36.54 y (standard deviation = 12.245), assigned by simple random selection to an experimental group with ultrasound treatment and a control group with placebo ultrasound. Treatment consisted of 10 sessions of an ultrasound treatment protocol, followed by 15 sessions of a protocol identical for both groups without ultrasound. The variables assessed were pain and joint mobility. There was no significant difference (p > 0.05) between groups in the first 10 sessions of treatment. However, there was a statistically significant difference (p < 0.05) between groups on the pain variable, 20 days after completion of the US. High-active ultrasound treatment is more effective than placebo in reducing pain.


      PubDate: 2014-07-25T19:18:46Z
       
  • Non-contact High-Frequency Ultrasound Microbeam Stimulation for Studying
           Mechanotransduction in Human Umbilical Vein Endothelial Cells
    • Abstract: Publication date: Available online 9 July 2014
      Source:Ultrasound in Medicine & Biology
      Author(s): Jae Youn Hwang , Hae Gyun Lim , Chi Woo Yoon , Kwok Ho Lam , Sangpil Yoon , Changyang Lee , Chi Tat Chiu , Bong Jin Kang , Hyung Ham Kim , K. Kirk Shung
      We describe how contactless high-frequency ultrasound microbeam stimulation (HFUMS) is capable of eliciting cytoplasmic calcium (Ca2+) elevation in human umbilical vein endothelial cells. The cellular mechanotransduction process, which includes cell sensing and adaptation to the mechanical micro-environment, has been studied extensively in recent years. A variety of tools for mechanical stimulation have been developed to produce cellular responses. We developed a novel tool, a highly focused ultrasound microbeam, for non-contact cell stimulation at a microscale. This tool, at 200 MHz, was applied to human umbilical vein endothelial cells to investigate its potential to elicit an elevation in cytoplasmic Ca2+ levels. It was found that the response was dose dependent, and moreover, extracellular Ca2+ and cytoplasmic Ca2+ stores were involved in the Ca2+ elevation. These results suggest that high-frequency ultrasound microbeam stimulation is potentially a novel non-contact tool for studying cellular mechanotransduction if the acoustic pressures at such high frequencies can be quantified.


      PubDate: 2014-07-25T19:18:46Z
       
  • Feasibility of Ultrasound Imaging of Osteochondral Defects in the
           Ankle: A Clinical Pilot Study
    • Abstract: Publication date: Available online 9 July 2014
      Source:Ultrasound in Medicine & Biology
      Author(s): A.C. Kok , M.P. Terra , S. Muller , C. Askeland , C.N. van Dijk , G.M.M.J. Kerkhoffs , G.J.M. Tuijthof
      Talar osteochondral defects (OCDs) are imaged using magnetic resonance imaging (MRI) or computed tomography (CT). For extensive follow-up, ultrasound might be a fast, non-invasive alternative that images both bone and cartilage. In this study the potential of ultrasound, as compared with CT, in the imaging and grading of OCDs is explored. On the basis of prior CT scans, nine ankles of patients without OCDs and nine ankles of patients with anterocentral OCDs were selected and classified using the Loomer CT classification. A blinded expert skeletal radiologist imaged all ankles with ultrasound and recorded the presence of OCDs. Similarly to CT, ultrasound revealed typical morphologic OCD features, for example, cortex irregularities and loose fragments. Cartilage disruptions, Loomer grades IV (displaced fragment) and V (cyst with fibrous roof), were visible as well. This study encourages further research on the use of ultrasound as a follow-up imaging modality for OCDs located anteriorly or centrally on the talar dome.


      PubDate: 2014-07-25T19:18:46Z
       
  • Evaluation of Statin Therapy on Endothelial Function in
           Hypercholesterolemic Rabbits by Automatic Measurement of Arterial Wall
           Movement Using Ultrasound Images
    • Abstract: Publication date: Available online 10 July 2014
      Source:Ultrasound in Medicine & Biology
      Author(s): Tavoos Rahmani-Cherati , Manijhe Mokhtari-Dizaji , Alireza Vajhi , Abdorrazzagh Rostami
      The aim of this study was to evaluate arterial endothelial function, assessed as acetylcholine-mediated dilation (AMD), in a hypercholesterolemic atherosclerotic rabbit model to investigate the effects of atorvastatin in the atherosclerotic process, using a new computerized analysis model and ultrasound images. Twenty-seven rabbits were fed a high-cholesterol (2%) diet for 6 wk and then divided into three groups for an additional 9 wk: Group A received regular chow food, group B received a 2% cholesterol-rich diet plus atorvastatin drug, and group C received regular chow food plus atorvastatin. Ultrasound examinations of endothelial function of the rabbit abdominal aorta artery were performed immediately after the 6 weeks (0 wk) and then 3, 6 and 9 wk after that. For off-line analysis, a computerized analysis method for evaluating instantaneous changes in the wall of the rabbit abdominal aorta was used. As parameters of improvement resulting from treatment, endothelium-dependent acetylcholine-induced dilation and endothelium-independent nitroglycerin-induced dilation were evaluated in treated rabbits. Differences among groups were tested using analysis of variance. On histopathology, intima-media thickness decreased after treatment in all groups. There were no significant differences in arterial diameter and blood velocity changes among treated rabbits at 0, 3, 6 and 9 wk of treatment in all groups, except in end-diastolic velocity, radial strain percentage, pulse index and resistance index in group C. In group A, AMD did not significantly improve after 3, 6 and 9 wk, as compared with 0 wk. Atorvastatin treatment significantly increased AMD (18%) at 3 wk in group B, compared with week 0. AMD significantly increased after 3 (26%), 6 (124%) and 9 (182%) wk in group C, compared with 0 wk. It is concluded that the new automatic method enables accurate and repeated evaluation of endothelial function during the progression and regression of atherosclerosis. Also, the results obtained in this study indicate that short-term administration of atorvastatin can improve endothelial function in cholesterol-fed rabbits.


      PubDate: 2014-07-25T19:18:46Z
       
  • Association Between Forearm Muscle Thickness and Age-related Loss of
           Skeletal Muscle Mass, Handgrip and Knee Extension Strength and Walking
           Performance in Old Men and Women: A Pilot Study
    • Abstract: Publication date: Available online 9 July 2014
      Source:Ultrasound in Medicine & Biology
      Author(s): Takashi Abe , Robert S. Thiebaud , Jeremy P. Loenneke , Madoka Ogawa , Naotoshi Mitsukawa
      Very little information is available concerning the relationship between handgrip strength and muscle size in the upper and lower extremities, especially the forearm muscle itself. To investigate the relationships among ultrasound-measured forearm muscle thickness from the radius and ulna bone interface with handgrip strength, knee extension strength, walking speed and absolute/relative total skeletal muscle mass (TMM), 32 Japanese men and 21 Japanese women ages 70–83 years had muscle thickness (MT) measured by ultrasound. In the forearm, two MTs (forearm-radius and forearm-ulna MT) were measured. TMM was estimated from an ultrasound-derived prediction equation. Handgrip-strength was significantly correlated with forearm-ulna MT in both men and women. There were no significant correlations between forearm MT and walking speed in either sex. In men, both forearm-radius and forearm-ulna MT were significantly correlated with TMM and TMM index. In women, a significant correlation was only observed between forearm-ulna MT and TMM index. Our results suggest that forearm-ulna MT may be a useful parameter for evaluating handgrip strength and TMM index in older Japanese men and women.


      PubDate: 2014-07-25T19:18:46Z
       
  • Ultrasound Arthroscopy of Human Knee Cartilage and Subchondral Bone
           in Vivo
    • Abstract: Publication date: Available online 9 July 2014
      Source:Ultrasound in Medicine & Biology
      Author(s): Jukka Liukkonen , Petri Lehenkari , Jukka Hirvasniemi , Antti Joukainen , Tuomas Virén , Simo Saarakkala , Miika T. Nieminen , Jukka S. Jurvelin , Juha Töyräs
      Arthroscopic ultrasound imaging enables quantitative evaluation of articular cartilage. However, the potential of this technique for evaluation of subchondral bone has not been investigated in vivo. In this study, we address this issue in clinical arthroscopy of the human knee (n = 11) by determining quantitative ultrasound (9 MHz) reflection and backscattering parameters for cartilage and subchondral bone. Furthermore, in each knee, seven anatomical sites were graded using the International Cartilage Repair Society (ICRS) system based on (i) conventional arthroscopy and (ii) ultrasound images acquired in arthroscopy with a miniature transducer. Ultrasound enabled visualization of articular cartilage and subchondral bone. ICRS grades based on ultrasound images were higher (p < 0.05) than those based on conventional arthroscopy. The higher ultrasound-based ICRS grades were expected as ultrasound reveals additional information on, for example, the relative depth of the lesion. In line with previous literature, ultrasound reflection and scattering in cartilage varied significantly (p < 0.05) along the ICRS scale. However, no significant correlation between ultrasound parameters and structure or density of subchondral bone could be demonstrated. To conclude, arthroscopic ultrasound imaging had a significant effect on clinical grading of cartilage, and it was found to provide quantitative information on cartilage. The lack of correlation between the ultrasound parameters and bone properties may be related to lesser bone change or excessive attenuation in overlying cartilage and insufficient power of the applied miniature transducer.


