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Journal Cover Ultrasound in Medicine & Biology
  [SJR: 0.885]   [H-I: 106]   [8 followers]  Follow
    
   Full-text available via subscription Subscription journal
   ISSN (Print) 0301-5629
   Published by Elsevier Homepage  [3043 journals]
  • Non-invasive Assessment of Liver Fibrosis with ElastPQ: Comparison with
           Transient Elastography and Serologic Fibrosis Marker Tests, and
           Correlation with Liver Pathology Results
    • Authors: Jeong Eun Lee; Kyung Sook Shin; June-Sik Cho; Sun Kyoung You; Ji Hye Min; Kyung-Hee Kim; In Sang Song; Kwang Sik Cheon
      Pages: 2515 - 2521
      Abstract: Publication date: November 2017
      Source:Ultrasound in Medicine & Biology, Volume 43, Issue 11
      Author(s): Jeong Eun Lee, Kyung Sook Shin, June-Sik Cho, Sun Kyoung You, Ji Hye Min, Kyung-Hee Kim, In Sang Song, Kwang Sik Cheon
      We investigated the feasibility of using ultrasound shear wave elastography point quantification (ElastPQ) for liver fibrosis staging and compared it with other non-invasive tools with respect to efficacy in liver stiffness measurement. A total of 106 patients who underwent liver stiffness measurements, using ElastPQ and biochemical investigations, before parenchymal liver biopsy or surgery were included. Among these, 51 also underwent transient elastography (TE). Correlations of ElastPQ, TE and aspartate aminotransferase-to-platelet ratio index (APRI) with histopathological findings (as the reference standard) were determined using Spearman's correlation coefficient. The diagnostic performance of ElastPQ, TE and APRI was evaluated using receiver operating characteristic (ROC) curve analysis. ElastPQ had good diagnostic accuracy in identifying each liver fibrosis stage, with an area under the ROC curve (AUC) of 0.810 to 0.864. Stiffness values obtained using ElastPQ, TE and APRI were significantly positively correlated (r = 0.686, r = 0.732 and r = 0.454, respectively) with histologic fibrosis staging (p < 0.001). According to the AUC for the diagnosis of significant fibrosis (≥F2) and cirrhosis (=F4), ElastPQ had better diagnostic accuracy (AUC = 0.929 and 0.834, respectively) than APRI (AUC = 0.656 and 0.618, respectively) (p < 0.05), and was similar to TE (AUC = 0.915 and 0.879, respectively). ElastPQ is a promising ultrasound-based imaging technique for evaluation of liver fibrosis, with a diagnostic accuracy comparable to that of TE.

      PubDate: 2017-09-19T08:00:03Z
      DOI: 10.1016/j.ultrasmedbio.2017.07.008
       
  • Imaging Features on Contrast-Enhanced Ultrasound and Clinical
           Characteristics of Hepatitis B Virus-Related Combined
           Hepatocellular–Cholangiocarcinoma: Comparison with Hepatitis B
           Virus-Related Hepatocellular Carcinoma
    • Authors: Jieyi Ye; Xiaoyan Xie; Baoxian Liu; Xiaoer Zhang; Wei Wang; Xiaowen Huang; Mingde Lu; Guangliang Huang
      Pages: 2530 - 2536
      Abstract: Publication date: November 2017
      Source:Ultrasound in Medicine & Biology, Volume 43, Issue 11
      Author(s): Jieyi Ye, Xiaoyan Xie, Baoxian Liu, Xiaoer Zhang, Wei Wang, Xiaowen Huang, Mingde Lu, Guangliang Huang
      The objective of this study was to compare the clinical characteristics and imaging features on contrast-enhanced ultrasound (CEUS) of hepatitis B virus (HBV)-related combined hepatocellular–cholangiocarcinoma (CHC) and hepatocellular carcinoma (HCC). Thirty-one pathologically proven CHCs were included and 31 HCCs were randomly selected as controls. Elevated carbohydrate antigen (CA) 19-9 alone and simultaneous elevation of α-fetoprotein and CA19-9 were more frequent in CHC than in HCC patients (p = 0.004 and 0.029, respectively). On CEUS, homogeneous, heterogeneous and peripheral irregular rim-like enhancement was illustrated in 8 (25.8%), 12 (38.7%) and 11 (35.5%) CHCs and in 6 (19.4%), 23 (74.1%) and 2 (6.5%) HCCs, respectively (p = 0.007). Multivariate logistic regression analysis revealed CA19-9 elevation (p = 0.011, odds ratio [OR] = 6.545) and peripheral irregular rim-like enhancement on CEUS (p = 0.017, OR = 7.718) were independent variables. A receiver operating characteristic curve was plotted and the area under the curve was 0.740. CHC should be watched for in HBV-infected patients with liver tumor manifesting peripheral irregular rim-like enhancement on CEUS, accompanied by CA19-9 elevation.

      PubDate: 2017-09-19T08:00:03Z
      DOI: 10.1016/j.ultrasmedbio.2017.07.016
       
  • Ultrasound Imaging of Muscle Contraction of the Tibialis Anterior in
           Patients with Facioscapulohumeral Dystrophy
    • Authors: Kaj Gijsbertse; Rianne Goselink; Saskia Lassche; Maartje Nillesen; André Sprengers; Nico Verdonschot; Nens van Alfen; Chris de Korte
      Pages: 2537 - 2545
      Abstract: Publication date: November 2017
      Source:Ultrasound in Medicine & Biology, Volume 43, Issue 11
      Author(s): Kaj Gijsbertse, Rianne Goselink, Saskia Lassche, Maartje Nillesen, André Sprengers, Nico Verdonschot, Nens van Alfen, Chris de Korte
      A need exists for biomarkers to diagnose, quantify and longitudinally follow facioscapulohumeral muscular dystrophy (FSHD) and many other neuromuscular disorders. Furthermore, the pathophysiological mechanisms leading to muscle weakness in most neuromuscular disorders are not completely understood. Dynamic ultrasound imaging (B-mode image sequences) in combination with speckle tracking is an easy, applicable and patient-friendly imaging tool to visualize and quantify muscle deformation. This dynamic information provides insight in the pathophysiological mechanisms and may help to distinguish the various stages of diseased muscle in FSHD. In this proof-of-principle study, we applied a speckle tracking technique to 2-D ultrasound image sequences to quantify the deformation of the tibialis anterior muscle in patients with FSHD and in healthy controls. The resulting deformation patterns were compared with muscle ultrasound echo intensity analysis (a measure of fat infiltration and dystrophy) and clinical outcome measures. Of the four FSHD patients, two patients had severe peroneal weakness and two patients had mild peroneal weakness on clinical examination. We found a markedly varied muscle deformation pattern between these groups: patients with severe peroneal weakness showed a different motion pattern of the tibialis anterior, with overall less displacement of the central tendon region, while healthy patients showed a non-uniform displacement pattern, with the central aponeurosis showing the largest displacement. Hence, dynamic muscle ultrasound of the tibialis anterior muscle in patients with FSHD revealed a distinctively different tissue deformation pattern among persons with and without tibialis anterior weakness. These findings could clarify the understanding of the pathophysiology of muscle weakness in FSHD patients. In addition, the change in muscle deformation shows good correlation with clinical measures and quantitative muscle ultrasound measurements. In conclusion, dynamic ultrasound in combination with speckle tracking allows the study of the effects of muscle pathology in relation to strength, force transmission and movement generation. Although further research is required, this technique can develop into a biomarker to quantify muscle disease severity.

      PubDate: 2017-09-19T08:00:03Z
      DOI: 10.1016/j.ultrasmedbio.2017.06.016
       
  • Ultrasound Imaging of the Renal Parenchyma of Premature Neonates for the
           Assessment of Renal Growth and Glomerulomegaly
    • Authors: Sonja Brennan; Yogavijayan Kandasamy
      Pages: 2546 - 2549
      Abstract: Publication date: November 2017
      Source:Ultrasound in Medicine & Biology, Volume 43, Issue 11
      Author(s): Sonja Brennan, Yogavijayan Kandasamy
      Evidence is increasingly showing that prematurity results in chronic kidney disease. We hypothesized that we could use ultrasound imaging to measure and monitor the growth of the renal parenchyma in premature neonates. We conducted a prospective, case-control study to compare renal parenchymal growth between neonates born prematurely and term neonates. The study patients underwent ultrasound assessment at 32 wk postmenstrual age (PMA) and 37 wk PMA. Term neonates (gestation >37 completed wk) admitted to the neonatal unit with minor neonatal conditions were recruited into the control group. Complete data sets were available in 91 premature neonates and during the same period, 56 term neonates were recruited as the control. The median birth weight (preterm babies) was 930 g (780–1220 g), and the mean gestational age was 27.0 wk (2.1 wk). Total renal volume (TRV) increased from 14.6 (4.3) cm3 to 20.5 (5.3) cm3 from 32 to 37 wk PMA. During the same period, the total renal parenchyma (TRP) thickness increased from 1.6 (0.3) cm to 1.8 (0.3) cm. At 37 wk PMA, ex-premature neonates have a significantly smaller total renal volume (20.5 [5.3] versus 25.9 [6.4] cm3; p < 0.001) and total renal parenchyma thickness (1.8 [0.3] versus 2.0 [0.2] cm; p = 0.015) compared with term (control) neonates. However, premature neonates at 37 wk PMA have a larger TRP:TRV ratio compared with term neonates (0.09 [0.02] versus 0.0 8 [0.02] cm−2; p < 0.001). Reduced nephron endowment as a result of prematurity may cause the remaining nephrons to undergo compensatory glomerulomegaly and we postulate this is the reason for the observed differences. Ultrasound imaging of the renal parenchyma shows promise in assessing the effects of prematurity on the developing kidney.

