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Journal Cover Ultrasound in Medicine & Biology
  [SJR: 0.939]   [H-I: 91]   [6 followers]  Follow
    
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   ISSN (Print) 0301-5629
   Published by Elsevier Homepage  [2970 journals]
  • Non-Invasive Ultrasound Liver Ablation Using Histotripsy: Chronic Study in
           an In Vivo Rodent Model
    • Abstract: Publication date: August 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 8
      Author(s): Eli Vlaisavljevich, Joan Greve, Xu Cheng, Kimberly Ives, Jiaqi Shi, Lifang Jin, Alexa Arvidson, Tim Hall, Theodore H. Welling, Gabe Owens, William Roberts, Zhen Xu
      Hepatocellular carcinoma, or liver cancer, has the fastest growing incidence among cancers in the United States. Current liver ablation methods are thermal-based and share limitations due to the heat sink effect from the blood flow through the highly vascular liver. Recently, our group has investigated histotripsy as a non-invasive liver cancer ablation method. Histotripsy is a non-thermal ultrasonic ablation method that fractionates tissue through the control of acoustic cavitation. Previous experiments in an in vivo porcine model show that histotripsy can create well-confined lesions in the liver through ribcage obstruction without damaging the overlying ribs and other tissues. Histotripsy can also completely fractionate liver tissue surrounding major vessels while preserving the vessels. In this study, we investigate the long-term effects of histotripsy liver ablation in a rodent model. We hypothesize that the fractionated histotripsy lesion will be resorbed by the liver, resulting in effective tissue healing. To test this hypothesis, the livers of 20 healthy rats were treated with histotripsy using an 8-element 1-MHz histotripsy transducer. Rats were euthanized after 0, 3, 7, 14 and 28 days (n = 4). In vivo and post mortem results showed histotripsy lesions were successfully generated through the intact abdomen in all 20 rats. Magnetic resonance imaging found primarily negative contrast on day 0, positive contrast on day 3 and rapid normalization of signal intensity thereafter (i.e., signal amplitude returned to baseline levels seen in healthy liver tissue). Histologically, lesions were completely fractionated into an acellular homogenate. The lesions had a maximum cross-sectional area of 17.2 ± 1.9 mm2 and sharp boundaries between the lesion and the healthy surrounding tissue after treatment. As the animals recovered after treatment, the histotripsy tissue homogenate was almost completely replaced by regenerated liver parenchyma, resulting in a small fibrous lesion (<1 mm2 maximum cross-section) remaining after 28 d. The results of this study suggest that histotripsy has potential as a non-invasive liver ablation method for effective tissue removal.


      PubDate: 2016-06-18T19:31:17Z
       
  • Shifting the Split Reflectors to Enhance Stone Fragmentation of Shock Wave
           Lithotripsy
    • Abstract: Publication date: August 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 8
      Author(s): Jen-Chieh Wang, Yufeng Zhou
      Shock wave lithotripsy (SWL) has been used widely in urology for about three decades to treat kidney calculi. Technical development to improve performance (i.e., stone fragmentation efficiency) is continuous. Low-pressure wide-focus lithotripters have already achieved promising results. In this study, the lithotripter field and profile of lithotripter shock waves were changed simultaneously using a cost-effective and convenient design. An intact parabolic reflector was split into four pieces, and each part was moved individually. By shifting the split reflectors, the focused acoustic beams were separated. As a result, the beam width in the focal region could be increased. Both numerical models of wave propagation using a k-wave approach and hydrophone measurements showed similar pressure waveforms at the focus and the distributions along and transverse to the lithotripter axis. The increase of the shifting distance from 0 mm to 7 mm resulted in the increase of −6 dB beam width from 7.1 mm to 13.9 mm and location of tensile peak on axis moving from z = −14 mm to 1 mm. The Lithotripters at 10 kV (intact reflector) and at 12 kV with the split reflectors shifted by 5 mm were compared with each other because of their similar peak positive pressures at the focus (8.07 MPa ± 0.05 MPa vs. 7.90 MPa ± 0.11 MPa, respectively). However, there were significant differences in their positive beam width (8.7 mm vs. 10.2 mm), peak negative pressure (−6.34 MPa ± 0.04 MPa vs. −7.13 MPa ± 0.13 MPa), the maximum tensile stress (7.55 MPa vs. 8.95 MPa) and shear stress (6.1 MPa vs. 7.76 MPa) in a 10-mm diameter spherical stone and bubble collapse time (127.6 μs ± 5.4 μs vs. 212.7 μs ± 8.2 μs). As a result, stone fragmentation efficiency was enhanced about 1.8-fold (57.9% ± 4.6% vs. 32.2% ± 5.6%, p < 0.05) when shifting the split reflectors. These results suggest that this new reflector design could change the characteristics of the lithotripter field and increase stone fragmentation efficiency.


      PubDate: 2016-06-18T19:31:17Z
       
  • The Effect of Radial Extracorporeal Shock Wave Stimulation on Upper Limb
           Spasticity in Chronic Stroke Patients: A Single–Blind, Randomized,
           Placebo-Controlled Study
    • Abstract: Publication date: August 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 8
      Author(s): Robert Dymarek, Jakub Taradaj, Joanna Rosińczuk
      The main purpose of this study was to determine the clinical, electrophysiological and thermal effects of radial extracorporeal shock wave (rESW) stimulation on upper limb muscles affected by spasticity in patients with chronic stroke. Patients included in the study were randomly assigned into the following two groups: 30 patients stimulated with active rESW (A); and 30 patients stimulated with placebo rESW (B). All patients were analyzed using the Modified Ashworth Scale (MAS) to test the spasticity levels of the elbow (E), radio carpal (RC) and fingers (FF) joints; surface electromyography (sEMG) was performed for the resting bioelectrical activity registration of the flexor carpi radialis (FCR) and flexor carpi ulnaris (FCU) muscles; and infrared thermal imaging (IRT) was used to assess the temperature distributions of the carpal flexor muscles (CFM). All assessments were performed at baseline (t0), immediately after rESW (t1) as well as 1 and 24 h following its finalization (t2 and t3). Patients treated with active rESW showed a statistically significant reduction in the MAS score for the RC joint at t1 and for the FF joints at t1, t2 and t3 (p < 0.05). A significant decrease in sEMG activity was observed in the FCR and FCU muscles at t1, t2 and t3 (p < 0.05); significant increases in the mean and maximum values of the IRT detection was observed using inter-group comparisons in t2 and t3 (p < 0.05). No significant alterations were observed in patients after placebo rESW stimulation (p > 0.05). Applications of rESW demonstrating positive effects at reducing the level of spastic hypertonia of the upper limb muscles in patients with chronic stroke. ESW treatments should be considered as a potential anti-spastic effect to regulate vasculature.


      PubDate: 2016-06-18T19:31:17Z
       
  • Ultrasound-Guided Transesophageal High-Intensity Focused Ultrasound
           Cardiac Ablation in a Beating Heart: A Pilot Feasibility Study in Pigs
    • Abstract: Publication date: August 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 8
      Author(s): Francis Bessiere, W. Apoutou N'djin, Elodie Constanciel Colas, Françoise Chavrier, Paul Greillier, Jean Yves Chapelon, Philippe Chevalier, Cyril Lafon
      Catheter ablation for the treatment of arrhythmia is associated with significant complications and often-repeated procedures. Consequently, a less invasive and more efficient technique is required. Because high-intensity focused ultrasound (HIFU) enables the generation of precise thermal ablations in deep-seated tissues without harming the tissues in the propagation path, it has the potential to be used as a new ablation technique. A system capable of delivering HIFU into the heart by a transesophageal route using ultrasound (US) imaging guidance was developed and tested in vivo in six male pigs. HIFU exposures were performed on atria and ventricles. At the time of autopsy, visual inspection identified thermal lesions in the targeted areas in three of the animals. These lesions were confirmed by histologic analysis (mean size: 5.5 mm2 × 11 mm2). No esophageal thermal injury was observed. One animal presented with bradycardia due to an atrio-ventricular block, which provides real-time confirmation of an interaction between HIFU and the electrical circuits of the heart. Thus, US-guided HIFU has the potential to minimally invasively create myocardial lesions without an intra-cardiac device.