      PubDate: 2014-07-25T19:18:46Z
       
  • Dynamics of Targeted Microbubble Adhesion Under Pulsatile Compared with
           Steady Flow
    • Abstract: Publication date: Available online 9 July 2014
      Source:Ultrasound in Medicine & Biology
      Author(s): Charles A. Sennoga , John M. Seddon , Jennifer A. Frueh , Dong Zhang , Dorian O. Haskard , Robert J. Eckersley , Meng-Xing Tang
      Hemodynamic flow variations at low fluid shear stress are thought to play a critical role in local atherosclerotic plaque initiation and development and to affect plaque instability. Targeted microbubbles are being developed as intravascular agents for identifying atherosclerotic lesions using ultrasound. How variations in local hydrodynamic flow influence the adhesiveness of targeted microbubbles is not well understood. We postulated that rates of targeted microbubble binding and accumulation differ when subjected to steady flow (SF) as compared with oscillatory or pulsatile flow (PF), because PF imposes non-uniform blood rheology and periodic acceleration and deceleration of blood velocity, when compared with SF. We assessed the binding rates of targeted microbubbles in seven randomly assigned PF and seven matched SF replicate runs at low (<1 Pa) and intermediate (≥1 and <2.5 Pa) wall shear stress (WSS) by drawing 4.8 × 106 microbubbles mL−1 over streptavidin-coated substrates, immobilized within a parallel plate flow chamber at a calculated density of 81 binding sites μm-2. Selective binding and accumulation of targeted microbubbles was recorded in a single field of view using real-time video microscopy. Microbubble accumulation was modeled to obtain flow-mediated microbubble binding kinetics (amplitude, A, and rate constant, k). PF elicited higher microbubble accumulation rates, in comparison to SF. The rates of microbubble accumulation differed significantly between PF and SF (p < 0.05) at intermediate WSS but not at low WSS (p > 0.05). The rate of microbubble accumulation decreased as WSS increased.


      PubDate: 2014-07-25T19:18:46Z
       
  • Early Detection of Liver Fibrosis in Rats Using 3-D Ultrasound Nakagami
           Imaging: A Feasibility Evaluation
    • Abstract: Publication date: Available online 9 July 2014
      Source:Ultrasound in Medicine & Biology
      Author(s): Ming-Chih Ho , Po-Hsiang Tsui , Yu-Hsin Lee , Yung-Sheng Chen , Chiung-Nien Chen , Jen-Jen Lin , Chien-Cheng Chang
      We investigated the feasibility of using 3-D ultrasound Nakagami imaging to detect the early stages of liver fibrosis in rats. Fibrosis was induced in livers of rats (n = 60) by intraperitoneal injection of 0.5% dimethylnitrosamine (DMN). Group 1 was the control group, and rats in groups 2–6 received DMN injections for 1–5 weeks, respectively. Each rat was sacrificed to perform 3-D ultrasound scanning of the liver in vitro using a single-element transducer of 6.5 MHz. The 3-D raw data acquired at a sampling rate of 50 MHz were used to construct 3-D Nakagami images. The liver specimen was further used for histologic analysis with hematoxylin and eosin and Masson staining to score the degree of liver fibrosis. The results indicate that the Metavir scores of the hematoxylin and eosin-stained sections in Groups 1–4 were 0 (defined as early liver fibrosis in this study), and those in groups 5 and 6 ranged from 1 to 2 and 2 to 3, respectively. To quantify the degree of early liver fibrosis, the histologic sections with Masson stain were analyzed to calculate the number of fiber-related blue pixels. The number of blue pixels increased from (2.36 ± 0.79) × 104 (group 1) to (7.68 ± 2.62) × 104 (group 4) after DMN injections for 3 weeks, indicating that early stages of liver fibrosis were successfully induced in rats. The Nakagami parameter increased from 0.36 ± 0.02 (group 1) to 0.55 ± 0.03 (group 4), with increasing numbers of blue pixels in the Masson-stained sections (p-value < 0.05, t-test). We concluded that 3-D Nakagami imaging has potential in the early detection of liver fibrosis in rats and may serve as an image-based pathologic model to visually track fibrosis formation and growth.


      PubDate: 2014-07-25T19:18:46Z
       
  • Application of Vertebral Artery Ultrasonography in Enlistment-Age Male
           Student Pilots
    • Abstract: Publication date: Available online 9 July 2014
      Source:Ultrasound in Medicine & Biology
      Author(s): Shuping Liu , Li Li , Kechun Yao , Wenxiu Li , Na Wang , Li Cui , Zhikang Zou , Zhongli Ma
      The aim of this study was to investigate the vertebral artery (VA) morphology of enlistment-age male student pilots with ultrasound to provide a basis for early diagnosis of potentially asymptomatic cervical vertigo. Ultrasound results of the origin position, diameter and hemodynamics of the VA in 935 cases of student pilots with a mean age of 18.0 y were analyzed. The inner diameters of both sides of the VA differ: the left is larger than the right statistically (p < 0.001). Moreover, the peak systolic velocity of the left VA is significantly greater than that of the right (p < 0.001). Congenital VA anomalies in age-appropriate male student pilots included inner diameter variation, course variation and origin position variation. The incidence of course variation or origin position proportion was low (3.46%, 32/925), and origin position variation was often accompanied by inner diameter variation or course variation. This study confirms that there are a variety of congenital abnormalities in the vertebral arteries of enlistment-age male student pilots, and a VA diameter <2.5 mm may be a reasonable criterion for diagnosis of VA hypoplasia.


      PubDate: 2014-07-25T19:18:46Z
       
  • Comparison of Two Contrast Agents for Right-to-Left Shunt Diagnosis with
           Contrast-Enhanced Transcranial Doppler
    • Abstract: Publication date: Available online 9 July 2014
      Source:Ultrasound in Medicine & Biology
      Author(s): Na Hao , Kangding Liu , Zhen-Ni Guo , Xiujuan Wu , Yi Yang , Yingqi Xing
      We compared two contrast agents, agitated saline and agitated saline with blood, with respect to their efficacy in the diagnosis of right-to-left shunt with contrast-enhanced transcranial Doppler. Three hundred thirty Chinese patients underwent examinations with one of four different methods in random order: (i) 9 mL agitated saline solution with 1 mL air without the Valsalva maneuver (ASwoVM); (ii) 9 mL agitated saline solution with 1 mL air with the Valsalva maneuver (ASwVM); (iii) 9 mL agitated saline solution, 1 mL air and a drop of the patient's blood without the Valsalva maneuver (ASbwoVM); and (iv) 9 mL agitated saline solution, 1 mL air and a drop of the patient's blood, with the Valsalva maneuver (ASbwVM). Rates of detection were 11.5%, 17.9%, 16.7% and 23.6% for the ASwoVM, ASwVM, ASbwoVM, and ASbwVM examinations, respectively. The embolus track numbers for these examinations were 4.0 ± 1.83, 11.5 ± 6.2, 10.5 ± 4.9 and 33.7 ± 14.9, respectively. There were significant differences between the four groups (all comparisons, p < 0.001). For contrast-enhanced transcranial Doppler examinations, the agitated saline/blood agent yielded better rates of diagnosis of right to-left shunt than did the agitated saline alone.


      PubDate: 2014-07-25T19:18:46Z
       
  • Monitoring Plant Response to Environmental Stimuli by Ultrasonic Sensing
           of the Leaves
    • Abstract: Publication date: Available online 9 July 2014
      Source:Ultrasound in Medicine & Biology
      Author(s): Maria Dolores Fariñas , Domingo Sancho Knapik , Jose Javier Peguero Pina , Eustaquio Gil Pelegrin , Tomás E. Gómez Álvarez-Arenas
      Described here is the application of a technique based on the excitation, sensing and spectral analysis of thickness resonances of plant leaves using air-coupled and wide-band ultrasound pulses (150–900 kHz) to monitor variations in leaf properties caused by plant responses to different environmental stimuli, such as a sudden variation in light intensity (from 2000 to 150 μmol m−2 s−1), sudden watering after a drought period, and along the diurnal cycle (3–5 days, with continuous variation in light intensity from 150 to 2000 μmol m−2 s−1 and change in temperature of about 5°C). Four different widely available species, both monocots and dicots and evergreen and deciduous, with different leaf features (shape, size, thickness, flatness, vascular structure), were selected to test the technique. After a sudden decrease in light intensity, and depending on the species, there was a relative increase in the thickness resonant frequency from 8% to 12% over a 25- to 50-min period. After sudden watering, the relative increase in the resonant frequency varied from 5% to 30% and the period from 10 to 400 min. Finally, along the diurnal cycle, the measured relative variation is between 4% and 10%. The technique revealed differences in both the amplitude of the frequency oscillations and the kinetics of the leaf response for different species and also within the same species, but for specimens grown under different conditions that present different cell structures at the tissue level. The technique can be equally applied to the leaves of any species that present thickness resonances.


