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Sample records for bedside ultrasound measurement

  1. [Application of bedside ultrasound in measuring gastric residual volume in neurosurgical critical patients with enteral nutrition support].

    PubMed

    Cao, L; Ye, X H; Li, J; Zhang, L N; Li, L; Zhang, W Y; Deng, L L

    2017-03-07

    Objective: To explore the effect of bedside ultrasound in measuring gastric residual volume in neurosurgical critical patients with enteral nutrition support. Method: From March to August 2016, 70 critically neurological patients with continues enteral nutrition who admitted in Intensive Care Unit (ICU) were randomized into two groups. The observation group applied the bedside ultrasound monitoring gastric residual volume every day to guide the implementation of enteral nutrition. The control group used syringes withdrawing every 8 hours to measure the gastric residual volume. Results: There was no statistically significant difference in the incidence of complications include regurgitation and aspiration in this two group patients (P=0.356; P=1.000), while the times of interrupting enteral nutrition was lower in the observation group(25.7% vs 5.7%, 74.3% vs 94.3%, P=0.045), the length of target feeding time and the length of ICU stay, the operation time was shortened, with a statistically significant difference[(2.37±0.69) d vs (3.49±0.74) d, P=0.028; (8.52±5.45) d vs (6.40±2.71) d, P=0.022; (58.29±11.22)s vs (67.60±7.05) s, P=0.000]. Conclusion: The application of bedside ultrasound to measure gastric residual volume can be a scientific method to guide enteral nutrition in neurosurgical critical patients, which can reduce the times of interrupting enteral nutrition and shorten the length of target feeding time and ICU length of stay, reduce the workload of nurses.

  2. Bedside ultrasound in the pediatric emergency department.

    PubMed

    Levy, Jason A; Bachur, Richard G

    2008-06-01

    Emergency bedside ultrasound has been used by emergency and critical care physicians for over two decades. Its use has grown rapidly in emergency medicine and the range of diagnostic and procedural applications has continued to expand; only recently, however, has this tool been embraced by pediatric emergency and critical care physicians. As this technology develops and becomes more available pediatricians should understand its uses and limitations. Use of emergency bedside ultrasound for victims of trauma and for procedural applications such as central venous access are well established in adults. Recent published studies suggest that utilizing bedside ultrasound for these purposes may be beneficial in pediatric emergency medicine. Other reports portend future pediatric applications such as assessment of volume status and dehydration, fracture identification and reduction, and aiding in the performance of lumbar punctures. In a review of the literature, it is clear that emergency bedside ultrasound has a role in pediatric emergency and critical care medicine. Much more research is needed, however, to determine which sonographic assessments are of the greatest value. Collaborative efforts will likely be needed to establish definitive applications.

  3. Bedside Ultrasound Measurement of Rectus Femoris: A Tutorial for the Nutrition Support Clinician

    PubMed Central

    Monares Zepeda, Enrique; Lescas Méndez, Octavio Augusto

    2017-01-01

    Intensive care unit acquired weakness is a long-term consequence after critical illness; it has been related to muscle atrophy and can be considered as one of the main nutritional support challenges at the intensive care unit. Measuring muscle mass by image techniques has become a new area of research for the nutritional support field, extending our knowledge about muscle wasting and the impact of nutritional approaches in the critical care setting, although currently there is no universally accepted technique to perform muscle measurements by ultrasound. Because of this, we present this tutorial for nutrition support clinicians, in order to understand and perform muscle measurements by this reliable, accessible, low-cost, and easy-to-use technique. Reviewing issues such as quadriceps muscle anatomy, correct technique (do's and don'ts), identification of structures, and measurement of the rectus femoris and vastus intermedius muscles helps to acquire the basic concepts of this technique and encouraging more research in this field. PMID:28386479

  4. Acquiring credentials in bedside ultrasound: a cross-sectional survey

    PubMed Central

    Lewiss, Resa E; Saul, Turandot; Del Rios, Marina

    2013-01-01

    Objective Although there are training guidelines to credential emergency physicians in bedside ultrasound, many faculty groups have members who completed residency without a mandatory curriculum. These physicians are therefore required to learn bedside ultrasound while out in practice. The objective of this descriptive report is to illustrate a single academic facility's experience with acquiring credentials for emergency physicians in bedside ultrasound and the faculty's impressions on the motivators of and barriers to completion of the requirements. Design Cross-sectional survey. Setting Two urban teaching hospitals with a combined volume of 170 000 visits a year. Participants 41 emergency medicine attending physicians. Intervention Emergency medicine attending physicians underwent training and credentialing in the applications of aorta and pelvic ultrasound over a 9-month period. Outcome measure After the credentialing period, we conducted a survey to evaluate the physicians’ perceptions of this process. Results There were 41 faculty members during the credentialing survey period. 11 of the faculty members were exempt from ultrasound training. We asked attending physicians (N=41 exempt and non-exempt) to complete a web-based survey after the completion of the credentialing period. Questions about the potential barriers and incentives were listed and responders were asked to rank answers on a five-point Likert scale. Of the 31 respondents, 21 (67.7%) completed the credentialing requirements by the 9-month deadline. 19 of 26 emergency medicine residency trained physicians completed the requirements compared with 2/5 of those that were not emergency medicine residency trained. Our pilot study data suggest an association between fewer years in practice and completion of the requirements. Conclusions This is a report on a single academic institution's experience with a faculty credentialing programme in bedside ultrasound for physicians with a diversity of prior

  5. Emergency department bedside ultrasound diagnosis of retinoblastoma in a child.

    PubMed

    Presley, Bradley C; Flannigan, Matthew J

    2013-10-01

    A 30-month-old boy presented to a Haitian emergency department with proptosis, periorbital edema, and progressive blindness. Bedside ultrasound examination revealed bilateral ocular masses with dense calcifications pathognomonic for retinoblastoma. This case illustrates the diagnostic utility of bedside ultrasound for an advanced case of retinoblastoma in a resource-poor setting. Ocular ultrasound technique is also reviewed.

  6. Bedside ultrasound in pediatric emergency medicine.

    PubMed

    Levy, Jason A; Noble, Vicki E

    2008-05-01

    Bedside emergency ultrasound has been used by emergency physicians for >20 years for a variety of conditions. In adult centers, emergency ultrasound is routinely used in the management of victims of blunt abdominal trauma, in patients with abdominal aortic aneurysm and biliary disease, and in women with first-trimester pregnancy complications. Although its use has grown dramatically in the last decade in adult emergency departments, only recently has this tool been embraced by pediatric emergency physicians. As the modality advances and becomes more available, it will be important for primary care pediatricians to understand its uses and limitations and to ensure that pediatric emergency physicians have access to the proper training, equipment, and experience. This article is meant to review the current literature relating to emergency ultrasound in pediatric emergency medicine, as well as to describe potential pediatric applications.

  7. Bedside ultrasound diagnosis of pulmonary contusion.

    PubMed

    Stone, Michael B; Secko, Michael A

    2009-12-01

    A 10-year-old boy presented to the emergency department after being struck by a van while crossing the street. He complained of right side chest pain, and a chest radiography was suggestive of pulmonary contusion. The treating physician performed a bedside ultrasound that revealed a right-sided pulmonary contusion that was subsequently confirmed on computed tomography of the thorax. The sonographic features of pulmonary contusion are described, and the possible role of lung sonography in the assessment of pediatric thoracic trauma is discussed.

  8. Clinical review: Bedside lung ultrasound in critical care practice

    PubMed Central

    Bouhemad, Bélaïd; Zhang, Mao; Lu, Qin; Rouby, Jean-Jacques

    2007-01-01

    Lung ultrasound can be routinely performed at the bedside by intensive care unit physicians and may provide accurate information on lung status with diagnostic and therapeutic relevance. This article reviews the performance of bedside lung ultrasound for diagnosing pleural effusion, pneumothorax, alveolar-interstitial syndrome, lung consolidation, pulmonary abscess and lung recruitment/derecruitment in critically ill patients with acute lung injury. PMID:17316468

  9. Identification of unanticipated pelvic pathology on renal bedside ultrasound.

    PubMed

    Thorpe, Elizabeth L; Marin, Jennifer R

    2013-04-01

    Bedside emergency ultrasound can be a useful initial test in children who present with abdominal pain. Our case describes a teenager who presented to the emergency department with back pain and right lower quadrant pain, suspicious for nephrolithiasis. The use of bedside ultrasound enabled timely diagnosis and management of an unanticipated condition.

  10. Accidental Carotid Artery Cannulation Detected by Bedside Ultrasound

    PubMed Central

    Chiles, Kris; Nagdev, Arun

    2011-01-01

    This report highlights the importance of using bedside ultrasound in the emergency department to confirm guide-wire placement when performing central venous catheter placement prior to dilating and cannulating the vessel. PMID:21691480

  11. Bedside ultrasound procedures: musculoskeletal and non-musculoskeletal.

    PubMed

    Sahlani, Lydia; Thompson, Laura; Vira, Amar; Panchal, Ashish R

    2016-04-01

    The widespread availability of ultrasound (US) technology has increased its use for point of care applications in many health care settings. Focused (point of care) US is defined as the act of bringing US evaluation to the bedside for real-time performance. These images are collected immediately by the practitioner, allowing for direct integration into the physician's medical decision-making process. The real-time bedside diagnostic ability of US becomes a key tool for the management of patients. The purpose of this review is to (1) provide a general description of the use of focused US for bedside procedures; (2) specify the indications and common techniques used in bedside US procedures; and (3) describe the techniques used for each bedside intervention.

  12. Successful strategies for integrating bedside ultrasound into undergraduate medical education.

    PubMed

    Palma, James K

    2015-04-01

    Nearly all physician specialties currently utilize bedside ultrasound, and its applications continue to expand. Bedside ultrasound is becoming a core skill for physicians; as such, it should be taught during undergraduate medical education. When ultrasound is integrated in a longitudinal manner beginning in the preclerkship phase of medical school, it not only enhances teaching the basic science topics of anatomy, physiology, and pathology but also ties those skills and knowledge to the clerkship phase and medical decision-making. Bedside ultrasound is a natural bridge from basic science to clinical science. The Uniformed Services University of the Health Sciences, F. Edward Hébert School of Medicine is currently in its fourth year of implementing an integrated ultrasound curriculum in the school of medicine. In our experience, successful integration of a bedside ultrasound curriculum should: align with unique focuses of a medical schools' mission, simplify complex anatomy through multimodal teaching, correlate to teaching of the physical examination, solidify understanding of physiology and pathology, directly link to other concurrent content, narrow differential diagnoses, enhance medical decision-making, improve procedural skills, match to year-group skillsets, develop teaching and leadership abilities, and have elective experiences for advanced topics. Reprint & Copyright © 2015 Association of Military Surgeons of the U.S.

  13. Reliability of bedside ultrasound for measurement of quadriceps muscle thickness in critically ill patients with acute kidney injury.

    PubMed

    Sabatino, Alice; Regolisti, Giuseppe; Bozzoli, Laura; Fani, Filippo; Antoniotti, Riccardo; Maggiore, Umberto; Fiaccadori, Enrico

    2016-10-01

    In patients with Acute Kidney Injury there is a lack of nutritional variables that can assess nutritional status, more specifically lean body mass (LBM) and skeletal muscle mass, at the individual level. In this clinical setting, ultrasound (US)) of the quadriceps femoris could represent a widely available, non-invasive, affordable, and reliable tool to evaluate skeletal muscle. We performed a cross-sectional observational study in adult critically ill patients with KDIGO stage 3 AKI on dialysis. Quadriceps rectus femoris and vastus intermedius thickness were measured by two assessors. Intra- and interobserver reliability was evaluated using the intraclass correlation coefficient (ICC). The same US measures were obtained before and after dialysis. We enrolled 34 patients, 22 (65%) were male and the mean APACHE II score was 22.7 (±5.6). In the intraobserver reliability study, assessor 1 performed 288 paired measurements and assessor 2 performed 430 paired measurements in 34 patients, with an ICC equal to 0.99 and 1.00, respectively. There were 238 paired measurements (34 patients) in the interobserver reliability study, with an ICC = 0.92. No difference was found in the measurements obtained before and after dialysis (11.5 (4.2) vs 11.4 (4.1) mm, P = 0.2498), independently from acute body weight changes due to fluid removal. In patients with AKI, US of quadriceps femoris could represent a simple, accurate, and non-invasive method to evaluate quantitative changes in skeletal muscle. Copyright © 2016 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.

  14. Acquisition and Long-term Retention of Bedside Ultrasound Skills in First-Year Medical Students.

    PubMed

    Steinmetz, Peter; Oleskevich, Sharon; Lewis, John

    2016-09-01

    The purpose of this study was to assess bedside ultrasound skill acquisition and retention in medical students after completion of the first year of a new undergraduate bedside ultrasound curriculum at McGill University. Skill acquisition was assessed in first-year medical students (n = 195) on completion of their bedside ultrasound instruction. Instruction included 6 clinically based 60-minute practical teaching sessions evenly spaced throughout the academic year. Students' ability to meet course objectives was measured according to a 4-point Likert rating scale. Evaluations were performed by both instructors and the students themselves. Retention of skill acquisition was evaluated 8 months later on a year-end practical examination. The mean percentage ± SD of students assigned a rating of "strongly agree" or "agree" by instructors was 98% ± 0.4% for all 6 teaching sessions (strongly agree, 52% ± 3%; agree, 46% ± 3%). According to student self-evaluations, the mean percentage of students assigned a rating of strongly agree was significantly greater than the percentage assigned by instructors for all teaching sessions (86% ± 2% versus 52% ± 3%; P < .0005). Evaluation of skill retention on the year-end examination showed that 91% ± 2% of students were assigned a rating of strongly agree or agree for their ability to demonstrate skills learned 8 months previously. Ninety-five percent of students reported that bedside ultrasound improved their understanding of anatomy for all 6 teaching sessions (mean, 95% ± 0.01%). These results demonstrate that first-year medical students show acquisition and long-term retention of basic ultrasound skills on completion of newly implemented bedside ultrasound instruction.

  15. Predicting Fluid Responsiveness Using Bedside Ultrasound Measurements of the Inferior Vena Cava and Physician Gestalt in the Emergency Department of an Urban Public Hospital in Sub-Saharan Africa.

    PubMed

    Sawe, Hendry Robert; Haeffele, Cathryn; Mfinanga, Juma A; Mwafongo, Victor G; Reynolds, Teri A

    Bedside inferior vena cava (IVC) ultrasound has been proposed as a non-invasive measure of volume status. We compared ultrasound measurements of the caval index (CI) and physician gestalt to predict blood pressure response in patients requiring intravenous fluid resuscitation. This was a prospective study of adult emergency department patients requiring fluid resuscitation. A structured data sheet was used to record serial vital signs and the treating clinician's impression of patient volume status and cause of hypotension. Bedside ultrasound CI measurements were performed at baseline and after each 500mL of fluid. Receiver operating characteristic (ROC) curve analysis was performed to characterize the relationship between CI and Physician gestalt, and the change in mean arterial pressure (MAP). We enrolled 364 patients, 52% male, mean age 36 years. Indications for fluid resuscitation were haemorrhage (54%), dehydration (30%), and sepsis (17%). Receiver operating characteristic curve analysis found optimal CI cut-off values of 45%, 52% and 53% to predict a MAP rise of 5, 8 and 10 mmHg per litre of fluid, respectively. The sensitivity and specificity of CI of 50% for predicting a 10mmHg increase in MAP per litre were 88% (95%CI 81-93%) and 73% (95%CI 67-79%), respectively, area under the curve (AUC) = 0.85 (0.81-0.89). The sensitivity and specificity of physician gestalt estimate of volume depletion severity were 68% (95%CI 60-75%) and 86% (95%CI 80-90%), respectively, AUC = 0.83 (95% CI: 0.79-0.87). Those with a baseline CI ≥ 50% (51% of patients) had a 2.8-fold greater fluid responsiveness than those with a baseline CI<50% (p<0.0001). Ultrasound measurement of the CI can predict blood pressure response among patients requiring intravenous fluid resuscitation and may be useful in early identification of patients who will benefit most from volume resuscitation, and those who will likely require other interventions.

  16. Bedside Ultrasound in Resuscitation and the Rapid Ultrasound in Shock Protocol

    PubMed Central

    Seif, Dina; Perera, Phillips; Mailhot, Thomas; Riley, David; Mandavia, Diku

    2012-01-01

    Assessment of hemodynamic status in a shock state remains a challenging issue in Emergency Medicine and Critical Care. As the use of invasive hemodynamic monitoring declines, bedside-focused ultrasound has become a valuable tool in the evaluation and management of patients in shock. No longer a means to simply evaluate organ anatomy, ultrasound has expanded to become a rapid and noninvasive method for the assessment of patient physiology. Clinicians caring for critical patients should strongly consider integrating ultrasound into their resuscitation pathways. PMID:23133747

  17. Update on bedside ultrasound (US) diagnosis of acute cholecystitis (AC).

    PubMed

    Zenobii, Maria Francesca; Accogli, Esterita; Domanico, Andrea; Arienti, Vincenzo

    2016-03-01

    Acute cholecystitis (AC) represents a principal cause of morbidity worldwide and is one of the most frequent reasons for hospitalization due to gastroenteric tract diseases. AC should be suspected in presence of clinical signs and of gallstones on an imaging study. Upper abdominal US represents the first diagnostic imaging step in the case of suspected AC. Computed tomography (CT) with intravenous contrast (IV) or magnetic resonance imaging (MRI) with gadolinium contrast and technetium hepatobiliary iminodiacetic acid (Tc-HIDA) can be employed to exclude complications. US examination should be performed with right subcostal oblique, with longitudinal and intercostal scans. Normal gallbladder US findings and AC major and minor US signs are described. Polyps, sludge and gallbladder wall thickening represent the more frequent pitfalls and they must be differentiated from stones, duodenal artifacts and many other non-inflammatory conditions that cause wall thickening, respectively. By means of bedside ultrasound, the finding of gallstones in combination with acute pain, when the clinician presses the gallbladder with the US probe (the sonographic Murphy's sign), has a 92.2 % positive predictive value for AC. In our preliminary experience, bedside US-performed by echoscopy (ES) and/or point-of-care US (POCUS) demonstrated good reliability in detecting signs of AC, and was always integrated with physical examination and performed by a skilled operator.

  18. Predicting Fluid Responsiveness Using Bedside Ultrasound Measurements of the Inferior Vena Cava and Physician Gestalt in the Emergency Department of an Urban Public Hospital in Sub-Saharan Africa

    PubMed Central

    Haeffele, Cathryn; Mfinanga, Juma A.; Mwafongo, Victor G.; Reynolds, Teri A.

    2016-01-01

    Background Bedside inferior vena cava (IVC) ultrasound has been proposed as a non-invasive measure of volume status. We compared ultrasound measurements of the caval index (CI) and physician gestalt to predict blood pressure response in patients requiring intravenous fluid resuscitation. Methods This was a prospective study of adult emergency department patients requiring fluid resuscitation. A structured data sheet was used to record serial vital signs and the treating clinician’s impression of patient volume status and cause of hypotension. Bedside ultrasound CI measurements were performed at baseline and after each 500mL of fluid. Receiver operating characteristic (ROC) curve analysis was performed to characterize the relationship between CI and Physician gestalt, and the change in mean arterial pressure (MAP). Results We enrolled 364 patients, 52% male, mean age 36 years. Indications for fluid resuscitation were haemorrhage (54%), dehydration (30%), and sepsis (17%). Receiver operating characteristic curve analysis found optimal CI cut-off values of 45%, 52% and 53% to predict a MAP rise of 5, 8 and 10 mmHg per litre of fluid, respectively. The sensitivity and specificity of CI of 50% for predicting a 10mmHg increase in MAP per litre were 88% (95%CI 81–93%) and 73% (95%CI 67–79%), respectively, area under the curve (AUC) = 0.85 (0.81–0.89). The sensitivity and specificity of physician gestalt estimate of volume depletion severity were 68% (95%CI 60–75%) and 86% (95%CI 80–90%), respectively, AUC = 0.83 (95% CI: 0.79–0.87). Those with a baseline CI ≥ 50% (51% of patients) had a 2.8-fold greater fluid responsiveness than those with a baseline CI<50% (p<0.0001). Conclusion Ultrasound measurement of the CI can predict blood pressure response among patients requiring intravenous fluid resuscitation and may be useful in early identification of patients who will benefit most from volume resuscitation, and those who will likely require other

  19. Cardiac Limited Ultrasound Examination Techniques to Augment the Bedside Cardiac Physical Examination.

    PubMed

    Kimura, Bruce J; Shaw, David J; Amundson, Stan A; Phan, James N; Blanchard, Daniel G; DeMaria, Anthony N

    2015-09-01

    The current practice of physical diagnosis is dependent on physician skills and biases, inductive reasoning, and time efficiency. Although the clinical utility of echocardiography is well known, few data exist on how to integrate 2-dimensional screening "quick-look" ultrasound applications into a novel, modernized cardiac physical examination. We discuss the evidence basis behind ultrasound "signs" pertinent to the cardiovascular system and elemental in synthesis of bedside diagnoses and propose the application of a brief cardiac limited ultrasound examination based on these signs. An ultrasound-augmented cardiac physical examination can be taught in traditional medical education and has the potential to improve bedside diagnosis and patient care.