      PubDate: 2016-06-18T19:31:17Z
       
  • Diagnostic Accuracy of Computer-Aided Assessment of Intranodal Vascularity
           in Distinguishing Different Causes of Cervical Lymphadenopathy
    • Abstract: Publication date: August 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 8
      Author(s): Michael Ying, Sammy C.H. Cheng, Anil T. Ahuja
      Ultrasound is useful in assessing cervical lymphadenopathy. Advancement of computer science technology allows accurate and reliable assessment of medical images. The aim of the study described here was to evaluate the diagnostic accuracy of computer-aided assessment of the intranodal vascularity index (VI) in differentiating the various common causes of cervical lymphadenopathy. Power Doppler sonograms of 347 patients (155 with metastasis, 23 with lymphoma, 44 with tuberculous lymphadenitis, 125 reactive) with palpable cervical lymph nodes were reviewed. Ultrasound images of cervical nodes were evaluated, and the intranodal VI was quantified using a customized computer program. The diagnostic accuracy of using the intranodal VI to distinguish different disease groups was evaluated and compared. Metastatic and lymphomatous lymph nodes tend to be more vascular than tuberculous and reactive lymph nodes. The intranodal VI had the highest diagnostic accuracy in distinguishing metastatic and tuberculous nodes with a sensitivity of 80%, specificity of 73%, positive predictive value of 91%, negative predictive value of 51% and overall accuracy of 68% when a cutoff VI of 22% was used. Computer-aided assessment provides an objective and quantitative way to evaluate intranodal vascularity. The intranodal VI is a useful parameter in distinguishing certain causes of cervical lymphadenopathy and is particularly useful in differentiating metastatic and tuberculous lymph nodes. However, it has limited value in distinguishing lymphomatous nodes from metastatic and reactive nodes.


      PubDate: 2016-06-18T19:31:17Z
       
  • Multiview 3-D Echocardiography Fusion with Breath-Hold Position Tracking
           Using an Optical Tracking System
    • Abstract: Publication date: August 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 8
      Author(s): Kumaradevan Punithakumar, Abhilash R. Hareendranathan, Alexander McNulty, Marina Biamonte, Allen He, Michelle Noga, Pierre Boulanger, Harald Becher
      Recent advances in echocardiography allow real-time 3-D dynamic image acquisition of the heart. However, one of the major limitations of 3-D echocardiography is the limited field of view, which results in an acquisition insufficient to cover the whole geometry of the heart. This study proposes the novel approach of fusing multiple 3-D echocardiography images using an optical tracking system that incorporates breath-hold position tracking to infer that the heart remains at the same position during different acquisitions. In six healthy male volunteers, 18 pairs of apical/parasternal 3-D ultrasound data sets were acquired during a single breath-hold as well as in subsequent breath-holds. The proposed method yielded a field of view improvement of 35.4 ± 12.5%. To improve the quality of the fused image, a wavelet-based fusion algorithm was developed that computes pixelwise likelihood values for overlapping voxels from multiple image views. The proposed wavelet-based fusion approach yielded significant improvement in contrast (66.46 ± 21.68%), contrast-to-noise ratio (49.92 ± 28.71%), signal-to-noise ratio (57.59 ± 47.85%) and feature count (13.06 ± 7.44%) in comparison to individual views.


      PubDate: 2016-06-18T19:31:17Z
       
  • Improving Displacement Signal-to-Noise Ratio for Low-Signal Radiation
           Force Elasticity Imaging Using Bayesian Techniques
    • Abstract: Publication date: August 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 8
      Author(s): Douglas M. Dumont, Kristy M. Walsh, Brett C. Byram
      Radiation force–based elasticity imaging is currently being investigated as a possible diagnostic modality for a number of clinical tasks, including liver fibrosis staging and the characterization of cardiovascular tissue. In this study, we evaluate the relationship between peak displacement magnitude and image quality and propose using a Bayesian estimator to overcome the challenge of obtaining viable data in low displacement signal environments. Displacement data quality were quantified for two common radiation force–based applications, acoustic radiation force impulse imaging, which measures the displacement within the region of excitation, and shear wave elasticity imaging, which measures displacements outside the region of excitation. Performance as a function of peak displacement magnitude for acoustic radiation force impulse imaging was assessed in simulations and lesion phantoms by quantifying signal-to-noise ratio (SNR) and contrast-to-noise ratio for varying peak displacement magnitudes. Overall performance for shear wave elasticity imaging was assessed in ex vivo chicken breast samples by measuring the displacement SNR as a function of distance from the excitation source. The results show that for any given displacement magnitude level, the Bayesian estimator can increase the SNR by approximately 9 dB over normalized cross-correlation and the contrast-to-noise ratio by a factor of two. We conclude from the results that a Bayesian estimator may be useful for increasing data quality in SNR-limited imaging environments.


      PubDate: 2016-06-18T19:31:17Z
       
  • Efficacy of Combined Ultrasound-and-Microbubbles-Mediated Diclofenac Gel
           Delivery to Enhance Transdermal Permeation in Adjuvant-Induced Rheumatoid
           Arthritis in the Rat
    • Abstract: Publication date: August 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 8
      Author(s): Ai-Ho Liao, Huan-Yu Chung, Wen-Shiang Chen, Ming-Kung Yeh
      A previous study that investigated the effect of ultrasound (US) on the transdermal permeation of the non-steroidal anti-inflammatory drug diclofenac found that therapeutic US can increase circulation in an inflamed joint and decrease arthritic pain. Transdermal drug delivery has recently been demonstrated by US combined with microbubbles (MB) contrast agent (henceforth referred to as “US-MB”). The present study evaluated the efficacy of US-MB-mediated diclofenac delivery for treating adjuvant-induced rheumatoid arthritis (RA) in rats. RA was induced by injecting 100 μL of complete Freund's adjuvant into the ankle joint of male Sprague-Dawley rats (250–300 g) that were randomly divided into five treatment groups: (i) carbopol gel alone (the control [group C]), (ii) diclofenac-carbopol gel (group D), (iii) US plus carbopol gel (group U), (iv) US plus diclofenac-carbopol gel (group DU) and (v) US-MB plus diclofenac-carbopol gel (group DUB). The ankle width was measured over 10 d using high-frequency (40-MHz) US B-mode and color Doppler–mode imaging, covering the period before and after treatment. Longitudinal US images of the induced RA showed synovitis and neovascularity. Only a small amount of neovascularity was observed after treatment. The recovery rate on day 10 was significantly higher in group DUB (97.7% ± 2.7%, mean ± standard deviation [SD]) than in groups C (1.0% ± 2.7%), D (37.5% ± 4.6%), U (75.5% ± 4.2%) and DU (87.3% ± 5.2%) (p < 0.05). The results obtained indicate that combining US and MB can increase the skin permeability and thereby enhance the delivery of diclofenac sodium gel and thereby inhibit inflammation of the tissues surrounding the arthritic ankle. Color Doppler–mode imaging revealed that US-MB treatment induced a rapid reduction in synovial neoangiogenesis in the arthritic area.


      PubDate: 2016-06-18T19:31:17Z
       
  • Toward Deep Brain Monitoring with Superficial EEG Sensors Plus
           Neuromodulatory Focused Ultrasound
    • Abstract: Publication date: August 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 8
      Author(s): Felix Darvas, Edin Mehić, Connor J. Caler, Jeff G. Ojemann, Pierre D. Mourad
      Noninvasive recordings of electrophysiological activity have limited anatomic specificity and depth. We hypothesized that spatially tagging a small volume of brain with a unique electroencephalography (EEG) signal induced by pulsed focused ultrasound could overcome those limitations. As a first step toward testing this hypothesis, we applied transcranial ultrasound (2 MHz, 200-ms pulses applied at 1050 Hz for 1 s at a spatial peak temporal average intensity of 1.4 W/cm2) to the brains of anesthetized rats while simultaneously recording EEG signals. We observed a significant 1050-Hz electrophysiological signal only when ultrasound was applied to a living brain. Moreover, amplitude demodulation of the EEG signal at 1050 Hz yielded measurement of gamma band (>30 Hz) brain activity consistent with direct measurements of that activity. These results represent preliminary support for use of pulsed focused ultrasound as a spatial tagging mechanism for non-invasive EEG-based mapping of deep brain activity with high spatial resolution.


      PubDate: 2016-06-18T19:31:17Z
       
  • Low-Frequency Ultrasound Enhances Antimicrobial Activity of
           Colistin–Vancomycin Combination against Pan-Resistant Biofilm of
           Acinetobacter baumannii
    • Abstract: Publication date: August 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 8
      Author(s): Xu Liu, Hong Yin, Chun-Xiao Weng, Yun Cai
      Acinetobacter baumannii biofilms in catheters are very difficult to treat. Low-frequency ultrasound (LFU) may improve bactericidal or bacteriostatic activity. However, no previous studies have been reported on its efficacy against pan-resistant biofilms of A. baumannii. This study was designed to investigate whether LFU can enhance the activity of colistin, vancomycin and colistin–vancomycin combinations against pan-resistant biofilms of A. baumannii. The efficacy of colistin combinations was determined using the fractional inhibitory concentration index (FICI). The antibacterial effect was determined from bacteria counts in biofilms and the establishment of 24-h time-kill curves. A significantly synergistic effect was detected between colistin and vancomycin (FICI <0.05). We found that although application of LFU (40 kHz, 600 mW/cm2, 30 min, duty cycle 1:9) alone or in combination with a single agent failed to significantly reduce bacteria counts in biofilms, it apparently enhanced the antibacterial effectiveness of combinations of these agents. Moreover, higher concentrations of colistin in the combination treatments resulted in a better ultrasound-enhanced antibacterial effect. In 24-h time-kill curves, the combination of colistin (8 μg/mL) plus vancomycin (4 μg/mL) with LFU caused a significant reduction in bacteria counts in biofilms after 8 h and a continuing decline until 24 h. Bacterial counts were reduced by 3.77 log(CFU/mL) by LFU plus combinations, compared with combinations without LFU at 24 h. Our results indicate that LFU in combination with colistin plus vancomycin may be useful in treating pan-resistant A. baumannii infections.