      PubDate: 2014-07-25T19:18:46Z
       
  • Harmonic Imaging with Fresnel Beamforming in the Presence of Phase
           Aberration
    • Abstract: Publication date: Available online 10 July 2014
      Source:Ultrasound in Medicine & Biology
      Author(s): Man Minh Nguyen , Junseob Shin , Jesse Yen
      Fresnel beamforming is a beamforming method with a delay profile similar in shape to a physical Fresnel lens. The advantage of Fresnel beamforming is the reduced channel count, which consists of four to eight transmit and two analog-to-digital receive channels. Fresnel beamforming was found to perform comparably to conventional delay-and-sum beamforming. However, the performance of Fresnel beamforming is highly dependent on focal errors. These focal errors result in high side-lobe levels and further reduce the performance of Fresnel beamforming in the presence of phase aberration. With the advantages of lower side-lobe levels and suppression of aberration effects, harmonic imaging offers an effective solution to the limitations of Fresnel beamforming. We describe the implementation of tissue harmonic imaging and pulse inversion harmonic imaging in Fresnel beamforming, followed by dual apodization with cross-correlation, to improve image quality. Compared with conventional delay-and-sum beamforming, experimental results indicated contrast-to-noise ratio improvements of 10%, 49% and 264% for Fresnel beamforming using tissue harmonic imaging in the cases of no aberrator, 5-mm pork aberrator and 12-mm pork aberrator, respectively. These improvements were 22%, 57% and 352% for Fresnel beamforming using pulse inversion harmonic imaging. Moreover, dual apodization with cross-correlation was found to further improve the contrast-to-noise ratios in all cases. Harmonic imaging was also found to narrow the lateral beamwidth and shorten the axial pulse length by at least 25% and 21%, respectively, for Fresnel beamforming at different aberration levels. These results suggest the effectiveness of harmonic imaging in improving image quality for Fresnel beamforming, especially in the presence of phase aberration. Even though this combination of Fresnel beamforming and harmonic imaging does not outperform delay-and-sum beamforming combined with harmonic imaging, it provides the benefits of reduced channel count and potentially reduced cost and size of ultrasound systems.


      PubDate: 2014-07-25T19:18:46Z
       
  • A New Method of Measurement of Cerebral Circulation Time:
           Contrast-Enhanced Ultrasonography in Healthy Adults and Patients with
           Intracranial Shunts
    • Abstract: Publication date: Available online 10 July 2014
      Source:Ultrasound in Medicine & Biology
      Author(s): Xi Liu , Yi Lin Yang , Si Guo Sun , Rui Jing Yang , Jia Wang , Yi Li , Li Zhang , Yun You Duan
      Alterations in the cerebral circulation time (CCT) are observed in several cerebrovascular diseases. We designed a new method of global CCT measurement using gray-scale contrast-enhanced ultrasound and studied healthy Chinese adults and patients with intracranial shunts. Eighty-one healthy volunteers and eight patients with intracranial shunt disease were enrolled. The contrast agent Sonovue was used. Perfusion in the carotid artery and internal jugular vein bilaterally was recorded. Start and peak filling CCTs were calculated and analyzed. Imaging of carotid vessels was uncomplicated in all patients. The bilateral start CCT was 6.23 ± 1.39 s in healthy patients. There were no significant differences within subgroups and contrast-dosage groups. In the patient group, the mean start CCT was 3.0 ± 0.56 s. There was a significant difference between the control and patient groups (p < 0.001). This new method using gray-scale contrast imaging can measure CCT and cerebral blood volume accurately. It can be used to visualize blood flow differences in real time and is less dependent on the training of the operator.


      PubDate: 2014-07-25T19:18:46Z
       
  • Hepatic Filling Rate of a Microbubble Agent: A Novel Predictor of
           Long-Term Outcomes in Patients With Cirrhosis
    • Abstract: Publication date: Available online 10 July 2014
      Source:Ultrasound in Medicine & Biology
      Author(s): Tadashi Sekimoto , Hitoshi Maruyama , Soichiro Kiyono , Takayuki Kondo , Taro Shimada , Hiroyuki Ishibashi , Masanori Takahashi , Osamu Yokosuka , Tadashi Yamaguchi
      The aim of the study described here was to evaluate the significance of the hepatic filling rate of a perflubutane microbubble agent in predicting long-term outcomes and prognoses in 32 patients with cirrhosis (37–76 y, 20 females, Child–Pugh A16, B16). The time from delivery of the contrast agent to the hepatic artery to maximum enhancement of the liver parenchyma on the sonogram was defined as the hepatic filling rate (mean = 18.6 s). Hepatic filling rate did not correlate significantly with the Child–Pugh score or the model for end-stage liver disease score. However, the survival rate was lower (93.3% at 1 y, 60.2% at 3 y) and the rate of occurrence of hepatocellular carcinoma (HCC) was higher (13.3% at 1 y, 33.3% at 3 y) in the group with the slow filling rate (≥18 s) than in the group with the rapid filling rate (<18 s) (93.3% at 1 and 3 y for survival, 6.3% at 1 and 3 y for HCC occurrence). Hepatic filling rate may constitute a non-invasive marker for the occurrence of HCC and prognosis of cirrhosis.


      PubDate: 2014-07-25T19:18:46Z
       
  • Differentiation of Neural Stem/Progenitor Cells Using Low-Intensity
           Ultrasound
    • Abstract: Publication date: Available online 9 July 2014
      Source:Ultrasound in Medicine & Biology
      Author(s): I-Chi Lee , Tsu-Lin Lo , Tai-Horng Young , Yi-Chen Li , Nelson G. Chen , Chung-Hsuan Chen , Ying-Chih Chang
      Herein, we report the evaluation of apoptosis, cell differentiation, neurite outgrowth and differentiation of neural stem/progenitor cells (NSPCs) in response to low-intensity ultrasound (LIUS) exposure. NSPCs were cultured under different conditions, with and without LIUS exposure, to evaluate the single and complex effects of LIUS. A lactic dehydrogenase assay revealed that the cell viability of NSPCs was maintained with LIUS exposure at an intensity range from 100 to 500 mW/cm2. Additionally, in comparison with no LIUS exposure, the cell survival rate was improved with the combination of medium supplemented with nerve growth factor and LIUS exposure. Our results indicate that LIUS exposure promoted NSPC attachment and differentiation on a glass substrate. Neurite outgrowth assays revealed the generation of longer, thicker neurites after LIUS exposure. Furthermore, LIUS stimulation substantially increased the percentage of differentiating neural cells in NSPCs treated with nerve growth factor in comparison with the unstimulated group. The high percentage of differentiated neural cells indicated that LIUS induced neuronal networks denser than those observed in the unstimulated groups. Furthermore, the release of nitric oxide, an important small-molecule neurotransmitter, was significantly upregulated after LIUS exposure. It is therefore reasonable to suggest that LIUS promotes the differentiation of NSPCs into neural cells, induces neurite outgrowth and regulates nitric oxide production; thus, LIUS may be a potential candidate for NSPC induction and neural cell therapy.