  20. Incidental Identification of Right Atrial Mass Using Bedside Ultrasound: Cardiac Angiosarcoma

    PubMed Central

    Pourmand, Ali; Boniface, Keith

    2011-01-01

    Background Emergency ultrasound is now used in both community and academic hospitals for rapid diagnosis and treatment of life-threatening conditions. Bedside emergency echocardiography can rapidly identify significant pathology such as pericardial effusions and tamponade, right ventricle dilatation due to pulmonary embolism, and cardiac hypokinesis, and aid in the diagnosis and management of patients in emergency department (ED). Case Report A 41-year-old man presented twice to the ED with history of abdominal pain and was diagnosed with primary cardiac angiosarcoma with point-of-care ultrasound. Conclusion This case is illustrative of how bedside cardiac ultrasound in the ED can dramatically change a patient's hospital course. PMID:22224142

  1. Diagnostic Accuracy of Central Venous Catheter Confirmation by Bedside Ultrasound Versus Chest Radiography in Critically Ill Patients: A Systematic Review and Meta-Analysis.

    PubMed

    Ablordeppey, Enyo A; Drewry, Anne M; Beyer, Alexander B; Theodoro, Daniel L; Fowler, Susan A; Fuller, Brian M; Carpenter, Christopher R

    2017-04-01

    We performed a systematic review and meta-analysis to examine the accuracy of bedside ultrasound for confirmation of central venous catheter position and exclusion of pneumothorax compared with chest radiography. PubMed, Embase, Cochrane Central Register of Controlled Trials, reference lists, conference proceedings and ClinicalTrials.gov. Articles and abstracts describing the diagnostic accuracy of bedside ultrasound compared with chest radiography for confirmation of central venous catheters in sufficient detail to reconstruct 2 × 2 contingency tables were reviewed. Primary outcomes included the accuracy of confirming catheter positioning and detecting a pneumothorax. Secondary outcomes included feasibility, interrater reliability, and efficiency to complete bedside ultrasound confirmation of central venous catheter position. Investigators abstracted study details including research design and sonographic imaging technique to detect catheter malposition and procedure-related pneumothorax. Diagnostic accuracy measures included pooled sensitivity, specificity, positive likelihood ratio, and negative likelihood ratio. Fifteen studies with 1,553 central venous catheter placements were identified with a pooled sensitivity and specificity of catheter malposition by ultrasound of 0.82 (0.77-0.86) and 0.98 (0.97-0.99), respectively. The pooled positive and negative likelihood ratios of catheter malposition by ultrasound were 31.12 (14.72-65.78) and 0.25 (0.13-0.47). The sensitivity and specificity of ultrasound for pneumothorax detection was nearly 100% in the participating studies. Bedside ultrasound reduced mean central venous catheter confirmation time by 58.3 minutes. Risk of bias and clinical heterogeneity in the studies were high. Bedside ultrasound is faster than radiography at identifying pneumothorax after central venous catheter insertion. When a central venous catheter malposition exists, bedside ultrasound will identify four out of every five earlier than

  2. Bedside ultrasound in the diagnosis of uterine rupture following surgical abortion.

    PubMed

    Derr, Charlotte; Henry, Melinda

    2013-04-01

    Reports of uterine rupture following surgical abortion are rare but may result in hemorrhage, sepsis, and even death. In this unique case, we describe how a transabdominal pelvic ultrasound performed at the bedside by an emergency department physician identified uterine rupture with retained products of conception and led to an emergent laparotomy and hysterectomy. This case illustrates how bedside ultrasound may be used in patients presenting with abdominopelvic pain following surgical abortion to shorten the time to definitive treatment and ultimately lower the morbidity and mortality associated with a diagnosis of life-threatening uterine rupture.

  3. Point-of-care cardiac ultrasound techniques in the physical examination: better at the bedside.

    PubMed

    Kimura, Bruce J

    2017-03-04

    The development of hand-carried, battery-powered ultrasound devices has created a new practice in ultrasound diagnostic imaging, called 'point-of-care' ultrasound (POCUS). Capitalising on device portability, POCUS is marked by brief and limited ultrasound imaging performed by the physician at the bedside to increase diagnostic accuracy and expediency. The natural evolution of POCUS techniques in general medicine, particularly with pocket-sized devices, may be in the development of a basic ultrasound examination similar to the use of the binaural stethoscope. This paper will specifically review how POCUS improves the limited sensitivity of the current practice of traditional cardiac physical examination by both cardiologists and non-cardiologists. Signs of left ventricular systolic dysfunction, left atrial enlargement, lung congestion and elevated central venous pressures are often missed by physical techniques but can be easily detected by POCUS and have prognostic and treatment implications. Creating a general set of repetitive imaging skills for these entities for application on all patients during routine examination will standardise and reduce heterogeneity in cardiac bedside ultrasound applications, simplify teaching curricula, enhance learning and recollection, and unify competency thresholds and practice. The addition of POCUS to standard physical examination techniques in cardiovascular medicine will result in an ultrasound-augmented cardiac physical examination that reaffirms the value of bedside diagnosis.

  4. Portable bedside ultrasound: the visual stethoscope of the 21st century

    PubMed Central

    2012-01-01

    Over the past decade technological advances in the realm of ultrasound have allowed what was once a cumbersome and large machine to become essentially hand-held. This coupled with a greater understanding of lung sonography has revolutionized our bedside assessment of patients. Using ultrasound not as a diagnostic test, but instead as a component of the physical exam, may allow it to become the stethoscope of the 21st century. PMID:22400903

  5. Accuracy of emergency physician performed bedside ultrasound in determining gestational age in first trimester pregnancy

    PubMed Central

    2012-01-01

    Background Patient reported menstrual history, physician clinical evaluation, and ultrasonography are used to determine gestational age in the pregnant female. Previous studies have shown that pregnancy dating by last menstrual period (LMP) and physical examination findings can be inaccurate. An ultrasound performed in the radiology department is considered the standard for determining an accurate gestational age. The aim of this study is to determine the accuracy of emergency physician performed bedside ultrasound as an estimation of gestational age (EDUGA) as compared to the radiology department standard. Methods A prospective convenience sample of ED patients presenting in the first trimester of pregnancy (based upon self-reported LMP) regardless of their presenting complaint were enrolled. EDUGA was compared to gestational age estimated by ultrasound performed in the department of radiology (RGA) as the gold standard. Pearson’s product moment correlation coefficient was used to determine the correlation between EDUGA compared to RGA. Results Sixty-eight pregnant patients presumed to be in the 1st trimester of pregnancy based upon self-reported LMP consented to enrollment. When excluding the cases with no fetal pole, the median discrepancy of EDUGA versus RGA was 2 days (interquartile range (IQR) 1 to 3.25). The correlation coefficient of EDUGA with RGA was 0.978. When including the six cases without a fetal pole in the data analysis, the median discrepancy of EDUGA compared with RGA was 3 days (IQR 1 to 4). The correlation coefficient of EDUGA with RGA was 0.945. Conclusion Based on our comparison of EDUGA to RGA in patients presenting to the ED in the first trimester of pregnancy, we conclude that emergency physicians are capable of accurately performing this measurement. Emergency physicians should consider using ultrasound to estimate gestational age as it may be useful for the future care of that pregnant patient. PMID:23216683

  6. Bedside ultrasound diagnosis of atraumatic bladder rupture in an alcohol-intoxicated patient: a case report

    PubMed Central

    2012-01-01

    Most commonly, patients who present to the emergency department with a history and physical examination suggestive of urinary bladder rupture report a preceding traumatic event. Spontaneous atraumatic bladder rupture is relatively uncommon, but can occur in the context of a recent alcohol binge. The alcohol-intoxicated patient presents diagnostic and therapeutic challenges to the emergency physician (EP) that take on additional urgency given the high mortality of unrecognized bladder rupture. This case report reviews bladder anatomy, the unique physiological changes in the alcohol-intoxicated patient, and the high mortality rate of a ruptured urinary bladder. We review the historical diagnostic imaging options followed by a discussion of how bedside ultrasound could expedite diagnosis and management. We present the case of a patient with spontaneous atraumatic rupture of the urinary bladder after a recent alcohol binge. Bedside ultrasound was utilized by the EP to determine the need for emergent surgical consultation and intervention. We recommend that EPs consider bladder rupture in their initial evaluation of patients presenting with nonspecific abdominal pain in the context of recent alcohol intoxication. When using bedside ultrasound to evaluate the pelvis, the presence of anterior or posterior vesicular fluid collections, the loss of normal pelvic landmarks, or irregularities in the bladder wall may increase the EPs suspicion for this disease entity and expedite time-sensitive management. PMID:22870918

  7. Sensitivity of Emergency Bedside Ultrasound to Detect Hydronephrosis in Patients with Computed Tomography-proven Stones

    PubMed Central

    Riddell, Jeff; Case, Aaron; Wopat, Ross; Beckham, Stephen; Lucas, Mikael; McClung, Christian D.; Swadron, Stuart

    2014-01-01

    Introduction Non-contrast computed tomography (CT) is widely regarded as the gold standard for diagnosis of urolithiasis in emergency department (ED) patients. However, it is costly, time-consuming and exposes patients to significant doses of ionizing radiation. Hydronephrosis on bedside ultrasound is a sign of a ureteral stone, and has a reported sensitivity of 72–83% for identification of unilateral hydronephrosis when compared to CT. The purpose of this study was to evaluate trends in sensitivity related to stone size and number. Methods This was a structured, explicit, retrospective chart review. Two blinded investigators used reviewed charts of all adult patients over a 6-month period with a final diagnosis of renal colic. Of these charts, those with CT evidence of renal calculus by attending radiologist read were examined for results of bedside ultrasound performed by an emergency physician. We included only those patient encounters with both CT-proven renal calculi and documented bedside ultrasound results. Results 125 patients met inclusion criteria. The overall sensitivity of ultrasound for detection of hydronephrosis was 78.4% [95% confidence interval (CI)=70.2–85.3%]. The overall sensitivity of a positive ultrasound finding of either hydronephrosis or visualized stones was 82.4% [95%CI: 75.6%, 89.2%]. Based on a prior assumption that ultrasound would detect hydronephrosis more often in patients with larger stones, we found a statistically significant (p=0.016) difference in detecting hydronephrosis in patients with a stone ≥6 mm (sensitivity=90% [95% CI=82–98%]) compared to a stone <6 mm (sensitivity=75% [95% CI=65–86%]). For those with 3 or more stones, sensitivity was 100% [95% CI=63–100%]. There were no patients with stones ≥6 mm that had both a negative ultrasound and lack of hematuria. Conclusion In a population with CT-proven urolithiasis, ED bedside ultrasonography had similar overall sensitivity to previous reports but showed better

  8. Bedside ultrasound in the diagnosis of complex hand infections: a case series.

    PubMed

    Marvel, Brett A; Budhram, Gavin R

    2015-01-01

    The red, swollen, infected hand can be a diagnostically challenging presentation in the emergency department (ED). Hand infections are a relatively uncommon ED complaint, and diagnoses may range from simple cellulitis to deep space abscess, and even to suppurative flexor tenosynovitis. The accurate differentiation of these clinical entities is of paramount importance to healing and recovery of function. In this case series, we review 4 patients with similar presenting complaints of a red, swollen hand, but with much different diagnoses and eventual treatment strategies. We describe how ultrasound was used to assist in making the diagnosis and initiating the most appropriate therapy. Finally, we review techniques for sonographic evaluation of the hand and provide imaging tips to improve visualization and accurate diagnosis. Why should an emergency physician be aware of this? Bedside ultrasound may allow for a more rapid and accurate diagnosis of various hand infections when diagnosis by physical examination is unclear. Copyright © 2015 Elsevier Inc. All rights reserved.

  9. Development of a bedside viable ultrasound protocol to quantify appendicular lean tissue mass.

    PubMed

    Paris, Michael T; Lafleur, Benoit; Dubin, Joel A; Mourtzakis, Marina

    2017-07-19

    Ultrasound is a non-invasive and readily available tool that can be prospectively applied at the bedside to assess muscle mass in clinical settings. The four-site protocol, which images two anatomical sites on each quadriceps, may be a viable bedside method, but its ability to predict musculature has not been compared against whole-body reference methods. Our primary objectives were to (i) compare the four-site protocol's ability to predict appendicular lean tissue mass from dual-energy X-ray absorptiometry; (ii) optimize the predictability of the four-site protocol with additional anatomical muscle thicknesses and easily obtained covariates; and (iii) assess the ability of the optimized protocol to identify individuals with low lean tissue mass. This observational cross-sectional study recruited 96 university and community dwelling adults. Participants underwent ultrasound scans for assessment of muscle thickness and whole-body dual-energy X-ray absorptiometry scans for assessment of appendicular lean tissue. Ultrasound protocols included (i) the nine-site protocol, which images nine anterior and posterior muscle groups in supine and prone positions, and (ii) the four-site protocol, which images two anterior sites on each quadriceps muscle group in a supine position. The four-site protocol was strongly associated (R(2)  = 0.72) with appendicular lean tissue mass, but Bland-Altman analysis displayed wide limits of agreement (-5.67, 5.67 kg). Incorporating the anterior upper arm muscle thickness, and covariates age and sex, alongside the four-site protocol, improved the association (R(2)  = 0.91) with appendicular lean tissue and displayed narrower limits of agreement (-3.18, 3.18 kg). The optimized protocol demonstrated a strong ability to identify low lean tissue mass (area under the curve = 0.89). The four-site protocol can be improved with the addition of the anterior upper arm muscle thickness, sex, and age when predicting appendicular lean tissue mass

  10. A hand-held ultrasound machine vs. conventional ultrasound machine in the bedside assessment of post-liver transplant patients.

    PubMed

    Trinquart, Ludovic; Bruno, Onorina; Angeli, Maria Luigia; Belghiti, Jacques; Chatellier, Gilles; Vilgrain, Valérie

    2009-10-01

    The purpose was to assess the diagnostic accuracy of a hand-held Doppler ultrasound (US) machine for the bedside detection of liver and vascular abnormalities after liver transplantation in the intensive care unit. The IRB approved this study, and written informed consent was obtained from all patients or the patient's legal representative. Any liver transplant recipient at our institution who needed a bedside Doppler US examination in the intensive care unit was eligible. Patients underwent routine grey-scale, colour, and spectral Doppler US examinations of the liver with a conventional machine, which was taken as the reference method, and with a hand-held machine on the same day. Examinations followed one another and were performed in a blinded fashion by two radiologists. Over a 4-month period, 24 consecutive patients (16 men, median age 54 years old; 16 cadaveric and 8 living related right liver transplantations) underwent 43 examinations with both conventional and hand-held machines. Image quality and overall satisfaction scores of grey-scale were lower with the hand-held than with the conventional machine. The hand-held was similar to the conventional machine for assessing the patency of portal veins, hepatic veins and the IVC in all patients but one. The hand-held machine failed to detect signals in the right branch of the hepatic artery and in the hilum in two and one cases, respectively. There was no abnormal hepatic arterial flow with the conventional machine in any of the patients, and the results were the same with the hand-held machine. Total examination time was significantly longer with the hand-held machine. The hand-held US machine had a high diagnostic accuracy for both parenchymal and vascular analyses compared with a conventional US machine in the bedside assessment of post-liver transplant patients.

  11. The bedside insertion of inferior vena cava filters using ultrasound guidance.

    PubMed

    Uppal, Baljeet; Flinn, William R; Benjamin, Marshall E

    2007-03-01

    Since the introduction of inferior vena cava (IVC) filters more than 30 years ago, there has been a steady improvement in the design, ease, and safety of the delivery systems. Today, all of the commonly used filters can be placed via a peripheral vein by using standard percutaneous Seldinger technique. However, this typically requires fluoroscopy, intravenous contrast agents, radiation exposure, and transport of the patient to the interventional or operating suite. In the multiply injured trauma or critically-ill intensive care unit patient, often requiring inotropic and ventilator support, transport to these facilities can be hazardous. In addition, these patients frequently have a combination of neurospinal and long bone injuries, which require skeletal immobilization, thus further complicating transportation. Advancing technology with portable duplex ultrasound and improved deep abdominal duplex imaging has allowed for routine diagnostic evaluation of the IVC, renal veins, and surrounding visceral structures. This degree of accuracy has allowed numerous centers to gain experience with ultrasonic imaging of the IVC and insertion site after a filter has been placed. A logical progression has evolved to the point in which, today, duplex ultrasound can be used to guide the insertion of IVC filters. The following describes, in detail, a technique for the percutaneous placement of an IVC filter at the bedside using only duplex ultrasound guidance. The article also briefly compares and contrasts this technique with an alternate technique using intravascular ultrasound. Vena caval interruption can be safely performed under ultrasound guidance in a monitored, intensive care unit environment. In selected intensive care unit or multiply injured trauma patients, this will reduce the risk, complexity and cost of transport for these critically ill patients. Duplex-guided IVC filter placement also reduces procedural costs compared to an operating room or interventional suite

  12. Complicated bronchiolitis: another use for your bedside ultrasound in the emergency department.

    PubMed

    Soto, Fernando; Soltero, Roxana; Rovira, Helen

    2009-01-01

    Diaphragmatic eventration or diaphragmatic herniations are congenital defect that involve abnormal development of the diaphragm and stretching of the muscular fibers leading to protrusion of abdominal organs into the thoracic cavity. Left sided defects will lead to stomach contents into the chest cavity while, right sided defects will have bowel or liver in the thoracic cavity. Infants with Congenital diaphragmatic hernia often present with respiratory distress that can be life-threatening unless treated appropriately. Bedside ultrasound in the Emergency Department, performed by the Emergency Physician can be a very useful tool in diagnosing conditions such as this one. We present a case of diaphragmatic eventration in a two month old male sent to Emergency Department (ED) by his primary care physician due to a severe case of bronchiolitis.

  13. Can bedside ultrasound assist in determining whether serum creatinine is elevated in cases of acute urinary retention?

    PubMed

    Shah, Kaushal; Teng, Jennifer; Shah, Hiral; Choe, Alice; Darvish, Amir; Newman, David; Wiener, Dan

    2010-08-01

    There are no guidelines to determine which patients with acute urinary retention (AUR) require blood testing (i.e., serum creatinine) to assess for renal failure. To determine if hydronephrosis on bedside ultrasound correlates with an abnormal serum creatinine (Cr) level in cases of AUR. This was a prospective, observational study of subjects clinically diagnosed with AUR at two associated urban academic centers from October 2004 through August 2006. Emergency physicians completed a data form and performed a bedside ultrasound to determine the presence or absence of hydronephrosis. The data collected included suspected cause of AUR, amount of urinary output after Foley insertion, and blood test results. Follow-up was obtained by telephone and electronic medical record for 1 month. Standard statistics were employed. Among 96 enrolled subjects with AUR, 43 had a serum Cr level obtained on the initial visit, and 10 (23%; 95% confidence interval [CI] 11-36) of these had an elevated Cr (10% [95% CI 4-16] of the study cohort). The test characteristics of hydronephrosis on bedside ultrasound to detect elevation in Cr were a sensitivity, specificity, positive predictive value, and negative predictive value of 70%, 67%, 39%, and 88%, respectively. In cases of AUR, the prevalence of elevated creatinine is high, and hydronephrosis based on bedside ultrasonography does not correlate with elevation in creatinine. Copyright 2010 Elsevier Inc. All rights reserved.

  14. Three-view bedside ultrasound for the differentiation of acute respiratory distress syndrome from cardiogenic pulmonary edema.

    PubMed

    Mantuani, Daniel; Nagdev, Arun; Stone, Michael

    2012-09-01

    Bedside ultrasound is being increasingly used by emergency physicians (EPs) for the differentiation of acute dyspnea in critically ill patients. Lung ultrasound is emerging as a highly sensitive tool in diagnosing alveolar interstitial edema with the presence of diffuse “B-lines” arising from the pleural line. However, when used independently, lung ultrasound is unable to differentiate between cardiogenic and noncardiogenic causes of pulmonary edema. This case report describes a rapid 3-view or “triple scan” sonographic examination to differentiate acute respiratory distress syndrome (ARDS) from cardiogenic pulmonary edema.

  15. Validation of Bedside Ultrasound of Muscle Layer Thickness of the Quadriceps in the Critically Ill Patient (VALIDUM Study).