      PubDate: 2016-06-18T19:31:17Z
       
  • A Novel Approach to Ultrasound-Mediated Tissue Decellularization and
           Intra-Hepatic Cell Delivery in Rats
    • Abstract: Publication date: August 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 8
      Author(s): Ki Joo Pahk, Goran Hamid Mohammad, Massimo Malago, Nader Saffari, Dipok Kumar Dhar
      Liver transplantation is the mainstay of treatment for end stage liver diseases, including metabolic and congenital liver diseases. The number of suitable donor organs is, however, limited, and a whole-liver transplant requires complex surgery. Cell therapy, such as intra-portal hepatocytes transplantation, has been considered as a bridging therapy to liver transplantation but has shown a mixed clinical outcome with limited success, including low level of engraftment of transplanted hepatocytes. Here, we report a novel cell delivery technique in a rat model by creating a cavity inside the liver parenchyma by non-invasive high intensity focused ultrasound histotripsy. Our in vivo experimental results together with histologic observations show that direct injection of cells inside the cavity can facilitate successful uptake, proliferation and integration of the transplanted hepatocytes in the recipient liver. We were able to restore the plasma albumin level to 50% of the normal level in Nagase analbuminemic rats (serum albumin level of the Nagase rats was initially nil) by cell therapy after high intensity focused ultrasound–mediated histotripsy. We believe that this novel technique would enable the delivery of a large number of cells into the liver to restore liver function, particularly as a treatment for metabolic liver diseases. This novel method of intra-hepatic hepatocyte transplantation might be an invaluable tool for cell therapy in the future.


      PubDate: 2016-06-18T19:31:17Z
       
  • Ultrasound-Guided Percutaneous Microwave Ablation for Hepatocellular
           Carcinoma in the Caudate Lobe
    • Abstract: Publication date: August 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 8
      Author(s): Jian-Ping Dou, Jie Yu, Zhi-Gang Cheng, Zhi-Yu Han, Fang-Yi Liu, Xiao-Ling Yu, Ping Liang
      Treatment for liver tumors in the caudate lobe is challenging because of their location and complex anatomy. This study was intended to evaluate the feasibility, efficacy and tolerability of ultrasound-guided percutaneous microwave (MW) ablation for treating hepatocellular carcinoma (HCC) in the caudate lobe. From December 2011 to May 2015, a total of 20 patients (mean age: 62 ± 11 y) with HCC in the caudate lobe were enrolled in this study. Patient characteristics and tumor features were analyzed. The epigastric approach, intercostal approach and the combination were used in 4, 14 and 2 patients, respectively. Contrast-enhanced ultrasound (CEUS) guidance and temperature monitoring were applied as ancillary techniques. Ethanol injection was performed for tumors adjacent to the inferior vena cava or hepatic hilum. Contrast images were performed to evaluate treatment response after ablation. Technical success, technique efficacy, local tumor progression and complications were documented. Technique efficacy was achieved in 18 patients (18/20, 90%). Two patients received 125I brachytherapy as palliative therapy for residual tumors that could not be ablated technically after the first ablation. Technical success was achieved in 16 patients (16/20, 80%). In 2 patients, ablation was completed after two sessions. CEUS was applied in 5 patients and temperature monitoring in 2 patients. Eight patients received an ethanol injection during ablation. Eleven patients achieved a minimum 5-mm safety margins. Local tumor progression was detected in 3 patients (16.7%, 3/18) during a median follow-up of 18.4 mo (range: 3–45 mo). Tumors in these 3 patients were all larger than 2.0 cm. No major or minor complications were observed. In conclusion, ultrasound-guided percutaneous microwave ablation combined with CEUS, temperature monitoring, and ethanol injection is a tolerable and relatively effective treatment for HCC in the caudate lobe.


      PubDate: 2016-06-18T19:31:17Z
       
  • Ultrasonographic Differentiation Between Nodular Hyperplasia and
           Neoplastic Follicular-Patterned Lesions of the Thyroid Gland
    • Abstract: Publication date: August 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 8
      Author(s): Yong Sub Song, Ji-hoon Kim, Dong Gyu Na, Hye Sook Min, Jae-Kyung Won, Tae Jin Yun, Seung Hong Choi, Chul-Ho Sohn
      We evaluate the gray-scale ultrasonographic characteristics that differentiate between nodular hyperplasia (NH) and neoplastic follicular-patterned lesions (NFPLs) of the thyroid gland. Ultrasonographic features of 750 patients with 832 thyroid nodules (NH, n = 361; or NFPLs, follicular adenoma, n = 123; follicular carcinoma, n = 159; and follicular variant papillary carcinoma, n = 189) were analyzed. Except for echogenicity, over two-thirds of the cases of NH and NFPLs share the ultrasonographic characteristics of solid internal content, a well-defined smooth margin and round-to-ovoid shape. Independent predictors for NH were non-solid internal content (sensitivity 27.1%, specificity 90.2%), isoechogenicity (sensitivity 69.5%, specificity 63.5%) and an ill-defined margin (sensitivity 18.8%, specificity 94.5%). Independent predictors for NFPLs were hypoechogenicity (sensitivity 60.5%, specificity 70.4%), marked hypoechogenicity (sensitivity 2.8%, specificity 99.4%) and taller-than-wide shape (sensitivity 6.6%, specificity 98.1%). Although NH and NFPLs commonly share ultrasonographic characteristics, non-solid internal content and ill-defined margin are specific to NH and marked hypoechogenicity and taller-than-wide shape are specific to NFPLs.


      PubDate: 2016-06-18T19:31:17Z
       
  • Real-Time Elastography and Contrast-Enhanced Ultrasonography in the
           Evaluation of Testicular Masses: A Comparative Prospective Study
    • Abstract: Publication date: August 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 8
      Author(s): Claudia Schröder, Guntram Lock, Christa Schmidt, Thomas Löning, Klaus-Peter Dieckmann
      This study investigates the usefulness of contrast-enhanced ultrasound (CEUS) and real-time elastography (RTE) for the characterization of testicular masses by comparing pre-operative ultrasound findings with post-operative histology. Sixty-seven patients with 68 sonographically detected testicular masses underwent B-mode, color-coded Doppler sonography (CCDS), CEUS and RTE according to defined criteria. For RTE, elasticity score (ES), difference of elasticity score (D-ES), strain ratio (SR) and size quotient (Qsize) were evaluated. Histopathologically, 54/68 testicular lesions were neoplastic (47 malignant, 7 benign). Descriptive statistics revealed the following results (neoplastic vs. non-neoplastic) for sensitivity, specificity, positive predictive value, negative predictive value and accuracy, respectively: B-mode, 100%, 43%, 87%, 100%, 88%; CCDS 81%, 86%, 96%, 55%, 82%; CEUS 93%, 85%, 96%, 73%, 91%; ES 98%, 25%, 85%, 75%, 85%; D-ES 98%, 50%, 90%, 83%, 89%; SR 90%, 45%, 86%, 56%, 81%; and Qsize 57%, 83%, 94%, 28%, 61%. B-mode with CCDS remains the standard for assessing testicular masses. In characterization of testicular lesions, CEUS clearly outperformed all other modalities. Our study does not support the routine use of RTE in testicular ultrasonography because of its low specificity.


      PubDate: 2016-06-18T19:31:17Z
       
  • Semi-Quantitative Strain Ratio in the Differential Diagnosis of Breast
           Masses: Measurements Using One Region-of-Interest
    • Abstract: Publication date: August 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 8
      Author(s): Jung Hyun Yoon, Mi Kyung Song, Eun-Kyung Kim
      The purpose of this study was to evaluate the diagnostic performances of semi-quantitative strain ratio measured by using one region-of-interest (ROI) on breast US elastography images. Two hundred one breast masses of 165 women (mean age: 47.2 y) were included. Ultrasonography (US) and elastography images of the masses were obtained and prospectively analyzed according to elasticity pattern, strain ratio, and final Breast Imaging-Reporting and Data System (BI-RADS) assessments. Of the 201 breast masses, 127 (63.2%) were benign and 74 (36.8%) were malignant. Elastography pattern and strain ratio (cut-off of 1.44) had significantly higher specificity than gray-scale US, 39.4% and 61.4% versus 29.1%, respectively (all p < 0.05). Area under the receiver operating characteristics curve (Az) was highest for gray-scale US (0.646), without statistical significances, than for elastography pattern (0.596, p = 0.159) or strain ratio (0.625, p = 0.610). Semi-quantitative strain ratio measured from one ROI has comparable diagnostic performances to gray-scale US, which may contribute to more accurate differential diagnosis of breast masses seen on US.