      PubDate: 2014-07-25T19:18:46Z
       
  • Emerging Imaging Technologies in Medicine Mark A. Anastasio and Patrick La
           Riviere. CRC Press, Boca Raton, FL, USA, 2013, 361 pages. ISBN number:
           1439880417
    • Abstract: Publication date: Available online 9 July 2014
      Source:Ultrasound in Medicine & Biology
      Author(s): Meng-Xing Tang



      PubDate: 2014-07-25T19:18:46Z
       
  • 5-Aminolevulinic Acid–mediated Sonodynamic Therapy Reverses
           Macrophage and Dendritic Cell Passivity in Murine Melanoma Xenografts
    • Abstract: Publication date: Available online 9 July 2014
      Source:Ultrasound in Medicine & Biology
      Author(s): Shan Wang , Zheng Hu , Xiaolong Wang , Chuanwen Gu , Zhongxiuzi Gao , Wenwu Cao , Jinhua Zheng
      Sonodynamic therapy (SDT) uses a combination of sonosensitizing drugs and low-intensity therapeutic ultrasound to cause apoptosis and autophagy of tumor cells. However, its effects on the tumor microenvironment, especially on the immune state, remain unknown. In this study, we investigated the transformation of macrophages and dendritic cells (DCs) in the tumor microenvironment during 5-aminolevulinic acid (5-ALA)–mediated SDT in mice transplanted with B16F10 melanomas. Tumor growth and mouse weight were measured. Hematoxylin-eosin staining was used to evaluate tumor morphology to quantify the anti-tumor efficacy of 5-ALA–mediated SDT. We investigated anti-tumor immunity in the tumor microenvironment by immunocytochemical staining of CD68, CD163, CD80, CD86, tumor necrosis factor α (TNF-α), interleukin 10 (IL-10) and interferon γ (IFN-γ). Tumor growth was restrained by 5-ALA–mediated SDT in B16F10 melanoma-bearing mice. CD68 levels increased and CD163 decreased, indicating that M2 macrophages were converted to the M1 phenotype in the tumor. The increase in CD80 and CD86 showed that DCs in the tumor microenvironment tend to mature after SDT treatment. The cytokines INF-γ, TNF-α and IL-10 significantly increased in SDT. Application of low-intensity therapeutic ultrasound alone also led to similar trends in our study, but combined treatment with 5-ALA yielded a change. The original stabilized immune state in the tumor microenvironment can be interrupted by low-intensity therapeutic ultrasound combined with 5-ALA, which enhanced the pro-inflammatory response and reversed the passive properties of macrophages and dendritic cells.


      PubDate: 2014-07-25T19:18:46Z
       
  • Relationship between CHADS2 Score and Complex Aortic Plaques by
           Transesophageal Echocardiography in Patients with Nonvalvular Atrial
           Fibrillation
    • Abstract: Publication date: Available online 9 July 2014
      Source:Ultrasound in Medicine & Biology
      Author(s): Kenichi Sugioka , Suwako Fujita , Shinichi Iwata , Asahiro Ito , Yoshiki Matsumura , Akihisa Hanatani , Atsushi Doi , Masahiko Takagi , Takahiko Naruko , Makiko Ueda , Minoru Yoshiyama
      The CHADS2 score is widely used for risk stratification of thromboembolism in patients with non-valvular atrial fibrillation (NVAF). Although the correlation of CHADS2 score with left atrial (LA) abnormality as detected by transesophageal echocardiography (TEE) has been reported in previous studies, the relationship between CHADS2 score and complex aortic plaque, which is also a significant risk factor for thromboembolism, has not been fully investigated. We assessed aortic plaques by TEE in 150 patients age ≥ 55 y with NVAF. The prevalence of complex aortic plaques increased along with increases in CHADS2 score (p = 0.001). In a multivariate analysis that included atherosclerotic risk factors and LA abnormality, a CHADS2 score ≥2 was independently associated with the presence of complex aortic plaques (odds ratio [OR] 3.39; 95% confidence interval [CI], 1.29–8.90). A high CHADS2 score is closely associated with the presence of complex aortic plaques, which explains, in part, the increased risk of thromboembolism in NVAF patients with high CHADS2 score.


      PubDate: 2014-07-25T19:18:46Z
       
  • Age-Related Ultrasonic Properties of Breast Tissue In Vivo
    • Abstract: Publication date: Available online 9 July 2014
      Source:Ultrasound in Medicine & Biology
      Author(s): Ilana Katz-Hanani , Tamara Rothstein , Diana Gaitini , Zahava Gallimidi , Haim Azhari
      The aim of the current work was to quantify the ultrasonic properties of the whole breast in vivo as a function of age. Forty-four women were scanned using a computerized ultrasonic scanner developed in our laboratory. Raster scans in two orthogonal views, mediolateral and craniocaudal, were obtained using the ultrasonic through-transmission method. By combining the information from the two views, we estimated two acoustic properties: speed of sound and attenuation coefficient. On the basis of the results, both the attenuation coefficient and the speed of sound follow a three-phase age-related pattern. During the first phase, which corresponds to ages 20 to 35 y, both properties decrease with time and then remain roughly unchanged until about 55 y. During the third phase corresponding to ages >55 y, values decrease again with time. The mean speed of sound decreases from 1504 ± 35 m/s at <30 y to 1452 ± 9 m/s at >60 y (p < 0.01), and the attenuation coefficient decreases from 1.27 ± 0.32 to 0.96 ± 0.13 dB/cm/MHz (p < 0.03), respectively. In conclusion, both the ultrasonic speed of sound and the attenuation coefficient of breast tissue are age related. Both parameters decrease during life, markedly during the first and third phases. These changes may be attributed to anatomic and physiologic changes associated with reproductivity and menopause.


      PubDate: 2014-07-25T19:18:46Z
       
  • A Prediction Model for Unstable Carotid Atheromatous Plaque in Acute
           Ischemic Stroke Patients: Proposal and Internal Validation
    • Abstract: Publication date: Available online 9 July 2014
      Source:Ultrasound in Medicine & Biology
      Author(s): Gerardo Ruiz-Ares , Blanca Fuentes , Patricia Martínez-Sánchez , Exuperio Díez-Tejedor
      The aim of this prospective study was to analyze the utility of a gray-scale median (GSM) system for identifying unstable plaques and to design and validate a prediction model for unstable plaques in symptomatic atheromatous carotid arteries. Fifty-two patients with non-cardioembolic cerebral infarction were included in the study. The receiver operating characteristic analysis revealed 76% sensitivity and 82% specificity for a GSM of 29 (p < 0.001) as a cutoff point for unstable plaques. A logistic regression model indicated that a GSM <29, male gender and not having been treated with angiotensin-converting enzyme inhibitors were independently associated with an unstable plaque classification. A probability model for unstable plaques was achieved by combining the strength of each variable (high blood pressure, hypercholesterolemia, smoking, previous stroke, anti-hypertensive drugs, calcium channel blockers, intima–media thickness). The model was tested with receiver operating characteristic curve analysis (p < 0.001) and validated by the leave-one-out cross-validation method (p < 0.001). The prediction model based on a GSM <29, male gender and not having been treated with angiotensin-converting enzyme inhibitors resulted in a probable unstable plaque assessment.


      PubDate: 2014-07-25T19:18:46Z
       
  • Polymerase Chain Reaction Amplifying Mycobacterial DNA from Aspirates
           Obtained by Endoscopic Ultrasound Allows Accurate Diagnosis of
           Mycobacterial Disease in HIV-Positive Patients with Abdominal
           Lymphadenopathy
    • Abstract: Publication date: Available online 9 July 2014
      Source:Ultrasound in Medicine & Biology
      Author(s): Martin Nieuwoudt , Roeland Lameris , Craig Corcoran , Theresa M. Rossouw , Tomas Slavik , Johannie Du Plessis , Jones A.O. Omoshoro-Jones , Paraskevi Stivaktas , Fritz Potgieter , Schalk W. Van der Merwe
      Abdominal lymphadenopathy in human immunodeficiency virus (HIV) infection remains a diagnostic challenge. We performed a prospective cohort study by recruiting 31 symptomatic HIV + patients with abdominal lymphadenopathy and assessing the diagnostic yield of endoscopic ultrasound fine-needle aspiration (EUS-FNA). Mean age was 38 years; 52% were female; and mean CD4 count and viral load were 124 cells/μL and 4 log, respectively. EUS confirmed additional mediastinal nodes in 26%. The porta hepatis was the most common abdominal site. Aspirates obtained by EUS-FNA were subjected to cytology, culture and polymerase chain reaction (PCR) analysis. Mycobacterial infections were confirmed in 67.7%, and 31% had reactive lymphadenopathy. Cytology and culture had low sensitivity, whereas PCR identified 90% of mycobacterial infections. By combining the appearance of aspirates obtained by EUS-FNA and cytologic specimens, we developed a diagnostic algorithm to indicate when analysis with PCR would be useful. PCR performed on material obtained by EUS-FNA was highly accurate in confirming mycobacterial disease and determining genotypic drug resistance.


      PubDate: 2014-07-25T19:18:46Z
       
  • Elastography Can Effectively Decrease the Number of Fine-Needle Aspiration
           Biopsies in Patients with Calcified Thyroid Nodules
    • Abstract: Publication date: Available online 9 July 2014
      Source:Ultrasound in Medicine & Biology
      Author(s): Min-Hee Kim , Si Luo , Sun Hee Ko , So-Lyung Jung , Dong-Jun Lim , Yongmin Kim
      When calcification, frequently found in both benign and malignant nodules, is present in thyroid nodules, non-invasive differentiation with ultrasound becomes challenging. The goal of this study was to evaluate the utility of elastography in differentiating calcified thyroid nodules. Consecutive patients (165 patients with 196 nodules) referred for fine-needle aspiration who had undergone both ultrasound elastography and B-mode examinations were analyzed retrospectively. Calcification was present in 45 benign and 20 malignant nodules. On 65 calcified nodules, elastography had 95% sensitivity, 51.1% specificity, 46.3% positive predictive value and 95.8% negative predictive value in detecting malignancy. Twenty-three of 45 benign calcified nodules were correctly diagnosed with elastography compared with 4 of 45 by B-mode ultrasound. Although it is difficult to differentiate benign and malignant calcified thyroid nodules solely with B-mode ultrasound, elastography has the potential to reduce the number of fine-needle aspiration biopsies performed on calcified nodules.