    PubMed

    Paris, Michael T; Mourtzakis, Marina; Day, Andrew; Leung, Roger; Watharkar, Snehal; Kozar, Rosemary; Earthman, Carrie; Kuchnia, Adam; Dhaliwal, Rupinder; Moisey, Lesley; Compher, Charlene; Martin, Niels; Nicolo, Michelle; White, Tom; Roosevelt, Hannah; Peterson, Sarah; Heyland, Daren K

    2017-02-01

    In critically ill patients, muscle atrophy is associated with long-term disability and mortality. Bedside ultrasound may quantify muscle mass, but it has not been validated in the intensive care unit (ICU). Here, we compared ultrasound-based quadriceps muscle layer thickness (QMLT) with precise quantifications of computed tomography (CT)-based muscle cross-sectional area (CSA). Patients ≥18 years old with abdominal CT scans performed for clinical reasons were recruited from 9 ICUs for an ultrasound assessment of the quadriceps. CT scans of the third lumbar vertebra, performed <24 hours before or <72 hours after ICU admission, were analyzed for CSA. Low muscularity was defined as 170 cm(2) for men and 110 cm(2) for women. The ultrasound probe was maximally compressed against the skin and QMLT was measured on 2 sites of each quadriceps <72 hours of the CT scan. Mean CT-derived muscle CSA was 109 ± 25 cm(2) for women and 168 ± 37 cm(2) for men, where 58% of patients exhibited low muscularity; only 2.7% patients were underweight according to body mass index. QMLT was positively correlated with CT CSA ( r = 0.45, P < .001). Based on logistic regression to predict low muscularity, QMLT independently generated a concordance index ( c) of 0.67 ( P < .002), which increased to 0.77 ( P < .001) when age, sex, body mass index, Charlson Comorbidity Index, and admission type (surgical vs medical) were added. Our results suggest that QMLT alone with our current protocol may not accurately identify patients with low muscle mass.

  16. Teaching the internist to see: effectiveness of a 1-day workshop in bedside ultrasound for internal medicine residents.

    PubMed

    Clay, Ryan D; Lee, Elizabeth C; Kurtzman, Marc F; Dversdal, Renee K

    2016-12-01

    A growing body of evidence supports the use of bedside ultrasound for core Internal Medicine procedures and increasingly as augmentation of the physical exam. The literature also supports that trainees, both medical students and residents, can acquire these skills. However, there is no consensus on training approach. To implement and study the effectiveness of a high-yield and expedited curriculum to train internal medicine interns to use bedside ultrasound for physical examination and procedures. The study was conducted at a metropolitan, academic medical center and included 33 Internal Medicine interns. This was a prospective cohort study of a new educational intervention consisting of a single-day intensive bedside ultrasound workshop followed by two optional hour-long workshops later in the year. The investigation was conducted at Oregon Health & Science University in Portland, Oregon. The intensive day consisted of alternating didactic sessions with small group hands-on ultrasound practice sessions and ultrasound simulations. A 30-question assessment was used to assess ultrasound interpretation knowledge prior to, immediately post, and 6 months post intervention. Thirty-three interns served as their own historical controls. Assessment performance significantly increased after the intervention from a mean pre-test score of 18.3 (60.9 % correct) to a mean post-test score 25.5 (85.0 % correct), P value of <0.0001. This performance remained significantly better at 6 months with a mean score of 23.8 (79.3 % correct), P value <0.0001. There was significant knowledge attrition compared to the immediate post-assessment, P value 0.0099. A single-day ultrasound training session followed by two optional noon conference sessions yielded significantly improved ultrasound interpretation skills in internal medicine interns.

  17. Three-view bedside ultrasound to differentiate acute decompensated heart failure from chronic obstructive pulmonary disease.

    PubMed

    Mantuani, Daniel; Nagdev, Arun

    2013-04-01

    Identifying the cause of acute dyspnea in the emergency department is often challenging, even for the most experienced provider. Distinguishing chronic obstructive pulmonary disease from acute decompensated heart failure in the acutely dyspneic patient who presents in respiratory distress is often difficult. Patients are often unable to give a detailed history when in extremis, yet primary management needs to be initiated before further testing can be completed. Bedside diagnostic ultrasound has emerged as a tool for emergency physicians to rapidly evaluate the cardiopulmonary status in patients presenting with undifferentiated shortness of breath [1-3]. A rapid 3-view sonographic evaluation of the heart, lungs, and inferior vena cava or “Triple Scan” may be a useful tool in identifying the cause of acute dyspnea and may aid the clinician in the initial management of the critically ill dyspneic patient. We present a case where a 3-view ultrasound examination, the “Triple Scan,” allowed for detection of new onset congestive heart failure and initiation of appropriate medical therapy without waiting for further standard diagnostic testing.

  18. [Focused surgical bedside ultrasound: E-FAST (focused assessment with sonography in trauma) - abdominal aortic aneurysm - cholecystolithiasis - acute appendicitis].

    PubMed

    Studer, Maria; Studer, Peter

    2014-06-04

    Ultrasound is an easy to learn and highly efficient diagnostic tool to complete the clinical examination and improve bedside decision-making. In the trauma room, surgeons are often required to make a quick decision as to whether or not a patient needs an emergency intervention or whether further diagnostics are required. For this reason, education of surgeons in performing focused emergency ultrasound is pivotal. The goal of ICAN is to improve and expand the education of surgeons in Switzerland. This article provides a short review of the most frequent surgical pathologies encountered in the emergency room.

  19. Comparison of Inferior Vena Cava Filters Placed at the Bedside via Intravenous Ultrasound Guidance Versus Fluoroscopic Guidance.

    PubMed

    Ganguli, Suvranu; Hawkins, Beau M; Abtahian, Farhad; Abu-Fadel, Mazen S; Walker, Thomas G; MacKay, Cheryl; Jaff, Michael R; Weinberg, Ido

    2017-02-01

    IVCFs are usually placed under fluoroscopic guidance in dedicated angiography suites. Bedside placement of inferior vena cava filters (IVCF) is possible in patients not suitable for transportation, but data regarding their use are limited. The objective of this study is to compare utilization, procedural outcomes, complications, and long-term patient outcomes associated with bedside placement of IVCFs using intravascular ultrasound (IVUS) and fluoroscopic placement of IVCF. All patients receiving IVCF between January 2009 and December 2011 at a tertiary care institution were retrospectively identified. Data regarding patient characteristics, IVCF indications, complications, and outcomes were collected, and comparisons were made between patients receiving fluoroscopic-guided and IVUS-guided bedside IVCF. There were 117 bedside and 571 fluoroscopic-guided IVCF placed during this period. Patients receiving bedside IVCF were younger (50.8 vs. 60.7 years, P < 0.001), less often had malignancy (22.2% vs. 42.6%, P < 0.001), and received prophylactic filters more commonly (59.9% vs. 29.9%, P < 0.001). Placement-related complications occurred in 4.3% and 0.6%, respectively (bedside IVCF: 4 malpositions, 1 severe tilt; fluoroscopic-guided IVCF: 1 malposition, 1 severe tilt, P = 0.01). Indwelling IVCF-related complications occurred equally during median follow-up of 463 and 488 days, respectively (deep vein thrombosis: 13.7% vs. 13.3%, P = 0.92; pulmonary embolism: 5.1% vs. 4.0%, P = 0.61; filter thrombosis: 3.4% vs. 3.9%, P = 0.82). Time to indwelling complication was similar between groups (74 vs. 127 days, P = 0.29). Bedside placement of IVUS-guided IVCF is safe, but with higher procedural complications when compared with fluoroscopic placement. Long-term indwelling complications are similar between IVCF placed via bedside IVUS guidance and fluoroscopic approach. Copyright © 2016 Elsevier Inc. All rights reserved.

  20. Geriatricians' interest to learn bedside portable ultrasound (GEBUS) for application in the clinical practice and in education.

    PubMed

    Leone, Andres F; Schumacher, Sarah M; Krotish, Debra E; Eleazer, G Paul

    2012-03-01

    Technological advances have allowed ultrasound machines to become portable, pocket-size aids to diagnosis and clinical examination. As technology becomes more available, physicians are challenged to educate themselves and new generations of health providers in the usage of bedside portable ultrasonography. The aim of this study was to survey a representative sample of geriatricians in South Carolina to evaluate their current knowledge about the use of ultrasound machines in the primary care of the elderly, to determine their willingness to adopt the technology and willingness to educate physicians and medical students, and to identify hurdles for the implementation in the clinical and educational environment. Fourteen physicians and geriatricians participated in the survey. Outpatient geriatric practice, Program of All-inclusive Care for the Elderly, inpatient geriatric practice, home-based care, Veterans Affairs hospital program. A 22-item survey regarding geriatric bedside ultrasound (GEBUS) in the clinical setting and in education. Most physicians (92.8%) had heard of GEBUS performed by primary care physicians, and 21.4% had previous formal training. That same percentage also had some training in interpreting ultrasound. Only one physician felt comfortable using the machine and none felt ready to instruct other medical staff and students. Most of the participating group of physicians (71%-85%) expressed an interest in learning this new skill to apply in clinic, research, and medical education. Challenges for wide implementation were identified. GEBUS is a technology that is now available to the practitioner. Participating geriatricians are ready to embrace this technology in clinical practice and in medical education. Challenges to current implementation include cost, training, liability, credentialing, and lack of reimbursement. Copyright © 2012 American Medical Directors Association, Inc. Published by Elsevier Inc. All rights reserved.

  1. Validation of an Ultrasound Cardiac Output Monitor as a Bedside Tool for Pediatric Patients.

    PubMed

    Beltramo, Fernando; Menteer, Jondavid; Razavi, Asma; Khemani, Robinder G; Szmuszkovicz, Jacqueline; Newth, Christopher J L; Ross, Patrick A

    2016-01-01

    The aim of our study was to determine the validity of cardiac output (CO) measurements taken with the ultrasonic cardiac output monitor (USCOM) by comparing to CO measured by pulmonary arterial catheter (PAC) thermodilution during cardiac catheterization. We enrolled thirty-one children (<18 years) undergoing cardiac catheterization in this double-blinded, prospective, observational study. The median CO measured by USCOM was 4.37 L/min (IQR 3.73, 5.60 L/min) compared to 4.28 L/min (IQR 3.52, 5.26 L/min) by PAC thermodilution. The bias (mean difference) between the two methods was 0.2 L/min, and the 95% limits of agreement were -1.2 to 1.6 L/min. The mean percentage error of CO between USCOM and PAC thermodilution was 11%. When excluding a sole outlier, the bias between the two measures decreased to 0.1 L/min (95% limits of agreement -0.6 to 0.9 L/min), and the percentage error was reduced to 8%. The median SVRI measured by USCOM was 22.0 Wood Units (IQR 17.0, 26.8 Wood Units) compared to 22.1 Wood Units (IQR 17.6, 27.4 Wood Units) by PAC thermodilution. Bias (mean difference) between the two methods was -0.6 Wood Units, and the 95% limits of agreement were -8.2 to 6.9 Wood Units. We found that the estimation of CO and by extension SVRI with USCOM is reliable against pulmonary artery catheter thermodilution in children with normal cardiac anatomy. Given the noninvasive nature of USCOM, speed of measurement, and relative ease of use, it may be useful as a bedside tool for pediatric patients.

  2. BE-SAFE: Bedside sonography for assessment of the fetus in emergencies: educational intervention for late-pregnancy obstetric ultrasound.

    PubMed

    Shah, Sachita; Adedipe, Adeyinka; Ruffatto, Benjamin; Backlund, Brandon H; Sajed, Dana; Rood, Kari; Fernandez, Rosemarie

    2014-09-01

    Late obstetric emergencies are time critical presentations in the emergency department. Evaluation to ensure the safety of mother and child includes rapid assessment of fetal viability, fetal heart rate (FHR), fetal lie, and estimated gestational age (EGA). Point-of-care (POC) obstetric ultrasound (OBUS) offers the advantage of being able to provide all these measurements. We studied the impact of POC OBUS training on emergency physician (EP) confidence, knowledge, and OBUS skill performance on a live model. This is a prospective observational study evaluating an educational intervention we designed, called the BE-SAFE curriculum (BEdside Sonography for the Assessment of the Fetus in Emergencies). Subjects were a convenience sample of EP attendings (N=17) and residents (N=14). Prior to the educational intervention, participants completed a self-assessment survey on their confidence regarding OBUS, and took a pre-test to assess their baseline knowledge of OBUS. They then completed a 3-hour training session consisting of didactic and hands-on education in OBUS. After training, each subject's time and accuracy of performance of FHR, EGA, and fetal lie was recorded. Post-intervention knowledge tests and confidence surveys were administered. Results were compared with non-parametric t-tests. Pre- and post-test knowledge assessment scores for previously untrained EPs improved from 65.7% [SD=20.8] to 90% [SD=8.2] (p<0.0007). Self-confidence on a scale of 1-6 improved significantly for identification of FHR, fetal lie, and EGA. After training, the average times for completion of OBUS critical skills were as follows: cardiac activity (9s), FHR (68.6s), fetal lie (28.1s), and EGA (158.1 sec). EGA estimates averaged 28w0d (25w0d-30w6d) for the model's true gestational age of 27w0d. After a focused POC OBUS training intervention, the BE-SAFE educational intervention, EPs can accurately and rapidly use ultrasound to determine FHR, fetal lie, and estimate gestational age in mid

  3. Low-pressure cardiac tamponade masquerading as severe sepsis diagnosed with a bedside ultrasound and as the initial presentation of malignancy.

    PubMed

    Conti, Ricardo Augusto Slaibi; Oppenheim, Ian Mandeville

    2014-01-01

    We report a patient with low-pressure cardiac tamponade masquerading as sepsis and as the initial presentation of malignancy. A quick diagnosis was done by the intensivist performing a bedside ultrasound. The diagnosis of low-pressure cardiac tamponade is a challenge because the classic physical signs of cardiac tamponade can be absent. It is made even more challenging when the vital sign changes and physical examination findings mimic severe sepsis. One of the benefits of a bedside ultrasound in the assessment of a patient with an initial diagnosis of severe sepsis or septic shock is the rapid diagnosis of cardiac tamponade if it is present. A 55-year-old male presented to the emergency department with weakness, cough, and syncope. His examination was notable only for dusky mottling of his cheeks, chest, and neck. Specifically, there was no jugular venous distension or pulsus paradoxus. A chest radiograph showed a right upper lobe infiltrate, whereas his electrocardiogram showed only sinus tachycardia. His white blood cell count and lactic acid were elevated. The sepsis protocol was started and a bedside ultrasound revealed signs of cardiac tamponade. The patient immediately improved after a pericardiocentesis. Analysis of the pericardial biopsy revealed adenocarcinoma, later determined to be from a pulmonary primary source. Because low-pressure cardiac tamponade is life-threatening and difficult to diagnose, evaluation of the pericardium with a bedside ultrasound should be considered in patients with syncope, severe sepsis, or shock.

  4. Establishing intensivist-driven ultrasound at the PICU bedside--it's about time*.

    PubMed

    Su, Erik; Pustavoitau, Aliaksei; Hirshberg, Elliotte L; Nishisaki, Akira; Conlon, Thomas; Kantor, David B; Weber, Mark D; Godshall, Aaron J; Burzynski, Jeffrey H; Thompson, Ann E

    2014-09-01

    To discuss pediatric intensivist-driven ultrasound and the exigent need for research and practice definitions pertaining to its implementation within pediatric critical care, specifically addressing issues in ultrasound-guided vascular access and intensivist-driven echocardiography. Intensivist-driven ultrasound improves procedure safety and reduces time to diagnosis in clinical ultrasound applications, as demonstrated primarily in adult patients. Translating these applications to the PICU requires thoughtful integration of the technology into practice and would best be informed by dedicated ultrasound research in critically ill children.

  5. [The value of bedside lung ultrasound in emergency-plus protocol for the assessment of lung consolidation and atelectasis in critical patients].

    PubMed

    Wang, Xiao-ting; Liu, Da-wei; Zhang, Hong-min; He, Huai-wu; Liu, Ye; Chai, Wen-zhao; Du, Wei

    2012-12-01

    To investigate the effect of the bedside lung ultrasound in emergency(BLUE)-plus lung ultrasound protocol on lung consolidation and atelectasis of critical patients. All patients who need to receive mechanical ventilation for more than 48 hours in ICU from June 2010 to December 2011 in Peking Union Medical College Hospital were included in the study. BLUE-plus and BLUE lung ultrasound, bedside X-ray, lung CT examination were performed on all patients at the same time. The condition of lung consolidation and atelectasis discovered by BLUE-plus lung ultrasound protocol was recorded and compared with bedside X-ray or lung CT. The difference in assessment of lung consolidation and atelectasis between BLUE-plus lung ultrasound protocol and BLUE protocol was compared. A total of 78 patients were finally enrolled in the study. The lung CT found 70 cases (89.74%) had different degrees of lung consolidation and atelectasis. The sensitivity, specificity and diagnostic accuracy of lung consolidation and atelectasis by the bedside chest X-ray were 31.29%, 75.00% and 38.46%, respectively. BLUE-plus lung ultrasound protocol found 68 cases with lung consolidation and atelectasis, and its sensitivity, specificity, and diagnostic accuracy were 95.71%, 87.50% and 94.87%, respectively, which were significantly higher than those of lung CT. BLUE protocol found 48 cases of lung consolidation and atelectasis, and its sensitivity, specificity, and diagnostic accuracy were 65.71%, 75.00% and 66.67%, respectively. The position of lung consolidation and atelectasis which hadn't been found by BLUE protocol was mainly proved to be located in the basement of lung by lung CT. The incidence of lung consolidation and atelectasis in critical patients who received mechanical ventilation is high. The BLUE-plus lung ultrasound protocol has a relatively higher sensitivity, specificity and diagnostic accuracy for consolidation and atelectasis, which can find majority of consolidation and atelectasis

  6. Assessment of the safety and efficacy of bedside ultrasound guidance for inferior vena cava filter placement in critically ill intensive care unit patients.

    PubMed

    Liu, Ying; Zhou, Hong; Chen, ChangYu; Cui, Chi; Liu, XiPin; Liu, Qinwen; Ye, Ming; Wang, Jing

    2015-04-01

    Inferior vena cava filters (IVCFs) have been used clinically for approximately 45 y, but only a few studies of these devices have involved intensive care unit (ICU) patients who were critically ill and had multiple-organ dysfunction or were otherwise too unstable for transport. The purpose of this research was to assess the tolerability and efficacy of bedside ultrasound-guided IVCF placement in ICU patients. A retrospective analysis of both bedside ultrasound-guided and X-ray-guided ICVF placement was performed from November of 2011 to August of 2013. The total success rate for ultrasound-guided IVCF placement was 93.4%, which included a 96.0% success rate in 25 ICU patients with an average age of 69.46 y. Six-month follow-up studies revealed no significant differences in long-term complications between the ultrasound- and X-ray-guided groups. IVCFs may be safely implanted under ultrasound guidance in a monitored ICU environment. Our conclusion is that patients should be fasting and should receive an enema and that pre-operative surface marking and dynamic monitoring should be employed. Further research is needed to develop specific ultrasound guidelines.

  7. Changes in the availability of bedside ultrasound practice in emergency rooms and prehospital settings in France.

    PubMed

    Bobbia, X; Abou-Badra, M; Hansel, N; Pes, P; Petrovic, T; Claret, P G; Lefrant, J Y; de La Coussaye, J E

    2017-08-04

    Ensuring the availability of ultrasound devices is the initial step in implementing clinical ultrasound (CUS) in emergency services. In France in 2011, 52% of emergency departments (EDs) and only 9% of mobile intensive care stations (MICS) were equipped with ultrasound devices. The main goal of this study was to determine the movement of these rates since 2011. We conducted a cross-sectional, descriptive, multicentre study in the form of a questionnaire. To estimate the numbers of EDs and MICS equipped with at least one ultrasound system with a confidence level of 95% and margin of error of 5%, 170 responding EDs and 145 MICS were required. Each service was solicited three times by secure online questionnaire and then by phone. Three hundred and twenty-eight (84%) services responded to the questionnaire: 179 (86%) EDs and 149 (82%) MICS. At least one ultrasound machine was available in 127 (71%, 95% CI [64; 78]) EDs vs. 52% in 2011 (P<0.01). 42 (28%, 95% CI [21; 35]) MICS were equipped vs. 9% in 2011 (P<0.01). In 97 (76%) EDs and 24 (55%) MICS, less than a half of physicians were trained. CUS was used at least three times a day in 52 (41%) EDs and in 8 (19%) MICS. Our study demonstrates improved access to ultrasound devices in French EDs and MICS. Almost three-quarters of EDs and nearly one-third of MICS are now equipped with at least one ultrasound device. However, the rate of physicians trained per service remains insufficient. Copyright © 2017 Société française d'anesthésie et de réanimation (Sfar). Published by Elsevier Masson SAS. All rights reserved.

  8. Bedside Ultrasound Reduces Diagnostic Uncertainty and Guides Resuscitation in Patients With Undifferentiated Hypotension.