      PubDate: 2016-06-18T19:31:17Z
       
  • Non-Invasive Diagnosis of Portal Hypertensive Gastropathy: Quantitative
           Analysis of Microbubble-Induced Stomach Wall Enhancement
    • Abstract: Publication date: August 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 8
      Author(s): Soichiro Kiyono, Hitoshi Maruyama, Kazufumi Kobayashi, Takayuki Kondo, Tadashi Sekimoto, Taro Shimada, Osamu Yokosuka, Tadashi Yamaguchi
      The aim of the study described here was to elucidate the efficacy of contrast-enhanced ultrasound (CEUS) prospectively as a tool in the diagnosis of portal hypertensive gastropathy (PHG). The peak enhancement time at the upper stomach wall (PT) and intensity ratio at the upper stomach/the spleen (IR) between pre- and peak enhancement were evaluated by CEUS with perflubutane microbubble agent in 56 patients, 42 with cirrhosis (16 with PHG) and 14 controls. The IR was higher in patients with PHG (1.21 ± 0.11) than in those without (0.91 ± 0.15, p < 0.05) and the controls (0.78 ± 0.11, p < 0.01), although PT did not differ between these groups. The area under the receiver operating characteristic curve for IR was 0.8199 in the presence of PHG, with the best cutoff value of 0.94, sensitivity 65.9%, specificity 72.6%, positive predictive value 62.2%, negative predictive value 73.1% and accuracy 70.4%. CEUS may have potential as a less invasive tool for diagnosis of PHG in patients with cirrhosis.


      PubDate: 2016-06-18T19:31:17Z
       
  • Preliminary Analysis of Clinical Situations Involved in Quantification of
           Contrast-Enhanced Ultrasound in Crohn's Disease
    • Abstract: Publication date: August 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 8
      Author(s): Wenjie Cheng, Xiang Gao, Weili Wang, Min Zhi, Jian Tang, Yan-ling Wen, Junli Yu, Yao Chen, Xiaoyin Liu, Chuan Yang, Pinjin Hu, Guangjian Liu
      To assess influencing factors for quantitative analysis of contrast-enhanced ultrasound (CEUS) in Crohn's disease (CD), dynamic CEUS examinations from 77 consecutive CD patients were recorded. Peak intensity (PI) values were calculated using the pre-installed quantification software of the ultrasound scanner. The influence of depth, pressure from the ultrasound probe and intraluminal gas was analyzed. The PI value of the anterior wall was lower than that of the posterior wall when the depth was ≤3.4 cm (17.9 dB vs. 21.3 dB; p < 0.05) or evident pressure was exerted (19.1 dB vs. 22.5 dB; p < 0.01). In the presence of intraluminal gas, the PI of the anterior wall was higher than that of the posterior wall (20.7 dB vs. 18.8 dB; p < 0.05). Nevertheless, no significant difference was found between the PI value of anterior and posterior walls when the depth was >3.4 cm (19.8 dB vs. 20.3 dB), moderate pressure was exerted (20.5 dB vs. 21.1 dB) or luminal gas was excluded between the two bowel walls (18.9 dB vs. 21.2 dB; p ≥ 0.05). The factors of depth, pressure from the ultrasound probe and intraluminal gas can affect the quantification results of CEUS. It is preferable to place the region of interest in the posterior wall when luminal gas is absent and in the anterior wall when luminal gas is present. In the latter case, more attention should be paid to reducing pressure by the ultrasound probe.


      PubDate: 2016-06-18T19:31:17Z
       
  • Computer-Assisted Hepatocellular Carcinoma Ablation Planning Based on 3-D
           Ultrasound Imaging
    • Abstract: Publication date: August 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 8
      Author(s): Kai Li, Zhongzhen Su, Erjiao Xu, Peishan Guan, Liu-Jun Li, Rongqin Zheng
      To evaluate computer-assisted hepatocellular carcinoma (HCC) ablation planning based on 3-D ultrasound, 3-D ultrasound images of 60 HCC lesions from 58 patients were obtained and transferred to a research toolkit. Compared with virtual manual ablation planning (MAP), virtual computer-assisted ablation planning (CAP) consumed less time and needle insertion numbers and exhibited a higher rate of complete tumor coverage and lower rate of critical structure injury. In MAP, junior operators used less time, but had more critical structure injury than senior operators. For large lesions, CAP performed better than MAP. For lesions near critical structures, CAP resulted in better outcomes than MAP. Compared with MAP, CAP based on 3-D ultrasound imaging was more effective and achieved a higher rate of complete tumor coverage and a lower rate of critical structure injury; it is especially useful for junior operators and with large lesions, and lesions near critical structures.


      PubDate: 2016-06-18T19:31:17Z
       
  • Influence of Scan Duration on Pulmonary Capillary Hemorrhage Induced by
           Diagnostic Ultrasound
    • Abstract: Publication date: August 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 8
      Author(s): Douglas L. Miller, Zhihong Dong, Chunyan Dou, Krishnan Raghavendran
      Diagnostic ultrasound can induce pulmonary capillary hemorrhage (PCH) in rats and display this as “comet tail” artifacts (CTAs) after a time delay. To test the hypothesis that no PCH occurs for brief scans, anesthetized rats were scanned using a 6-MHz linear array for different durations. PCH was characterized by ultrasound CTAs, micro-computed tomography (μCT), and measurements of fixed lung tissue. The μCT images revealed regions of PCH, sometimes penetrating the entire depth of a lobe, which were reflected in the fixed tissue measurements. At −3 dB of power, PCH was substantial for 300-s scans, but not significant for 25-s scans. At 0 dB, PCH was not strongly dependent on scan durations of 300 to 10 s. Contrary to the hypothesis, CTAs were not evident during most 10-s scans (p > 0.05), but PCH was significant (p = 0.02), indicating that PCH could occur without evidence of the injury in the images.


      PubDate: 2016-06-18T19:31:17Z
       
  • Frequency Dependence of Petechial Hemorrhage and Cardiomyocyte Injury
           Induced during Myocardial Contrast Echocardiography
    • Abstract: Publication date: August 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 8
      Author(s): Douglas L. Miller, Xiaofang Lu, Mario Fabiilli, Kristina Fields, Chunyan Dou
      Myocardial contrast echocardiography (MCE) for perfusion imaging can induce microscale bio-effects during intermittent high-Mechanical Index scans. The dependence of MCE-induced bio-effects on the ultrasonic frequency was examined in rats at 1.6, 2.5 and 3.5 MHz. Premature complexes were counted in the electrocardiogram, petechial hemorrhages with microvascular leakage on the heart surface were observed at the time of exposure, plasma troponin elevation was measured after 4 h and cardiomyocyte injury was detected at 24 h. Increasing response to exposure above an apparent threshold was observed for all endpoints at each frequency. The effects decreased with increasing ultrasonic frequency, and the thresholds increased. Linear regressions for frequency-dependent thresholds indicated coefficients and exponents of 0.6 and 1.07 for petechial hemorrhages, respectively, and 1.02 and 0.8 for cardiomyocyte death, compared with 1.9 and 0.5 (square root) for the guideline limit of the mechanical index. The results clarify the dependence of cardiac bio-effects on frequency, and should allow development of theoretical descriptions of the phenomena and improved safety guidance for MCE.


      PubDate: 2016-06-18T19:31:17Z
       
  • Unexpected High Incidence of Coronary Vasoconstriction in the Reduction of
           Microvascular Injury Using Sonolysis (ROMIUS) Trial
    • Abstract: Publication date: August 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 8
      Author(s): Sebastiaan T. Roos, Lynda J.M. Juffermans, Niels van Royen, Albert C. van Rossum, Feng Xie, Yolande Appelman, Thomas R. Porter, Otto Kamp
      High-mechanical-index ultrasound and intravenous microbubbles might prove beneficial in treating microvascular obstruction caused by microthrombi after primary percutaneous coronary intervention for ST-segment elevation myocardial infarction (STEMI). Experiments in animals have revealed that longer-pulse-duration ultrasound is associated with an improvement in microvascular recovery. This trial tested long-pulse-duration, high-mechanical-index ultrasound in STEMI patients. Non-randomly assigned, non-blinded patients were included in this phase 2 trial. The primary endpoint was any side effect possibly related to the ultrasound treatment. The study was aborted after six patients were included; three patients experienced coronary vasoconstriction of the culprit artery, unresponsive to nitroglycerin. Therefore, coronary artery diameter was measured in five pigs. Coronary artery diameters distal to the injury site decreased after application of ultrasound, after balloon injury plus thrombus injection (from 1.89 ± 0.24 mm before to 1.78 ± 0.17 after ultrasound, p = 0.05). Long-pulse-duration ultrasound might cause coronary vasoconstriction distal to the culprit vessel location.