      PubDate: 2014-07-25T19:18:46Z
       
  • High-Intensity Focused Ultrasound Sonothrombolysis: The Use of
           Perfluorocarbon Droplets to Achieve Clot Lysis at Reduced Acoustic Power
    • Abstract: Publication date: Available online 9 July 2014
      Source:Ultrasound in Medicine & Biology
      Author(s): Daniel Pajek , Alison Burgess , Yuexi Huang , Kullervo Hynynen
      The purpose of this study was to evaluate use of intravascular perfluorocarbon droplets to reduce the sonication power required to achieve clot lysis with high-intensity focused ultrasound. High-intensity focused ultrasound with droplets was initially applied to blood clots in an in vitro flow apparatus, and inertial cavitation thresholds were determined. An embolic model for ischemic stroke was used to illustrate the feasibility of this technique in vivo. Recanalization with intravascular droplets was achieved in vivo at 24 ± 5% of the sonication power without droplets. Recanalization occurred in 71% of rabbits that received 1-ms pulsed sonications during continuous intravascular droplet infusion (p = 0.041 vs controls). Preliminary experiments indicated that damage was confined to the ultrasonic focus, suggesting that tolerable treatments would be possible with a more tightly focused hemispheric array that allows the whole focus to be placed inside of the main arteries in the human brain.


      PubDate: 2014-07-25T19:18:46Z
       
  • Correlation of Quantitative Texture Analysis of Cranial Ultrasound With
           Later Neurobehavior in Preterm Infants
    • Abstract: Publication date: Available online 9 July 2014
      Source:Ultrasound in Medicine & Biology
      Author(s): Violeta Tenorio , Elisenda Bonet-Carne , Francesc Figueras , Francesc Botet , Angela Arranz , Ivan Amat-Roldan , Eduard Gratacos
      The purpose of the study was to evaluate the association between a quantitative texture analysis of early neonatal brain ultrasound images and later neurobehavior in preterm infants. A prospective cohort study including 120 preterm (<33 wk of gestational age) infants was performed. Cranial ultrasound images taken early after birth were analyzed in six regions of interest using software based on texture analysis. The resulting texture scores were correlated with the Neonatal Behavioural Assessment Scale (NBAS) at term-equivalent age. The ability of texture scores, in combination with clinical data and standard ultrasound findings, to predict the NBAS results was evaluated. Texture scores were significantly associated with all but one NBAS domain and better predicted NBAS results than clinical data and standard ultrasound findings. The best predictive value was obtained by combining texture scores with clinical information and ultrasound standard findings (area under the curve = 0.94). We conclude that texture analysis of neonatal cranial ultrasound-extracted quantitative features that correlate with later neurobehavior has a higher predictive value than the combination of clinical data with abnormalities in conventional cranial ultrasound.


      PubDate: 2014-07-25T19:18:46Z
       
  • Influence of Repetitive Contrast Agent Injections on Functional and
           Molecular Ultrasound Measurements
    • Abstract: Publication date: Available online 9 July 2014
      Source:Ultrasound in Medicine & Biology
      Author(s): Anne Rix , Moritz Palmowski , Felix Gremse , Karin Palmowski , Wiltrud Lederle , Fabian Kiessling , Jessica Bzyl
      Quantitative contrast-enhanced ultrasound plays an important role in tumor characterization and treatment assessment. Besides established functional ultrasound techniques, ultrasound molecular imaging using microbubbles targeted to disease-associated markers is increasingly being applied in pre-clinical studies. Often, repeated injections of non-targeted or targeted microbubbles during the same imaging session are administered. However, the influence of repeated injections on the accuracy of the quantitative data is unclear. Therefore, in tumor-bearing mice, we investigated the influence of multiple injections of non-targeted microbubbles (SonoVue) on time to peak and peak enhancement in liver and tumor tissue and of vascular endothelial growth factor receptor 2 (VEGFR2)-targeted contrast agents (MicroMarker) on specific tumor accumulation. We found significantly decreasing values for time to peak and a tendency for increased values for peak enhancement after multiple injections. Repeated injections of VEGFR2-targeted microbubbles led to significantly increased tumor accumulation, which may result from the exposure of additional binding sites at endothelial surfaces caused by mechanical forces from destroyed microbubbles.


      PubDate: 2014-07-25T19:18:46Z
       
  • Evaluation of Gastric Emptying in Diabetic Gastropathy by an Ultrasonic
           Whole Stomach Cylinder Method
    • Abstract: Publication date: Available online 9 July 2014
      Source:Ultrasound in Medicine & Biology
      Author(s): Hao-lin Shen , Shu-ping Yang , Li-wei Hong , Li-qing Lin , Kang-jian Wang , Xiao-han Cai , Guo-rong Lv
      In order to explore the accuracy of ultrasonic whole stomach cylinder measurement (UWSCM) in the evaluation of gastric emptying, we measured the gastric emptying times (ET) at 25% (T1), 50% (T2) and 75% (T3) of healthy subjects and patients with diabetic gastropathy by UWSCM and scintigraphy. The ET of patients were compared with their clinical symptom scores. We found that the ET measured by UWSCM showed no significant difference with scintigraphy (p > 0.05). The correlation between them was good, and the correlation coefficient of T3 reached 0.744 (p < 0.05). All emptying times in the diabetic patients were longer than those in the healthy subjects (p < 0.05). The T3 in the diabetic group measured by UWSCM had the best correlation with the symptom index (r = 0.469, p < 0.05). We conclude that ET measured by UWSCM is accurate and T3 combining the symptoms index provides an accurate clinical basis for gastropathy.


      PubDate: 2014-07-25T19:18:46Z
       
  • Contents
    • Abstract: Publication date: August 2014
      Source:Ultrasound in Medicine & Biology, Volume 40, Issue 8




      PubDate: 2014-06-10T15:09:35Z
       
  • Application of Ultrasound in the Assessment of Plantar Fascia in Patients
           With Plantar Fasciitis: A Systematic Review
    • Abstract: Publication date: August 2014
      Source:Ultrasound in Medicine & Biology, Volume 40, Issue 8
      Author(s): Mohammad Ali Mohseni-Bandpei , Masoomeh Nakhaee , Mohammad Ebrahim Mousavi , Ali Shakourirad , Mohammad Reza Safari , Reza Vahab Kashani
      Plantar fasciitis (PFS) is one of the most common causes of heel pain, estimated to affect 10% of the general population during their lifetime. Ultrasound (US) imaging technique is increasingly being used to assess plantar fascia (PF) thickness, monitor the effect of different interventions and guide therapeutic interventions in patients with PFS. The purpose of the present study was to systematically review previously published studies concerning the application of US in the assessment of PF in patients with PFS. A literature search was performed for the period 2000–2012 using the Science Direct, Scopus, PubMed, CINAHL, Medline, Embase and Springer databases. The key words used were: ultrasound, sonography, imaging techniques, ultrasonography, interventional ultrasonography, plantar fascia and plantar fasciitis. The literature search yielded 34 relevant studies. Sixteen studies evaluated the effect of different interventions on PF thickness in patients with PFS using US; 12 studies compared PF thickness between patients with and without PFS using US; 6 studies investigated the application of US as a guide for therapeutic intervention in patients with PFS. There were variations among studies in terms of methodology used. The results indicated that US can be considered a reliable imaging technique for assessing PF thickness, monitoring the effect of different interventions and guiding therapeutic interventions in patients with PFS.


      PubDate: 2014-06-10T15:09:35Z
       
  • Gray-Scale Ultrasonography Combined with Elastography Imaging for the
           Evaluation of Papillary Thyroid Microcarcinoma: As a Prognostic
           Clinicopathology Factor
    • Abstract: Publication date: August 2014
      Source:Ultrasound in Medicine & Biology, Volume 40, Issue 8
      Author(s): Zhan-Qiang Jin , Mei-Ying Lin , Wen-Hua Hu , Wei-Yong Li , Shao-Jun Bai
      Ultrasonography (US) is the preferred imaging modality for papillary thyroid microcarcinoma (PTMC). The aim of this study was to evaluate the importance of gray-scale ultrasound combined with elastography to predict extrathyroidal extension and cervical lymph node (LN) metastasis in patients with PTMC. We retrospectively evaluated gray-scale ultrasonic and elastographic results from 119 consecutive cases of PTMC with 138 nodules and correlated the histopathological findings. The results indicated that pathological extrathyroidal extension was significantly associated with T staging on US, extrathyroidal extension on US, bilaterality on US, boundary, strain ratio and hard malignancy as measured with the Rago score. Central LN metastasis on pathology was significantly associated with central LN metastasis on US, lateral LN metastasis on US, multifocality on US and bilaterality on US. Lateral LN metastasis on US was significantly associated with lateral LN metastasis on pathology. On multivariate analysis, T staging on US, extrathyroidal extension on US and hard malignancy as measured with the Rago score were significantly associated with pathological extrathyroidal extension. Lateral LN metastasis on US and bilaterality on US were independent factors in predicting central LN metastasis on pathology. Lateral LN metastasis on US was the predictive factor for lateral LN metastasis on pathology. US should be helpful in the diagnosis of PTMC and in the evaluation of possible PTMC recurrence on US in routine clinical practice.