      PubDate: 2017-09-19T08:00:03Z
      DOI: 10.1016/j.ultrasmedbio.2017.06.033
       
  • Time-Harmonic Ultrasound elastography of the Descending Abdominal Aorta:
           Initial Results
    • Authors: Lars-Arne Schaafs; Heiko Tzschätzsch; Markus van der Giet; Alexander Reshetnik; Ingo G. Steffen; Bernd Hamm; Jürgen Braun; Ingolf Sack; Thomas Elgeti
      Pages: 2550 - 2557
      Abstract: Publication date: November 2017
      Source:Ultrasound in Medicine & Biology, Volume 43, Issue 11
      Author(s): Lars-Arne Schaafs, Heiko Tzschätzsch, Markus van der Giet, Alexander Reshetnik, Ingo G. Steffen, Bernd Hamm, Jürgen Braun, Ingolf Sack, Thomas Elgeti
      Stiffening of central large vessels is considered a key pathophysiologic factor within the cardiovascular system. Current diagnostic parameters such as pulse wave velocity (PWV) indirectly measure aortic stiffness, a hallmark of coronary diseases. The aim of the present study was to perform elastography of the proximal abdominal aorta based on externally induced time-harmonic shear waves. Experiments were performed in 30 healthy volunteers (25 young, 5 old, >50 y) and 5 patients with longstanding hypertension (PWV >10 m/s). B-Mode-guided sonographic time-harmonic elastography was used for measurement of externally induced shear waves at 30-Hz vibration frequency. Thirty-hertz shear wave amplitudes (SWAs) within the abdominal aorta were measured and displayed in real time and processed offline for differences in SWA between systole and diastole (ΔSWA). Data were analyzed using the Kruskal–Wallis test and receiver operating characteristic curve analysis. The change in SWA over the cardiac cycle was reduced significantly in all patients as assessed with ΔSWA (volunteers: mean = 10 ± 5 μm, patients: mean = 4 ± 1 μm; p < 0.001). The best separation of healthy volunteers from patients was obtained with a ΔSWA threshold of 4.7 μm, resulting in a sensitivity of 0.9 and a specificity of 1.0, with an overall area under the curve of 0.96. Time harmonic elastography of the abdominal aorta is feasible and shows promise for the exploitation of time-varying shear wave amplitudes as a diagnostic marker for aortic wall stiffening. Patients with elevated PWVs suggesting increased aortic wall stiffness were best identified by ΔSWA—a parameter that could be related to the ability of the vessel walls to distend on passages of the pulse wave.

      PubDate: 2017-09-19T08:00:03Z
      DOI: 10.1016/j.ultrasmedbio.2017.07.001
       
  • B-lines with Lung Ultrasound: The Optimal Scan Technique at Rest and
           During Stress
    • Authors: Maria Chiara Scali; Angela Zagatina; Iana Simova; Nadezhda Zhuravskaya; Quirino Ciampi; Marco Paterni; Mario Marzilli; Clara Carpeggiani; Eugenio Picano; Eugenio Picano; Quirino Ciampi; Rodolfo Citro; Antonello D'Andrea; Maria Chiara Scali; Lauro Cortigiani; Iacopo Olivotto; Fabio Mori; Maurizio Galderisi; Marco Fabio Costantino; Lorenza Pratali; Giovanni di Salvo; Eduardo Bossone; Francesco Ferrara; Jaroslaw D. Kasprszak; Fausto Rigo; Nicola Gaibazzi; Giuseppe Limongelli; Giuseppe Pacileo; Sergio Severino; Bruno Pinamonti; Laura Massa; Marco A.R. Torres; Marcelo H. Miglioranza; Clarissa Borguezan Daros; José Luis de Castro e Silva Pretto; Ana Djordjevic-Dikic; Milica Dekleva; Albert Varga; Gergely Agoston; Attila Palinkas; Angela Zagatina; Iana Simova; Miguel Amor; Jorge Lowenstein; Pablo Merlo; Jelena Celutkiene; Julio E. Perez; Paolo Trambaiolo; Dario Gregori; Paolo Colonna; Maria Grazia Andreassi; Michele De Nes; Ayana Arystan; Marco Paterni; Clara Carpeggiani
      Pages: 2558 - 2566
      Abstract: Publication date: November 2017
      Source:Ultrasound in Medicine & Biology, Volume 43, Issue 11
      Author(s): Maria Chiara Scali, Angela Zagatina, Iana Simova, Nadezhda Zhuravskaya, Quirino Ciampi, Marco Paterni, Mario Marzilli, Clara Carpeggiani, Eugenio Picano
      Various lung ultrasound (LUS) scanning modalities have been proposed for the detection of B-lines, also referred to as ultrasound lung comets, which are an important indication of extravascular lung water at rest and after exercise stress echo (ESE). The aim of our study was to assess the lung water spatial distribution (comet map) at rest and after ESE. We performed LUS at rest and immediately after semi-supine ESE in 135 patients (45 women, 90 men; age 62 ± 12 y, resting left ventricular ejection fraction = 41 ± 13%) with known or suspected heart failure or coronary artery disease. B-lines were measured by scanning 28 intercostal spaces (ISs) on the antero-lateral chest, 2nd–5th IS, along with the midaxillary (MA), anterior axillary (AA), mid-clavicular (MC) and parasternal (PS) lines. Complete 28-region, 16-region (3rd and 4th IS), 8-region (3rd IS), 4-region (3rd IS, only AA and MA) and 1-region (left 3rd IS, MA) scans were analyzed. In each space, the B-lines were counted from 0 = black lung to 10 = white lung. Interpretable images were obtained in all spaces (feasibility = 100 %). B-lines (>0 in at least 1 space) were present at ESE in 93 patients (69%) and absent in 42. More B-lines were found in the 3rd IS and along AA and MA lines. The B-line cumulative distribution was symmetric at rest (right/left = 1.10) and asymmetric with left lung predominance during stress (right/left = 0.67). The correlation of per-patient B-line number between 28-S and 16-S (R2 = 0.9478), 8-S (R2 = 0.9478) and 4-S scan (R2 = 0.9146) was excellent, but only good with 1-S (R2 = 0.8101). The average imaging and online analysis time were 5 s per space. In conclusion, during ESE, the comet map of lung water accumulation follows a predictable spatial pattern with wet spots preferentially aligned with the third IS and along the AA and MA lines. The time-saving 4-region scan is especially convenient during stress, simply dismissing dry regions and focusing on wet regions alone.

      PubDate: 2017-09-19T08:00:03Z
      DOI: 10.1016/j.ultrasmedbio.2017.07.007
       
  • Role of Contrast-Enhanced Ultrasound in the Pre-operative Diagnosis of
           Cervical Lymph Node Metastasis in Patients with Papillary Thyroid
           Carcinoma
    • Authors: Yu-Rong Hong; Zhi-Yan Luo; Guo-Qiang Mo; Ping Wang; Qin Ye; Pin-Tong Huang
      Pages: 2567 - 2575
      Abstract: Publication date: November 2017
      Source:Ultrasound in Medicine & Biology, Volume 43, Issue 11
      Author(s): Yu-Rong Hong, Zhi-Yan Luo, Guo-Qiang Mo, Ping Wang, Qin Ye, Pin-Tong Huang
      The objective of this study was to prospectively evaluate the diagnostic accuracy of contrast-enhanced ultrasonography (CEUS) in differentiating between benign and metastatic cervical lymph nodes in patients with papillary thyroid cancer (PTC). Three hundred nineteen cervical lymph nodes (162 metastatic from PTC and 157 benign) were evaluated using conventional ultrasonography (US) and CEUS before biopsy or surgery. Metastatic lymph nodes more often manifested centripetal or asynchronous perfusion, hyper-enhancement, heterogeneous enhancement, perfusion defects and ring-enhancing margins than benign lymph nodes at pre-operative CEUS (all p values < 0.001). The area under the receiver operating characteristic curve (AUC) for the combination of conventional US and CEUS (0.983, 95% confidence interval [CI]: 0.971–0.994) was higher than that of conventional US alone (0.929, 95% CI: 0.899–0.958) and CEUS (0.911, 95% CI: 0.876–0.947). In conclusion, CEUS is a promising tool in conjunction with conventional US for the pre-operative prediction of metastatic cervical lymph nodes in patients with PTC.

      PubDate: 2017-09-19T08:00:03Z
      DOI: 10.1016/j.ultrasmedbio.2017.07.010
       
  • Ultrasound-Guided Fine-Needle Aspiration of Non-palpable and Suspicious
           Axillary Lymph Nodes with Subsequent Removal after Tattooing:
           False-Negative Results and Concordance with Sentinel Lymph Nodes
    • Authors: Won Hwa Kim; Hye Jung Kim; Jin Hyang Jung; Ho Yong Park; Jeeyeon Lee; Wan Wook Kim; Ji Young Park; Hyejin Cheon; So Mi Lee; Seung Hyun Cho; Kyung Min Shin; Gab Chul Kim
      Pages: 2576 - 2581
      Abstract: Publication date: November 2017
      Source:Ultrasound in Medicine & Biology, Volume 43, Issue 11
      Author(s): Won Hwa Kim, Hye Jung Kim, Jin Hyang Jung, Ho Yong Park, Jeeyeon Lee, Wan Wook Kim, Ji Young Park, Hyejin Cheon, So Mi Lee, Seung Hyun Cho, Kyung Min Shin, Gab Chul Kim
      Ultrasonography-guided fine-needle aspiration (US-guided FNA) for axillary lymph nodes (ALNs) is currently used with various techniques for the initial staging of breast cancer and tagging of ALNs. With the implementation of the tattooing of biopsied ALNs, the rate of false-negative results of US-guided FNA for non-palpable and suspicious ALNs and concordance with sentinel lymph nodes were determined by node-to node analyses. A total of 61 patients with breast cancer had negative results for metastasis on US-guided FNA of their non-palpable and suspicious ALNs. The biopsied ALNs were tattooed with an injection of 1–3 mL Charcotrace (Phebra, Lane Cove West, Australia) ink and removed during sentinel lymph node biopsy or axillary dissection. We determined the rate of false-negative results and concordance with the sentinel lymph nodes by a retrospective review of surgical and pathologic findings. The association of false-negative results with clinical and imaging factors was evaluated using logistic regression. Of the 61 ALNs with negative results for US-guided FNA, 13 (21%) had metastases on final pathology. In 56 of 61 ALNs (92%), tattooed ALNs corresponded to the sentinel lymph nodes. Among the 5 patients (8%) without correspondence, 1 patient (2%) had 2 metastatic ALNs of 1 tattooed node and 1 sentinel lymph node. In multivariate analysis, atypical cells on FNA results (odds ratio = 20.7, p = 0.040) was independently associated with false-negative FNA results. False-negative ALNs after US-guided FNA occur at a rate of 21% and most of the tattooed ALNs showed concordance with sentinel lymph nodes.