      PubDate: 2016-06-18T19:31:17Z
       
  • Shear Modulus of the Lower Leg Muscles in Patients with Medial Tibial
           Stress Syndrome
    • Abstract: Publication date: August 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 8
      Author(s): Kei Akiyama, Ryota Akagi, Kuniaki Hirayama, Norikazu Hirose, Hideyuki Takahashi, Toru Fukubayshi
      This study aimed to investigate the in vivo kinematics of shear modulus of the lower leg muscles in patients with medial tibial stress syndrome (MTSS). The study population included 46 limbs with MTSS and 40 healthy limbs. The shear modulus of the medial head of the gastrocnemius, lateral head of the gastrocnemius, soleus, peroneus longus and tibialis anterior muscles were measured using shear wave ultrasound elastography. As a result, the shear modulus of the lower leg muscles was significantly greater in patients with MTSS than in healthy patients (p < 0.01). Based on the differences in shear modulus of lower leg muscles between the patients with MTSS and healthy patients, the measurements obtained via shear wave ultrasound elastography could be used to evaluate risk factors of MTSS.


      PubDate: 2016-06-18T19:31:17Z
       
  • Normal Values of Spleen Length and Volume: An Ultrasonographic Study in
           Children
    • Abstract: Publication date: August 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 8
      Author(s): Masoud Nemati, Parisa Hajalioghli, Shahram Jahed, Razieh Behzadmehr, Mandana Rafeey, Daniel F. Fouladi
      We aimed to determine normal ultrasonographic limits of spleen length and volume in healthy Caucasian neonates and children. A total of 458 healthy cases (age, 1 d to 15 y; sex, 241 males and 217 females) with normal body measurements were included. Spleen length and volume were obtained ultrasonographically. The two genders were comparable for the mean spleen length and volume. Lower and upper normal limits were tabulated according to age and sex groups. Significant correlations (Pearson r > 0.80; p < 0.001) were present between spleen length/volume and age, height and weight. Two equations were created to estimate spleen length and volume by age. Normal spleen lengths and volumes and their lower and upper limits were obtained ultrasonographically in a large sample of Caucasian pediatric patients.


      PubDate: 2016-06-18T19:31:17Z
       
  • Cardiac Variation of Internal Jugular Vein for the Evaluation of
           Hemodynamics
    • Abstract: Publication date: August 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 8
      Author(s): Kensuke Nakamura, Kun Qian, Takehiro Ando, Ryota Inokuchi, Kent Doi, Etsuko Kobayashi, Ichiro Sakuma, Susumu Nakajima, Naoki Yahagi
      Evaluations of intravascular fluid volume are considered to be one of the most important assessments in emergency and intensive care. Focusing on pulse-induced variation of the internal jugular vein (IJV) area, i.e., cardiac variation, we investigated its correlation with various hemodynamic indices using newly developed software. Software that automatically can track and analyze the IJV during ultrasonography was developed. Eleven healthy patients were subjected to an exercise load to increase their stroke volume (SV) and a dehydration load to decrease their central venous pressure (CVP). The cardiac variation in the area of the IJV, CVP, the SV and the respiratory variation in the inferior vena cava (IVC) were evaluated. The exercise protocol increased the patients' mean SV by 14.5 ± 3.7 mL, and the dehydration protocol caused their mean CVP to fall by 3.75 ± 0.33 cm H2O, which resulted in the collapse index (max IJV area − min IJV area/max IJV area) changing from 0.32 ± 0.04 to 0.44 ± 0.06 and 0.49 ± 0.04, respectively (p < 0.05). The SV exhibited a strong positive correlation with the collapse index (r = 0.59, p = 0.006), and CVP showed a strong positive correlation with the body height-adjusted mean area of the IJV (r = 0.72, p < 0.001). Cardiac variation in the area of the great veins is considered to be induced by venous return to the right atrium under negative pressure. It is possible that intravascular dehydration can be detected and hemodynamic indices, such as CVP and SV, can be estimated by evaluating cardiac variation in the area of the IJV.


      PubDate: 2016-06-18T19:31:17Z
       
  • Histotripsy Thrombolysis on Retracted Clots
    • Abstract: Publication date: August 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 8
      Author(s): Xi Zhang, Gabe E. Owens, Charles A. Cain, Hitinder S. Gurm, Jonathan Macoskey, Zhen Xu
      Retracted blood clots have been previously recognized to be more resistant to drug-based thrombolysis methods, even with ultrasound and microbubble enhancements. Microtripsy, a new histotripsy approach, has been investigated as a non-invasive, drug-free and image-guided method that uses ultrasound to break up clots with improved treatment accuracy and a lower risk of vessel damage compared with the traditional histotripsy thrombolysis approach. Unlike drug-mediated thrombolysis, which is dependent on the permeation of the thrombolytic agents into the clot, microtripsy controls acoustic cavitation to fractionate clots. We hypothesize that microtripsy thrombolysis is effective on retracted clots and that the treatment efficacy can be enhanced using strategies incorporating electronic focal steering. To test our hypothesis, retracted clots were prepared in vitro and the mechanical properties were quantitatively characterized. Microtripsy thrombolysis was applied on the retracted clots in an in vitro flow model using three different strategies: single-focus, electronically-steered multi-focus and dual-pass multi-focus. Results show that microtripsy was used to successfully generate a flow channel through the retracted clot and the flow was restored. The multi-focus and the dual-pass treatments incorporating the electronic focal steering significantly increased the recanalized flow channel size compared to the single-focus treatments. The dual-pass treatments achieved a restored flow rate up to 324 mL/min without cavitation contacting the vessel wall. The clot debris particles generated from microtripsy thrombolysis remained within the safe range. The results of this study show the potential of microtripsy thrombolysis for retracted clot recanalization with the enhancement of electronic focal steering.


      PubDate: 2016-06-18T19:31:17Z
       
  • Masthead
    • Abstract: Publication date: August 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 8




      PubDate: 2016-06-18T19:31:17Z
       
  • Editorial Advisory Board
    • Abstract: Publication date: August 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 8




      PubDate: 2016-06-18T19:31:17Z
       
  • Contents
    • Abstract: Publication date: August 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 8




      PubDate: 2016-06-18T19:31:17Z
       
  • Clinical Applicability of Assessment of Jugular Flow over the Individual
           Cardiac Cycle Compared with Current Ultrasound Methodology
    • Abstract: Publication date: August 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 8
      Author(s): Francesco Sisini, Mirko Tessari, Erica Menegatti, Maria Elena Vannini, Sergio Gianesini, Valentina Tavoni, Giacomo Gadda, Mauro Gambaccini, Angelo Taibi, Paolo Zamboni
      There is growing interest in measuring cerebral venous outflow with ultrasound (US). However, results obtained with the current US Doppler methodology, which uses just a single value of cross-sectional area (CSA) of the vessel, are highly variable and inconclusive. The product of CSA and time-averaged velocity in the case of pulsatile vessels may be a possible source of error, particularly for a pulsatile vein like the internal jugular vein (IJV), where the cardiac pump transmits a sequence of well-established waves along the conduit. We herein propose a novel technique for US IJV flow assessment that accurately accounts for IJV CSA variations during the cardiac cycle. Five subjects were investigated with a high-resolution real-time B-mode video, synchronized with an electrocardiography trace. In this approach, CSA variations representing the pulsatility of the IJV are overlapped with the velocity curve obtained by the usual spectral Doppler trace. The overlap is then phased point by point using the electrocardiography pacemaker. This allows us to experimentally measure the velocity variation in relation to the change in CSA precisely, ultimately enabling calculation of IJV flow. (i) The sequence of CSA variation with respect to the electrocardiography waves corresponds exactly to the jugular venous pulse as measured in physiology. (ii) The methodology permits us to phase the velocity and CSA, which is ultimately what is currently lacking to precisely calculate the flow in the IJV with US. (iii) The time-averaged flow, calculated with the described technique, is very close to that calculated assuming a constant IJV CSA, whereas the time-dependent flow shows differs as much as 40%. (iv) Finally, we tested the accuracy of the technique with a methodology that may allow for universal assessment of the accuracy of each personal US-based evaluation of flow rate.