    PubMed

    Shokoohi, Hamid; Boniface, Keith S; Pourmand, Ali; Liu, Yiju T; Davison, Danielle L; Hawkins, Katrina D; Buhumaid, Rasha E; Salimian, Mohammad; Yadav, Kabir

    2015-12-01

    Utilization of ultrasound in the evaluation of patients with undifferentiated hypotension has been proposed in several protocols. We sought to assess the impact of an ultrasound hypotension protocol on physicians' diagnostic certainty, diagnostic ability, and treatment and resource utilization. Prospective observational study. Emergency department in a single, academic tertiary care hospital. A convenience sample of patients with a systolic blood pressure less than 90 mm Hg after an initial fluid resuscitation, who lacked an obvious source of hypotension. An ultrasound-trained physician performed an ultrasound on each patient using a standardized hypotension protocol. Differential diagnosis and management plan was solicited from the treating physician immediately before and after the ultrasound. Blinded chart review was conducted for management and diagnosis during the emergency department and inpatient hospital stay. The primary endpoints were the identification of an accurate cause for hypotension and change in physicians' diagnostic uncertainty. The secondary endpoints were changes in treatment plan, use of resources, and changes in disposition after performing the ultrasound. One hundred eighteen patients with a mean age of 62 years were enrolled. There was a significant 27.7% decrease in the mean aggregate complexity of diagnostic uncertainty before and after the ultrasound hypotension protocol (1.85-1.34; -0.51 [95% CI, -0.41 to -0.62]) as well as a significant increase in the absolute proportion of patients with a definitive diagnosis from 0.8% to 12.7%. Overall, the leading diagnosis after the ultrasound hypotension protocol demonstrated excellent concordance with the blinded consensus final diagnosis (Cohen k = 0.80). Twenty-nine patients (24.6%) had a significant change in the use of IV fluids, vasoactive agents, or blood products. There were also significant changes in major diagnostic imaging (30.5%), consultation (13.6%), and emergency department

  9. An Experiential Learning Model Facilitates Learning of Bedside Ultrasound by Preclinical Medical Students.

    PubMed

    Shokoohi, Hamid; Boniface, Keith; Kaviany, Parisa; Armstrong, Paige; Calabrese, Kathleen; Pourmand, Ali

    2016-01-01

    To examine the effects of an experiential learning model of ultrasound training on preclinical medical students' knowledge and practice of Focused Assessment with Sonography for Trauma (FAST) examination. The study was conducted in 2 phases. In phase 1, first- and second-year medical students participated in a 45-minute didactic presentation and subsequent 1-hour hands-on practice followed by 3-5 precepted FAST examinations in the emergency department. A pretest or posttest design was used to examine the participants' knowledge interpreting ultrasound images of the FAST examination. In phase 2, students performed FAST scans on patients with abdominal complaints under the supervision of emergency ultrasound faculty over a 1-year period. The participants were scored based on window acquisition, quality of images, accuracy of FAST scan interpretation, confidence level rated by participant, and supervising attending physician. In phase 1, 68 novice medical students participated in 11 training sessions offered over a 1-year period. Students showed significant improvement in basic ultrasound and abdominal anatomy knowledge. The mean score improved from a pretest score of 5.8 of 10 (95% CI: 5.3-6.2) to a posttest score of 7.3 of 10 (95% CI: 7-7.6). The students also demonstrated a significant improvement in FAST image interpretation (pretest of 6.2 [95% CI: 5.9-6.6] and posttest of 7.6 [95% CI: 7.1-7.9]). In phase 2, 22 students performed 304 FAST examinations on patients. At the beginning of their training when they performed less than 10 FAST scans, students were able to complete the right upper quadrant view in 88.9%, left upper quadrant view in 69.7%, subxiphoid in 64.7%, and pelvic view in 70% of scans. Across all views of the FAST examination, increasing level of practice was associated with improvement in successfully completing the examination. The absolute increase in the proportion experiencing success in the right upper quadrant view was 1.6%, 3.6%, and 6

  10. Integrated use of bedside lung ultrasound and echocardiography in acute respiratory failure: a prospective observational study in ICU.

    PubMed

    Bataille, Benoit; Riu, Beatrice; Ferre, Fabrice; Moussot, Pierre Etienne; Mari, Arnaud; Brunel, Elodie; Ruiz, Jean; Mora, Michel; Fourcade, Olivier; Genestal, Michele; Silva, Stein

    2014-12-01

    It has been suggested that the complementary use of echocardiography could improve the diagnostic accuracy of lung ultrasonography (LUS) in patients with acute respiratory failure (ARF). Nevertheless, the additional diagnostic value of echocardiographic data when coupled with LUS is still debated in this setting. The aim of the current study was to compare the diagnostic accuracy of LUS and an integrative cardiopulmonary ultrasound approach (thoracic ultrasonography [TUS]) in patients with ARF. We prospectively recruited patients consecutively admitted for ARF to the ICU of a university teaching hospital over a 12-month period. Inclusion criteria were age ≥ 18 years and the presence of criteria for severe ARF justifying ICU admission. We compared both LUS and TUS approaches and the final diagnosis determined by a panel of experts using machine learning methods to improve the accuracy of the final diagnostic classifiers. One hundred thirty-six patients were included (age, 68 ± 15 years; sex ratio, 1). A three-dimensional partial least squares and multinomial logistic regression model was developed and subsequently tested in an independent sample of patients. Overall, the diagnostic accuracy of TUS was significantly greater than LUS (P < .05, learning and test sample). Comparisons between receiver operating characteristic curves showed that TUS significantly improves the diagnosis of cardiogenic edema (P < .001, learning and test samples), pneumonia (P < .001, learning and test samples), and pulmonary embolism (P < .001, learning sample). This study demonstrated for the first time to our knowledge a significantly better performance of TUS than LUS in the diagnosis of ARF. The value of the TUS approach was particularly important to disambiguate cases of hemodynamic pulmonary edema and pneumonia. We suggest that the bedside use of artificial intelligence methods in this setting could pave the way for the development of new clinically relevant integrative diagnostic

  11. Body Mass Index is a Poor Predictor of Bedside Appendix Ultrasound Success or Accuracy.

    PubMed

    Lam, Samuel H F; Kerwin, Christopher; Konicki, P John; Goodwine, Diana; Lambert, Michael J

    2016-07-01

    The objective of this study was to determine whether there is a relationship between body mass index (BMI) and success or accuracy rate of beside ultrasound (BUS) for the diagnosis of appendicitis. Patients four years of age and older presenting to the emergency department with suspected appendicitis were eligible. Enrollment was by convenience sampling. After informed consent, BUS was performed by trained emergency physicians who had undergone a minimum of one-hour didactic training on the use of BUS to diagnose appendicitis. We ascertained subject outcomes by a combination of medical record review and telephone follow up. Calculated BMI for adults and children were divided into four categories (underweight, normal, overweight, obese) according to Centers for Disease Control and Prevention classifications. A total of 125 subjects consented for the study, and 116 of them had adequate image data for final analysis. Seventy (60%) of the subjects were children. Prevalence of appendicitis was 39%. Fifty-two (45%) of the BUS studies were diagnostic (successful). Overall accuracy rate was 75%. Analysis by chi-square test or Mann-Whitney U test did not find any significant correlation between BMI category and BUS success. Similarly, there was no significant correlation between BMI category and BUS accuracy. The same conclusion was reached when children and adults were analyzed separately, or when subjects were dichotomized into underweight/normal and overweight/obese categories. BMI category alone is a poor predictor of appendix BUS success or accuracy.

  12. Bedside Ultrasound vs X-Ray for the Diagnosis of Forearm Fractures in Children.

    PubMed

    Rowlands, Rachel; Rippey, James; Tie, Sing; Flynn, James

    2017-02-01

    Painful forearm injuries after a fall occur frequently in children. X-ray study is currently the gold standard investigation. Ultrasound (US) is a potential alternative that avoids exposure to ionizing radiation and may be less painful than x-ray study; and familiarity and skill with US is increasing among emergency physicians. The primary aim of this study was to determine if a cohort of physicians with little or no previous experience with US could, after a short training program, safely exclude forearm fractures in children. Secondary aims were to compare any pain or discomfort associated with clinical examination, US, and x-ray study and to determine the acceptability of US as a diagnostic tool to parents and patients. A prospective, nonrandomized, interventional diagnostic study was performed on children between the ages of 0 and 16 years who had a suspected fracture of the forearm. US scanning was performed by a group of physicians, most with little or no previous US experience. After the brief training program, a group of pediatric emergency physicians could diagnose forearm fractures in children with a sensitivity of 91.5% and a specificity of 87.6%. Pain associated with US was no better or worse than pain associated with x-ray study. Patients and parents preferred US over x-ray study as an investigation modality for suspected forearm fractures. A group of pediatric emergency physicians with limited previous experience could, after a short training program, diagnose forearm fractures in children. Pain associated with US was no better or worse than pain associated with x-ray study. Crown Copyright © 2016. Published by Elsevier Inc. All rights reserved.

  13. Reliablity of measurements from ultrasound images

    NASA Astrophysics Data System (ADS)

    Hardin, Sarah M.; Frisch, Stefan A.

    2005-09-01

    As ultrasound imaging gains popularity in phonetic and speech science research, examining the reliability of measures taken from ultrasound images becomes important. This study assesses the reliability of hand measures of ultrasound data collected by graduate student researchers at the University of South Florida ultrasound imaging lab. Speech production data from two different experiments, ``Ultrasound analysis of velar fronting'' (Wodzinski, 2004) and ``Ultrasound study of errors in speech production'' [Frisch, (2003)] were analyzed by two different researchers to obtain inter-rater reliability measures. In addition, one data set was measured twice by the same researcher, once when inexperienced with ultrasound analysis and 7 months later after considerable experience had been gained. The study compared researcher's choice of image to analyze, the measures of the location of articulatory landmarks, and the measures used to quantify articulatory postures. Overall, hand measures of ultrasound images were found to be reliable. There were some differences in the absolute measures obtained, however, different researcher's measures of the same data led to the same conclusions about articulation. In addition, it was found that the measurements of different researchers became more similar to one another with experience.

  14. Ultrasound, normal fetus - head measurements (image)

    MedlinePlus

    ... Many health care providers like to have fetal measurements to verify the size of the fetus and ... any abnormalities. This ultrasound is of a head measurement, indicated by the cross hairs and dotted lines.

  15. Ultrasound, normal fetus - abdomen measurements (image)

    MedlinePlus

    ... Many health care providers like to have fetal measurements to verify the size of the fetus and ... any abnormalities. This ultrasound is of an abdominal measurement. It shows a cross-section of the abdomen, ...

  16. Multicenter validation of a bedside antisaccade task as a measure of executive function

    PubMed Central

    Hellmuth, J.; Mirsky, J.; Heuer, H.W.; Matlin, A.; Jafari, A.; Garbutt, S.; Widmeyer, M.; Berhel, A.; Sinha, L.; Miller, B.L.; Kramer, J.H.

    2012-01-01

    Objective: To create and validate a simple, standardized version of the antisaccade (AS) task that requires no specialized equipment for use as a measure of executive function in multicenter clinical studies. Methods: The bedside AS (BAS) task consisted of 40 pseudorandomized AS trials presented on a laptop computer. BAS performance was compared with AS performance measured using an infrared eye tracker in normal elders (NE) and individuals with mild cognitive impairment (MCI) or dementia (n = 33). The neuropsychological domain specificity of the BAS was then determined in a cohort of NE, MCI, and dementia (n = 103) at UCSF, and the BAS was validated as a measure of executive function in a 6-center cohort (n = 397) of normal adults and patients with a variety of brain diseases. Results: Performance on the BAS and laboratory AS task was strongly correlated and BAS performance was most strongly associated with neuropsychological measures of executive function. Even after controlling for disease severity and processing speed, BAS performance was associated with multiple assessments of executive function, most strongly the informant-based Frontal Systems Behavior Scale. Conclusions: The BAS is a simple, valid measure of executive function in aging and neurologic disease. PMID:22573640

  17. A practical method of serial bedside measurement of cerebral blood flow and metabolism during neurointensive care.

    PubMed Central

    Sharples, P M; Stuart, A G; Aynsley-Green, A; Heaviside, D; Pay, D A; McGann, A; Crawford, P J; Harpin, R; Eyre, J A

    1991-01-01

    Acute encephalopathy is a major cause of death and neurological handicap in children. The principle aims of treatment are to provide adequate cerebral blood flow for the brain's metabolic needs and to prevent intracranial pressure rising above the level at which brain herniation occurs. Rational management requires an understanding of the pathophysiological changes in cerebral blood flow and metabolism which occur. The paucity of data on this subject reflects the perceived difficulty of measuring cerebral blood flow and cerebral metabolism in children. A modification of the Kety Schmidt technique of measuring cerebral blood flow and cerebral metabolism is described. This modification makes it possible to perform serial bedside measurements in children receiving intensive care. This method was used to perform 348 measurements in 58 children. The method was reproducible and no significant complications were encountered. The results indicated that appreciable changes in cerebral blood flow and metabolism could occur in individual patients over time, emphasising the importance of serial measurements. This technique may provide a practical means of monitoring cerebral blood flow and metabolism in very sick children receiving neurointensive care and evaluating the efficacy of treatment. PMID:1755648

  18. The effects of oxygen induced pulmonary vasoconstriction on bedside measurement of pulmonary gas exchange.

    PubMed

    Weinreich, Ulla M; Thomsen, Lars P; Rees, Stephen E; Rasmussen, Bodil S

    2016-04-01

    In patients with respiratory failure measurements of pulmonary gas exchange are of importance. The bedside automatic lung parameter estimator (ALPE) of pulmonary gas exchange is based on changes in inspired oxygen (FiO2) assuming that these changes do not affect pulmonary circulation. This assumption is investigated in this study. Forty-two out of 65 patients undergoing coronary artery bypass grafting (CABG) had measurements of mean pulmonary arterial pressure (MPAP), cardiac output and pulmonary capillary wedge pressure thus enabling the calculation of pulmonary vascular resistance (PVR) at each FiO2 level. The research version of ALPE was used and FiO2 was step-wise reduced a median of 0.20 and ultimately returned towards baseline values, allowing 6-8 min' steady state period at each of 4-6 levels before recording the oxygen saturation (SpO2). FiO2 reduction led to median decrease in SpO2 from 99 to 92 %, an increase in MPAP of 4 mmHg and an increase in PVR of 36 dyn s cm(-5). Changes were immediately reversed on returning FiO2 towards baseline. In this study changes in MPAP and PVR are small and immediately reversible consistent with small changes in pulmonary gas exchange. This indicates that mild deoxygenation induced pulmonary vasoconstriction does not have significant influences on the ALPE parameters in patients after CABG.

  19. Measurement of tissue viscoelasticity with ultrasound

    NASA Astrophysics Data System (ADS)

    Greenleaf, J. F.; Alizad, A.

    2017-02-01

    Tissue properties such as elasticity and viscosity have been shown to be related to such tissue conditions as contraction, edema, fibrosis, and fat content among others. Magnetic Resonance Elastography has shown outstanding ability to measure the elasticity and in some cases the viscosity of tissues, especially in the liver, providing the ability to stage fibrotic liver disease similarly to biopsy. We discuss ultrasound methods of measuring elasticity and viscosity in tissues. Many of these methods are becoming widely available in the extant ultrasound machines distributed throughout the world. Some of the methods to be discussed are in the developmental stage. The advantages of the ultrasound methods are that the imaging instruments are widely available and that many of the viscoelastic measurements can be made during a short addition to the normal ultrasound examination time. In addition, the measurements can be made by ultrasound repetitively and quickly allowing evaluation of dynamic physiologic function in circumstances such as muscle contraction or artery relaxation. Measurement of viscoelastic tissue mechanical properties will become a consistent part of clinical ultrasound examinations in our opinion.

  20. Validity of bedside blood glucose measurement in critically ill patients with intensive insulin therapy

    PubMed Central

    Mahmoodpoor, Ata; Hamishehkar, Hadi; Shadvar, Kamran; Sanaie, Sarvin; Iranpour, Afshin; Fattahi, Vahid

    2016-01-01

    Background and Aims: There have been variable results on the practice of tight glycemic control, and studies have demonstrated that point-of-care (POC) glucometers have variable accuracy. Glucometers must be accurate, and many variables can affect blood glucose levels. The purpose of this study was to determine the difference between blood glucose concentrations obtained from POC glucometers and laboratory results in critically ill patients with intensive insulin therapy. Materials and Methods: This was a descriptive study which enrolled 300 critically ill patients. Four samples of arterial blood were collected and analyzed at the bedside with the POC glucometer and also in the central laboratory to obtain the blood glucose level. To define the effect of various factors on this relation, we noted the levels of hemoglobin (Hb), PaO2, body temperature, bilirubin, history of drug usage, and sepsis. Results: There were not any significant differences between blood sugar levels using laboratory and glucometer methods of measurements. There was a good and significant correlation between glucose levels between two methods (r = 0.81, P < 0.001). Among evaluated factors (body temperature, bilirubin level, blood pressure, Hb level, PaO2, sepsis, and drugs) which added one by one in model, just drugs decreased the correlation more than others (r = 0.78). Conclusions: The results of POC glucometer differ from laboratory glucose concentrations, especially in critically ill patients with unstable hemodynamic status while receiving several drugs. This may raise the concern about using POC devices for tight glycemic control in critically ill patients. These results should be interpreted with caution because of the large variation of accuracy among different glucometer devices. PMID:27994380

  1. Could the use of bedside lung ultrasound reduce the number of chest x-rays in the intensive care unit?

    PubMed

    Brogi, Etrusca; Bignami, Elena; Sidoti, Anna; Shawar, Mohammed; Gargani, Luna; Vetrugno, Luigi; Volpicelli, Giovanni; Forfori, Francesco

    2017-09-13

    Lung ultrasound can be used as an alternative to chest radiography (CXR) for the diagnosis and follow-up of various lung diseases in the intensive care unit (ICU). Our aim was to evaluate the influence that introducing a routine daily use of lung ultrasound in critically ill patients may have on the number of CXRs and as a consequence, on medical costs and radiation exposure. Data were collected by conducting a retrospective evaluation of the medical records of adult patients who needed thoracic imaging and were admitted to our academic polyvalent ICU. We compared the number of CXRs and relative costs before and after the introduction of lung ultrasound in our ICU. A total of 4134 medical records were collected from January 2010 to December 2014. We divided our population into two groups, before (Group A, 1869 patients) and after (Group B, 2265 patients) the introduction of a routine use of LUS in July 2012. Group A performed a higher number of CXRs compared to Group B (1810 vs 961, P = 0.012), at an average of 0.97 vs 0.42 exams per patient. The estimated reduction of costs between Groups A and B obtained after the introduction of LUS, was 57%. No statistically significant difference between the outcome parameters of the two groups was observed. Lung ultrasound was effective in reducing the number of CXRs and relative medical costs and radiation exposure in ICU, without affecting patient outcome.

  2. Computing Health Quality Measures Using Informatics for Integrating Biology and the Bedside

    PubMed Central

    Murphy, Shawn N

    2013-01-01

    Background The Health Quality Measures Format (HQMF) is a Health Level 7 (HL7) standard for expressing computable Clinical Quality Measures (CQMs). Creating tools to process HQMF queries in clinical databases will become increasingly important as the United States moves forward with its Health Information Technology Strategic Plan to Stages 2 and 3 of the Meaningful Use incentive program (MU2 and MU3). Informatics for Integrating Biology and the Bedside (i2b2) is one of the analytical databases used as part of the Office of the National Coordinator (ONC)’s Query Health platform to move toward this goal. Objective Our goal is to integrate i2b2 with the Query Health HQMF architecture, to prepare for other HQMF use-cases (such as MU2 and MU3), and to articulate the functional overlap between i2b2 and HQMF. Therefore, we analyze the structure of HQMF, and then we apply this understanding to HQMF computation on the i2b2 clinical analytical database platform. Specifically, we develop a translator between two query languages, HQMF and i2b2, so that the i2b2 platform can compute HQMF queries. Methods We use the HQMF structure of queries for aggregate reporting, which define clinical data elements and the temporal and logical relationships between them. We use the i2b2 XML format, which allows flexible querying of a complex clinical data repository in an easy-to-understand domain-specific language. Results The translator can represent nearly any i2b2-XML query as HQMF and execute in i2b2 nearly any HQMF query expressible in i2b2-XML. This translator is part of the freely available reference implementation of the QueryHealth initiative. We analyze limitations of the conversion and find it covers many, but not all, of the complex temporal and logical operators required by quality measures. Conclusions HQMF is an expressive language for defining quality measures, and it will be important to understand and implement for CQM computation, in both meaningful use and population

  3. Bedside ultrasonography in the ICU: part 2.

    PubMed

    Beaulieu, Yanick; Marik, Paul E

    2005-09-01

    This is the second of a two-part review on the application of bedside ultrasonography in the ICU. In this part, the following procedures will be covered: (1) echocardiography and cardiovascular diagnostics (second part); (2) the use of bedside ultrasound to facilitate central-line placement and to aid in the care of patients with pleural effusions and intra-abdominal fluid collections; (3) the role of hand-carried ultrasound in the ICU; and (4) the performance of bedside ultrasound by the intensivist. The safety and utility of bedside ultrasonography performed by adequately trained intensivists has now been well demonstrated. This technology, as a powerful adjunct to the physical examination, will become an indispensable tool in the management of critically ill patients.