      PubDate: 2017-09-19T08:00:03Z
      DOI: 10.1016/j.ultrasmedbio.2017.07.011
       
  • B-Mode Ultrasound Combined with Color Doppler and Strain Elastography in
           the Diagnosis of Non-mass Breast Lesions: A Prospective Study
    • Authors: Lujing Li; Xinchuan Zhou; Xinbao Zhao; Shaoyun Hao; Jiyi Yao; Wenjing Zhong; Hui Zhi
      Pages: 2582 - 2590
      Abstract: Publication date: November 2017
      Source:Ultrasound in Medicine & Biology, Volume 43, Issue 11
      Author(s): Lujing Li, Xinchuan Zhou, Xinbao Zhao, Shaoyun Hao, Jiyi Yao, Wenjing Zhong, Hui Zhi
      Non-mass breast lesions on ultrasound (US) are areas without an associated mass. The purpose of this study was to evaluate whether combining B-mode US with color Doppler US and strain elastography (SE) improves US differentiation between benign and malignant non-mass breast lesions and the decision for biopsy. In this prospective study, three different radiologists analyzed the US images of 77 non-mass lesions independently and recorded Breast Imaging Reporting and Data System (BI-RADS) categories for four data sets. The image characteristics and BI-RADS categories of the four data sets were analyzed by another radiologist. The final diagnosis was made on the basis of pathologic findings. Values for area under the receiver operating curve (AUC), sensitivity, specificity and accuracy were compared among the data sets. The AUC of B-mode US combined with both color Doppler US and SE was greater than that of B-mode US alone (0.666 vs. 0.828) (p = 0.011). The specificity of making the decision for biopsy increased from 6.5% to 38.7% when B-mode US was combined with color Doppler and SE, without a statistically significant change in sensitivity (p < 0.001). Combined use of color Doppler and SE could improve the diagnostic value of B-mode US in distinguishing benign from malignant non-mass breast lesions and the specificity of making the decision for biopsy of non-mass breast lesions.

      PubDate: 2017-09-19T08:00:03Z
      DOI: 10.1016/j.ultrasmedbio.2017.07.014
       
  • Fluid Resuscitation in Septic Patients Improves Systolic but not Diastolic
           Middle Cerebral Artery Flow Velocity
    • Authors: Annika A. de Goede; Bert G. Loef; Auke C. Reidinga; Arjen Schaafsma
      Pages: 2591 - 2600
      Abstract: Publication date: November 2017
      Source:Ultrasound in Medicine & Biology, Volume 43, Issue 11
      Author(s): Annika A. de Goede, Bert G. Loef, Auke C. Reidinga, Arjen Schaafsma
      To investigate the effects of fluid resuscitation on cerebral hemodynamics in sepsis, the following set of transcranial Doppler (TCD) parameters was used: maximal change in flow velocity (FV) during stroke onset (acc), maximal FV during first (sys1) or second (sys2) phase of systole and mean diastolic FV (dias@560). We aim to evaluate changes in cerebral hemodynamics that result from (i) sepsis and (ii) adequate fluid resuscitation in critically ill septic patients. In the majority of 16 septic patients sys2 was initially absent but reappeared during the period of fluid resuscitation; whereas sys2 absence was never seen in healthy controls. Second, adequate fluid resuscitation resulted in a significant increase of the systolic FV components (acc, sys1, sys2 and systolic blood pressure); whereas the diastolic components (dias@560 and diastolic blood pressure) remained unchanged. Sys2 absence and reappearance in sepsis suggests that TCD could become a non-invasive alternative for hemodynamic monitoring.

      PubDate: 2017-09-19T08:00:03Z
      DOI: 10.1016/j.ultrasmedbio.2017.06.027
       
  • Vector Flow Visualization of Urinary Flow Dynamics in a Bladder
           Outlet Obstruction Model
    • Authors: Takuro Ishii; Billy Y.S. Yiu; Alfred C.H. Yu
      Pages: 2601 - 2610
      Abstract: Publication date: November 2017
      Source:Ultrasound in Medicine & Biology, Volume 43, Issue 11
      Author(s): Takuro Ishii, Billy Y.S. Yiu, Alfred C.H. Yu
      Voiding dysfunction that results from bladder outlet (BO) obstruction is known to alter significantly the dynamics of urine passage through the urinary tract. To non-invasively image this phenomenon on a time-resolved basis, we pursued the first application of a recently developed flow visualization technique called vector projectile imaging (VPI) that can track the spatiotemporal dynamics of flow vector fields at a frame rate of 10,000 fps (based on plane wave excitation and least-squares Doppler vector estimation principles). For this investigation, we designed a new anthropomorphic urethral tract phantom to reconstruct urinary flow dynamics under controlled conditions (300 mm H2O inlet pressure and atmospheric outlet pressure). Both a normal model and a diseased model with BO obstruction were developed for experimentation. VPI cine loops were derived from these urinary flow phantoms. Results show that VPI is capable of depicting differences in the flow dynamics of normal and diseased urinary tracts. In the case with BO obstruction, VPI depicted the presence of BO flow jet and vortices in the prostatic urethra. The corresponding spatial-maximum flow velocity magnitude was estimated to be 2.43 m/s, and it is significantly faster than that for the normal model (1.52 m/s) and is in line with values derived from computational fluid dynamics simulations. Overall, this investigation demonstrates the feasibility of using vector flow visualization techniques to non-invasively examine internal flow characteristics related to voiding dysfunction in the urethral tract.

      PubDate: 2017-09-19T08:00:03Z
      DOI: 10.1016/j.ultrasmedbio.2017.07.006
       
  • Feasibility of UltraFast Doppler in Post-operative Evaluation of Hepatic
           Artery in Recipients following Liver Transplantation
    • Authors: Se-Young Kim; Kyoung Won Kim; Sang Hyun Choi; Jae Hyun Kwon; Gi-Won Song; Heon-Ju Kwon; Young Ju Yun; Jeongjin Lee; Sung-Gyu Lee
      Pages: 2611 - 2618
      Abstract: Publication date: November 2017
      Source:Ultrasound in Medicine & Biology, Volume 43, Issue 11
      Author(s): Se-Young Kim, Kyoung Won Kim, Sang Hyun Choi, Jae Hyun Kwon, Gi-Won Song, Heon-Ju Kwon, Young Ju Yun, Jeongjin Lee, Sung-Gyu Lee
      To determine the feasibility of using UltraFast Doppler in post-operative evaluation of the hepatic artery (HA) after liver transplantation (LT), we evaluated 283 simultaneous conventional and UltraFast Doppler sessions in 126 recipients over a 2-mo period after LT, using an Aixplorer scanner The Doppler indexes of the HA (peak systolic velocity [PSV], end-diastolic velocity [EDV], resistive index [RI] and systolic acceleration time [SAT]) by retrospective analysis of retrieved waves from UltraFast Doppler clips were compared with those obtained by conventional spectral Doppler. Correlation, performance in diagnosing the pathologic wave, examination time and reproducibility were evaluated. The PSV, EDV, RI and SAT of spectral and UltraFast Doppler measurements exhibited excellent correlation with favorable diagnostic performance. During the bedside examination, the mean time spent for UltraFast clip storing was significantly shorter than that for conventional Doppler US measurements. Both conventional and UltraFast Doppler exhibited good to excellent inter-analysis consistency. In conclusion, compared with conventional spectral Doppler, UltraFast Doppler values correlated excellently and yielded acceptable pathologic wave diagnostic performance with reduced examination time at the bedside and excellent reproducibility.

      PubDate: 2017-09-19T08:00:03Z
      DOI: 10.1016/j.ultrasmedbio.2017.07.018
       
  • Evaluation of Non-alcoholic Fatty Liver Disease Using Acoustic Radiation
           Force Impulse Imaging Elastography in Rat Models
    • Authors: Yanrong Guo; Changfeng Dong; Haoming Lin; Xinyu Zhang; Huiying Wen; Yuanyuan Shen; Tianfu Wang; Siping Chen; Yingxia Liu; Xin Chen
      Pages: 2619 - 2628
      Abstract: Publication date: November 2017
      Source:Ultrasound in Medicine & Biology, Volume 43, Issue 11
      Author(s): Yanrong Guo, Changfeng Dong, Haoming Lin, Xinyu Zhang, Huiying Wen, Yuanyuan Shen, Tianfu Wang, Siping Chen, Yingxia Liu, Xin Chen
      The aim of this study is to evaluate the utility of acoustic radiation force impulse (ARFI) elastography for assessing hepatic fibrosis stage and non-alcoholic fatty liver disease (NAFLD) severity, as well as the relationship among hepatic histologic changes using shear wave velocity (SWV). Animal models with various degrees of NAFLD were established in 110 rats. The right liver lobe was processed and embedded in a fabricated gelatin solution (porcine skin). Liver mechanics were measured using SWV induced by acoustic radiation force. Among the histologic findings, liver elasticity could be used to differentiate normal rats from rats with simple steatosis (SS) as well as distinguish SS from non-alcoholic steatohepatitis (NASH), with areas under the receiver operating characteristic curves (AUROC) of 0.963 (95% confidence interval = 0.871–0.973) and 0.882 (95% confidence interval = 0.807–0.956), respectively. For NAFLD rats, the diagnostic performance of ARFI elastography in predicting significant fibrosis (F ≥ 2) had an AUROC of 0.963. For evaluating steatosis severity, we found a progressive increase in ARFI velocity proportional to steatotic severity in NAFLD rat models, but we observed no significant differences for steatotic severity after excluding the rats with fibrosis. ARFI elastography may be used to differentiate among degrees of severity of NAFLD and hepatic fibrotic stages in NAFLD rat models.