      PubDate: 2016-06-18T19:31:17Z
       
  • Left Ventricular Strain and Rotation by 2-D Speckle Tracking
           Echocardiography Identify Early Alcoholic Cardiomyopathy
    • Abstract: Publication date: August 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 8
      Author(s): Yuanzheng Wang, Guangsen Li, Yanhong Sun, Guoxin Shan, Rui Xu, Lijuan Guo
      This study assessed whether 2-D speckle tracking echocardiography (STE) derived from left ventricular (LV) strain and rotation is capable of detecting LV dysfunction associated with alcoholic cardiomyopathy. Ninety-two male chronic alcoholic patients were grouped by alcohol intake amount and duration: mild (n = 30; >90 mg ethanol daily, 3–5 d per wk for 5–8 y); moderate (n = 30; >90–150 mg ethanol daily, 3–5 d per wk for 9–20 y); and severe (n = 32; >150 mg ethanol daily, 6–7 d per wk for >10 y). Thirty non-drinkers were recruited as healthy controls. Rotation and twist values were lower in the severe group compared with the other groups (p < 0.05). The moderate and severe alcohol groups demonstrated lower longitudinal, circumferential and radial strain values and early to late filling (E/A) ratios compared with the mild group and non-drinkers (all p < 0.05). 2-D STE–derived strain and rotation are reliable echocardiographic markers for detecting left ventricular dysfunction in patients at risk of developing alcoholic cardiomyopathy.


      PubDate: 2016-06-18T19:31:17Z
       
  • Left Ventricular Energy Loss Assessed by Vector Flow Mapping in Patients
           with Prediabetes and Type 2 Diabetes Mellitus
    • Abstract: Publication date: August 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 8
      Author(s): Yi Wang, Rongchuan Ma, Geqi Ding, Dailun Hou, Zhaohuan Li, Lixue Yin, Mei Zhang
      The aim of this study was to assess left ventricular (LV) energy loss (EL) using vector flow mapping in patients with prediabetes (pre-DM) and type 2 diabetes mellitus (DM). Thirty pre-DM patients, 51 DM patients, and 38 controls were studied by transthoracic echocardiography. EL-total, EL-base, EL-mid and EL-apex climaxed at different phases. Compared with controls, pre-DM and DM patients showed increased EL-total during slow ejection, isovolumic relaxation, rapid filling and slow filling (p < 0.05). Similarly, EL-base, EL-mid and EL-apex increased during certain phases. Stepwise multiple regression analysis revealed that the early transmitral valve blood flow velocity E, the late transmitral valve blood flow velocity A, the ratio of E/A, LV peak torsion, diastolic untwisting velocity, vortex circulation and area were independently associated with EL during different phases (all p < 0.05). Our study suggests that LV EL is increased during diastole and certain phases of systole in DM patients compared with controls. The changes in LV vortex and deformation mechanics were correlated with EL.


      PubDate: 2016-06-18T19:31:17Z
       
  • Pediatric Cardiac Shear Wave Elastography for Quantitative Assessment of
           Myocardial Stiffness: A Pilot Study in Healthy Controls
    • Abstract: Publication date: August 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 8
      Author(s): Pengfei Song, Xiaojun Bi, Daniel C. Mellema, Armando Manduca, Matthew W. Urban, Patricia A. Pellikka, Shigao Chen, James F. Greenleaf
      The long-term goal of this study is to assess chemotherapy-induced cardiotoxicity for pediatric cancer patients using cardiac ultrasound shear wave (SW) elastography. This pilot study aimed to systematically investigate the feasibility of using cardiac SW elastography in children and provide myocardial stiffness control data for cancer patients. Twenty healthy volunteers (ages 5–18) were recruited. A novel cardiac SW elastography sequence with pulse-inversion harmonic imaging and time-aligned sequential tracking was developed for this study. Cardiac SW elastography produces and detects transient SWs propagating in the myocardium in late-diastole, which can be used to quantify myocardial stiffness. The parasternal long-axis (L-A) and short-axis (S-A) views of the interventricular septum (IVS) were feasible for pediatric cardiac SW elastography. The L-A and S-A views of the basal and mid IVS provided better success rates than those of the apical IVS. Success rates decreased with increased body mass index (BMI), but did not differ with age or gender. Two-dimensional SW speed measurements were 1.26, 1.22, 1.71 and 1.67 m/s for L-A base, L-A mid, S-A base and S-A mid IVS, respectively. All S-A SW speed values were significantly higher (p < 0.01) than L-A values due to myocardial anisotropy. No SW speed difference was observed for different ages and genders. This pilot study demonstrated, for the first time, the feasibility of using cardiac SW elastography to measure quantitative myocardial stiffness in children, and established control SW speed values for using SW elastography to assess chemo-induced cardiotoxicity for pediatric cancer patients. The results showed that the myocardial anisotropy needs to be accounted for when comparing SW speed from different imaging axes.


      PubDate: 2016-06-18T19:31:17Z
       
  • Delivery of Liposomes with Different Sizes to Mice Brain
           after Sonication by Focused Ultrasound in the Presence
           of Microbubbles
    • Abstract: Publication date: July 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 7
      Author(s): Yuanyuan Shen, Jinxuan Guo, Gaoshu Chen, Chien Ting Chin, Xin Chen, Jian Chen, Feng Wang, Shiguo Chen, Guo Dan
      Imaging or therapeutic agents larger than the blood–brain barrier's (BBB) exclusion threshold of 400 Da could be delivered locally, non-invasively and reversibly by focused ultrasound (FUS) with circulating microbubbles. The size of agents is an important factor to the delivery outcome using this method. Liposomes are important drug carriers with controllable sizes in a range of nanometers. However, discrepancies among deliveries of intact liposomes with different sizes, especially those larger than 50 nm, across the BBB opened by FUS with microbubbles remain unexplored. In the present study, rhodamine-labeled long-circulating pegylated liposomes with diameters of 55 nm, 120 nm and 200 nm were delivered to mice brains after BBB disruption by pulsed FUS with microbubbles. Four groups of peak rarefactional pressure and microbubble dosages were used: 0.53 MPa with 0.1 μL/g (group 1), 0.53 MPa with 0.5 μL/g (group 2), 0.64 MPa with 0.1 μL/g (group 3) and 0.64 MPa with 0.5 μL/g (group 4). The delivery outcome was observed using fluorescence imaging of brain sections. It was found that the delivery of 55-nm liposomes showed higher success rates than 120-nm or 200-nm liposomes from groups 1–3. The result indicated that it may be more difficult to deliver larger liposomes (>120 nm) passively than 55-nm liposomes after BBB opening by FUS with microbubbles. The relative fluorescence area of 55-nm liposomes to the total area of the sonicated region was statistically larger than that of the 120-nm or 200-nm liposomes. Increasing peak rarefactional pressure amplitude or microbubble dose could induce more accumulation of liposomes in the brain using FUS with microbubbles. Moreover, the distribution pattern of delivered liposomes was heterogeneous and characterized by separated fluorescence spots with cloud-like periphery surrounding a bright center, indicating confined diffusion in the extracellular matrix after extravasation from the microvasculature. These findings are expected to provide useful information for developing FUS with microbubbles as an effective trans-BBB liposomal drug delivery strategy.


      PubDate: 2016-06-18T19:31:17Z
       
  • Frequency Dependence of Ultrasound Neurostimulation in the Mouse Brain
    • Abstract: Publication date: July 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 7
      Author(s): Patrick Peiyong Ye, Julian R. Brown, Kim Butts Pauly
      Ultrasound neuromodulation holds promise as a non-invasive technique for neuromodulation of the central nervous system. However, much remains to be determined about how the technique can be transformed into a useful technology, including the effect of ultrasound frequency. Previous studies have demonstrated neuromodulation in vivo using frequencies <1 MHz, with a trend toward improved efficacy with lower frequency. However, using higher frequencies could offer improved ultrasound spatial resolution. We investigate the ultrasound neuromodulation effects in mice at various frequencies both below and above 1 MHz. We find that frequencies up to 2.9 MHz can still be effective for generating motor responses, but we also confirm that as frequency increases, sonications require significantly more intensity to achieve equivalent efficacy. We argue that our results provide evidence that favors either a particle displacement or a cavitation-based mechanism for the phenomenon of ultrasound neuromodulation.


      PubDate: 2016-06-18T19:31:17Z
       
  • Histotripsy Liquefaction of Large Hematomas
    • Abstract: Publication date: July 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 7
      Author(s): Tatiana D. Khokhlova, Wayne L. Monsky, Yasser A. Haider, Adam D. Maxwell, Yak-Nam Wang, Thomas J. Matula
      Intra- and extra-muscular hematomas result from repetitive injury as well as sharp and blunt limb trauma. The clinical consequences can be serious, including debilitating pain and functional deficit. There are currently no short-term treatment options for large hematomas, only lengthy conservative treatment. The goal of this work was to evaluate the feasibility of a high intensity focused ultrasound (HIFU)-based technique, termed histotripsy, for rapid (within a clinically relevant timeframe of 15–20 min) liquefaction of large volume (up to 20 mL) extra-vascular hematomas for subsequent fine-needle aspiration. Experiments were performed using in vitro extravascular hematoma phantoms—fresh bovine blood poured into 50 mL molds and allowed to clot. The resulting phantoms were treated by boiling histotripsy (BH), cavitation histotripsy (CH) or a combination in a degassed water tank under ultrasound guidance. Two different transducers operating at 1 MHz and 1.5 MHz with f-number = 1 were used. The liquefied lysate was aspirated and analyzed by histology and sized in a Coulter Counter. The peak instantaneous power to achieve BH was lower than (at 1.5 MHz) or equal to (at 1 MHz) that which was required to initiate CH. Under the same exposure duration, BH-induced cavities were one and a half to two times larger than the CH-induced cavities, but the CH-induced cavities were more regularly shaped, facilitating easier aspiration. The lysates contained a small amount of debris larger than 70 μm, and 99% of particulates were smaller than 10 μm. A combination treatment of BH (for initial debulking) and CH (for liquefaction of small residual fragments) yielded 20 mL of lysate within 17.5 minutes of treatment and was found to be most optimal for liquefaction of large extravascular hematomas.