  4. Ultrasound propagation measurements and applications

    NASA Technical Reports Server (NTRS)

    Lynnworth, L. C.; Papadakis, E. P.; Fowler, K. A.

    1977-01-01

    This paper reviews three systems designed for accurately measuring the propagation of ultrasonic pulses. The three systems are presented in order of velocity-measuring precision: + or - 100 ns, + or - 1 ns, + or - 0.2 ns. Also included is a brief discussion of phase and group velocities, with reference to dispersive, highly attenuating materials. Measurement of attenuation by pulse-echo buffer rod techniques is described briefly. These techniques and instruments have been used to measure sound velocity and attenuation in a variety of materials and shapes, over a wide temperature range.

  5. Ultrasound propagation measurements and applications

    NASA Technical Reports Server (NTRS)

    Lynnworth, L. C.; Papadakis, E. P.; Fowler, K. A.

    1977-01-01

    This paper reviews three systems designed for accurately measuring the propagation of ultrasonic pulses. The three systems are presented in order of velocity-measuring precision: + or - 100 ns, + or - 1 ns, + or - 0.2 ns. Also included is a brief discussion of phase and group velocities, with reference to dispersive, highly attenuating materials. Measurement of attenuation by pulse-echo buffer rod techniques is described briefly. These techniques and instruments have been used to measure sound velocity and attenuation in a variety of materials and shapes, over a wide temperature range.

  6. In vitro enamel thickness measurements with ultrasound.

    PubMed

    Sindi, Khalid Hussain; Bubb, Nigel Lawrence; Gutteridge, Diana Lynn; Evans, Joseph Anthony

    2015-01-01

    In the work described here, agreement between ultrasound and histologic measurements of enamel thickness in vitro was investigated. Fifteen extracted human premolars were sectioned coronally to produce 30 sections. The enamel thickness of each specimen was measured with a 15-MHz hand-held ultrasound probe and verified with histology. The speed of sound in enamel was established. Bland-Altman analysis, intra-class correlation coefficient and Wilcoxon sign rank test were used to assess agreement. The mean speed of sound in enamel was 6191 ± 199 m s(-1). Bland-Altman limits of agreement were -0.16 to 0.18 mm when the speed of sound for each specimen was used, and -0.17 to 0.21 mm when the mean speed of sound was used. Intra-class correlation coefficient agreement was 0.97, and the Wilcoxon sign rank test yielded a p-value of 0.55. Using the speed of sound for each specimen results in more accurate measurement of enamel thickness. Ultrasound measurements were in good agreement with histology, which highlights its potential for monitoring the progressive loss of enamel thickness in erosive tooth surface loss.

  7. Fuzzy similarity measures for ultrasound tissue characterization

    NASA Astrophysics Data System (ADS)

    Emara, Salem M.; Badawi, Ahmed M.; Youssef, Abou-Bakr M.

    1995-03-01

    Computerized ultrasound tissue characterization has become an objective means for diagnosis of diseases. It is difficult to differentiate diffuse liver diseases, namely cirrhotic and fatty liver from a normal one, by visual inspection from the ultrasound images. The visual criteria for differentiating diffused diseases is rather confusing and highly dependent upon the sonographer's experience. The need for computerized tissue characterization is thus justified to quantitatively assist the sonographer for accurate differentiation and to minimize the degree of risk from erroneous interpretation. In this paper we used the fuzzy similarity measure as an approximate reasoning technique to find the maximum degree of matching between an unknown case defined by a feature vector and a family of prototypes (knowledge base). The feature vector used for the matching process contains 8 quantitative parameters (textural, acoustical, and speckle parameters) extracted from the ultrasound image. The steps done to match an unknown case with the family of prototypes (cirr, fatty, normal) are: Choosing the membership functions for each parameter, then obtaining the fuzzification matrix for the unknown case and the family of prototypes, then by the linguistic evaluation of two fuzzy quantities we obtain the similarity matrix, then by a simple aggregation method and the fuzzy integrals we obtain the degree of similarity. Finally, we find that the similarity measure results are comparable to the neural network classification techniques and it can be used in medical diagnosis to determine the pathology of the liver and to monitor the extent of the disease.

  8. Frequency and number of ultrasound lung rockets (B-lines) using a regionally based lung ultrasound examination named vet BLUE (veterinary bedside lung ultrasound exam) in dogs with radiographically normal lung findings.

    PubMed

    Lisciandro, Gregory R; Fosgate, Geoffrey T; Fulton, Robert M

    2014-01-01

    Lung ultrasound is superior to lung auscultation and supine chest radiography for many respiratory conditions in human patients. Ultrasound diagnoses are based on easily learned patterns of sonographic findings and artifacts in standardized images. By applying the wet lung (ultrasound lung rockets or B-lines, representing interstitial edema) versus dry lung (A-lines with a glide sign) concept many respiratory conditions can be diagnosed or excluded. The ultrasound probe can be used as a visual stethoscope for the evaluation of human lungs because dry artifacts (A-lines with a glide sign) predominate over wet artifacts (ultrasound lung rockets or B-lines). However, the frequency and number of wet lung ultrasound artifacts in dogs with radiographically normal lungs is unknown. Thus, the primary objective was to determine the baseline frequency and number of ultrasound lung rockets in dogs without clinical signs of respiratory disease and with radiographically normal lung findings using an 8-view novel regionally based lung ultrasound examination called Vet BLUE. Frequency of ultrasound lung rockets were statistically compared based on signalment, body condition score, investigator, and reasons for radiography. Ten left-sided heart failure dogs were similarly enrolled. Overall frequency of ultrasound lung rockets was 11% (95% confidence interval, 6-19%) in dogs without respiratory disease versus 100% (95% confidence interval, 74-100%) in those with left-sided heart failure. The low frequency and number of ultrasound lung rockets observed in dogs without respiratory disease and with radiographically normal lungs suggests that Vet BLUE will be clinically useful for the identification of canine respiratory conditions. © 2014 American College of Veterinary Radiology.

  9. Ultrasound image velocimetry for rheological measurements

    NASA Astrophysics Data System (ADS)

    Gurung, A.; Haverkort, J. W.; Drost, S.; Norder, B.; Westerweel, J.; Poelma, C.

    2016-09-01

    Ultrasound image velocimetry (UIV) allows for the non-intrusive measurement of a wide range of flows without the need for optical transparency. In this study, we used UIV to measure the local velocity field of a model drilling fluid that exhibits yield stress flow behavior. The radial velocity profile was used to determine the yield stress and the Herschel-Bulkley model flow index n and the consistency index k. Reference data were obtained using the conventional offline Couette rheometry. A comparison showed reasonable agreement between the two methods. The discrepancy in model parameters could be attributed to inherent differences between the methods, which cannot be captured by the three-parameter model used. Overall, with a whole flow field measurement technique such as UIV, we were able to quantify the complex rheology of a model drilling fluid. These preliminary results show that UIV can be used as a non-intrusive diagnostic for in situ, real-time measurement of complex opaque flow rheology.

  10. Resonant ultrasound spectroscopy for elastic constant measurements

    SciTech Connect

    Dixon, R.D.; Migliori, A.; Roe, L.H.

    1993-12-31

    All objects exhibit vibrational resonances when mechanically excited. These resonant frequencies are determined by density, geometry, and elastic moduli. Resonant ultrasound spectroscopy (RUS) takes advantage of the known relationship between the parameters. In particular, for a freely suspended object, with three of the four parameters (vibrational spectra, density, geometry, or elastic moduli) known the remaining one can be calculated. From a materials characterization standpoint it is straight-forward to measure density and geometry but less so to measure all the elastic moduli. It has recently become possible to quickly and accurately measure vibrational spectra, and using code written at Los Alamos, calculate all the elastic moduli simultaneously. This is done to an accuracy of better than one percent for compression and 0.1 percent for shear. RUS provides rapid acquisition of materials information here-to-fore obtainable only with difficulty. It will greatly facilitate the use of real materials properties in models and thus make possible more realistic modeling results. The technique is sensitive to phase changes and microstructure. This offers a change to input real data into microstructure and phase change models. It will also enable measurement of moduli at locations in and about a weld thus providing information for a validating coupled thermomechanical calculations.

  11. Ultrasound measurement of inferior vena cava collapse predicts propofol-induced hypotension.

    PubMed

    Au, Arthur K; Steinberg, Dean; Thom, Christopher; Shirazi, Maziar; Papanagnou, Dimitrios; Ku, Bon S; Fields, J Matthew

    2016-06-01

    Hypotension is a common side effect of propofol, but there are no reliable methods to determine which patients are at risk for significant propofol-induced hypotension (PIH). Ultrasound has been used to estimate volume status by visualization of inferior vena cava (IVC) collapse. This study explores whether IVC assessment by ultrasound can assist in predicting which patients may experience significant hypotension. This was a prospective observational study conducted in the operating suite of an urban community hospital. A convenience sample of consenting adults planned to receive propofol for induction of anesthesia during scheduled surgical procedures were enrolled. Bedside ultrasound was used to measure maximum (IVCmax) and minimum (IVCmin) IVC diameters. IVC-CI was calculated as [(IVCmax-IVCmin)/IVCmax × 100%]. The primary outcome was significant hypotension defined as systolic blood pressure (BP) below 90mmHg and/or administration of a vasopressor to increase BP during surgery. The study sample comprised 40 patients who met inclusion criteria. Mean age was 55years, (95%CI, 49-60) with 53% female. 55% of patients had significant hypotension after propofol administration. 76% of patients with IVC-CI≥50% had significant hypotension compared to 39% with IVC-CI<50%, P=.02. IVC-CI≥50% had a specificity of 77.27% (95%CI, 64.29%-90.26%) and sensitivity of 66.67% (95%CI, 52.06%-81.28%) in predicting PIH. The odds ratio for PIH in patients with IVC-CI≥50% was 6.9 (95%CI, 1.7-27.5). Patients with IVC-CI≥50% were more likely to develop significant hypotension from propofol. IVC ultrasound may be a useful tool to predict which patients are at increased risk for PIH. Copyright © 2016 Elsevier Inc. All rights reserved.

  12. Ultrasound field measurement using a binary lens

    PubMed Central

    Clement, G.T.; Nomura, H.; Kamakura, T.

    2014-01-01

    Field characterization methods using a scattering target in the absence of a point-like receiver have been well described in which scattering is recorded by a relatively large receiver located outside the field of measurement. Unfortunately, such methods are prone to artifacts due to averaging across the receiver surface. To avoid this problem while simultaneously increasing the gain of a received signal, the present study introduces a binary plate lens designed to focus spherically-spreading waves onto a planar region having a nearly-uniform phase proportional to that of the target location. The lens is similar to a zone plate, but modified to produce a biconvex-like behavior, such that it focuses both planar and spherically spreading waves. A measurement device suitable for characterizing narrowband ultrasound signals in air is designed around this lens by coupling it to a target and planar receiver. A prototype device is constructed and used to characterize the field of a highly-focused 400 kHz air transducer along 2 radial lines. Comparison of the measurements with numeric predictions formed from nonlinear acoustic simulation showed good relative pressure correlation, with mean differences of 10% and 12% over center 3dB FWHM drop and 12% and 17% over 6dB. PMID:25643084

  13. Ultrasound physics.

    PubMed

    Shriki, Jesse

    2014-01-01

    Bedside ultrasound has become an important modality for obtaining critical information in the acute care of patients. It is important to understand the physics of ultrasound in order to perform and interpret images at the bedside. The physics of both continuous wave and pulsed wave sound underlies diagnostic ultrasound. The instrumentation, including transducers and image processing, is important in the acquisition of appropriate sonographic images. Understanding how these concepts interplay with each other enables practitioners to obtain the best possible images. Copyright © 2014 Elsevier Inc. All rights reserved.

  14. Automated bedside flow cytometer for mHLA-DR expression measurement: a comparison study with reference protocol.

    PubMed

    Zouiouich, Mehdi; Gossez, Morgane; Venet, Fabienne; Rimmelé, Thomas; Monneret, Guillaume

    2017-08-30

    In various ICU conditions, measurement of diminished expression of human leukocyte antigen-DR on circulating monocytes (mHLA-DR) by flow cytometry appears to be a reliable marker of acquired immunosuppression. Low mHLA-DR is associated with an increased risk of nosocomial infections and mortality. Nevertheless, its use remains somewhat limited and has not been adopted in common medical practice. The main drawback of mHLA-DR measurement is likely related to the use of flow cytometry that is not accessible everywhere on a 24/7 basis. Recently, the Accellix system, a fully automated table top cytometer, was developed for use at bedside or emergency labs. The objective was to assess the performance of the Accellix (beta site evaluation including repeatability and method comparison with reference protocol) for the measurement of mHLA-DR expression. Accellix repeatability at low and high expression levels of mHLA-DR was < 10% (i.e., within the range of acceptability for clinical flow cytometry). In comparison study including 139 blood samples (67 septic shock patients and 17 healthy volunteers), Pearson's correlation parameters (r (2)) ranged from 0.71 to 0.97 (p < 0.001). Intra-class correlation coefficient was 0.92. This fully automated table top cytometer appears to be a suitable tool for ICU patient monitoring and on-going clinical trials as there is no sample preparation and no need for specific skills in flow cytometry. Upon validation in a larger cohort study to reinforce reliability, Accellix could represent a major step to make flow cytometry accessible to clinicians by placing the instrument inside intensive care units or emergency laboratories.

  15. Capillary bedside blood glucose measurement in neonates: missing a diagnosis of galactosemia.

    PubMed

    Özbek, Mehmet Nuri; Öcal, Murat; Tanrıverdi, Sibel; Baysal, Birsen; Deniz, Ahmet; Öncel, Kahraman; Demirbilek, Hüseyin

    2015-03-01

    A number of factors may lead to inaccuracy in measurement of capillary blood glucose with a glucometer. Measurement of other carbohydrate molecules such as galactose and fructose along with glucose can potentially be a cause of error. We report a newborn patient who was referred to our hospital with conjugated bilirubinemia, hepatomegaly and high capillary blood glucose levels measured with a glucometer. Simultaneous biochemical measurements revealed normal blood glucose levels. Further investigation led to a diagnosis of classical galactosemia. Capillary blood glucose level measured with glucometer also dropped to normal values following cessation of breastfeeding and initiation of feeding with a lactose-free formula.

  16. Comparative evaluation of ultrasound scanner accuracy in distance measurement

    NASA Astrophysics Data System (ADS)

    Branca, F. P.; Sciuto, S. A.; Scorza, A.

    2012-10-01

    The aim of the present study is to develop and compare two different automatic methods for accuracy evaluation in ultrasound phantom measurements on B-mode images: both of them give as a result the relative error e between measured distances, performed by 14 brand new ultrasound medical scanners, and nominal distances, among nylon wires embedded in a reference test object. The first method is based on a least squares estimation, while the second one applies the mean value of the same distance evaluated at different locations in ultrasound image (same distance method). Results for both of them are proposed and explained.

  17. Measurement of the frequency and source of interruptions occurring during bedside nursing handover in the intensive care unit: An observational study.

    PubMed

    Spooner, Amy J; Corley, Amanda; Chaboyer, Wendy; Hammond, Naomi E; Fraser, John F

    2015-02-01

    Effective clinical handover involves the communication of relevant patient information from one care provider to another and is critical in ensuring patient safety. Interruptions may contribute to errors and are potentially a significant barrier to the delivery of effective handovers. The study objective was to measure the frequency and source of interruptions during intensive care (ICU) bedside nursing handover. Twenty observations of bedside handover in an ICU were performed and the frequency and source of interruptions were recorded by the observer for each handover. Observations occurred Monday to Friday during shift change; night to day shift and day to evening shift. Interruptions were defined as a break in performance of an activity. The mean handover time was 11 (± 4)min with a range of 5-22 min. The mean number of interruptions was 2 (± 2) per handover with a range of 0-7. The most frequent number of interruptions was seven, occurring during a 15 min handover. Doctors, nurses and alarming intravenous pumps were the most frequent source of interruptions, with administration staff and wards people also disrupting handovers. Nurses, doctors and alarming intravenous pumps frequently interrupt ICU bedside handovers, which may lead to loss of critical information and result in adverse patient events. Increased knowledge in this area will ensure appropriate strategies are developed and implemented in healthcare areas to manage interruptions effectively and improve patient safety. Copyright © 2014. Published by Elsevier Ltd.

  18. Bedside capillary blood glucose measurements in critically ill patients: influence of catecholamine therapy.

    PubMed

    Fekih Hassen, M; Ayed, S; Gharbi, R; Ben Sik Ali, H; Marghli, S; Elatrous, S

    2010-01-01

    To evaluate the effects of catecholamine therapy on the accuracy of capillary glucose measurements in hyperglycemic patients. 43 hyperglycemic patients older than 18 years admitted to the intensive care unit of a tertiary medical center were included from December 2005 to March 2006. This prospective study compares fingerstick and earlobe measurements simultaneously to sampled laboratory venous glucose in patients treated without (group 1) or with (group 2) catecholamine. Three venous samples for serum glucose analysis at three fixed hours and simultaneously two capillary glucose determinations were performed during the two first successive days after inclusion. A difference between the methods of glucose measurements greater than 2.3 mmol/l was considered significant. The mean difference between the two methods was -0.05 mmol/l in group 1 and +0.29 mmol/l in group 2, while the limits of agreement were +4.03 and -4.13 mmol/l and +5.63 and -5.05 mmol/l in groups 1 and 2, respectively. A difference between paired measurements greater than 2.3 mmol/l was observed in 29% in group 1 and in 40% in group 2 (p=0.038). The alternative site did not improve the accuracy. In critically ill patients treated with catecholamine capillary fingerstick blood glucose measurement seems inaccurate. Earlobe sampling does not improve accuracy. Copyright 2009 Elsevier Ireland Ltd. All rights reserved.

  19. Two-dimensional ultrasound measurement of thyroid gland volume: a new equation with higher correlation with 3-D ultrasound measurement.

    PubMed

    Ying, Michael; Yung, Dennis M C; Ho, Karen K L

    2008-01-01

    This study aimed to develop a new two-dimensional (2-D) ultrasound thyroid volume estimation equation using three-dimensional (3-D) ultrasound as the standard of reference, and to compare the thyroid volume estimation accuracy of the new equation with three previously reported equations. 2-D and 3-D ultrasound examinations of the thyroid gland were performed in 150 subjects with normal serum thyrotropin (TSH, thyroid-stimulating hormone) and free thyroxine (fT4) levels (63 men and 87 women, age range: 17 to 71 y). In each subject, the volume of both thyroid lobes was measured by 3-D ultrasound. On 2-D ultrasound, the craniocaudal (CC), lateromedial (LM) and anteroposterior (AP) dimensions of the thyroid lobes were measured. The equation was derived by correlating the volume of the thyroid lobes measured with 3-D ultrasound and the product of the three dimensions measured with 2-D ultrasound using linear regression analysis, in 75 subjects without thyroid nodule. The accuracy of thyroid volume estimation of the new equation and the three previously reported equations was evaluated and compared in another 75 subjects (without thyroid nodule, n = 30; with thyroid nodule, n = 45). It is suggested that volume of thyroid lobe may be estimated as: volume of thyroid lobe = 0.38.(CC.LM.AP) + 1.76. Result showed that the new equation (16.9% to 36.1%) had a significantly smaller thyroid volume estimation error than the previously reported equations (20.8% to 54.9%) (p < 0.05). There was a significantly larger thyroid volume estimation error when thyroid glands with nodules were examined (p < 0.05). With the use of the appropriate thyroid volume equation, 2-D ultrasound can be a useful alternative in thyroid volume measurement when 3-D ultrasound is not available.

  20. Cracks measurement using fiber-phased array laser ultrasound generation

    NASA Astrophysics Data System (ADS)

    Pei, Cuixiang; Demachi, Kazuyuki; Fukuchi, Tetsuo; Koyama, Kazuyoshi; Uesaka, Mitsuru

    2013-04-01

    A phased array laser ultrasound generation system by using fiber optic delivery and a custom-designed focusing objective lens has been developed for crack inspection. The enhancement of crack tip diffraction by using phased array laser ultrasound is simulated with finite element method and validated by experiment. A non-contact and non-destructive measurement of inner-surface cracks by time-of-flight diffraction method using fiber-phased array laser ultrasound generation and electromagnetic acoustic transducer detection has been studied.