      PubDate: 2017-09-19T08:00:03Z
      DOI: 10.1016/j.ultrasmedbio.2017.06.026
       
  • Measurement of Liver Stiffness Using Shear Wave Elastography in a Rat
           Model: Factors Impacting Stiffness Measurement with Multiple- and
           Single-Tracking-Location Techniques
    • Authors: Jonathan H. Langdon; Etana Elegbe; Raul S. Gonzalez; Laurentius Osapoetra; Tristan Ford; Stephen A. McAleavey
      Pages: 2629 - 2639
      Abstract: Publication date: November 2017
      Source:Ultrasound in Medicine & Biology, Volume 43, Issue 11
      Author(s): Jonathan H. Langdon, Etana Elegbe, Raul S. Gonzalez, Laurentius Osapoetra, Tristan Ford, Stephen A. McAleavey
      The clinical use of elastography for monitoring fibrosis progression is challenged by the subtle changes in liver stiffness associated with early-stage fibrosis and the comparatively large variance in stiffness estimates provided by elastography. Single-tracking-location (STL) shear wave elasticity imaging (SWEI) is an ultrasound elastography technique previously found to provide improved estimate precision compared with multiple-tracking-location (MTL) SWEI. Because of the improved precision, it is reasonable to expect that STL-SWEI would provide improved ability to differentiate liver fibrosis stage compared with MTL-SWEI. However, this expectation has not been previously challenged rigorously. In this work, the performance of STL- and MTL-SWEI in the setting of a rat model of liver fibrosis is characterized, and the advantages of STL-SWEI in staging fibrosis are explored. The purpose of this study was to determine what advantages, if any, arise from using STL-SWEI instead of MTL-SWEI in the characterization of fibrotic liver. Thus, the ability of STL-SWEI to differentiate livers at various METAVIR fibrosis scores, for ex vivo postmortem measurements, is explored. In addition, we examined the effect of the common confounding factor of fluid versus solid boundary conditions in SWEI experiments. Sprague-Dawley rats were treated with carbon tetrachloride over several weeks to produce liver disease of varying severity. STL and MTL stiffness measurements were performed ex vivo and compared with the METAVIR scores from histological analysis and the duration of treatment. A strong association was observed between liver stiffness and weeks of treatment with the liver toxin carbon tetrachloride. Direct comparison of STL- and MTL-SWEI measurements revealed no significant difference in ability to differentiate fibrosis stages based on SWEI mean values. However, image interquartile range was greatly improved in the case of STL-SWEI, compared with MTL-SWEI, at small beam spacing.

      PubDate: 2017-09-19T08:00:03Z
      DOI: 10.1016/j.ultrasmedbio.2017.07.004
       
  • The Combination of Glycolytic Inhibitor 2-Deoxyglucose and Microbubbles
           Increases the Effect of 5-Aminolevulinic Acid-Sonodynamic Therapy in Liver
           Cancer Cells
    • Authors: Rui Xie; Tongying Xu; Jiuxin Zhu; Xiaoli Wei; Wenting Zhu; Longmin Li; Yufeng Wang; Yu Han; Jianhua Zhou; Yuxian Bai
      Pages: 2640 - 2650
      Abstract: Publication date: November 2017
      Source:Ultrasound in Medicine & Biology, Volume 43, Issue 11
      Author(s): Rui Xie, Tongying Xu, Jiuxin Zhu, Xiaoli Wei, Wenting Zhu, Longmin Li, Yufeng Wang, Yu Han, Jianhua Zhou, Yuxian Bai
      Sonodynamic therapy (SDT) overcomes the shortcoming of photodynamic therapy in the treatment of cancer. Previous studies indicated that the glycolysis inhibitor 2-deoxyglucose (2-DG) potentiated photodynamic therapy induced tumor cell death and microbubbles (MBs) improved the SDT performance. We hypothesized that the combination of 2-DG and MBs will increase the effect of 5-aminolevulinic acid (ALA)-SDT in HepG2 liver cancer cells. When cells were treated with 5-min ALA-SDT and 2-mmol/L 2-DG, the cell survival rate decreased to 73.0 ± 7.1% and 75.2 ± 7.9%, respectively. Furthermore, 2 mmol/L 2-DG increased 5-min ALA-SDT induced growth inhibition and augmented ALA-SDT induced cell apoptotic rate from 9.8 ± 0.7% to 17.4 ± 2.2%. In the combination group (2-DG and ALA-SDT group), HepG2 cells possessed typical apoptotic characters. 2-DG also increased ALA-SDT associated intracellular reactive oxygen species generation and loss of mitochondrial membrane potential. Moreover, SonoVue MBs had stimulatory function on cell viability inhibition, apoptosis, reactive oxygen species production and mitochondrial membrane potential loss for combination treatment. This study suggests a promising therapeutic strategy using a combination of 2-DG, MBs and ALA-SDT for treating liver cancer.

      PubDate: 2017-09-19T08:00:03Z
      DOI: 10.1016/j.ultrasmedbio.2017.06.031
       
  • Ultrasound Improves the Delivery and Therapeutic Effect
           of Nanoparticle-Stabilized Microbubbles in Breast Cancer Xenografts
    • Authors: Sofie Snipstad; Sigrid Berg; Ýrr Mørch; Astrid Bjørkøy; Einar Sulheim; Rune Hansen; Ingeborg Grimstad; Annemieke van Wamel; Astri F. Maaland; Sverre H. Torp; Catharina de Lange Davies
      Pages: 2651 - 2669
      Abstract: Publication date: November 2017
      Source:Ultrasound in Medicine & Biology, Volume 43, Issue 11
      Author(s): Sofie Snipstad, Sigrid Berg, Ýrr Mørch, Astrid Bjørkøy, Einar Sulheim, Rune Hansen, Ingeborg Grimstad, Annemieke van Wamel, Astri F. Maaland, Sverre H. Torp, Catharina de Lange Davies
      Compared with conventional chemotherapy, encapsulation of drugs in nanoparticles can improve efficacy and reduce toxicity. However, delivery of nanoparticles is often insufficient and heterogeneous because of various biological barriers and uneven tumor perfusion. We investigated a unique multifunctional drug delivery system consisting of microbubbles stabilized by polymeric nanoparticles (NPMBs), enabling ultrasound-mediated drug delivery. The aim was to examine mechanisms of ultrasound-mediated delivery and to determine if increased tumor uptake had a therapeutic benefit. Cellular uptake and toxicity, circulation and biodistribution were characterized. After intravenous injection of NPMBs into mice, tumors were treated with ultrasound of various pressures and pulse lengths, and distribution of nanoparticles was imaged on tumor sections. No effects of low pressures were observed, whereas complete bubble destruction at higher pressures improved tumor uptake 2.3 times, without tissue damage. An enhanced therapeutic effect was illustrated in a promising proof-of-concept study, in which all tumors exhibited regression into complete remission.

      PubDate: 2017-09-19T08:00:03Z
      DOI: 10.1016/j.ultrasmedbio.2017.06.029
       
  • Toward a Standardization of Ultrasound Scanners for Dynamic
           Contrast-Enhanced Ultrasonography: Methodology and Phantoms
    • Authors: Stéphanie Pitre-Champagnat; Bénédicte Coiffier; Laurène Jourdain; Baya Benatsou; Ingrid Leguerney; Nathalie Lassau
      Pages: 2670 - 2677
      Abstract: Publication date: November 2017
      Source:Ultrasound in Medicine & Biology, Volume 43, Issue 11
      Author(s): Stéphanie Pitre-Champagnat, Bénédicte Coiffier, Laurène Jourdain, Baya Benatsou, Ingrid Leguerney, Nathalie Lassau
      The standardization of ultrasound scanners for dynamic contrast-enhanced ultrasonography (DCE-US) is mandatory for evaluation of clinical multicenter studies. We propose a robust method using a phantom for measuring the variation of the harmonic signal intensity obtained from the area under the time-intensity curve versus various contrast-agent concentrations. The slope of this measured curve is the calibration parameter. We tested our method on two devices from the same manufacturer (AplioXV and Aplio500, Toshiba, Tokyo, Japan) using the same settings as defined for a French multicenter study. The Aplio500's settings were adjusted to match the slopes of the AplioXV, resulting in the following settings on the Aplio500: at 3.5 MHz: MI = 0.15; CG = 35 dB and at 8 MHz: MI = 0.10; CG = 32 dB. This calibration method is very important for future DCE-US multicenter studies.

      PubDate: 2017-09-19T08:00:03Z
      DOI: 10.1016/j.ultrasmedbio.2017.06.032
       
  • Mechanistic Insight into Sonoporation with Ultrasound-Stimulated Polymer
           Microbubbles
    • Authors: Brandon L. Helfield; Xucai Chen; Bin Qin; Simon C. Watkins; Flordeliza S. Villanueva
      Pages: 2678 - 2689
      Abstract: Publication date: November 2017
      Source:Ultrasound in Medicine & Biology, Volume 43, Issue 11
      Author(s): Brandon L. Helfield, Xucai Chen, Bin Qin, Simon C. Watkins, Flordeliza S. Villanueva
      Sonoporation is emerging as a feasible, non-viral gene delivery platform for the treatment of cardiovascular disease and cancer. Despite promising results, this approach remains less efficient than viral methods. The objective of this work is to help substantiate the merit of polymeric microbubble sonoporation as a non-viral, localized cell permeation and payload delivery strategy by taking a ground-up approach to elucidating the fundamental mechanisms at play. In this study, we apply simultaneous microscopy of polymeric microbubble sonoporation over its intrinsic biophysical timescales–with sub-microsecond resolution to examine microbubble cavitation and millisecond resolution over several minutes to examine local macromolecule uptake through enhanced endothelial cell membrane permeability–bridging over six orders of magnitude in time. We quantified microbubble behavior and resulting sonoporation thresholds at transmit frequencies of 0.5, 1 and 2 MHz, and determined that sonic cracking is a necessary but insufficient condition to induce sonoporation. Further, sonoporation propensity increases with the extent of sonic cracking, namely, from partial to complete gas escape from the polymeric encapsulation. For the subset that exhibited complete gas escape from sonic cracking, a proportional relationship between the maximum projected gas area and resulting macromolecule uptake was observed. These results have revealed one aspect of polymeric bubble activity on the microsecond time scale that is associated with eliciting sonoporation in adjacent endothelial cells, and contributes toward an understanding of the physical rationale for sonoporation with polymer-encapsulated microbubble contrast agents.