      PubDate: 2016-06-18T19:31:17Z
       
  • Validity Study of Vertebral Rotation Measurement Using 3-D Ultrasound in
           Adolescent Idiopathic Scoliosis
    • Abstract: Publication date: July 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 7
      Author(s): Qian Wang, Meng Li, Edmond H.M. Lou, Winnie C.W. Chu, Tsz-ping Lam, Jack C.Y. Cheng, Man-sang Wong
      This study aimed to assess the validity of 3-D ultrasound measurements on the vertebral rotation of adolescent idiopathic scoliosis (AIS) under clinical settings. Thirty curves (mean Cobb angle: 21.7° ± 15.9°) from 16 patients with AIS were recruited. 3-D ultrasound and magnetic resonance imaging scans were performed at the supine position. Each of the two raters measured the apical vertebral rotation using the center of laminae (COL) method in the 3-D ultrasound images and the Aaro-Dahlborn method in the magnetic resonance images. The intra- and inter-reliability of the COL method was demonstrated by the intra-class correlation coefficient (ICC) (both [2, K] >0.9, p < 0.05). The COL method showed no significant difference (p < 0.05) compared with the Aaro-Dahlborn method. Furthermore, the agreement between these two methods was demonstrated by the Bland-Altman method, and high correlation was found (r > 0.9, p < 0.05). These results validated the proposed 3-D ultrasound method in the measurements of vertebral rotation in the patients with AIS.


      PubDate: 2016-06-18T19:31:17Z
       
  • Correlation Between Sonographic and In Vivo Measurement of A1 Pulleys
           in Trigger Fingers
    • Abstract: Publication date: July 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 7
      Author(s): Andres Spirig, Bettina Juon, Yara Banz, Robert Rieben, Esther Vögelin
      The thickness of 210 A1 pulleys of 21 male and female healthy volunteers in two different age groups (20–35 y and 50–70 y) were measured by ultrasound. In a second group, the thickness of 15 diseased A1 pulleys and 15 A1 pulleys of the corresponding other hand of 10 patients with the clinical diagnosis of trigger finger were measured by ultrasound. During open trigger finger release, a strip of A1 pulley was excised and immediately measured using an electronic caliper. The average pulley thickness of healthy volunteers was 0.43–0.47 mm, compared to 0.77–0.79 mm in patients with trigger finger. Based on the receiver operating characteristic (ROC) curve, a diagnostic cut-off value of the pulley thickness at 0.62 mm was defined in order to differ a trigger finger from a healthy finger (sensitivity and specificity of 85%). The correlation between sonographic and effective intra-operative measurements of pulley thickness was linear and very strong (Pearson coefficient 0.86–0.90). In order to distinguish between healthy and diseased A1 pulleys, 0.62 mm is a simple value to use, which can be applied regardless of age, sex, body mass index (BMI) and height in adults.


      PubDate: 2016-06-18T19:31:17Z
       
  • Breast Lesions Evaluated by Color-Coded Acoustic Radiation Force Impulse
           (ARFI) Imaging
    • Abstract: Publication date: July 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 7
      Author(s): JianQiao Zhou, ZhiFang Yang, WeiWei Zhan, JingWen Zhang, Na Hu, YiJie Dong, YingYing Wang
      The goal of our study was to investigate the value of color-coded Virtual Touch tissue imaging (VTI) using acoustic radiation force impulse (ARFI) technology in the characterization of breast lesions and to compare it with conventional ultrasound (US). Conventional US and color-coded VTI were performed in 196 solid breast lesions in 196 consecutive women (age range 17–91 y; mean 48.17 ± 14.46 y). A four-point scale VTI score was assigned for each lesion according to the color pattern both in the lesion and in the surrounding breast tissue. The mean VTI score was significantly higher for malignant lesions (3.80 ± 0.66, range 1–4) than for benign ones (2.02 ± 1.20, range 1–4) (p < 0.001), and the optimal cut-off value was between score 3 and score 4. The area under the receiver operating characteristic (ROC) curve for combined conventional US and VTI (0.945) was significantly higher than that for conventional US (0.902) and for VTI (0.871) (p = 0.0021 and p < 0.001, respectively). It was concluded that color-coded VTI with the proposed four-point scale score system combined with conventional US might have the potential to aid in the characterization of benign and malignant breast lesions.


      PubDate: 2016-06-18T19:31:17Z
       
  • Calendar
    • Abstract: Publication date: August 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 8




      PubDate: 2016-06-18T19:31:17Z
       
  • Masthead
    • Abstract: Publication date: July 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 7




      PubDate: 2016-06-18T19:31:17Z
       
  • Editorial Advisory Board
    • Abstract: Publication date: July 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 7




      PubDate: 2016-06-18T19:31:17Z
       
  • Contents
    • Abstract: Publication date: July 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 7




      PubDate: 2016-06-18T19:31:17Z
       
  • Preoperative Gross Classification of Gastric Adenocarcinoma: Comparison of
           Double Contrast-Enhanced Ultrasound and Multi-Detector Row CT
    • Abstract: Publication date: July 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 7
      Author(s): Caoxin Yan, Xiaofeng Bao, Weihui Shentu, Jian Chen, Chunmei Liu, Qin Ye, Liuhong Wang, Yangbin Tan, Pintong Huang
      The aim of this study was to compare the accuracy of multi-detector computed tomography (MDCT) with double contrast-enhanced ultrasound (DCEUS), in which intravenous microbubbles are used alongside oral contrast-enhanced ultrasound, in determining the gross classification of patients with gastric carcinoma (GC). Altogether, 239 patients with GC proved by histology after endoscopic biopsy were included in this study. DCEUS and MDCT were performed pre-operatively. The diagnostic accuracies of DCEUS and MDCT in determining the gross classification were calculated and compared. The overall accuracy of DCEUS in determining the gross appearance of GC was higher than that of MDCT (84.9% vs. 79.9%, p < 0.001). There was no significant difference in accuracy between DCEUS and MDCT for Borrmann I and IV classifications of advanced gastric cancer (χ2, p = 0.323 for Borrmann type I, p = 0.141 for Borrmann type IV). The accuracy of DCEUS for early GC and Borrmann II and III classifications of GC was higher than that of MDCT (χ2, p = 0.000 for all). DCEUS may be regarded as a valuable complementary tool to MDCT in determining the gross appearance of gastric adenocarcinoma pre-operatively.


      PubDate: 2016-06-18T19:31:17Z
       
  • Registration of Real-Time 3-D Ultrasound to Tomographic Images of the
           Abdominal Aorta
    • Abstract: Publication date: August 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 8
      Author(s): Reidar Brekken, Daniel Høyer Iversen, Geir Arne Tangen, Torbjørn Dahl
      The purpose of this study was to develop an image-based method for registration of real-time 3-D ultrasound to computed tomography (CT) of the abdominal aorta, targeting future use in ultrasound-guided endovascular intervention. We proposed a method in which a surface model of the aortic wall was segmented from CT, and the approximate initial location of this model relative to the ultrasound volume was manually indicated. The model was iteratively transformed to automatically optimize correspondence to the ultrasound data. Feasibility was studied using data from a silicon phantom and in vivo data from a volunteer with previously acquired CT. Through visual evaluation, the ultrasound and CT data were seen to correspond well after registration. Both aortic lumen and branching arteries were well aligned. The processing was done offline, and the registration took approximately 0.2 s per ultrasound volume. The results encourage further patient studies to investigate accuracy, robustness and clinical value of the approach.


      PubDate: 2016-06-18T19:31:17Z
       
  • The Feasibility of Thermal Imaging as a Future Portal Imaging Device for
           Therapeutic Ultrasound
    • Abstract: Publication date: August 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 8
      Author(s): Piero Miloro, John Civale, Ian Rivens, Adam Shaw
      This technical note describes a prototype thermally based portal imaging device that allows mapping of energy deposition on the surface of a tissue mimicking material in a focused ultrasound surgery (FUS) beam by using an infrared camera to measure the temperature change on that surface. The aim of the work is to explore the feasibility of designing and building a system suitable for rapid quality assurance (QA) for use with both ultrasound- and magnetic resonance (MR) imaging–guided clinical therapy ultrasound systems. The prototype was tested using an MR-guided Sonalleve FUS system (with the treatment couch outside the magnet bore). The system's effective thermal noise was 0.02°C, and temperature changes as low as 0.1°C were easily quantifiable. The advantages and drawbacks of thermal imaging for QA are presented through analysis of the results of an experimental session.