  1. Transperineal ultrasound for measurement of prostate volume: validation against transrectal ultrasound.

    PubMed

    Griffiths, Kaye A; Ly, Lam P; Jin, Bo; Chan, Lewis; Handelsman, David J

    2007-10-01

    We evaluated the transperineal ultrasound method to measure total and central prostate volume compared with the standard transrectal ultrasound. Healthy men without prostate disease underwent transperineal and transrectal ultrasound at a single session to calculate total and central prostate volume by the ellipsoidal formula from maximal measured dimensions. Reproducibility within and between methods was evaluated by ICC, CV and Bland-Altman plots. In 13 men measured on 3 occasions within 2 weeks transperineal and transrectal ultrasound had high within method (ICC 0.92 and 0.97, and CV 7.2% and 5.1%, respectively) and between method (ICC 0.98 and CV 5.4%) agreement. Agreement for central prostate volume was good but it was lower within method (ICC 0.74 and 0.73, and CV 20.5% and 20.3%, respectively) and between method (ICC 0.85 and CV 19.7%). Transperineal ultrasound bias was -2.7% for total and -8.9% for central prostate volume. Of 287 healthy men the methods highly correlated for total prostate volume in 245 (ICC 0.92, 95% CI 0.90 to 0.94) and for central prostate volume in 217 (ICC 0.87, 95% CI 0.83 to 0.90). Transperineal ultrasound had minimal bias for total prostate volume (-3.7%, mean -1.0 ml, 95% CI -1.7 to -0.2 ml) and no bias for central prostate volume (-3.0%, mean bias 0.10 ml, 95% CI -0.3 to 0.5 ml). Transperineal ultrasound was more acceptable but it had a higher technical failure rate for total and central prostate volume (13.6% vs 1.4% and 23.7% vs 3.5%, respectively). Transperineal ultrasound provides an accurate, less invasive and more acceptable alternative but with a higher technical failure rate than transrectal ultrasound, especially for central prostate volume. By trading off acceptability for the failure rate transperineal ultrasound may enhance the feasibility of valid studies requiring repeat prostate volume measurement in asymptomatic men.

  2. Ultrasound

    MedlinePlus

    Ultrasound is a type of imaging. It uses high-frequency sound waves to look at organs and ... liver, and other organs. During pregnancy, doctors use ultrasound to view the fetus. Unlike x-rays, ultrasound ...

  3. Bedside measures of malnutrition and association with mortality in hospitalized adults.

    PubMed

    Asiimwe, Stephen B; Muzoora, Conrad; Wilson, L Anthony; Moore, Christopher C

    2015-04-01

    The impact of malnutrition on the outcomes of hospitalized adults in resource-limited settings such as sub-Saharan Africa (SSA) is not fully described. We aimed to determine the association between malnutrition and mortality in adults admitted to hospital in the resource-limited setting of Southwestern Uganda. We performed a cohort study of adults admitted to the medical ward of Mbarara Regional Referral Hospital. Measures of nutritional status included: 1) body mass index (BMI), 2) the mini-nutritional assessment short form (MNA-sf), and 3) mid-upper arm circumference (MUAC). Subjects were followed until death or 30 days from admission. We used proportional hazards regression to assess associations between malnutrition and in-hospital and 30-day mortality. We enrolled 318 subjects. The prevalence of malnutrition was 25-59% depending on the measure used. In-hospital and 30-day mortality were 18% and 37% respectively. In the adjusted analysis, subjects with MNA-sf score 0-7 had a 2.7-fold higher risk of in-hospital mortality (95% CI: 1.3-5.9, p = 0.011) than those with a score of 8-14, and subjects with malnutrition determined by MUAC (<20 cm for males, and <19 cm for females) had a 1.8-fold higher risk of in-hospital mortality (95% CI: 0.98-3.4, p = 0.06) than those normally nourished. MNA-sf (HR 1.6, 95% CI: 1.02-2.6, p = 0.039) and MUAC (HR 1.6, 95% CI: 1.0-2.3, p = 0.048) were independently predictive of 30-day mortality. BMI <18.5 was not associated with in-hospital or 30-day mortality. Malnutrition was common and simple measures of nutritional status predicted in-hospital and 30-day mortality. Further research is needed to understand the pathophysiology of malnutrition during acute illness and mitigate its effects. Copyright © 2014 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.

  4. Validation of Navigation Ultrasound for Clavicular Length Measurement.

    PubMed

    Thorsmark Høj, Anders; Villa, Chiara; Christensen, Ole M; Torp-Pedersen, Søren; Overgaard, Søren; Frich, Lars H

    2017-08-01

    Accurate clavicular length measurement is considered important for the selection of patients requiring surgical treatment after a midclavicular fracture. As radiographic length measurements can be inaccurate to varying degrees, new measurement methods are needed. Use of novel technology, navigation ultrasound, to deliver accurate measurements seems promising. To examine the reliability and validity of navigation ultrasound for length measurements of the clavicle, a study was performed using length measurements performed before forensic autopsies from 2012 to 2013. In total, 38 bodies with a median age of 52.5 (range: 21-78 y) were included. Navigation ultrasound exhibited high reliability (intra-class correlation coefficient: 0.942-0.997, standard error of the mean: 0.7-2.9 mm, minimal detectable change: 2.3-8.1 mm) and validity (measurement error: 1.3%-1.8%, limits of agreement (95% confidence interval): approximately ± 7.5 mm, Pearson's correlation R: 0.948-0.974). Navigation ultrasound can measure clavicular length with an intra-rater reliability matching that of 3-D rendered computed tomography scans and with high validity. Its use could spread to other fields requiring accurate musculoskeletal length measurements. Copyright © 2017 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

  5. Spectral image reconstruction for transcranial ultrasound measurement.

    PubMed

    Clement, Greg T

    2005-12-07

    An approach aimed at improved ultrasound resolution and signal strength through highly attenuating media is presented. The method delivers a series of multiple-cycle bursts in order to construct a discrete spectral (frequency domain) response in one dimension. Cross-correlation of this ultrasound A-mode response with its transmitted signal results in time-localized peaks that correspond to scattering locations. The approach is particularly relevant to the problem of transcranial ultrasound imaging, as it combines numerous smaller signals into a single signal whose net power may exceed that which could be achieved using a single burst. Tests are performed with human skull fragments and nylon-wire targets embedded in a tissue phantom. Skulls are oriented to produce both lateral and shear modes of transcranial propagation. A total of nine locations distributed over three ex vivo human skull samples are studied. Compared with pulsed and chirped signals, results indicate more localized peaks when using the multi-cycle approach, with more accurate positioning when combined with the transcranial shear mode.

  6. Spectral image reconstruction for transcranial ultrasound measurement

    NASA Astrophysics Data System (ADS)

    Clement, Greg T.

    2005-12-01

    An approach aimed at improved ultrasound resolution and signal strength through highly attenuating media is presented. The method delivers a series of multiple-cycle bursts in order to construct a discrete spectral (frequency domain) response in one dimension. Cross-correlation of this ultrasound A-mode response with its transmitted signal results in time-localized peaks that correspond to scattering locations. The approach is particularly relevant to the problem of transcranial ultrasound imaging, as it combines numerous smaller signals into a single signal whose net power may exceed that which could be achieved using a single burst. Tests are performed with human skull fragments and nylon-wire targets embedded in a tissue phantom. Skulls are oriented to produce both lateral and shear modes of transcranial propagation. A total of nine locations distributed over three ex vivo human skull samples are studied. Compared with pulsed and chirped signals, results indicate more localized peaks when using the multi-cycle approach, with more accurate positioning when combined with the transcranial shear mode.

  7. Clinical workflow for spinal curvature measurement with portable ultrasound

    NASA Astrophysics Data System (ADS)

    Tabanfar, Reza; Yan, Christina; Kempston, Michael; Borschneck, Daniel; Ungi, Tamas; Fichtinger, Gabor

    2016-03-01

    PURPOSE: Spinal curvature monitoring is essential in making treatment decisions in scoliosis. Monitoring entails radiographic examinations, however repeated ionizing radiation exposure has been shown to increase cancer risk. Ultrasound does not emit ionizing radiation and is safer for spinal curvature monitoring. We investigated a clinical sonography protocol and challenges associated with position-tracked ultrasound in spinal curvature measurement in scoliosis. METHODS: Transverse processes were landmarked along each vertebra using tracked ultrasound snapshots. The transverse process angle was used to determine the orientation of each vertebra. We tested our methodology on five patients in a local pediatric scoliosis clinic, comparing ultrasound to radiographic curvature measurements. RESULTS: Despite strong correlation between radiographic and ultrasound curvature angles in phantom studies, we encountered new challenges in the clinical setting. Our main challenge was differentiating transverse processes from ribs and other structures during landmarking. We observed up to 13° angle variability for a single vertebra and a 9.85° +/- 10.81° difference between ultrasound and radiographic Cobb angles for thoracic curvatures. Additionally, we were unable to visualize anatomical landmarks in the lumbar region where soft tissue depth was 25-35mm. In volunteers with large Cobb angles (greater than 40° thoracic and 60° lumbar), we observed spinal protrusions resulting in incomplete probe-skin contact and partial ultrasound images not suitable for landmarking. CONCLUSION: Spinal curvature measurement using tracked ultrasound is viable on phantom spine models. In the clinic, new challenges were encountered which must be resolved before a universal sonography protocol can be developed.

  8. In vitro measurement of muscle volume with 3-dimensional ultrasound.

    PubMed

    Delcker, A; Walker, F; Caress, J; Hunt, C; Tegeler, C

    1999-05-01

    The aim was to test the accuracy of muscle volume measurements with a new 3-dimensional (3-D) ultrasound system, which allows a freehand scanning of the transducer with an improved quality of the ultrasound images and therefore the outlines of the muscles. Five resected cadaveric hand muscles were insonated and the muscle volumes calculated by 3-D reconstructions of the acquired 2-D ultrasound sections. Intra-reader, inter-reader and follow-up variability were calculated, as well as the volume of the muscle tissue measured by water displacement. In the results, 3-D ultrasound and water displacement measurements showed an average deviation of 10.1%; Data of 3-D ultrasound measurements were: intra-reader variability 2.8%; inter-reader variability 2.4% and follow-up variability 2.3%. 3-D measurements of muscle volume are valid and reliable. Serial sonographic measurements of muscle may be able to quantitate changes in muscle volume that occur in disease and recovery.

  9. Measurement of corneal tangent modulus using ultrasound indentation.

    PubMed

    Wang, Li-Ke; Huang, Yan-Ping; Tian, Lei; Kee, Chea-Su; Zheng, Yong-Ping

    2016-09-01

    Biomechanical properties are potential information for the diagnosis of corneal pathologies. An ultrasound indentation probe consisting of a load cell and a miniature ultrasound transducer as indenter was developed to detect the force-indentation relationship of the cornea. The key idea was to utilize the ultrasound transducer to compress the cornea and to ultrasonically measure the corneal deformation with the eyeball overall displacement compensated. Twelve corneal silicone phantoms were fabricated with different stiffness for the validation of measurement with reference to an extension test. In addition, fifteen fresh porcine eyes were measured by the developed system in vitro. The tangent moduli of the corneal phantoms calculated using the ultrasound indentation data agreed well with the results from the tensile test of the corresponding phantom strips (R(2)=0.96). The mean tangent moduli of the porcine corneas measured by the proposed method were 0.089±0.026MPa at intraocular pressure (IOP) of 15mmHg and 0.220±0.053MPa at IOP of 30mmHg, respectively. The coefficient of variation (CV) and intraclass correlation coefficient (ICC) of tangent modulus were 14.4% and 0.765 at 15mmHg, and 8.6% and 0.870 at 30mmHg, respectively. The preliminary study showed that ultrasound indentation could be applied to the measurement of corneal tangent modulus with good repeatability and improved measurement accuracy compared to conventional surface displacement-based measurement method. The ultrasound indentation can be a potential tool for the corneal biomechanical properties measurement in vivo.

  10. Noninvasive measurement of local thermal diffusivity using backscattered ultrasound and focused ultrasound heating.

    PubMed

    Anand, Ajay; Kaczkowski, Peter J

    2008-09-01

    Previously, noninvasive methods of estimating local tissue thermal and acoustic properties using backscattered ultrasound have been proposed in the literature. In this article, a noninvasive method of estimating local thermal diffusivity in situ during focused ultrasound heating using beamformed acoustic backscatter data and applying novel signal processing techniques is developed. A high intensity focused ultrasound (HIFU) transducer operating at subablative intensities is employed to create a brief local temperature rise of no more than 10 degrees C. Beamformed radio-frequency (RF) data are collected during heating and cooling using a clinical ultrasound scanner. Measurements of the time-varying "acoustic strain", that is, spatiotemporal variations in the RF echo shifts induced by the temperature related sound speed changes, are related to a solution of the heat transfer equation to estimate the thermal diffusivity in the heated zone. Numerical simulations and experiments performed in vitro in tissue mimicking phantoms and excised turkey breast muscle tissue demonstrate agreement between the ultrasound derived thermal diffusivity estimates and independent estimates made by a traditional hot-wire technique. The new noninvasive ultrasonic method has potential applications in thermal therapy planning and monitoring, physiological monitoring and as a means of noninvasive tissue characterization.

  11. Underestimation of access flow by ultrasound dilution flow measurements

    NASA Astrophysics Data System (ADS)

    Bos, Clemens; Smits, Johannes H. M.; Zijlstra, Jan J.; Blankestijn, Peter J.; Bakker, Chris J. G.; Viergever, Max A.

    2002-02-01

    For hemodialysis access surveillance, flow measurements are increasingly considered important because they identify accesses at risk of thrombosis. Usually these flow measurements are performed with the ultrasound dilution technique. In a previous patient study it was observed that the resulting flow values were systematically low as compared to magnetic resonance flow measurements, but a satisfactory explanation was lacking. In the present study, we will demonstrate by hemodynamic calculations and in vitro experiments that this discrepancy can be explained by a temporary reduction of the access flow rate, caused by the reversed needle configuration during ultrasound dilution flow measurements. In this configuration, blood is injected retrogressively at one needle and flow between the needles is increased, causing an increased dissipation of energy. The proposed explanation is subsequently confirmed in a patient with a loop graft, by measuring the blood velocity by Doppler ultrasound as a function of reversed dialyzer flow rate. Apart from the ultrasound dilution technique, these findings are applicable to other recently proposed methods for measuring access flow that employ the reversed needle configuration.

  12. Discrepancy between ultrasound and final pathologic measurements in thyroid cancer.

    PubMed

    Sowerby, Leigh; Franklin, Jason H; Chin, Christopher J; Turner, Benjamin; Fung, Kevin; Zaleski, Witek; Yoo, John

    2011-12-01

    The size of the malignancy in well-differentiated thyroid carcinoma (WDTC) is an important factor in patient risk stratification. Final pathologic measurements are currently used for treatment decisions. Measurements are made by both ultrasonography and on final pathology and should, theoretically, agree with each other. To evaluate the agreement between ultrasound and final pathologic measurements in thyroid nodules and WDTC. A retrospective chart review of all total thyroidectomies between 1998 and 2007 was completed by four different surgeons at one centre. Thyroid specimens with a solitary nodule and complete ultrasound and pathologic data were included. A comparison of discrepancy and concordance of the largest dimension of the nodule by ultrasound and pathologic measurement was made. A total of 263 thyroid specimens with a solitary nodule were identified. Of these, 68 were found to harbour WDTC. A median underestimation by pathology of 0.54 cm was present in WDTC, averaging 20% of the nodule size by pathology. This trend was consistent with subgroup analysis for size, pathology, and nodularity. An underestimation by pathology of 0.4 cm was present for papillary carcinoma under 1 cm. Grouping nodules by size, a concordance of 80% was present for nodules under 1 cm. Statistical testing revealed weak correlation and a kappa of approximately 0.3 for agreement. Weighted kappa was approximately 0.5 for agreement. The recent advances in ultrasonography and the constraints of pathology preparation allow an argument to be made for investigation of using ultrasound measurements as an adjunct in making treatment decisions.

  13. Ultrasound-guided tunneled lower extremity peripherally inserted central catheter placement in infants.

    PubMed

    Subramanian, Subramanian; Moe, David C; Vo, Jack N

    2013-12-01

    Tunneled lower extremity peripherally inserted central catheters (PICCs) are placed in infants under combined ultrasound and fluoroscopic guidance in the interventional radiology suite. In infants requiring a bedside procedure, image guidance is limited, often using portable radiographs during the procedure. This report demonstrates feasibility of placing tunneled lower extremity PICCs using ultrasound as the sole imaging modality for vascular access, intravascular length measurement, and final confirmation of catheter tip position in a case series of 15 critically ill infants. The technique negates the need for added imaging confirmation methods that use ionizing radiation and can be performed at the bedside.

  14. Locally adaptive Nakagami-based ultrasound similarity measures.

    PubMed

    Wachinger, Christian; Klein, Tassilo; Navab, Nassir

    2012-04-01

    The derivation of statistically optimal similarity measures for intensity-based registration is possible by modeling the underlying image noise distribution. The parameters of these distributions are, however, commonly set heuristically across all images. In this article, we show that the estimation of the parameters on the present images largely improves the registration, which is a consequence of the more accurate characterization of the image noise. More precisely, instead of having constant parameters over the entire image domain, we estimate them on patches, leading to a local adaptation of the similarity measure. While this basic idea of creating locally adaptive metrics is interesting for various fields of application, we present the derivation for ultrasound imaging. The domain of ultrasound is particularly appealing for this approach, due to the inherent contamination with speckle noise. Furthermore, there exist detailed analyses of suitable noise distributions in the literature. We present experiments for applying a bivariate Nakagami distribution that facilitates modeling of several scattering scenarios prominent in medical ultrasound. Depending on the number of scatterers per resolution cell and the presence of coherent structures, different Nakagami parameters are required to obtain a valid approximation of the intensity statistics and to account for distributional locality. Our registration results on radio-frequency ultrasound data confirm the theoretical necessity for a spatial adaptation of similarity metrics.

  15. Pulmonary blood volume measured by contrast enhanced ultrasound: a comparison with transpulmonary thermodilution.

    PubMed

    Herold, I H F; Soliman Hamad, M A; van Assen, H C; Bouwman, R A; Korsten, H H M; Mischi, M

    2015-07-01

    Blood volume quantification is essential for haemodynamic evaluation guiding fluid management in anaesthesia and intensive care practice. Ultrasound contrast agent (UCA)-dilution measured by contrast enhanced ultrasound (CEUS) can provide the UCA mean transit time (MTT) between the right and left heart, enabling the assessment of the intrathoracic blood volume (ITBV(UCA)). The purpose of the present study was to investigate the agreement between UCA-dilution using CEUS and transpulmonary thermodilution (TPTD) in vitro and in vivo. In an in vitro setup, with variable flows and volumes, we injected a double indicator, ice-cold saline with SonoVue(®), and performed volume measurements using transesophageal echo and thermodilution by PiCCO(®). In a pilot study, we assigned 17 patients undergoing elective cardiac surgery for pulmonary blood volume (PBV) measurement using TPTD by PiCCO(®) and ITBV by UCA-dilution. Correlation coefficients and Bland-Altman analysis were performed for all volume measurements. In vitro, 73 experimental MTT's were obtained using PiCCO(®) and UCA-dilution. The volumes by PiCCO(®) and UCA-dilution correlated with true volumes; r(s)=0.96 (95% CI, 0.93-0.97; P<0.0001) and r(s)=0.97 (95% CI, 0.95-0.98; P<0.0001), respectively. The bias of PBV by PiCCO(®) and ITBV(UCA) were -380 ml and -42 ml, respectively. In 16 patients, 86 measurements were performed. The correlation between PBV by PiCCO(®) and ITBV(UCA) was r(s)=0.69 (95% CI 0.55-0.79; P<0.0001). Bland-Altman analysis revealed a bias of -323 ml. ITBV assessment with CEUS seems a promising technique for blood volume measurement, which is minimally-invasive and bedside applicable. ISRCTN90330260. © The Author 2015. Published by Oxford University Press on behalf of the British Journal of Anaesthesia. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  16. Ultrasound settings significantly alter arterial lumen and wall thickness measurements

    PubMed Central

    Potter, Kathleen; Reed, Christopher J; Green, Daniel J; Hankey, Graeme J; Arnolda, Leonard F

    2008-01-01

    Background Flow-mediated dilation (FMD) and carotid intima-medial thickness (CIMT), measured by ultrasound, are widely used to test the efficacy of cardioprotective interventions. Although assessment methods vary, automated edge-detecting image analysis software is routinely used to measure changes in FMD and CIMT. We aimed to quantify the effect that commonly adjusted ultrasound settings have on arterial lumen and wall thickness measurements made with CIMT measurement software. Methods We constructed phantom arteries from a tissue-mimicking agar compound and scanned them in a water bath with a 10 MHz multi-frequency linear-array probe attached to a high-resolution ultrasound machine. B-mode images of the phantoms were recorded with dynamic range (DR) and gain set at five decibel (dB) increments from 40 dB to 60 dB and -10 dB to +10 dB respectively. Lumen diameter and wall-thickness were measured off-line using CIMT measurement software. Results Lumen measurements: there was a strong linear relationship between DR and gain and measured lumen diameter. For a given gain level, a 5 dB increase in DR reduced the measured lumen diameter by 0.02 ± 0.004 mm (p < 0.001). For a given DR level, a 5 dB increase in gain reduced measured lumen diameter by 0.04 ± 0.004 mm (p < 0.001). A 5 mm increase in distance between the ultrasound probe and the artery reduced measured lumen diameter by 0.04 ± 0.03 mm (p < 0.001) CIMT measurements: For a fixed gain level, a 5 dB increase in DR increased measured wall thickness by 0.003 ± 0.002 mm (p < 0.001). The effects of increasing gain were not consistent and appeared to vary depending on the distance between the artery and the ultrasound probe and the thickness of the artery wall. Conclusion DR, gain and probe distance significantly alter lumen diameter and CIMT measurements made using image analysis software. When CIMT and FMD are used to test the efficacy of cardioprotective interventions, the DR, gain and probe position used to

  17. Measuring Residual Stress Using Nonlinear Ultrasound

    NASA Astrophysics Data System (ADS)

    Liu, M.; Kim, J.-Y.; Qu, J.; Jacobs, L. J.