      PubDate: 2017-09-19T08:00:03Z
      DOI: 10.1016/j.ultrasmedbio.2017.07.017
       
  • Efficacy of Indocyanine Green-Mediated Sonodynamic Therapy on Rheumatoid
           Arthritis Fibroblast-like Synoviocytes
    • Authors: Qin Tang; Shufang Chang; Zhonghua Tian; Jiangchuan Sun; Lan Hao; Zhigang Wang; Shenyin Zhu
      Pages: 2690 - 2698
      Abstract: Publication date: November 2017
      Source:Ultrasound in Medicine & Biology, Volume 43, Issue 11
      Author(s): Qin Tang, Shufang Chang, Zhonghua Tian, Jiangchuan Sun, Lan Hao, Zhigang Wang, Shenyin Zhu
      Sonodynamic therapy (SDT) has become a new therapeutic method because of its activation of certain sensitizers by ultrasound. Some studies have reported that indocyanine green (ICG) has the characteristics of a sonosensitizer and favorable fluorescence imaging in synovitis of early inflammatory arthritis. In this study, we aimed to investigate the cytotoxic effect of ICG-mediated SDT on MH7A cells in vitro and the potential mechanisms involved. ICG was found to be taken up mainly in cytoplasm, with maximal uptake in 4 h. Cell viability in ICG-mediated SDT (SDT-0.5 and SDT-1.0) groups decreased significantly to 73.09 ± 1.97% and 54.24 ± 4.66%, respectively; cell apoptosis increased significantly to 26.43 ± 0.91% and 45.93 ± 6.17%, respectively. Moreover, marked loss in mitochondrial membrane potential and greatly increased generation of reactive oxygen species were observed in ICG-mediated SDT groups. Interestingly, the loss in cell viability could be effectively rescued with pretreatment with the reactive oxygen species scavenger N-acetylcysteine. These results indicate that ICG-mediated SDT is cytotoxic to fibroblast-like synoviocytes and is a potential modality for targeted therapy of synovitis in rheumatoid arthritis.

      PubDate: 2017-09-19T08:00:03Z
      DOI: 10.1016/j.ultrasmedbio.2017.06.030
       
  • Role of Reactive Oxygen Species during Low-Intensity Pulsed Ultrasound
           Application in MC-3 T3 E1 Pre-osteoblast Cell Culture
    • Authors: Harmanpreet Kaur; Arno G. Siraki; Hasan Uludağ; Douglas N. Dederich; Patrick Flood; Tarek El-Bialy
      Pages: 2699 - 2712
      Abstract: Publication date: November 2017
      Source:Ultrasound in Medicine & Biology, Volume 43, Issue 11
      Author(s): Harmanpreet Kaur, Arno G. Siraki, Hasan Uludağ, Douglas N. Dederich, Patrick Flood, Tarek El-Bialy
      We evaluated the activation of mitogen-activated protein kinase (MAPK) activation through reactive oxygen species (ROS) by application of low-intensity ultrasound (LIPUS) to MC-3 T3 E1 pre-osteoblasts. The cells were subjected to one LIPUS application for either 10 or 20 min, and the control group was exposed to a sham transducer. For ROS inhibition, 10 μM diphenylene iodonium (DPI) was added to the cells an hour before LIPUS application. Samples were collected 1, 3, 6, 12 and 24 h after LIPUS application, and cells were evaluated for ROS generation, cell viability, gene expression and MAPK activation by immunoblot analyses. LIPUS caused a significant increase in ROS and cell viability in the non-DPI-treated group. Expression of RUNX2, OCN and OPN mRNA was higher in the LIPUS-treated groups at 1 h in both the DPI-treated and non-DPI-treated groups; RUNX2 and OCN mRNA levels increased at 6 h. ERK1/2 activation was increased in the LIPUS-treated groups. These results indicate that LIPUS activates MAPK by ROS generation in MC-3 T3 E1 pre-osteoblasts.

      PubDate: 2017-09-19T08:00:03Z
      DOI: 10.1016/j.ultrasmedbio.2017.07.002
       
  • Respiratory Variation in Femoral Vein Diameter Has Moderate Accuracy as a
           Marker of Fluid Responsivity in Mechanically Ventilated Septic Shock
           Patients
    • Authors: Wagner Luis Nedel; Daniele Moraes Simas; Luiz Gustavo Marin; Vinicius Daudt Morais; Gilberto Friedman
      Pages: 2713 - 2717
      Abstract: Publication date: November 2017
      Source:Ultrasound in Medicine & Biology, Volume 43, Issue 11
      Author(s): Wagner Luis Nedel, Daniele Moraes Simas, Luiz Gustavo Marin, Vinicius Daudt Morais, Gilberto Friedman
      Ultrasound (US) is considered the first step in evaluation of patients with shock; respiratory variation of the inferior vena cava (inferior vena cava collapsibility [IVCc]) is an important measurement in this scenario that can be impaired by patient condition or technical skills. The main objective of this study was to evaluate if respiratory variation of the femoral vein (femoral vein collapsibility [FVc]), which is easier to visualize, can adequately predict fluid responsiveness in septic shock patients. Forty-five mechanically ventilated septic shock patients in a mixed clinical–surgical, 30-bed intensive care unit were enrolled in this study. All patients underwent assessments of FVc, IVCc and cardiac output using a portable US device. The passive leg raising test was used to evaluate fluid responsiveness. FVc presented an area under the receiver operating characteristic curve of 0.678 (95% confidence interval: 0.519–0.837, p = 0.044) with a cutoff point of 17%, yielding a sensitivity of 62% and specificity of 65% in predicting fluid responsiveness. IVCc had greater diagnostic accuracy compared with FVc, with an area under the receiver operating characteristic curve of 0.733 (95% confidence interval: 0.563–0.903, p = 0.024) and a cutoff point of 29%, yielding a sensitivity of 47% and specificity of 86%. In conclusion, FVc has moderate accuracy when employed as an indicator of fluid responsiveness in spontaneously mechanically ventilated septic shock patients.

      PubDate: 2017-09-19T08:00:03Z
      DOI: 10.1016/j.ultrasmedbio.2017.06.023
       
  • Non-Invasive Intra-cardiac Pressure Measurements Using Subharmonic-Aided
           Pressure Estimation: Proof of Concept in Humans
    • Authors: Jaydev K. Dave; Sushmita V. Kulkarni; Purva P. Pangaonkar; Maria Stanczak; Maureen E. McDonald; Ira S. Cohen; Praveen Mehrotra; Michael P. Savage; Paul Walinsky; Nicholas J. Ruggiero; David L. Fischman; David Ogilby; Carolyn VanWhy; Matthew Lombardi; Flemming Forsberg
      Pages: 2718 - 2724
      Abstract: Publication date: November 2017
      Source:Ultrasound in Medicine & Biology, Volume 43, Issue 11
      Author(s): Jaydev K. Dave, Sushmita V. Kulkarni, Purva P. Pangaonkar, Maria Stanczak, Maureen E. McDonald, Ira S. Cohen, Praveen Mehrotra, Michael P. Savage, Paul Walinsky, Nicholas J. Ruggiero, David L. Fischman, David Ogilby, Carolyn VanWhy, Matthew Lombardi, Flemming Forsberg
      This study evaluated the feasibility of employing non-invasive intra-cardiac pressure estimation using subharmonic signals from ultrasound contrast agents in humans. This institutional review board–approved proof-of-concept study included 15 consenting patients scheduled for left and right heart catheterization. During the catheterization procedure, Definity was infused intra-venously at 4–10 mL/min. Ultrasound scanning was performed with a Sonix RP using pulse inversion, three incident acoustic output levels and 2.5-MHz transmit frequency. Radiofrequency data were processed and subharmonic amplitudes were compared with the pressure catheter data. The correlation coefficient between subharmonic signals and pressure catheter data ranged from −0.3 to −0.9. For acquisitions with optimum acoustic output, pressure errors between the subharmonic technique and catheter were as low as 2.6 mmHg. However, automatically determining optimum acoustic output during scanning for each patient remains to be addressed before clinical applicability can be decided.

      PubDate: 2017-09-19T08:00:03Z
      DOI: 10.1016/j.ultrasmedbio.2017.07.009
       
  • Combining Subharmonic and Ultraharmonic Modes for Intravascular Ultrasound
           Imaging: A Preliminary Evaluation
    • Authors: Himanshu Shekhar; Jeffrey S. Rowan; Marvin M. Doyley
      Pages: 2725 - 2732
      Abstract: Publication date: November 2017
      Source:Ultrasound in Medicine & Biology, Volume 43, Issue 11
      Author(s): Himanshu Shekhar, Jeffrey S. Rowan, Marvin M. Doyley
      Contrast-enhanced intra-vascular ultrasound (CE-IVUS) imaging could provide clinicians a valuable tool to assess cardiovascular risk and guide the choice of therapeutic strategies. In this technical note, we evaluated the feasibility of combining subharmonic and ultraharmonic imaging to improve the performance of CE-IVUS. Vessel phantoms perfused with phospholipid-shelled ultrasound contrast agents were visualized using subharmonic, ultraharmonic and combined CE-IVUS modes with commercial peripheral and coronary imaging catheters. Flow channels as small as 0.8 mm and 0.5 mm were imaged at 12-MHz and 30-MHz transmit frequencies, respectively. Subharmonic and ultraharmonic imaging modes achieved a contrast-to-tissue ratio (CTR) up to 18.1 ± 1.8 dB and 19.6 ± 1.9 dB at 12-MHz, and 8.8 ± 1.8 and 12.5 ± 1.1 dB at 30-MHz transmit frequencies, respectively. Combining these modes improved the CTR to 32.5 ± 3.0 dB and 25.0 ± 1.6 dB at 12-MHz and 30-MHz transmit frequencies. These results underscore the potential of combined-mode CE-IVUS imaging. Furthermore, the demonstration of this approach with commercial catheters may serve as a first step toward the clinical translation of CE-IVUS.

      PubDate: 2017-09-19T08:00:03Z
      DOI: 10.1016/j.ultrasmedbio.2017.07.012
       
  • Pilot Investigation into the Use of an Anthropomorphic Breast Sonography
           Phantom as a Training and Assessment Tool
    • Authors: Jacinta E. Browne; Louise M. Cannon; Ronan McDermott; Max Ryan; Andrew J. Fagan
      Pages: 2733 - 2740
      Abstract: Publication date: November 2017
      Source:Ultrasound in Medicine & Biology, Volume 43, Issue 11
      Author(s): Jacinta E. Browne, Louise M. Cannon, Ronan McDermott, Max Ryan, Andrew J. Fagan
      A device for the training and quantitative assessment of the competency of trainee radiologists in the technically challenging area of breast sonography was developed and evaluated. Currently, suitable commercially available devices are lacking, and there is a growing realization that the reliance on direct exposure to patients for learning may not represent best practice from either the trainees' or patients' perspective. Three devices (PI, PII and PIII) were designed to produce very realistic sonographic images of breast morphology with a range of embedded pathologies. The pilot evaluation used a case study research design to evaluate the role of the anthropomorphic breast sonography training device in training and assessment in a clinical environment. Through the case study, it was possible to evaluate the process and relationships when using this type of training intervention for a small group of radiology resident trainees. The investigation involved a baseline assessment of trainees' (n = 4) ability to detect and characterize all lesions in PI, followed by a 4-wk training period on PII and a post-training assessment using PIII. The evaluation revealed an improvement of 30% ± 8% in the trainee's performance from pre- to post-training. It was expected that the performance of the trainees would improve as the training phantom described in this study aligns with the learning theory of constructivism and fits the ideal specifications of a medical training device in terms of its realism and facilitation of self-directed learning and deliberate practice of the trainees. The device provides a useful platform upon which training and assessment can be facilitated.