      PubDate: 2014-06-10T15:09:35Z
       
  • Re: “Acoustic Radiation Force Impulse and Supersonic Shear Imaging
           Versus Transient Elastography for Liver Fibrosis Assessment”
    • Abstract: Publication date: August 2014
      Source:Ultrasound in Medicine & Biology, Volume 40, Issue 8
      Author(s): Masato Yoneda , Emmanuel Thomas , Eugene R. Schiff



      PubDate: 2014-06-10T15:09:35Z
       
  • Reply to Letter to the Editor re: “Acoustic Radiation Force Impulse
           and Supersonic Shear Imaging versus Transient Elastography for Liver
           Fibrosis Assessment”
    • Abstract: Publication date: August 2014
      Source:Ultrasound in Medicine & Biology, Volume 40, Issue 8
      Author(s): Ioan Sporea , Roxana Şirli



      PubDate: 2014-06-10T15:09:35Z
       
  • Biomedical Signal and Imaging Processing (Second Edition) Kayvan Najarian
           and Robert Splinter. CRC Press, Boca Raton, Florida, USA, 2012, 385 pages.
           ISBN number: 9781439870334
    • Abstract: Publication date: August 2014
      Source:Ultrasound in Medicine & Biology, Volume 40, Issue 8
      Author(s): Robert J. Eckersley



      PubDate: 2014-06-10T15:09:35Z
       
  • Calendar
    • Abstract: Publication date: August 2014
      Source:Ultrasound in Medicine & Biology, Volume 40, Issue 8




      PubDate: 2014-06-10T15:09:35Z
       
  • Synergistic Ablation of Liver Tissue and Liver Cancer Cells with
           High-Intensity Focused Ultrasound and Ethanol
    • Abstract: Publication date: August 2014
      Source:Ultrasound in Medicine & Biology, Volume 40, Issue 8
      Author(s): Nguyen H. Hoang , Hakm Y. Murad , Sithira H. Ratnayaka , Chong Chen , Damir B. Khismatullin
      We investigated the combined effect of ethanol and high-intensity focused ultrasound (HIFU), first, on heating and cavitation bubble activity in tissue-mimicking phantoms and porcine liver tissues and, second, on the viability of HepG2 liver cancer cells. Phantoms or porcine tissues were injected with ethanol and then subjected to HIFU at acoustic power ranging from 1.2 to 20.5 W (HIFU levels 1–7). Cavitation events and the temperature around the focal zone were measured with a passive cavitation detector and embedded type K thermocouples, respectively. HepG2 cells were subjected to 4% ethanol solution in growth medium (v/v) just before the cells were exposed to HIFU at 2.7, 8.7 or 12.0 W for 30 s. Cell viability was measured 2, 24 and 72 h post-treatment. The results indicate that ethanol and HIFU have a synergistic effect on liver cancer ablation as manifested by greater temperature rise and lesion volume in liver tissues and reduced viability of liver cancer cells. This effect is likely caused by reduction of the cavitation threshold in the presence of ethanol and the increased rate of ethanol diffusion through the cell membrane caused by HIFU-induced streaming, sonoporation and heating.


      PubDate: 2014-06-10T15:09:35Z
       
  • Variations in Temperature Distribution and Tissue Lesion Formation Induced
           by Tissue Inhomogeneity for Therapeutic Ultrasound
    • Abstract: Publication date: August 2014
      Source:Ultrasound in Medicine & Biology, Volume 40, Issue 8
      Author(s): Zhenbo Liu , Xiasheng Guo , Juan Tu , Dong Zhang
      Tissue inhomogeneity might have an important effect on the treatment accuracy of therapeutic ultrasound. Both computer simulation and measurement were performed to study the influence of tissue inhomogeneity on the temperature distribution and tissue lesion formation induced by focused ultrasound. The inhomogeneous tissue is considered a combination of a homogeneous medium and a phase aberration screen in this article. Temperature distributions and lesion dimensions were predicted using the combination of acoustic non-linear and bio-heat transfer equations. To verify the theoretical predictions, polyethylene plates with phase distributions of different correlation lengths and standard deviations were made to mimic inhomogeneous tissues such as human abdominal tissue, and a series of experiments were performed, including acoustic and thermal measurements. The results indicate that the tissue inhomogeneity caused phase aberration of the ultrasound beam. With increasing standard deviation and correlation length of phase aberration, the scattering level of the acoustic field increased, while ultrasound-induced peak temperature and lesion size decreased. This study provides a theoretical and experimental basis for future development of accurate treatment plans for high-intensity focused ultrasound.


      PubDate: 2014-06-10T15:09:35Z
       
  • Masthead
    • Abstract: Publication date: August 2014
      Source:Ultrasound in Medicine & Biology, Volume 40, Issue 8




      PubDate: 2014-06-10T15:09:35Z
       
  • Editorial Advisory Board
    • Abstract: Publication date: August 2014
      Source:Ultrasound in Medicine & Biology, Volume 40, Issue 8




      PubDate: 2014-06-10T15:09:35Z
       
  • RNA Biomarker Release with Ultrasound and Phase-Change Nanodroplets
    • Abstract: Publication date: August 2014
      Source:Ultrasound in Medicine & Biology, Volume 40, Issue 8
      Author(s): Robert J. Paproski , Alexander Forbrich , Mary Hitt , Roger Zemp
      Microbubbles driven by ultrasound are capable of permeabilizing cell membranes and allowing biomarkers or therapeutics to exit from or enter cancer cells, respectively. Unfortunately, the relatively large size of microbubbles prevents extravasation. Lipid-based perfluorobutane microbubbles can be made seven-fold smaller by pressurization, creating 430-nm nanodroplets. The present study compares microbubbles and nanodroplets with respect to their ability to enhance miR-21 and mammaglobin mRNA release from cultured ZR-75-1 cells. Mammaglobin mRNA and miR-21 release increased with escalating concentrations of nanodroplets up to, respectively, 25- and 42-fold with 2% nanodroplets (v/v), compared with pre-ultrasound levels, whereas cell viability decreased to 62.4%. Sonication of ZR-75-1 cells incubated with microbubbles or nanodroplets caused relatively similar levels of cell death and miR-21 release, suggesting that nanodroplets are similar to microbubbles in enhancing cell permeability, but may be more advantageous because of their smaller size, which may allow extravasation through leaky tumor vasculature.


      PubDate: 2014-06-10T15:09:35Z
       
  • Quantification of Carotid Plaque Neovascularization Using
           Contrast-Enhanced Ultrasound With Histopathologic Validation
    • Abstract: Publication date: August 2014
      Source:Ultrasound in Medicine & Biology, Volume 40, Issue 8
      Author(s): Chaolun Li , Wanyuan He , Daqiao Guo , Lingli Chen , Xuejuan Jin , Weiping Wang , Beijian Huang , Wenping Wang
      We sought to evaluate contrast-enhanced ultrasound (CEUS) imaging for the quantification of carotid plaque neovascularization. Seventeen patients underwent carotid endarterectomy after standard ultrasound and CEUS. Semiquantitative and quantitative analyses of contrast enhancement within the plaque were performed using a visual interpretation scale and quantitative analysis software, respectively. Enhancement intensity (dB) was measured at the plaque (EIplaque). Each specimen was stained with CD34 and CD68 to assess for microvessels and macrophages, respectively. Semiquantitative CEUS analyses were correlated with neovascularization at histology (r = 0.70, p = 0.002). Quantitative analysis was also correlated with neovascularization at histology (EIplaque r = 0.81, p < 0.001). EIplaque (r = 0.64, p = 0.01) was correlated with the degree of enhancement as assessed visually. Semiquantitative and quantitative analyses were not correlated with macrophage infiltration at the plaque. Contrast enhancement in the carotid plaque was correlated with neovascularity at the histopathologic exam. Furthermore, semiquantitative and quantitative measurements were highly correlated with each other, suggesting that either can be used to detect intraplaque neovascularization.