    2010-02-01

    Near-surface compressive residual stresses, which are generated by shot peening, are known to retard crack initiation and thus extend the fatigue life of a metal component. The ability to effectively measure these near-surface residual stresses would greatly help predict the fatigue life of shot-peened components. This research uses the nonlinear surface acoustic wave technique to measure the residual stresses in a shot-peened component. Experiments are conducted on three different aluminum alloy (AA 7075) samples: as-received with no peeing, and shot-peened at the Almen intensities of 8A and 16A. Surface roughness measurements are also carried out for these three samples. The nonlinear ultrasonic results show that the measured acoustic nonlinearity parameter increases by 81% and 115% for the 8A and 16A samples. These large increases in measured acoustic nonlinearity clearly indicate the potential of the nonlinear ultrasonic technique as an NDE tool to measure the near-surface residual stresses. The effects of surface roughness on the ultrasonic measurement are briefly examined. Finally, a preliminary model prediction is presented to interpret the experimental results.

  18. Estimation of Measurement Characteristics of Ultrasound Fetal Heart Rate Monitor

    NASA Astrophysics Data System (ADS)

    Noguchi, Yasuaki; Mamune, Hideyuki; Sugimoto, Suguru; Yoshida, Atsushi; Sasa, Hidenori; Kobayashi, Hisaaki; Kobayashi, Mitsunao

    1995-05-01

    Ultrasound fetal heart rate monitoring is very useful to determine the status of the fetus because it is noninvasive. In order to ensure the accuracy of the fetal heart rate (FHR) obtained from the ultrasound Doppler data, we measure the fetal electrocardiogram (ECG) directly and obtain the Doppler data simultaneously. The FHR differences of the Doppler data from the direct ECG data are concentrated at 0 bpm (beats per minute), and are practically symmetrical. The distribution is found to be very close to the Student's t distribution by the test of goodness of fit with the chi-square test. The spectral density of the FHR differences shows the white noise spectrum without any dominant peaks. Furthermore, the f-n (n>1) fluctuation is observed both with the ultrasound Doppler FHR and with the direct ECG FHR. Thus, it is confirmed that the FHR observation and observation of the f-n (n>1) fluctuation using the ultrasound Doppler FHR are as useful as the direct ECG.

  19. Ultrasound transmission measurements for tensile strength evaluation of tablets.

    PubMed

    Simonaho, Simo-Pekka; Takala, T Aleksi; Kuosmanen, Marko; Ketolainen, Jarkko

    2011-05-16

    Ultrasound transmission measurements were performed to evaluate the tensile strength of tablets. Tablets consisting of one ingredient were compressed from dibasic calcium phosphate dehydrate, two grades of microcrystalline cellulose and two grades of lactose monohydrate powders. From each powder, tablets with five different tensile strengths were directly compressed. Ultrasound transmission measurements were conducted on every tablet at frequencies of 2.25 MHz, 5 MHz and 10 MHz and the speed of sound was calculated from the acquired waveforms. The tensile strength of the tablets was determined using a diametrical mechanical testing machine and compared to the calculated speed of sound values. It was found that the speed of sound increased with the tensile strength for the tested excipients. There was a good correlation between the speed of sound and tensile strength. Moreover, based on the statistical tests, the groups with different tensile strengths can be differentiated from each other by measuring the speed of sound. Thus, the ultrasound transmission measurement technique is a potentially useful method for non-destructive and fast evaluation of the tensile strength of tablets. Copyright © 2011 Elsevier B.V. All rights reserved.

  20. Non-Invasive Measurement of Intracranial Pressure Pulsation using Ultrasound

    NASA Technical Reports Server (NTRS)

    Ueno, Toshiaki; Ballard, R. E.; Yost, W. T.; Hargens, A. R.

    1997-01-01

    Exposure to microgravity causes a cephalad fluid shift which may elevate intracranial pressure (ICP). Elevation in ICP may affect cerebral hemodynamics in astronauts during space flight. ICP is, however, a difficult parameter to measure due to the invasiveness of currently available techniques. We already reported our development of a non-invasive ultrasound device for measurement of ICP. We recently modified the device so that we might reproducibly estimate ICP changes in association with cardiac cycles. In the first experiment, we measured changes in cranial distance with the ultrasound device in cadavera while changing ICP by infusing saline into the lateral ventricle. In the second experiment, we measured changes in cranial distance in five healthy volunteers while placing them in 60 deg, 30 deg head-up tilt, supine, and 10 deg head-down tilt position. In the cadaver study, fast Fourier transformation revealed that cranial pulsation is clearly associated with ICP pulsation. The ratio of cranial distance and ICP pulsation is 1.3microns/mmHg. In the tilting study, the magnitudes of cranial pulsation are linearly correlated to tilt angles (r=0.87). The ultrasound device has sufficient sensitivity to detect cranial pulsation in association with cardiac cycles. By analyzing the magnitude of cranial pulsation, estimates of ICP during space flight are possible.

  1. Using Ultrasound to Measure Mud Rheological Properties

    NASA Astrophysics Data System (ADS)

    Maa, P. Y. P. Y.; Kwon, J. I.; Park, K. S.

    2015-12-01

    In order to predict the dynamic responses of newly consolidated cohesive sediment beds, a better understanding of the material rheological properties (bulk density, ρ, kinematic viscosity, ν, and shear modulus, G, assuming mud is a simple Voigt viscoelastic model) of these sediment beds is needed. An acoustic approach that uses a commercially available 250 kHz shear wave transducer and tone-burst waves has been developed to measure those properties. This approach uses a 86.3 mm long delay-line (DL) to separate the generated pressure and shear waves, and measures the reflected shear waves as well as the reflected pressure waves caused at the interface between the delay line and the mud to interpret these properties. By using materials (i.e., air, water, olive oil, and honey) with available rheological properties to establish a calibration relationship between the information carried by the measured reflected waves and those given material properties, the mud properties as well as thνe change of these properties during consolidation can be interpreted. Using jelly pudding as a check, a value of G ≈ 12310 N/m2 and ν ≈ 5 x 10-5 m2/s were estimated. For the consolidating kaolinite bed (with zero salinity and initial suspended sediment concentration about 420 g/cm3), the measurements show that the shear modulus developed after about 40 hours and approached a value on the order of 15000 N/m2 after about 100 hours. The initial kinematic viscosity was about 5 x 10-4 m2/s, and it decreased slowly with time and approached a low plateau between 10-6 and 10-7 m2/s after 300 hours. The measured bulk density showed a small increasing rate during the entire consolidation period, except at a short period between 80 and 90 hours after consolidation. Results from this study suggest a promising approach for developing an in-situ instrument to measure mud properties, as well as many other materials in other industries.

  2. Normal nipple position in term infants measured on breastfeeding ultrasound.

    PubMed

    Jacobs, Lorili Audrey; Dickinson, Jan E; Hart, Philip David; Doherty, Dorota A; Faulkner, Shani Jean

    2007-02-01

    Nipple position is believed to influence breastfeeding success. To investigate this belief, submental ultrasound images were obtained during breastfeeding of normal term infants. This study measured nipple to hard-soft palate distance (NHSPD) in 18 mother-infant pairs during the first and fourth weeks of life. Median NHSPD was 5 mm (interquartile: 4, 6 mm). There were no significant differences in median NHSPD between first, second, and fifth minutes of feeding (P = .675) or between week 1 and week 4 (P = .320). The nipple was not stationary during feeding, with mean nipple movement of 4.0 -/+ 1.3 mm. Further research is required with more infants to confirm the boundaries of normality for ultrasound measurements of nipple position during successful breastfeeding.

  3. Association between ultrasound measurements of muscle thickness, pennation angle, echogenicity and skeletal muscle strength in the elderly.

    PubMed

    Strasser, Eva Maria; Draskovits, Thomas; Praschak, Markus; Quittan, Michael; Graf, Alexandra

    2013-12-01

    The increase of elderly in our society requires simple tools for quantification of sarcopenia in inpatient and outpatient settings. The aim of this study was to compare parameters determined with musculoskeletal ultrasound (M-US) with muscle strength in young and elderly patients. In this prospective, randomised and observer blind study, 26 young (24.2 ± 3.7 years) and 26 old (age 67.8 ± 4.8 years) patients were included. Muscle thickness, pennation angle and echogenicity of all muscles of musculus quadriceps were measured by M-US and correlated with isometric maximum voluntary contraction force (MVC) of musculus quadriceps. Reproducibility of M-US measurements as well as simple and multiple regression models were calculated. Of all measured M-US variables the highest reproducibility was found for measurements of thickness (intraclass correlation coefficients, 85-97%). Simple regression analysis showed a highly significant correlation of thickness measurements of all muscles of musculus quadriceps with MVC in the elderly and in the young. Multiple regression analysis revealed that thickness of musculus vastus medialis had the best correlation with MVC in the elderly. This study showed that measurement of muscle thickness, especially of musculus vastus medialis, by M-US is a reliable, bedside method for monitoring the extent of sarcopenia.

  4. Methods for blood flow measurements using ultrasound contrast agents

    NASA Astrophysics Data System (ADS)

    Fowlkes, J. Brian

    2003-10-01

    Blood flow measurements using ultrasound contrast agents are being investigated for myocardial perfusion and more recently in other organ systems. The methods are based largely on the relative increase in echogenicity due to the concentration of bubbles present in the ultrasound beam. In the simplest form, regional differences in blood volume can be inferred but the possibility exists to extract perfusion from the transit of contrast agent through tissue. Perfusion measurements rely on determining the flux of blood through a tissue volume and as such require knowledge of the fractional blood volume (FBV), i.e., ml blood/g tissue and the rate of exchange, commonly measured as the mean transit time (MTT). This presentation will discuss methods of determining each of these values and their combination to estimate tissue perfusion. Underlying principles of indicator-dilution theory will be provided in the context of ultrasound contrast agents. Current methods for determining MTT will include imaging of the intravenous bolus, in-plane contrast disruption with interval and real-time contrast recovery imaging, and control of contrast agent flow using arterial disruption (contrast interruption). The advantages and limitations of the methods will be examined along with current applications. [Work supported in part by NIH.

  5. Teaching Evidence-Based Physical Diagnosis: Six Bedside Lessons.

    PubMed

    McGee, Steven

    2016-12-01

    Evidence-based physical diagnosis is an essential part of the bedside curriculum. By using the likelihood ratio, a simple measure of diagnostic accuracy, teachers can quickly adapt this approach to their bedside teaching. Six recurring themes in evidence-based physical diagnosis are fully reviewed, with examples, in this article.

  6. Ultrasound measurements of the masseter muscle as predictors of cephalometric indices in orthodontics: a pilot study.

    PubMed

    Naser-Ud-Din, S; Sampson, W J; Dreyer, C W; Thoirs, K

    2010-09-01

    This study investigated the potential of ultrasound measurements of the masseter muscle to accurately predict indices normally derived from cephalograms. Masseter muscle measurements on 11 adults (22 to 30 y) were made using lateral cephalometrics and extended field-of-view ultrasound. The ultrasound technique was validated in a simulation pilot study using 12 dry skulls and raw chicken breasts. Twenty cephalometric variables were analyzed against four ultrasound measurements of the masseter muscle. Highly significant correlations (r = 0.81-0.85, p = 0.001-0.002) between ultrasound measurements of the masseter muscle and cephalometric measurements representing the length of the superficial masseter muscle, the length and shape of the mandible and vertical facial proportions were demonstrated. Predictive equations from regression analyses were constructed to deduce ramus length and shape from the ultrasound measurements. The results provide pilot data suggesting that ultrasound is a potential clinical tool for sequential evaluation of masseter muscle length in orthodontics and facial muscle growth studies.

  7. Fast bedside measurement of blood count and C-reactive protein in newborns compared with conventional methods.

    PubMed

    Papa, F; Rongioletti, M; Majolini, M B; Collegiani, V; Vaccarella, C; Notarmuzi, M L; Cortesi, M; Pasqualetti, P; Cicchese, M; Agostino, R; Liumbruno, G M

    2012-01-01

    Abnormal complete blood count (CBC) and high plasma C-reactive protein (CRP) are associated with neonatal infections and could be helpful in the diagnosis of neonatal sepsis and to monitor the antibiotic treatment. The aim of this work is to evaluate and compare the performance of a bedside analyzer for blood count and C-reactive protein (CRP) with a conventional analyzer in a neonatal population. 150 capillary or venous blood samples of term and preterm newborns were processed on an ABX-MicrosCRP200 analyzer and on a SysmexXE2100 (conventional hematology analyzer) for CBC, leukocyte differential, reticulocytes, and nucleated red blood cells (NRBC); high-sensitivity CRP (hs-CRP) was performed on a ModularPE. The differences between complete blood count and CRP were regressed against their means and assessed by means of intra-class-correlation. The intra-class-correlation for white blood cell (WBC) was 0.98, for hemoglobin 0.97, for hematocrit 0.96, for mean corpuscular volume 0.95, and for platelet 0.98. ABX-MicrosCRP200 overestimated the WBC (+1.27 x 10(3)/microL; p < 0.001), hematocrit (+1.80%; p < 0.001), and platelet (+13.55 x 10(3)/microL; p < 0.001). The intra-class-correlation for CRP was high (0.97), without systematic difference between the two values (p = 0.64). The agreement between the two methods was high for both tests. However, the SD of the difference for WBC and platelet could be clinically important in leukopenic or thrombocytopenic newborns.

  8. Ultrasound

    MedlinePlus Videos and Cool Tools

    ... baby's development in the uterus. Ultrasound uses inaudible sound waves to produce a two-dimensional image of the baby while inside the mother's uterus. The sound waves bounce off solid structures in the body ...

  9. Ultrasound

    MedlinePlus

    ... called multiples) To screen for birth defects, like spina bifida or heart defects . Screening means seeing if your ... example, if the ultrasound shows your baby has spina bifida, she may be treated in the womb before ...

  10. Ultrasound

    MedlinePlus

    ... a pregnant woman and assess her fetus Diagnose gallbladder disease Evaluate flow in blood vessels Guide a ... For some ultrasound exams, such as of the gallbladder, your doctor may ask that you not eat ...

  11. Efficacy of percutaneous pigtail catheters for thoracostomy at bedside

    PubMed Central

    Penupolu, Sudheer; Flores, David

    2012-01-01

    Objective Given the potential morbidity of traditional chest tube insertion, use of pigtail is desirable. The purpose of this case series is to determine the efficacy of bedside pigtail thoracostomy catheters in Adult population by using bedside ultrasound by the pulmonologists. Methods It is a retrospective case series, which describes the importance of bedside pigtail catheters placements for emergent symptomatic relief for the patients. Predicting a successful drainage, procedure is a complex and multifactorial process based on size, location, character and configuration of the abscess. Results Our experience shows that the use of standard size (7-8.5 F) pigtail catheters is usually very successful in draining of the pleural fluids. Less time consumption, lower cost and bedside technique makes it superior to conventional chest tube placement in many aspects. Conclusions Percutaneous pigtail catheters are useful in the drainage of pleural fluids. The pigtail catheters can be placed successful at bedside by the pulmonologists under ultrasound guidance with minimal complications and marked clinical improvement. The cost effectives of this procedure over the conventional chest tube placement, makes this procedure more desirable in most of the hospital settings. PMID:22754668

  12. Ultrasound Velocity Measurement in a Liquid Metal Electrode.

    PubMed

    Perez, Adalberto; Kelley, Douglas H

    2015-08-05

    A growing number of electrochemical technologies depend on fluid flow, and often that fluid is opaque. Measuring the flow of an opaque fluid is inherently more difficult than measuring the flow of a transparent fluid, since optical methods are not applicable. Ultrasound can be used to measure the velocity of an opaque fluid, not only at isolated points, but at hundreds or thousands of points arrayed along lines, with good temporal resolution. When applied to a liquid metal electrode, ultrasound velocimetry involves additional challenges: high temperature, chemical activity, and electrical conductivity. Here we describe the experimental apparatus and methods that overcome these challenges and allow the measurement of flow in a liquid metal electrode, as it conducts current, at operating temperature. Temperature is regulated within ±2 °C using a Proportional-Integral-Derivative (PID) controller that powers a custom-built furnace. Chemical activity is managed by choosing vessel materials carefully and enclosing the experimental setup in an argon-filled glovebox. Finally, unintended electrical paths are carefully prevented. An automated system logs control settings and experimental measurements, using hardware trigger signals to synchronize devices. This apparatus and these methods can produce measurements that are impossible with other techniques, and allow optimization and control of electrochemical technologies like liquid metal batteries.

  13. Ultrasound Velocity Measurement in a Liquid Metal Electrode

    PubMed Central

    Perez, Adalberto; Kelley, Douglas H.

    2015-01-01

    A growing number of electrochemical technologies depend on fluid flow, and often that fluid is opaque. Measuring the flow of an opaque fluid is inherently more difficult than measuring the flow of a transparent fluid, since optical methods are not applicable. Ultrasound can be used to measure the velocity of an opaque fluid, not only at isolated points, but at hundreds or thousands of points arrayed along lines, with good temporal resolution. When applied to a liquid metal electrode, ultrasound velocimetry involves additional challenges: high temperature, chemical activity, and electrical conductivity. Here we describe the experimental apparatus and methods that overcome these challenges and allow the measurement of flow in a liquid metal electrode, as it conducts current, at operating temperature. Temperature is regulated within ±2 °C using a Proportional-Integral-Derivative (PID) controller that powers a custom-built furnace. Chemical activity is managed by choosing vessel materials carefully and enclosing the experimental setup in an argon-filled glovebox. Finally, unintended electrical paths are carefully prevented. An automated system logs control settings and experimental measurements, using hardware trigger signals to synchronize devices. This apparatus and these methods can produce measurements that are impossible with other techniques, and allow optimization and control of electrochemical technologies like liquid metal batteries. PMID:26273726

  14. Statistical shape modeling based renal volume measurement using tracked ultrasound

    NASA Astrophysics Data System (ADS)

    Pai Raikar, Vipul; Kwartowitz, David M.

    2017-03-01

    Autosomal dominant polycystic kidney disease (ADPKD) is the fourth most common cause of kidney transplant worldwide accounting for 7-10% of all cases. Although ADPKD usually progresses over many decades, accurate risk prediction is an important task.1 Identifying patients with progressive disease is vital to providing new treatments being developed and enable them to enter clinical trials for new therapy. Among other factors, total kidney volume (TKV) is a major biomarker predicting the progression of ADPKD. Consortium for Radiologic Imaging Studies in Polycystic Kidney Disease (CRISP)2 have shown that TKV is an early, and accurate measure of cystic burden and likely growth rate. It is strongly associated with loss of renal function.3 While ultrasound (US) has proven as an excellent tool for diagnosing the disease; monitoring short-term changes using ultrasound has been shown to not be accurate. This is attributed to high operator variability and reproducibility as compared to tomographic modalities such as CT and MR (Gold standard). Ultrasound has emerged as one of the standout modality for intra-procedural imaging and with methods for spatial localization has afforded us the ability to track 2D ultrasound in physical space which it is being used. In addition to this, the vast amount of recorded tomographic data can be used to generate statistical shape models that allow us to extract clinical value from archived image sets. In this work, we aim at improving the prognostic value of US in managing ADPKD by assessing the accuracy of using statistical shape model augmented US data, to predict TKV, with the end goal of monitoring short-term changes.

  15. Phased-array ultrasound technology enhances accuracy of dual frequency ultrasound measurements - towards improved ultrasound bone diagnostics.

    PubMed

    Linder, Hans; Malo, Markus K H; Liukkonen, Jukka; Jurvelin, Jukka S; Töyräs, Juha

    2016-08-01

    Overlying soft tissues attenuate ultrasound backscattered from bone, complicating diagnostics of osteoporosis at the most important fracture sites. Dual-frequency ultrasound technique (DFUS) has been proposed to solve this problem through determination of thickness and composition of overlying soft tissue. This study applies DFUS technique for the first time with a phased-array transducer to investigate if the thickness of two interfering layers (oil and water) can be accurately determined in a variety of configurations. Results indicate that DFUS may be used with phased-array ultrasound systems, making them a suitable combination to consider in future development of clinical in vivo ultrasound methodologies.