      PubDate: 2017-09-19T08:00:03Z
      DOI: 10.1016/j.ultrasmedbio.2017.07.015
       
  • Evolution of Ultrasonography Since the 1970s
    • Authors: David Owen Cosgrove
      Pages: 2741 - 2742
      Abstract: Publication date: November 2017
      Source:Ultrasound in Medicine & Biology, Volume 43, Issue 11
      Author(s): David Owen Cosgrove


      PubDate: 2017-09-19T08:00:03Z
      DOI: 10.1016/j.ultrasmedbio.2017.06.015
       
  • In Memoriam: David Cosgrove (1938–2017)
    • Authors: Jeffrey Bamber; Robert J. Eckersley; Chris Harvey; Adrian Lim; Paul Sidhu; Meng-Xing Tang
      Pages: 2743 - 2745
      Abstract: Publication date: November 2017
      Source:Ultrasound in Medicine & Biology, Volume 43, Issue 11
      Author(s): Jeffrey Bamber, Robert J. Eckersley, Chris Harvey, Adrian Lim, Paul Sidhu, Meng-Xing Tang


      PubDate: 2017-09-19T08:00:03Z
      DOI: 10.1016/j.ultrasmedbio.2017.07.005
       
  • Erratum to ‘Could Linear Hysteresis Contribute to Shear Wave Losses in
           Tissues' [Ultrasound Med Biol 41 (2015) 1100–1104]
    • Authors: Kevin J. Parker
      First page: 2746
      Abstract: Publication date: November 2017
      Source:Ultrasound in Medicine & Biology, Volume 43, Issue 11
      Author(s): Kevin J. Parker


      PubDate: 2017-09-19T08:00:03Z
      DOI: 10.1016/j.ultrasmedbio.2017.07.019
       
  • Freehand 3-D Ultrasound Imaging: A Systematic Review
    • Authors: Mohammad Hamed Mozaffari; Won-Sook Lee
      Pages: 2099 - 2124
      Abstract: Publication date: October 2017
      Source:Ultrasound in Medicine & Biology, Volume 43, Issue 10
      Author(s): Mohammad Hamed Mozaffari, Won-Sook Lee
      Two-dimensional ultrasound (US) imaging has been successfully used in clinical applications as a low-cost, portable and non-invasive image modality for more than three decades. Recent advances in computer science and technology illustrate the promise of the 3-D US modality as a medical imaging technique that is comparable to other prevalent modalities and that overcomes certain drawbacks of 2-D US. This systematic review covers freehand 3-D US imaging between 1970 and 2017, highlighting the current trends in research fields, the research methods, the main limitations, the leading researchers, standard assessment criteria and clinical applications. Freehand 3-D US systems are more prevalent in the academic environment, whereas in clinical applications and industrial research, most studies have focused on 3-D US transducers and improvement of hardware performance. This topic is still an interesting active area for researchers, and there remain many unsolved problems to be addressed.

      PubDate: 2017-09-12T03:49:04Z
      DOI: 10.1016/j.ultrasmedbio.2017.06.009
       
  • Training Midwives to Perform Basic Obstetric Point-of-Care Ultrasound in
           Rural Areas Using a Tablet Platform and Mobile Phone Transmission
           Technology—A WFUMB COE Project
    • Authors: Sudhir Vinayak; Joyce Sande; Harvey Nisenbaum; Christian Pállson Nolsøe
      Pages: 2125 - 2132
      Abstract: Publication date: October 2017
      Source:Ultrasound in Medicine & Biology, Volume 43, Issue 10
      Author(s): Sudhir Vinayak, Joyce Sande, Harvey Nisenbaum, Christian Pállson Nolsøe
      Point-of-care ultrasound (POCUS) has become a topical subject and can be applied in a variety of ways with differing outcomes. The cost of all diagnostic procedures including obstetric ultrasound examinations is a major factor in the developing world and POCUS is only useful if it can be equated to good outcomes at a lower cost than a routine obstetric examination. The aim of this study was to assess a number of processes including accuracy of images and reports generated by midwives, performance of a tablet-sized ultrasound scanner, training of midwives to complete ultrasounds, teleradiology solution transmissions of images via internet, review of images by a radiologist, communication between midwife and radiologist, use of this technique to identify high-risk patients and improvement of the education and teleradiology model components. The midwives had no previous experience in ultrasound. They were stationed in rural locations where POCUS was available for the first time. After scanning the patients, an interim report was generated by the midwives and sent electronically together with all images to the main hospital for validation. Unique software was used to send lossless images by mobile phone using a modem. Transmission times were short and quality of images transmitted was excellent. All reports were validated by two experienced radiologists in our department and returned to the centers using the same transmission software. The transmission times, quality of scans, quality of reports and other parameters were recorded and monitored. Analysis showed excellent correlation between provisional and validated reports. Reporting accuracy of scans performed by the midwives was 99.63%. Overall flow turnaround time (from patient presentation to validated report) was initially 35 min but reduced to 25 min. The unique mobile phone transmission was faultless and there was no degradation of image quality. We found excellent correlation between final outcomes of the pregnancies and diagnoses on the basis of reports generated by the midwives. Only 1 discrepancy was found in the midwives' reports. Scan results versus actual outcomes revealed 2 discrepancies in the 20 patients identified as high risk. In conclusion, we found that it is valuable to train midwives in POCUS to use an ultrasound tablet device and transmit images and reports via the internet to radiologists for review of accuracy. This focus on the identification of high-risk patients can be valuable in a remote healthcare facility.

      PubDate: 2017-09-12T03:49:04Z
      DOI: 10.1016/j.ultrasmedbio.2017.05.024
       
  • Comparing Performance of Combinations of Shear Wave Elastography and
           B-Mode Ultrasound in Diagnosing Breast Masses: Is It Influenced by Mass
           Size'
    • Authors: Rui Cong; Jing Li; Xuejiao Wang
      Pages: 2133 - 2143
      Abstract: Publication date: October 2017
      Source:Ultrasound in Medicine & Biology, Volume 43, Issue 10
      Author(s): Rui Cong, Jing Li, Xuejiao Wang
      We determined the diagnostic performance of combinations of shear wave elastography (SWE) and B-mode ultrasound (US) in differentiating malignant from benign breast masses, and we investigated whether performance is affected by mass size. In this prospective study of 315 consecutive patients with 326 breast masses, US and SWE were performed before biopsy. Masses were categorized into two subgroups on the basis of mass size (≤15 mm and >15 mm), and the optimal thresholds for the SWE parameters were determined for each subgroup using receiver operating characteristic curves. The combination proposed here achieved an area under the receiver operating characteristic curve of 0.943, 95.00% sensitivity and 81.18% specificity, which approximated the diagnostic performance of US alone. The performance of the combinations using the subgroups' thresholds did not differ significantly from those based on the entire study group's thresholds, but the optimal thresholds were higher in the subgroup of larger masses. Further research is needed to determine whether mass size affects the performance of combinations of SWE and US.

      PubDate: 2017-09-12T03:49:04Z
      DOI: 10.1016/j.ultrasmedbio.2017.04.015
       
  • A Model-Based Prediction of the Probability of Hepatocellular Adenoma
           and Focal Nodular Hyperplasia Based on Characteristics on
           Contrast-Enhanced Ultrasound
    • Authors: Pavel Taimr; Mirelle E.E. Bröker; Roy S. Dwarkasing; Bettina E. Hansen; Robert J. de Knegt; Robert A. De Man; Jan N.M. IJzermans
      Pages: 2144 - 2150
      Abstract: Publication date: October 2017
      Source:Ultrasound in Medicine & Biology, Volume 43, Issue 10
      Author(s): Pavel Taimr, Mirelle E.E. Bröker, Roy S. Dwarkasing, Bettina E. Hansen, Robert J. de Knegt, Robert A. De Man, Jan N.M. IJzermans
      Contrast-enhanced ultrasound (CEUS) is an emerging imaging technique that is increasingly used to diagnose liver lesions. It is of the utmost importance to differentiate between the two most common solid focal liver lesions (i.e., hepatocellular adenoma [HCA] and focal nodular hyperplasia [FNH]), because their management and follow-up differ greatly. The main objective of this study was to determine how frequently the specific CEUS features of HCA and FNH are visible on CEUS and to define their predictive value for discrimination between HCA and FNH. We included 324 CEUS examinations performed on patients with FNH (n = 181) or HCA (n = 143). Patients with HCA and FNH significantly differed with respect to age and CEUS features of steatosis, echogenicity, homogeneity, the presence of a central scar, central artery, arterial enhancement pattern, necrosis or thrombus and enhancement in the late venous phase.

      PubDate: 2017-09-12T03:49:04Z
      DOI: 10.1016/j.ultrasmedbio.2017.05.011
       
  • Histology-Based Assessment of Sonazoid-Enhanced Ultrasonography for the
           Diagnosis of Liver Metastasis
    • Authors: Kazufumi Kobayashi; Hitoshi Maruyama; Soichiro Kiyono; Osamu Yokosuka; Masayuki Ohtsuka; Masaru Miyazaki; Jun Matsushima; Takashi Kishimoto; Yukio Nakatani
      Pages: 2151 - 2158
      Abstract: Publication date: October 2017
      Source:Ultrasound in Medicine & Biology, Volume 43, Issue 10
      Author(s): Kazufumi Kobayashi, Hitoshi Maruyama, Soichiro Kiyono, Osamu Yokosuka, Masayuki Ohtsuka, Masaru Miyazaki, Jun Matsushima, Takashi Kishimoto, Yukio Nakatani
      This retrospective study aimed to assess the diagnostic performance of contrast-enhanced ultrasound with Sonazoid (S-CEUS) for liver metastasis. We enrolled in this study 98 patients with 148 histologically proven liver lesions, with 121 metastases and 27 non-metastases. The S-CEUS technique showed sensitivity in 95.0% (115 of 121), specificity in 44.4% (12 of 27) and accuracy in 85.8% (127 of 148) for the diagnosis of metastasis. Higher body mass index had a negative influence on the positive predictive value and accuracy, and a greater depth of the lesion had a negative influence on the accuracy. The management was changed in 8 patients (8.2%) because of S-CEUS findings. In conclusion, the addition of S-CEUS may offer a great benefit by improvement of the quality of diagnosis and management for patients with cancer who have a tentative diagnosis of liver metastasis by contrast-enhanced computed tomography.