      PubDate: 2016-06-18T19:31:17Z
       
  • Frequency Analysis of the Photoacoustic Signal Generated by Coronary
           Atherosclerotic Plaque
    • Abstract: Publication date: August 2016
      Source:Ultrasound in Medicine & Biology, Volume 42, Issue 8
      Author(s): Verya Daeichin, Min Wu, Nico De Jong, Antonius F.W. van der Steen, Gijs van Soest
      The identification of unstable atherosclerotic plaques in the coronary arteries is emerging as an important tool for guiding percutaneous coronary interventions and may enable preventive treatment of such plaques in the future. Assessment of plaque stability requires imaging of both structure and composition. Spectroscopic photoacoustic (sPA) imaging can visualize atherosclerotic plaque composition on the basis of the optical absorption contrast. It is an established fact that the frequency content of the photoacoustic (PA) signal is correlated with structural tissue properties. As PA signals can be weak, it is important to match the transducer bandwidth to the signal frequency content for in vivo imaging. In this ex vivo study on human coronary arteries, we combined sPA imaging and analysis of frequency content of the PA signals. Using a broadband transducer (−3-dB one-way bandwidth of 10–35 MHz) and a 1-mm needle hydrophone (calibrated for 1–20 MHz), we covered a large frequency range of 1–35 MHz for receiving the PA signals. Spectroscopic PA imaging was performed at wavelengths ranging from 1125 to 1275 nm with a step of 2 nm, allowing discrimination between plaque lipids and adventitial tissue. Under sPA imaging guidance, the frequency content of the PA signals from the plaque lipids was quantified. Our data indicate that more than 80% of the PA energy of the coronary plaque lipids lies in the frequency band below 8 MHz. This frequency information can guide the choice of the transducer element used for PA catheter fabrication.


      PubDate: 2016-06-18T19:31:17Z
       
  • Evaluation of Gastric Volumes: Comparison of 3-D Ultrasound and Magnetic
           Resonance Imaging
    • Abstract: Publication date: Available online 8 April 2016
      Source:Ultrasound in Medicine & Biology
      Author(s): Wijnand J. Buisman, Femke A. Mauritz, Wouter E. Westerhuis, Odd Helge Gilja, David C. van der Zee, Maud Y.A. van Herwaarden-Lindeboom
      To investigate gastric accommodation, accurate measurements of gastric volumes are necessary. An excellent technique to measure gastric volumes is dynamic magnetic resonance imaging (MRI). Unfortunately, dynamic MRI is expensive and not always available. A new 3-D ultrasound (US) method using a matrix transducer was developed to measure gastric volumes. In this prospective study, 14 healthy volunteers underwent a dynamic MRI and a 3-D US. Gastric volumes were calculated with intra-gastric liquid content and total gastric volume. Mean postprandial liquid gastric content was 397 ± 96.5 mL. Mean volume difference was 1.0 mL with limits of agreement of −8.9 to 10.9 mL. When gastric air was taken into account, mean total gastric volume was 540 ± 115.4 mL SD. Mean volume difference was 2.3 mL with limits of agreement of −21.1 to 26.4 mL. The matrix 3-D US showed excellent agreement with dynamic MRI. Therefore matrix 3-D US is a reliable alternative to measure gastric volumes.


      PubDate: 2016-04-09T06:38:50Z
       
  • A New Method for Discriminating between Bronchial and Pulmonary Arterial
           Phases using Contrast-enhanced Ultrasound
    • Abstract: Publication date: Available online 8 April 2016
      Source:Ultrasound in Medicine & Biology
      Author(s): Zhang Hong-xia, He Wen, Cheng Ling-gang, Cai Wen-jia, Li Shuo, Du Li-juan, Song Hai-man, Zhao Yang
      This study aimed to explore the value of a real-time comparative observation method using contrast-enhanced ultrasound (CEUS) for discriminating between bronchial and pulmonary arterial phases in diagnosing lung diseases. Forty-nine patients with 50 pulmonary lesions (45 peripheral lesions and five central lesions with obstructive atelectasis, including 36 malignant tumors, five tuberculomas, four inflammatory pseudotumors and five pneumonia lesions) detected via computed tomography and visible on ultrasonography were enrolled in this study. The arterial phases were determined by comparing contrast agent arrival time (AT) in the peripheral lung lesion with that in adjacent lung tissue, referred to as a real-time comparative observation method. Detection rates of this observation method were 100% (50/50) for pulmonary arterial phase and 88% (44/50) for bronchial arterial phase. Using the instrument's built-in graphing and analysis software, a time-intensity curve was constructed based on a chosen region of interest within the lesion where enhancement was the most obvious. Commonly used perfusion indicators in CEUS, such as AT, time-to-peak and peak intensity, were obtained from the time-intensity curve. Percutaneous puncture biopsies were performed under ultrasound guidance, and specimens of all 50 lesions were examined pathologically. AT was significantly shorter in patients with pneumonia than in those with malignant tumors or chronic inflammation (p < 0.05), whereas no difference was seen between those with malignant tumors and those with chronic inflammation. No significant differences in time-to-peak or peak intensity were seen among those with various lung diseases (p > 0.05). This is the first description of a real-time comparative observation method using CEUS for determining the arterial phases in the lungs. This method is accurate, simple to perform and provides a direct display. It is expected to become a practical and feasible tool for diagnosing lung diseases.


      PubDate: 2016-04-09T06:38:50Z
       
  • Diagnosis of Columnar Cell Lesions and Atypical Ductal Hyperplasia by
           Ultrasound-Guided Core Biopsy: Findings Associated with Underestimation of
           Breast Carcinoma
    • Abstract: Publication date: Available online 8 April 2016
      Source:Ultrasound in Medicine & Biology
      Author(s): Hye Shin Ahn, Mijung Jang, Sun Mi Kim, Bo La Yun, Sung-Won Kim, Eun Young Kang, So Yeon Park
      The aim of the study described here was to determine underestimation rates and identify radiologic predictors of underestimation for columnar cell lesions (CCLs) and atypical ductal hyperplasia (ADH) detected by ultrasound-guided core needle biopsy. A total of 103 CCLs and ADH lesions in 100 patients diagnosed by ultrasound-guided core needle biopsy were evaluated. Breast sonographic and mammographic findings were reviewed, and underestimation rates were determined by surgical excision, percutaneous vacuum-assisted excision or 2-y imaging follow-up. All underestimated lesions were ductal carcinoma in situ, and the underestimation rates of flat epithelial atypia (FEA), FEA + ADH and ADH were 5.9% (1/17), 44.4% (4/9) and 27.3% (12/44), respectively. There was no underestimation of CCLs without atypia. The presence of calcifications on ultrasound was significantly associated with underestimation (p = 0.010). Therefore, except for CCLs without atypia, all other lesions may require excision, especially when calcification is present on ultrasound or when FEA + ADH is found.


      PubDate: 2016-04-09T06:38:50Z
       
  • Reproducibility of Brachial Vascular Changes with Alterations in End-Tidal
           Carbon Dioxide
    • Abstract: Publication date: Available online 6 April 2016
      Source:Ultrasound in Medicine & Biology
      Author(s): Justin R. Geijer, Nicholas G. Evanoff, Aaron S. Kelly, Michael A. Chernin, Matthew G. Stoltman, Donald R. Dengel
      The purpose of this study was to examine the reproducibility of the peripheral vascular response to hypercapnia. Healthy college-aged men (n = 7) and women (n = 10) underwent an iso-oxic 10-mm Hg increase in PetCO2 for 12 min. Brachial artery diameter changes were measured using ultrasound imaging. Two tests were completed on day 1 with 15 min of rest between tests. Tests were repeated on day 2. Paired t-tests, Bland–Altman plots and intra-class correlations (ICCs) determined reproducibility. There were no significant differences in peak dilation within day (5.33 ± 3.73% vs. 4.52 ± 2.49%, p = 0.378). The within-day ICC was poor (0.213). Within-day time-to-peak dilation did not significantly differ (660.0 ± 231.8 s vs. 602.7 ± 259.9 s, p = 0.379), and the ICC was fair (0.416, p = 0.113). Between-day peak dilation did not significantly differ (5.24 ± 3.84% vs. 4.71 ± 3.17%, p = 0.123), and the ICC was fair (0.419). Hypercapnia-induced brachial artery dilation is similar within day and between days. The ICC for peak dilation suggests the methodology is not reproducible.


      PubDate: 2016-04-08T06:38:30Z
       
 
 
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