      PubDate: 2014-06-10T15:09:35Z
       
  • Early Pregnancy Placental Bed and Fetal Vascular Volume Measurements Using
           3-D Virtual Reality
    • Abstract: Publication date: August 2014
      Source:Ultrasound in Medicine & Biology, Volume 40, Issue 8
      Author(s): Averil D. Reus , Josine Klop-van der Aa , Maria S. Rifouna , Anton H.J. Koning , Niek Exalto , Peter J. van der Spek , Eric A.P. Steegers
      In this study, a new 3-D Virtual Reality (3D VR) technique for examining placental and uterine vasculature was investigated. The validity of placental bed vascular volume (PBVV) and fetal vascular volume (FVV) measurements was assessed and associations of PBVV and FVV with embryonic volume, crown-rump length, fetal birth weight and maternal parity were investigated. One hundred thirty-two patients were included in this study, and measurements were performed in 100 patients. Using V-Scope software, 100 3-D Power Doppler data sets of 100 pregnancies at 12 wk of gestation were analyzed with 3D VR in the I-Space Virtual Reality system. Volume measurements were performed with semi-automatic, pre-defined parameters. The inter-observer and intra-observer agreement was excellent with all intra-class correlation coefficients >0.93. PBVVs of multiparous women were significantly larger than the PBVVs of primiparous women (p = 0.008). In this study, no other associations were found. In conclusion, V-Scope offers a reproducible method for measuring PBVV and FVV at 12 wk of gestation, although we are unsure whether the volume measured represents the true volume of the vasculature. Maternal parity influences PBVV.


      PubDate: 2014-06-10T15:09:35Z
       
  • Predominant Patterns of Median Nerve Displacement and Deformation during
           Individual Finger Motion in Early Carpal Tunnel Syndrome
    • Abstract: Publication date: August 2014
      Source:Ultrasound in Medicine & Biology, Volume 40, Issue 8
      Author(s): Kyrin Liong , Amitabha Lahiri , Shujin Lee , Dawn Chia , Arijit Biswas , Heow Pueh Lee
      Idiopathic carpal tunnel syndrome (CTS) is a common neuropathy, yet the pathologic changes do not explain the fleeting dynamic symptoms. Dynamic nerve-tendon interaction may be a contributing factor. Based on dynamic ultrasonographic examination of the carpal tunnel, we quantified nerve-tendon movement in thumb, index finger and middle finger flexion in normal subjects and those with mild-idiopathic CTS. Predominant motion patterns were identified. The nerve consistently moves volar-ulnarly. In thumb and index finger flexion, the associated tendons move similarly, whereas the tendon moves dorsoradially in middle finger flexion. Nerve displacement and deformation increased from thumb to index finger to middle finger flexion. Predomination motion patterns may be applied in computational simulations to prescribe specific motions to the tendons and to observe resultant nerve pressures. By identification of the greatest pressure-inducing motions, CTS treatment may be better developed. Symptomatic subjects displayed reduced nerve movement and deformation relative to controls, elucidating the physiologic changes that occur during mild CTS.


      PubDate: 2014-06-10T15:09:35Z
       
  • Comparative Study of Ultrasound and Computed Tomography for Incidentally
           Detecting Diffuse Thyroid Disease
    • Abstract: Publication date: August 2014
      Source:Ultrasound in Medicine & Biology, Volume 40, Issue 8
      Author(s): Dong Wook Kim , Soo Jin Jung , Tae Kwun Ha , Ha Kyoung Park , Taewoo Kang
      The aim of this study was to compare the diagnostic values of thyroid ultrasound (US) and neck computed tomography (CT) in incidentally detecting diffuse thyroid disease (DTD). A single radiologist made US and CT diagnoses of incidentally detected DTD in 130 consecutive patients before thyroidectomy for various malignancies. Histopathologic examinations confirmed normal thyroid (n = 80), Hashimoto thyroiditis (n = 20), non-Hashimoto lymphocytic thyroiditis (n = 28) and diffuse hyperplasia (n = 2). Receiver operating characteristic curves revealed that the best diagnostic indices of both imaging methods were achieved on the basis of two or more abnormal imaging findings. The sensitivity, specificity and accuracy of US and CT in incidentally detecting DTD by this classification were 72% and 72%, 87.5% and 91.3% and 81.5% and 83.8%, respectively. Thyroid US and neck CT have similar diagnostic values for differentiating incidental DTD from normal thyroid.


      PubDate: 2014-06-10T15:09:35Z
       
  • Viscoelastic Properties of Normal and Infarcted Myocardium Measured by a
           Multifrequency Shear Wave Method: Comparison with Pressure-Segment Length
           Method
    • Abstract: Publication date: Available online 6 May 2014
      Source:Ultrasound in Medicine & Biology
      Author(s): Cristina Pislaru , Matthew W. Urban , Sorin V. Pislaru , Randall R. Kinnick , James F. Greenleaf
      Our aims were (i) to compare in vivo measurements of myocardial elasticity by shear wave dispersion ultrasound vibrometry (SDUV) with those by the conventional pressure-segment length method, and (ii) to quantify changes in myocardial viscoelasticity during systole and diastole after reperfused acute myocardial infarction. The shear elastic modulus (μ1) and viscous coefficient (μ2) of left ventricular myocardium were measured by SDUV in 10 pigs. Young's elastic modulus was independently measured by the pressure-segment length method. Measurements made with the SDUV and pressure-segment length methods were strongly correlated. At reperfusion, μ1 and μ2 in end-diastole were increased. Less consistent changes were found during systole. In all animals, μ1 increased linearly with left ventricular pressure developed during systole. Preliminary results suggest that μ1 is preload dependent. This is the first study to validate in vivo measurements of myocardial elasticity by a shear wave method. In this animal model, the alterations in myocardial viscoelasticity after a myocardial infarction were most consistently detected during diastole.


      PubDate: 2014-05-12T06:31:40Z
       
  • A Method to Validate Quantitative High-Frequency Power Doppler Ultrasound
           With Fluorescence in Vivo Video Microscopy
    • Abstract: Publication date: Available online 3 May 2014
      Source:Ultrasound in Medicine & Biology
      Author(s): Stephen Z. Pinter , Dae-Ro Kim , M. Nicole Hague , Ann F. Chambers , Ian C. MacDonald , James C. Lacefield
      Flow quantification with high-frequency (>20 MHz) power Doppler ultrasound can be performed objectively using the wall-filter selection curve (WFSC) method to select the cutoff velocity that yields a best-estimate color pixel density (CPD). An in vivo video microscopy system (IVVM) is combined with high-frequency power Doppler ultrasound to provide a method for validation of CPD measurements based on WFSCs in mouse testicular vessels. The ultrasound and IVVM systems are instrumented so that the mouse remains on the same imaging platform when switching between the two modalities. In vivo video microscopy provides gold-standard measurements of vascular diameter to validate power Doppler CPD estimates. Measurements in four image planes from three mice exhibit wide variation in the optimal cutoff velocity and indicate that a predetermined cutoff velocity setting can introduce significant errors in studies intended to quantify vascularity. Consistent with previously published flow-phantom data, in vivo WFSCs exhibited three characteristic regions and detectable plateaus. Selection of a cutoff velocity at the right end of the plateau yielded a CPD close to the gold-standard vascular volume fraction estimated using IVVM. An investigator can implement the WFSC method to help adapt cutoff velocity to current blood flow conditions and thereby improve the accuracy of power Doppler for quantitative microvascular imaging.


      PubDate: 2014-05-07T06:50:32Z
       
  • Vascular Elastography: A Validation Study
    • Abstract: Publication date: Available online 3 May 2014
      Source:Ultrasound in Medicine & Biology
      Author(s): Richard G.P. Lopata , Mathijs F.J. Peters , Jan Nijs , Cees W.J. Oomens , Marcel C.M. Rutten , Frans N. van de Vosse
      Vascular elastography techniques are promising tools for mechanical characterization of diseased arteries. These techniques are usually validated with simulations or phantoms or by comparing results with histology or other imaging modalities. In the study described here, vascular elastography was applied to porcine aortas in vitro during inflation testing (n = 10) and results were compared with those of standard bi-axial tensile testing, a technique that directly measures the force applied to the tissue. A neo-Hookean model was fit to the stress-strain data, valid for large deformations. Results indicated good correspondence between the two techniques, with GUS = 110 ± 11 kPa and G TT = 108 ± 10 kPa for ultrasound and tensile testing, respectively. Bland-Altman analysis revealed little bias (GUS−GTT = 2 ± 20 kPa). The next step will be the application of a non-linear material model that is also adaptable for in vivo measurements.