      PubDate: 2017-09-12T03:49:04Z
      DOI: 10.1016/j.ultrasmedbio.2017.06.014
       
  • Ultrasound-Based Shear Wave Elastography in the Assessment of Patients
           with Diabetic Kidney Disease
    • Authors: Flaviu Bob; Iulia Grosu; Ioan Sporea; Simona Bota; Alina Popescu; Alexandra Sima; Roxana Şirli; Ligia Petrica; Romulus Timar; Adalbert Schiller
      Pages: 2159 - 2166
      Abstract: Publication date: October 2017
      Source:Ultrasound in Medicine & Biology, Volume 43, Issue 10
      Author(s): Flaviu Bob, Iulia Grosu, Ioan Sporea, Simona Bota, Alina Popescu, Alexandra Sima, Roxana Şirli, Ligia Petrica, Romulus Timar, Adalbert Schiller
      In previous studies of acoustic radiation force impulse (ARFI) elastography, using Virtual Touch tissue quantification (VTQ) (Siemens Acuson S2000), it was reported that the measurement of renal shear wave speed in patients with chronic kidney disease (CKD) is not influenced exclusively by renal fibrosis. The purpose of the present study was to analyze the role of VTQ in patients with diabetic kidney disease, considered the main cause of CKD. The study group included 164 patients: 80 patients with diabetic kidney disease (DKD) and 84 without renal disease or diabetes mellitus. In each subject in lateral decubitus, five valid VTQ measurements were performed in each kidney and a median value was calculated, the result being expressed in meters/second. The following means of the median values were obtained In DKD patients, the means of the median values were for VTQ right kidney, 2.21 ± 0.71 m/s, and for VTQ left kidney, 2.13 ± 0.72 m/s, whereas in the normal controls statistically significant higher values were obtained: 2.58 ± 0.78 m/s for VTQ right kidney (p = 0.0017) and 2.46 ± 0.81 m/s for VTQ left kidney (p = 0.006). Patients with an estimated glomerular filtration rate (eGFR) >60 mL/min (DKD stages 1 and 2 together with normal controls) had a significantly higher kidney shear wave speed compared with patients with an eGFR <60 mL/min (2.53 m/s vs. 2.09 m/s, p < 0.05). In the DKD group, there was a significant correlation between eGFR and VTQ levels for the right kidney (r = 0.28, p = 0.04). There was no correlation of VTQ values with proteinuria level, stage of diabetic retinopathy or glycated hemoglobin. Our study indicates that shear wave speed values in patients with diabetic kidney disease and eGFRs <60 mL/min are significantly lower compared with those of patients with eGFRs >60 mL/min (either normal controls or diabetic patients with DKD stages 1 and 2), and values decrease with the decrease in eGFR. However, proteinuria, diabetic retinopathy and glycated hemoglobin have no influence on VTQ.

      PubDate: 2017-09-12T03:49:04Z
      DOI: 10.1016/j.ultrasmedbio.2017.04.019
       
  • Transabdominal Ultrasound Colonography for Detection of Colorectal
           Neoplasms: Initial Clinical Experience
    • Authors: Jin-Ya Liu; Li-Da Chen; Jian-Bo Xu; Hui Wu; Jin-Ning Ye; Xin-Hua Zhang; Xiao-Yan Xie; Wei Wang; Ming-De Lu
      Pages: 2174 - 2181
      Abstract: Publication date: October 2017
      Source:Ultrasound in Medicine & Biology, Volume 43, Issue 10
      Author(s): Jin-Ya Liu, Li-Da Chen, Jian-Bo Xu, Hui Wu, Jin-Ning Ye, Xin-Hua Zhang, Xiao-Yan Xie, Wei Wang, Ming-De Lu
      We investigated the feasibility of using ultrasound colonography (USC) to visualize the healthy colon and rectum and detect colorectal polyps. Eight healthy volunteers underwent USC after standard bowel preparation. The feasibility and image quality of USC in different segments were evaluated. Then, USC was conducted on eight patients with known colonic neoplasms using colonoscopy as the reference standard. For volunteers, USC examinations were successfully performed on four (50.0%) ascending, three (37.5%) transverse and eight (100%) descending colons, as well as all sigmoid colons and rectums. One of four (25.0%) ascending, two of eight (25.0%) descending and all sigmoid colons and rectums were well visualized and free of artifacts. For patients, colonoscopy revealed that eight patients had 17 neoplasms in the distal sigmoid colon and rectum, which included 3 lesions ≤5 mm, 3 lesions 6–9 mm and 11 lesions ≥10 mm. USC visualized 12 of 17 (70.6%) neoplasms. Lesion detection by USC was 0% (0/3), 33.3% (1/3) and 100% (11/11) for neoplasms ≤5, 6–9 mm and ≥10 mm in size. USC can visualize the sigmoid colon and rectum well and detect distal sigmoid and rectal neoplasms ≥10 mm in diameter.

      PubDate: 2017-09-12T03:49:04Z
      DOI: 10.1016/j.ultrasmedbio.2017.05.020
       
  • Correlation between Disease Activity and Endorectal Ultrasound Findings of
           Chronic Radiation Proctitis
    • Authors: Fei Cao; Teng-hui Ma; Guang-jian Liu; Yan-Ling Wen; Huai-ming Wang; Ying-yi Kuang; Si Qin; Xiao-yin Liu; Bin-jie Huang; Lei Wang
      Pages: 2182 - 2191
      Abstract: Publication date: October 2017
      Source:Ultrasound in Medicine & Biology, Volume 43, Issue 10
      Author(s): Fei Cao, Teng-hui Ma, Guang-jian Liu, Yan-Ling Wen, Huai-ming Wang, Ying-yi Kuang, Si Qin, Xiao-yin Liu, Bin-jie Huang, Lei Wang
      The aim of this study was to summarize the imaging features of chronic radiation proctitis (CRP) on endorectal ultrasound (ERUS) and investigate the value of ERUS in the evaluation of disease activity. 40 CRP patients and 30 control patients were investigated by ERUS. Rectal wall thickness and layers, ulcers and rectovaginal fistulas were evaluated by B-mode ultrasound. Power Doppler imaging was used to evaluate the vascularity of the rectal wall using a semiquantitative score. Disease activity was calculated according to the National Cancer Institute Common Terminology Criteria for Adverse Events 4.0 (CTCAE 4.0). Imaging findings for patients with mild and severe CRP were compared. For 30 patients in the control group, the average maximum thickness of the rectal wall was 3.07 ± 0.73 mm, with all exhibiting typical wall stratification and level 0 vascularity. For the 40 CRP patients, there was marked thickening of the rectal wall (average thickness = 9.42 ± 1.94 mm), which was significantly thicker than in the control group (p < 0.05). The rectal walls of the mild group were significantly thinner than those of the severe group (8.71 ± 1.67 mm vs. 10.00 ± 2.00 mm, p < 0.05). Among the 22 severe cases, 19 cases (19/22, 86.4%) exhibited hyper-vascularity (level IV) or blurred wall stratification (including hypo-echoic submucosa, ulcer and fistula); 12 of the 18 mild cases (166.7%) exhibited a vascularity of level III and typical wall stratification. A significant association (p < 0.05) was observed between stratification and vascularity of the rectal wall and CRP activity. When ERUS findings of blurred rectal wall stratification or increasing vascularity (level IV) were used to evaluate CRP activity, the sensitivity was 86.4% (95% confidence interval: 64.0–96.4) and the specificity was 66.7% (95% confidence interval: 41.2–85.6). Thickening of the rectal wall, blurred wall stratification and increased vascularity are characteristic ERUS findings of CRP. ERUS is helpful in the comprehensive evaluation of disease activity and may provide objective evidence during treatment planning and follow-up.

      PubDate: 2017-09-12T03:49:04Z
      DOI: 10.1016/j.ultrasmedbio.2017.06.025
       
  • Effect of Preterm Birth on Echogenicity in Basal Ganglia
    • Authors: Robbin de Goederen; Marlou M.A. Raets; Ginette M. Ecury-Goossen; Rogier C.J. de Jonge; Luca A. Ramenghi; Irene V. Koning; Paul Govaert; Jeroen Dudink
      Pages: 2192 - 2199
      Abstract: Publication date: October 2017
      Source:Ultrasound in Medicine & Biology, Volume 43, Issue 10
      Author(s): Robbin de Goederen, Marlou M.A. Raets, Ginette M. Ecury-Goossen, Rogier C.J. de Jonge, Luca A. Ramenghi, Irene V. Koning, Paul Govaert, Jeroen Dudink
      In this study, the influence of prematurity on echogenicity of deep gray matter at 30-wk corrected age was assessed using ultrasound measurements. In an observational cohort study, ultrasound scans of 224 extremely preterm infants were prospectively collected. Gray values were assessed in putamen and globus pallidus. Intra- and inter-observer reliability was analyzed and showed excellent agreement. The globus pallidus to putamen ratio was significantly related to gestational age at birth, adjusted regression coefficient in points per wk: 1.28 (95% confidence interval [CI]: 0.38–2.19) for left and 2.12 (95% CI: 1.23–3.02) for right-side images. At 30-wk corrected age this was still the case, adjusted regression coefficient: 0.45 (95% CI: −0.57 to 1.47) for left and 1.29 (95% CI: 0.10–2.48) for right. The putamen is more hyperechoic with lower gestational age. Measuring ultrasound gray values in deep gray matter seems highly reproducible. Prematurity shows a negative correlation with echogenicity of the putamen, this persists at 30-wk corrected age, suggesting altered maturation.

      PubDate: 2017-09-12T03:49:04Z
      DOI: 10.1016/j.ultrasmedbio.2017.06.017
       
  • Hybrid Photoacoustic/Ultrasound Tomograph for Real-Time Finger Imaging
    • Authors: Milan Oeri; Wolfgang Bost; Nicolas Sénégond; Steffen Tretbar; Marc Fournelle
      Pages: 2200 - 2212
      Abstract: Publication date: October 2017
      Source:Ultrasound in Medicine & Biology, Volume 43, Issue 10
      Author(s): Milan Oeri, Wolfgang Bost, Nicolas Sénégond, Steffen Tretbar, Marc Fournelle
      We report a target-enclosing, hybrid tomograph with a total of 768 elements based on capacitive micromachined ultrasound transducer technology and providing fast, high-resolution 2-D/3-D photoacoustic and ultrasound tomography tailored to finger imaging. A freely programmable ultrasound beamforming platform sampling data at 80 MHz was developed to realize plane wave transmission under multiple angles. A multiplexing unit enables the connection and control of a large number of elements. Fast image reconstruction is provided by GPU processing. The tomograph is composed of four independent and fully automated movable arc-shaped transducers, allowing imaging of all three finger joints. The system benefits from photoacoustics, yielding high optical contrast and enabling visualization of finger vascularization, and ultrasound provides morphologic information on joints and surrounding tissue. A diode-pumped, Q-switched Nd:YAG laser and an optical parametric oscillator are used to broaden the spectrum of emitted wavelengths to provide multispectral imaging. Custom-made optical fiber bundles enable illumination of the region of interest in the plane of acoustic detection. Precision in positioning of the probe in motion is ensured by use of a motor-driven guide slide. The current position of the probe is encoded by the stage and used to relate ultrasound and photoacoustic signals to the corresponding region of interest of the suspicious finger joint. The system is characterized in phantoms and a healthy human finger in vivo. The results obtained promise to provide new opportunities in finger diagnostics and establish photoacoustic/ultrasound-tomography in medical routine.

      PubDate: 2017-09-12T03:49:04Z
      DOI: 10.1016/j.ultrasmedbio.2017.05.015
       
  • Common Carotid Artery Flow Measured by 3-D Ultrasonic Vector Flow Imaging
           and Validated with Magnetic Resonance Imaging
    • Authors: Simon Holbek; Kristoffer Lindskov Hansen; Hamed Bouzari; Caroline Ewertsen; Matthias Bo Stuart; Carsten Thomsen; Michael Bachmann Nielsen; Jørgen Arendt Jensen
      Pages: 2213 - 2220
      Abstract: Publication date: October 2017
      Source:Ultrasound in Medicine & Biology, Volume 43, Issue 10
      Author(s): Simon Holbek, Kristoffer Lindskov Hansen, Hamed Bouzari, Caroline Ewertsen, Matthias Bo Stuart, Carsten Thomsen, Michael Bachmann Nielsen, Jørgen Arendt Jensen
      Ultrasound (US) examination of the common carotid artery was compared with a through-plane magnetic resonance imaging (MRI) sequence to validate a recently proposed technique for 3-D US vector flow imaging. Data from the first volunteer examined were used as the training set, before volume flow and peak velocities were calculated for the remaining eight volunteers. Peak systolic velocities (PSVs) and volume flow obtained with 3-D US were, on average, 34% higher and 24% lower than those obtained with MRI, respectively. A high correlation was observed for PSV (r = 0.79), whereas a lower correlation was observed for volume flow (r = 0.43). The overall standard deviations were ±5.7% and ±5.7% for volume flow and PSV with 3-D US, compared with ±2.7% and ±3.2% for MRI. Finally, the data were re-processed with a change in the parameter settings for the echo-canceling filter to investigate its influence on overall performance. PSV was less affected by the re-processing, whereas the difference in volume flow between 3-D vector flow imaging and MRI was reduced to −9%, and with an improved overall standard deviation of ±4.7%. The results illustrate the feasibility of using 3-D US for precise and angle-independent volume flow and PSV estimation in vivo.

      PubDate: 2017-09-12T03:49:04Z
      DOI: 10.1016/j.ultrasmedbio.2017.06.007
       
  • A Temporal and Spatial Analysis Approach to Automated Segmentation of
           Microbubble Signals in Contrast-Enhanced Ultrasound Images: Application to
           Quantification of Active Vascular Density in Human Lower Limbs
    • Authors: Wing Keung Cheung; Katherine J. Williams; Kirsten Christensen-Jeffries; Brahman Dharmarajah; Robert J. Eckersley; Alun H. Davies; Meng-Xing Tang
      Pages: 2221 - 2234
      Abstract: Publication date: October 2017
      Source:Ultrasound in Medicine & Biology, Volume 43, Issue 10
      Author(s): Wing Keung Cheung, Katherine J. Williams, Kirsten Christensen-Jeffries, Brahman Dharmarajah, Robert J. Eckersley, Alun H. Davies, Meng-Xing Tang
      Contrast-enhanced ultrasound (CEUS) using microbubble contrast agents has shown great promise in visualising and quantifying active vascular density. Most existing approaches for vascular density quantification using CEUS are calculated based on image intensity and are susceptible to confounding factors and imaging artefact. Poor reproducibility is a key challenge to clinical translation. In this study, a new automated temporal and spatial signal analysis approach is developed for reproducible microbubble segmentation and quantification of contrast enhancement in human lower limbs. The approach is evaluated in vitro on phantoms and in vivo in lower limbs of healthy volunteers before and after physical exercise. In this approach, vascular density is quantified based on the relative areas microbubbles occupy instead of their image intensity. Temporal features of the CEUS image sequences are used to identify pixels that contain microbubble signals. A microbubble track density (MTD) measure, the ratio of the segmented microbubble area to the whole tissue area, is calculated as a surrogate for active capillary density. In vitro results reveal a good correlation (r 2 = 0.89) between the calculated MTD measure and the known bubble concentration. For in vivo results, a significant increase (129% in average) in the MTD measure is found in lower limbs of healthy volunteers after exercise, with excellent repeatability over a series of days (intra-class correlation coefficient = 0.96). This compares to the existing state-of-the-art approach of destruction and replenishment analysis on the same patients (intra-class correlation coefficient ≤0.78). The proposed new approach shows great potential as an accurate and highly reproducible clinical tool for quantification of active vascular density.

      PubDate: 2017-09-12T03:49:04Z
      DOI: 10.1016/j.ultrasmedbio.2017.05.021
       
  • Reproducible Computer-Assisted Quantification of Myocardial Perfusion with
           Contrast-Enhanced Ultrasound
    • Authors: Yuanwei Li; Navtej Chahal; Roxy Senior; Meng-Xing Tang
      Pages: 2235 - 2246
      Abstract: Publication date: October 2017
      Source:Ultrasound in Medicine & Biology, Volume 43, Issue 10
      Author(s): Yuanwei Li, Navtej Chahal, Roxy Senior, Meng-Xing Tang
      Myocardial perfusion can be quantified by myocardial contrast echocardiography (MCE) and is used for the diagnosis of coronary artery disease (CAD). However, existing MCE quantification software is highly operator dependent and has poor reproducibility and ease of usage. The aim of this study was to develop robust and easy-to-use software that can perform MCE quantification accurately, reproducibly and rapidly. The developed software has the following features: (i) semi-automatic segmentation of the myocardium; (ii) automatic rejection of MCE data with poor image quality; (iii) automatic computation of perfusion parameters such as myocardial blood flow (MBF). MCE sequences of 18 individuals (9 normal, 9 with CAD) undergoing vasodilator stress with dipyridamole were analysed quantitatively using the software. When evaluated against coronary angiography, the software achieved a sensitivity of 71% and a specificity of 91% for hyperemic MBF. With the automatic rejection algorithm, the sensitivity and specificity further improved to 77% and 94%, respectively. For MBF reproducibility, the percentage agreement is 85% (κ = 0.65) for inter-observer variability and 88% (κ = 0.72) for intra-observer variability. The intra-class correlation coefficients are 0.94 (inter-observer) and 0.96 (intra-observer). The time taken to analyse one MCE sequence using the software is about 3 min on a PC. The software has exhibited good diagnostic performance and reproducibility for CAD detection and is rapid and user-friendly.

      PubDate: 2017-09-12T03:49:04Z
      DOI: 10.1016/j.ultrasmedbio.2017.05.001
       
  • Non-invasive Evaluation of Right Ventricular Function with Real-Time 3-D
           Echocardiography
    • Authors: Ran Chen; Meihua Zhu; Kacie Amacher; Xia Wu; David J. Sahn; Muhammad Ashraf
      Pages: 2247 - 2255
      Abstract: Publication date: October 2017
      Source:Ultrasound in Medicine & Biology, Volume 43, Issue 10
      Author(s): Ran Chen, Meihua Zhu, Kacie Amacher, Xia Wu, David J. Sahn, Muhammad Ashraf
      The aim of this study was to evaluate the accuracy and feasibility of real-time 3-D echocardiography (3-DE) in assessing right ventricular (RV) systolic function. A latex balloon was inserted into the right ventricle of 20 freshly harvested pig hearts which were then passively driven by a pulsatile pump apparatus. The RV global longitudinal strain (GLS), global circumferential strain (GCS), global area strain (GAS) and RV ejection fraction (RVEF), derived from 3-DE, as well as the RVEF obtained from 2-D echocardiography (2-DE) were quantified at different stroke volumes (30–70 mL) and compared with sonomicrometry data. In all comparisons, 3-D GLS, GCS, GAS, 2-D RVEF and 3-D RVEF exhibited strong correlations with sonomicrometry data (r = 0.89, 0.79, 0.74, 0.80, and 0.93, respectively; all p values < 0.001). Bland–Altman analyses revealed slight overestimations of echo-derived GLS, GCS, 2-DE RVEF and 3-DE RVEF compared with sonomicrometry values (bias = 1.55, 2.72, 3.59 and 2.21, respectively). Furthermore, there is better agreement among GLS, 3-D RVEF and the sonomicrometry values than between GCS and 2-D RVEF. Real-time 3-DE is more feasible and accurate for assessing RV function than 2-DE. GLS is a potential alternative parameter for quantifying RV systolic function.

      PubDate: 2017-09-12T03:49:04Z
      DOI: 10.1016/j.ultrasmedbio.2017.05.007
       
  • Editorial Advisory Board
    • Abstract: Publication date: November 2017
      Source:Ultrasound in Medicine & Biology, Volume 43, Issue 11


      PubDate: 2017-09-19T08:00:03Z
       
  • Calendar
    • Abstract: Publication date: November 2017
      Source:Ultrasound in Medicine & Biology, Volume 43, Issue 11


      PubDate: 2017-09-19T08:00:03Z
       
  • Editorial Advisory Board
    • Abstract: Publication date: October 2017
      Source:Ultrasound in Medicine & Biology, Volume 43, Issue 10


      PubDate: 2017-09-12T03:49:04Z
       
 
 
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