      PubDate: 2014-05-07T06:50:32Z
       
  • A Cadaveric and Preliminary Clinical Study of Ultrasonographically
           Assisted Percutaneous Carpal Tunnel Release
    • Abstract: Publication date: Available online 3 May 2014
      Source:Ultrasound in Medicine & Biology
      Author(s): Tai-Chang Chern , Kuo-Chen Wu , Lee-Wen Huang , Chung-Jung Shao , Tong-Tai Wu , Li-Chieh Kuo , I-Ming Jou
      The aim of this study was to assess the effectiveness and safety profile of a new technique for ultrasonographically assisted percutaneous carpal tunnel release. Experiments were performed on 40 hands in 20 cadavers. We first performed a detailed ultrasonographic examination and correlation study that included surgical dissection of the transverse carpal ligament, the related neurovascular structures and the bony landmarks of the radiocarpal, midcarpal and carpometacarpal joints of the right hand. We then used the measurements we made for percutaneous carpal tunnel release of the transverse carpal ligament using intra-operative ultrasonography for guidance and a hook knife on the left-hand side. The completeness of the release and the potential risks of injury to the flexor tendon and neurovascular bundles were examined. Using real-time intra-operative ultrasonographic monitoring to clearly delineate these targets, we were able to percutaneously release the transverse carpal ligament completely in 18 (90%) of the 20 hands and partially release it in 2 without injuring any neurovascular bundles. We then performed the procedure on 91 consecutive cases of carpal tunnel syndrome and found that the sensory disturbances disappeared in 100% patients 12 mo post-operatively; only 2 hands were graded as unsatisfactory. There were no intra- or post-operative complications. Based on the results from the cadaveric studies and our successful preliminary clinical outcomes, we conclude that this method is tolerable and that its clinical application can be encouraged.


      PubDate: 2014-05-07T06:50:32Z
       
  • Lipid Shedding from Single Oscillating Microbubbles
    • Abstract: Publication date: Available online 3 May 2014
      Source:Ultrasound in Medicine & Biology
      Author(s): Ying Luan , Guillaume Lajoinie , Erik Gelderblom , Ilya Skachkov , Antonius F.W. van der Steen , Hendrik J. Vos , Michel Versluis , Nico De Jong
      Lipid-coated microbubbles are used clinically as contrast agents for ultrasound imaging and are being developed for a variety of therapeutic applications. The lipid encapsulation and shedding of the lipids by acoustic driving of the microbubble has a crucial role in microbubble stability and in ultrasound-triggered drug delivery; however, little is known about the dynamics of lipid shedding under ultrasound excitation. Here we describe a study that optically characterized the lipid shedding behavior of individual microbubbles on a time scale of nanoseconds to microseconds. A single ultrasound burst of 20 to 1000 cycles, with a frequency of 1 MHz and an acoustic pressure varying from 50 to 425 kPa, was applied. In the first step, high-speed fluorescence imaging was performed at 150,000 frames per second to capture the instantaneous dynamics of lipid shedding. Lipid detachment was observed within the first few cycles of ultrasound. Subsequently, the detached lipids were transported by the surrounding flow field, either parallel to the focal plane (in-plane shedding) or in a trajectory perpendicular to the focal plane (out-of-plane shedding). In the second step, the onset of lipid shedding was studied as a function of the acoustic driving parameters, for example, pressure, number of cycles, bubble size and oscillation amplitude. The latter was recorded with an ultrafast framing camera running at 10 million frames per second. A threshold for lipid shedding under ultrasound excitation was found for a relative bubble oscillation amplitude >30%. Lipid shedding was found to be reproducible, indicating that the shedding event can be controlled.


      PubDate: 2014-05-07T06:50:32Z
       
  • Time Efficiency and Diagnostic Agreement of 2-D Versus 3-D Ultrasound
           Acquisition of the Neonatal Brain
    • Abstract: Publication date: Available online 3 May 2014
      Source:Ultrasound in Medicine & Biology
      Author(s): Javier M. Romero , Neil Madan , Ilda Betancur , Adrian Ciobanu , Erin Murphy , Danielle McCullough , P. Ellen Grant
      The purpose of this study was to compare acquisition time efficiency and diagnostic agreement of neonatal brain ultrasound (US) scans obtained with a 3-D volume US acquisition protocol and the conventional 2-D acquisition protocol. Ninety-one consecutive premature neonatal brain ultrasound scans were prospectively performed on 59 neonates with the conventional 2-D acquisition protocol. Immediately after the 2-D study, a coronal 3-D ultrasound volume was acquired and later reconstructed into axial and sagittal planes. All 59 neonates were imaged in the neonatal intensive care unit to rule out intracranial hemorrhage. Total time for 2-D and 3-D acquisition protocols was recorded, and a two-tailed t-test was used to determine if study durations differed significantly. One pediatric neuroradiologist reviewed the reformatted 3-D images, tomographic ultrasound images. Results were compared with the clinical interpretation of the 2-D conventional study. The mean scanning time for the 2-D US acquisition protocol was 10.56 min (standard deviation [SD] = 7.11), and that for the 3-D volume US acquisition protocol was 1.48 min (SD = 0.59) (p ≤ 0.001). Inter-observer agreement revealed k values of 0.84 for hydrocephalus, 0.80 for germinal matrix hemorrhage/intraventricular hemorrhage, 0.74 for periventricular leukomalacia and 0.91 for subdural collection, hence near-perfect to substantial agreement between imaging protocols. There was a significant decrease in acquisition time for the 3-D volume ultrasound acquisition protocol compared with the conventional 2-D US protocol (p = <0.001), without compromising the diagnostic quality compared with a conventional 2-D US imaging protocol.


      PubDate: 2014-05-07T06:50:32Z
       
  • Assessing the Imaging Capabilities of Radial Mechanical and Electronic
           Echo-endoscopes Using the Resolution Integral
    • Abstract: Publication date: Available online 3 May 2014
      Source:Ultrasound in Medicine & Biology
      Author(s): Scott Inglis , Anna Janeczko , William Ellis , John N. Plevris , Stephen D. Pye
      Over the past decade there have been significant advances in endoscopic ultrasound (EUS) technology. Although there is an expectation that new technology will deliver improved image quality, there are few methods or phantoms available for assessing the capabilities of mechanical and electronic EUS systems. The aim of this study was to investigate the possibility of assessing the imaging capability of available EUS technologies using measurements of the resolution integral made with an Edinburgh Pipe Phantom. Various radial EUS echo-endoscopes and probes were assessed using an Edinburgh Pipe Phantom. Measurements of the resolution integral (R), depth of field (L R) and characteristic resolution (D R) were made at all operating frequencies. The mean R value for Fuji miniprobes was 16.0. The GF-UM20 and GF-UM2000 mechanical radial scopes had mean R values of 24.0 and 28.5, respectively. The two electronic radial echo-endoscopes had similar mean R values of 34.3 and 34.6 for the Olympus GF-UE260 and Fujinon EG-530 UR scopes, respectively. Despite being older technology, the mechanical GF-UM2000 scope had superior characteristic resolution (D R ), but could not compare with the depths of field (L R ) delivered by the current generation of electronic radial scopes, especially at the standard operating frequencies of 7.5 and 12 MHz.


      PubDate: 2014-05-07T06:50:32Z
       
  • Ex Vivo and In Vivo Assessment of the Non-linearity of
           Elasticity Properties of Breast Tissues for Quantitative Strain
           Elastography
    • Abstract: Publication date: Available online 5 May 2014
      Source:Ultrasound in Medicine & Biology
      Author(s): Takeshi Umemoto , Ei Ueno , Takeshi Matsumura , Makoto Yamakawa , Hiroko Bando , Tsuyoshi Mitake , Tsuyoshi Shiina
      The aim of this study was to reveal the background to the image variations in strain elastography (strain imaging [SI]) depending on the manner of manipulation (compression magnitude) during elasticity image (EI) acquisition. Thirty patients with 33 breast lesions who had undergone surgery followed by SI assessment in vivo were analyzed. An analytical approach to tissue elasticity based on the stress-elastic modulus (Young's modulus) relationship was adopted. Young's moduli were directly measured ex vivo in surgical specimens ranging from 2.60 kPa (fat) to 16.08 kPa (invasive carcinoma) under the weak-stress condition (<0.2–0.4 kPa, which corresponds to the appropriate “light touch” technique in SI investigation. The contrast (ratio) of lesion to fat in elasticity ex vivo gradually decreased as the stress applied increased (around 1.0 kPa) on the background of significant non-linearity of the breast tissue. Our results indicate that the differences in non-linearity in elasticity between the different tissues within the breast under minimal stress conditions are closely related to the variation in EI quality. The significance of the “pre-load compression” concept in tissue elasticity evaluation is recognized. Non-linearity of elasticity is an essential attribute of living subjects and could provide useful information having a considerable impact on clinical diagnosis in quantitative ultrasound elastography.


      PubDate: 2014-05-07T06:50:32Z
       
 
 
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