  16. Panoramic ultrasound to measure in vivo tendo Achilles strain.

    PubMed

    Stokes, Oliver M; Theobald, Peter S; Pugh, Neil D; Nokes, Leonard D M

    2010-10-01

    The tendo Achilles (TA) is a tendon very susceptible to injury. Biomechanical methodologies for exploring tendon strain are limited, however, as they are typically performed in vitro or by indirectly measuring the displacement of reference markers. By using panoramic ultrasound, this study reports a novel approach to acquire direct, in vivo tendon extension data. Sonographic scans were acquired between two in vivo landmarks following a consistent pathway along the long axis of the distal TA. Ten subjects were scanned with an unloaded tendon and then when resisting a range of loads. Tendon cross-sectional area was measured following coronal scans of the TA in three subjects, allowing for calculation and plotting of stress versus strain. Coefficients of variation were also calculated to measure the reliability and robustness of the protocol. Data from all ten subjects were found to fit with classic tendon force versus extension trend. The stress versus strain plot indicated that the wavy collagen fibers were fully straightened at 4% to 6% strain, which is comparable to results reported in other studies. The Young's modulus of 0.5 to 2.1 GPa also compared favorably to published data. Coefficients of variation indicated that the protocol was repeatable, although the technique for measuring cross-sectional area could be improved. As the reported data is comparable to previous invasive and in vitro studies, we believe sports medicine specialists and orthopaedic surgeons can utilize panoramic ultrasound to directly measure in vivo tendon strain.

  17. Ultrasound measurement of transcranial distance during head-down tilt

    NASA Technical Reports Server (NTRS)

    Torikoshi, S.; Wilson, M. H.; Ballard, R. E.; Watenpaugh, D. E.; Murthy, G.; Yost, W. T.; Cantrell, J. H.; Chang, D. S.; Hargens, A. R.

    1995-01-01

    Exposure to microgravity elevates blood pressure and flow in the head, which may increase intracranial volume (ICV) and intracranial pressure (ICP). Rhesus monkeys exposed to simulated microgravity in the form of 6 degree head-down tilt (HDT) experience elevated ICP. With humans, twenty-four hours of 6 degree HDT bed rest increases cerebral blood flow velocity relative to pre-HDT upright posture. Humans exposed to acute 6 degree HDT experiments increased ICP, measured with the tympanic membrane displacement (TMD) technique. Other studies suggest that increased ICP in humans and cats causes measurable cranial bone movement across the sagittal suture. Due to the slightly compliant nature of the cranium, elevation of the ICP will increase ICV and transcranial distance. Currently, several non-invasive approaches to monitor ICP are being investigated. Such techniques include TMD and modal analysis of the skull. TMD may not be reliable over a large range of ICP and neither method is capable of measuring the small changes in pressure. Ultrasound, however, may reliably measure small distance changes that accompany ICP fluctuations. The purpose of our study was to develop and evaluate an ultrasound technique to measure transcranial distance changes during HDT.

  18. Validation of a novel ultrasound measurement of achilles tendon length.

    PubMed

    Barfod, Kristoffer Weisskirchner; Riecke, Anja Falk; Boesen, Anders; Hansen, Philip; Maier, Jens Friedrich; Døssing, Simon; Troelsen, Anders

    2015-11-01

    A clinically applicable and accurate method for measuring Achilles tendon length is needed to investigate the influence of elongation of the Achilles tendon after acute rupture. The purpose of this study was to develop and validate an ultrasonographic (US) length measurement of the Achilles tendon-aponeurosis complex. Both legs of 19 non-injured subjects were examined by magnetic resonance imaging (MRI) and US. The length from calcaneus to the medial head of m. Gastrocnemius was measured by three independent US examiners. Repeated US measurements were performed and compared to MRI measurements. Intra-rater and inter-rater reliability and the agreement between MRI and US were determined. Data were evaluated using the intraclass correlation coefficient (ICC), the standard error of the measurement (SEM) and the minimal detectable change (MDC). Intra-rater reliability of US assessment showed no significant differences between test days: ICC 0.96, SEM 4 mm and MDC 10 mm. Inter-rater reliability showed a systematic difference between US observers of 2-5 mm (p = 0.001-0.036); ICC 0.97, SEM 3 mm and MDC 9 mm. MRI measurements were on average 4 mm longer than US (p = 0.001). The novel ultrasound measurement showed good reliability and accuracy. For comparison between groups of non-injured subjects differences of more than 4 mm can be detected. For repeated assessment of individual subjects differences of more than 10 mm can be detected. The measurement needs to be further assessed in the setting of acute Achilles tendon rupture. This new ultrasound measurement might allow for length measurement of ruptured Achilles tendons in the acute and chronic state after rupture. II.

  19. Diagnostic image quality in gynaecological ultrasound: Who should measure it, what should we measure and how?

    PubMed

    Cantin, Peter; Knapp, Karen

    2014-02-01

    Assessment of diagnostic image quality in gynaecological ultrasound is an important aspect of imaging department quality assurance. This may be addressed through audit, but who should undertake the audit, what should be measured and how, remains contentious. The aim of this study was to identify whether peer audit is a suitable method of assessing the diagnostic quality of gynaecological ultrasound images. Nineteen gynaecological ultrasound studies were independently assessed by six sonographers utilising a pilot version of an audit tool. Outcome measures were levels of inter-rater agreement using different data collection methods (binary scores, Likert scale, continuous scale), effect of ultrasound study difficulty on study score and whether systematic differences were present between reviewers of different clinical grades and length of experience. Inter-rater agreement ranged from moderate to good depending on the data collection method. A continuous scale gave the highest level of inter-rater agreement with an intra-class correlation coefficient of 0.73. A strong correlation (r = 0.89) between study difficulty and study score was yielded. Length of clinical experience between reviewers had no effect on the audit scores, but individuals of a higher clinical grade gave significantly lower scores than those of a lower grade (p = 0.04). Peer audit is a promising tool in the assessment of ultrasound image quality. Continuous scales seem to be the best method of data collection implying a strong element of heuristically driven decision making by reviewing ultrasound practitioners.

  20. Diagnostic image quality in gynaecological ultrasound: Who should measure it, what should we measure and how?

    PubMed Central

    Knapp, Karen

    2013-01-01

    Assessment of diagnostic image quality in gynaecological ultrasound is an important aspect of imaging department quality assurance. This may be addressed through audit, but who should undertake the audit, what should be measured and how, remains contentious. The aim of this study was to identify whether peer audit is a suitable method of assessing the diagnostic quality of gynaecological ultrasound images. Nineteen gynaecological ultrasound studies were independently assessed by six sonographers utilising a pilot version of an audit tool. Outcome measures were levels of inter-rater agreement using different data collection methods (binary scores, Likert scale, continuous scale), effect of ultrasound study difficulty on study score and whether systematic differences were present between reviewers of different clinical grades and length of experience. Inter-rater agreement ranged from moderate to good depending on the data collection method. A continuous scale gave the highest level of inter-rater agreement with an intra-class correlation coefficient of 0.73. A strong correlation (r = 0.89) between study difficulty and study score was yielded. Length of clinical experience between reviewers had no effect on the audit scores, but individuals of a higher clinical grade gave significantly lower scores than those of a lower grade (p = 0.04). Peer audit is a promising tool in the assessment of ultrasound image quality. Continuous scales seem to be the best method of data collection implying a strong element of heuristically driven decision making by reviewing ultrasound practitioners. PMID:27433192

  1. Improved self- and external assessment of the clinical abilities of medical students through structured improvement measures in an internal medicine bedside course

    PubMed Central

    Fünger, S. M.; Lesevic, H.; Rosner, S.; Ott, I.; Berberat, P.; Nikendei, C.; Sonne, C.

    2016-01-01

    Background: Bedside courses are of outstanding importance when training medical students. The fact that less and less teaching is taking place nowadays at the patient's bedside makes it all the more important that the available time be put to effective use. The aim of this study was to check whether structured improvement measures in the course (scripts, lecturer briefing, e-learning cases) would improve the abilities of the students on the basis of a subjective self-assessment as well as an external assessment by the lecturers with respect to clinical abilities. Methods: Bedside teaching takes place in the fourth study year in the Medical Clinics of the TU Munich. Both students and lecturers had the chance to hand in an anonymous, quantitative self- and external assessment of the clinical abilities of the students (German grading system) after every course date. This assessment took place online in the three categories "Medical history & examination", "Diagnosis" and "Therapy". An overall period of four semesters, each with 6 course dates, was investigated. After two of the total of four semesters in the study, the course was changed by introducing scripts, lecturer briefing as well as interactive e-learning cases. The self- and external assessment was compared both within the semester (date 1-3: A; date 4-6: B), during the course as well as before and after introducing the improvement measures ("before" (T0): SS 2012, SS 2013, "after" (T1): WS 2013/2014, SS 2014). Results: There was a significant improvement in one's own abilities on the basis of the self-assessment within each semester when comparing the first (A) and the last (B) course dates. Moreover, there was a significant improvement in the performances in all three categories when T0 was compared with T1, from both the point of view of the students ("Medical history & examination": T0 =2.5±0.9, T1=2.2±0.7, pp<0.001; "Diagnosis" T0=3.1±1.0, T1=2.8 ±0.9, pp<0.001; "Therapy": T0=3.8±1.3, T1=3.5±1.2, pp

  2. Measuring shape complexity of breast lesions on ultrasound images

    NASA Astrophysics Data System (ADS)

    Yang, Wei; Zhang, Su; Chen, Yazhu; Li, Wenying; Chen, Yaqing

    2008-03-01

    The shapes of malignant breast tumors are more complex than the benign lesions due to their nature of infiltration into surrounding tissues. We investigated the efficacy of shape features and presented a method using polygon shape complexity to improve the discrimination of benign and malignant breast lesions on ultrasound. First, 63 lesions (32 benign and 31 malignant) were segmented by K-way normalized cut with the priori rules on the ultrasound images. Then, the shape measures were computed from the automatically extracted lesion contours. A polygon shape complexity measure (SCM) was introduced to characterize the complexity of breast lesion contour, which was calculated from the polygonal model of lesion contour. Three new statistical parameters were derived from the local integral invariant signatures to quantify the local property of the lesion contour. Receiver operating characteristic (ROC) analysis was carried on to evaluate the performance of each individual shape feature. SCM outperformed the other shape measures, the area under ROC curve (AUC) of SCM was 0.91, and the sensitivity of SCM could reach 0.97 with the specificity 0.66. The measures of shape feature and margin feature were combined in a linear discriminant classifier. The resubstitution and leave-one-out AUC of the linear discriminant classifier were 0.94 and 0.92, respectively. The distinguishing ability of SCM showed that it could be a useful index for the clinical diagnosis and computer-aided diagnosis to reduce the number of unnecessary biopsies.

  3. Concentration measurement of yeast suspensions using high frequency ultrasound backscattering.

    PubMed

    Elvira, Luis; Vera, Pedro; Cañadas, Francisco Jesús; Shukla, Shiva Kant; Montero, Francisco

    2016-01-01

    This work proposes the use of an ultrasound based technique to measure the concentration of yeasts in liquid suspension. This measurement was achieved by the detection and quantification of ultrasonic echoes backscattered by the cells. More specifically, the technique was applied to the detection and quantification of Saccharomyces cerevisiae. A theoretical approach was proposed to get the average density and sound speed of the yeasts, which were found to be 1116 kg/m(3) and 1679 m/s, respectively. These parameters were needed to model the waves backscattered by each single cell. A pulse-echo arrangement working around 50 MHz, being able to detect echoes from single yeasts was used to characterize experimentally yeast solutions from 10(2) to 10(7)cells/ml. The Non-negative Matrix Factorization denoising technique was applied for data analysis. This technique required a previous learning of the spectral patterns of the echoes reflected from yeasts in solution and the base noise from the liquid medium. Comparison between pulse correlation (without denoising) and theoretical and experimental pattern learning was made to select the best signal processing. A linear relation between ultrasound output and concentration was obtained with correlation coefficient R(2)=0.996 for the experimental learning. Concentrations from 10(4) to 10(7)cells/ml were detected above the base noise. These results show the viability of using the ultrasound backscattering technique to detect yeasts and measure their concentration in liquid cultures, improving the sensitivity obtained using spectrophotometric methods by one order of magnitude.

  4. Ultrasound backscatter measurements of intact human proximal femurs--relationships of ultrasound parameters with tissue structure and mineral density.

    PubMed

    Malo, M K H; Töyräs, J; Karjalainen, J P; Isaksson, H; Riekkinen, O; Jurvelin, J S

    2014-07-01

    Ultrasound reflection and backscatter parameters are related to the mechanical and structural properties of bone in vitro. However, the potential of ultrasound reflection and backscatter measurements has not been tested with intact human proximal femurs ex vivo. We hypothesize that ultrasound backscatter can be measured from intact femurs and that the measured backscattered signal is associated with cadaver age, bone mineral density (BMD) and trabecular bone microstructure. In this study, human femoral bones of 16 male cadavers (47.0±16.1 years, range: 21-77 years) were investigated using pulse-echo ultrasound measurements at the femoral neck in the antero-posterior direction and at the trochanter major in the anteroposterior and lateromedial directions. Recently introduced ultrasound backscatter parameters, independent of cortical thickness, e.g., time slope of apparent integrated backscatter (TSAB) and mean of the backscatter difference technique (MBD) were obtained and compared with the structural properties of trabecular bone samples, extracted from the locations of ultrasound measurements. Moreover, more conventional backscatter parameters, e.g., apparent integrated backscatter (AIB) and frequency slope of apparent integrated backscatter (FSAB) were analyzed. Bone mineral density of the intact femurs was evaluated using dual energy X-ray absorptiometry (DXA). AIB and MDB measured from the femoral neck correlated significantly (p<0.01) with the neck BMD (R2=0.44 and 0.45), cadaver age (R2=0.61 and 0.41) and several structural parameters, e.g., bone volume fraction (R2=0.33 and 0.39, p<0.05 and p<0.01), respectively. To conclude, ultrasound backscatter parameters, measured from intact proximal femurs, are significantly related (p<0.05) to structural properties and mineral density of trabecular bone.

  5. Measurement of Mechanical Properties of Soft Tissue with Ultrasound Vibrometry

    NASA Astrophysics Data System (ADS)

    Nenadich, I.; Bernal, M.; Greenleaf, J. F.

    The cardiovascular diseases atherosclerosis, coronary artery disease, hypertension and heart failure have been related to stiffening of vessels and myocardium. Noninvasive measurements of mechanical properties of cardiovascular tissue would facilitate detection and treatment of disease in early stages, thus reducing mortality and possibly reducing cost of treatment. While techniques capable of measuring tissue elasticity have been reported, the knowledge of both elasticity and viscosity is necessary to fully characterize mechanical properties of soft tissues. In this article, we summarize the Shearwave Dispersion Ultrasound Vibrometry (SDUV) method developed by our group and report on advances made in characterizing stiffness of large vessels and myocardium. The method uses radiation forceFadiation force to excite shear waves in soft tissue and pulse echo ultrasound to measure the motion. The speed of propagation of shear waves at different frequencies is used to generate dispersions curves for excised porcine left-ventricular free-wall myocardium and carotid arteries. An antisymmetric Lamb wave model was fitted to the LV myocardium dispersion curves to obtain elasticity and viscosity moduli. The results suggest that the speed of shear wave propagation in four orthogonal directions on the surface of the excised myocardium is similar. These studies show that the SDUV method has potential for clinical application in noninvasive quantification of elasticity and viscosity of vessels and myocardium.

  6. Objective measurement of accommodative biometric changes using ultrasound biomicroscopy

    PubMed Central

    Ramasubramanian, Viswanathan; Glasser, Adrian

    2015-01-01

    PURPOSE To demonstrate that ultrasound biomicroscopy (UBM) can be used for objective quantitative measurements of anterior segment accommodative changes. SETTING College of Optometry, University of Houston, Houston, Texas, USA. DESIGN Prospective cross-sectional study. METHODS Anterior segment biometric changes in response to 0 to 6.0 diopters (D) of accommodative stimuli in 1.0 D steps were measured in eyes of human subjects aged 21 to 36 years. Imaging was performed in the left eye using a 35 MHz UBM (Vumax) and an A-scan ultrasound (A-5500) while the right eye viewed the accommodative stimuli. An automated Matlab image-analysis program was developed to measure the biometry parameters from the UBM images. RESULTS The UBM-measured accommodative changes in anterior chamber depth (ACD), lens thickness, anterior lens radius of curvature, posterior lens radius of curvature, and anterior segment length were statistically significantly (P < .0001) linearly correlated with accommodative stimulus amplitudes. Standard deviations of the UBM-measured parameters were independent of the accommodative stimulus demands (ACD 0.0176 mm, lens thickness 0.0294 mm, anterior lens radius of curvature 0.3350 mm, posterior lens radius of curvature 0.1580 mm, and anterior segment length 0.0340 mm). The mean difference between the A-scan and UBM measurements was −0.070 mm for ACD and 0.166 mm for lens thickness. CONCLUSIONS Accommodating phakic eyes imaged using UBM allowed visualization of the accommodative response, and automated image analysis of the UBM images allowed reliable, objective, quantitative measurements of the accommodative intraocular biometric changes. PMID:25804579

  7. Reliability of the inter-rectus distance measured by palpation. Comparison of palpation and ultrasound measurements.

    PubMed

    Mota, Patrícia; Pascoal, Augusto Gil; Sancho, Fátima; Carita, Ana Isabel; Bø, Kari

    2013-08-01

    An increased inter-rectus distance (IRD) is a common condition in late pregnancy and in the postnatal period. The condition is difficult to assess. Palpation is the most commonly used method to assess IRD. To date there is scant knowledge of intra and inter-tester reliability of palpation to measure IRD and how palpation compares with ultrasound measurements. The aims of this study were: 1) evaluate intra and inter-rater reliability of abdominal palpation; 2) validate abdominal palpation of IRD measurements using ultrasound imaging as a reference. Two physiotherapists (PTs) conducted the palpation study in random order, blinded to each other's assessments. IRD was measured as finger widths between the two rectus abdominis (RA) muscles. Ultrasound images were recorded at the same locations as the palpation test. A blinded investigator measured the IRD offline. Palpation showed good intra-rater reliability between days expressed by a weighted Kappa (wK) higher than 0.7 for both physiotherapists, and moderate inter-rater reliability (wK = 0.534). Ultrasound was found to be more responsive for differences in IRD compared with values obtained by palpation. The intra-rater reliability was higher than the inter-rater reliability. Besides the difference in experience with palpation testing between the PTs, this result may be due to differences in finger width and/or the subjective interpretation of abdominal soft-tissues pressure. Ultrasound measures are highly sensitive to changes of IRD, which is not possible to replicate by palpation assessment using a finger width scale. Palpation has sufficient reliability to be used in clinical practice. However, ultrasound is a more accurate and valid method and is recommended in future research of IRD.

  8. The Use of Ultrasound to Measure Dislocation Density

    NASA Astrophysics Data System (ADS)

    Barra, Felipe; Espinoza-González, Rodrigo; Fernández, Henry; Lund, Fernando; Maurel, Agnès; Pagneux, Vincent

    2015-08-01

    Dislocations are at the heart of the plastic behavior of materials yet they are very difficult to probe experimentally. Lack of a practical nonintrusive measuring tool for, say, dislocation density, seriously hampers modeling efforts, as there is little guidance from data in the form of quantitative measurements, as opposed to visualizations. Dislocation density can be measured using transmission electron microscopy (TEM) and x-ray diffraction (XRD). TEM can directly show the strain field around dislocations, which allows for the counting of the number of dislocations in a micrograph. This procedure is very laborious and local, since samples have to be very small and thin, and is difficult to apply when dislocation densities are high. XRD relies on the broadening of diffraction peaks induced by the loss of crystalline order induced by the dislocations. This broadening can be very small, and finding the dislocation density involves unknown parameters that have to be fitted with the data. Both methods, but especially TEM, are intrusive, in the sense that samples must be especially treated, mechanically and chemically. A nonintrusive method to measure dislocation density would be desirable. This paper reviews recent developments in the theoretical treatment of the interaction of an elastic wave with dislocations that have led to formulae that relate dislocation density to quantities that can be measured with samples of cm size. Experimental results that use resonant ultrasound spectroscopy supporting this assertion are reported, and the outlook for the development of a practical, nonintrusive, method to measure dislocation density is discussed.

  9. Measurement of Angle Kappa Using Ultrasound Biomicroscopy and Corneal Topography.

    PubMed

    Yeo, Joon Hyung; Moon, Nam Ju; Lee, Jeong Kyu

    2017-06-01

    To introduce a new convenient and accurate method to measure the angle kappa using ultrasound biomicroscopy (UBM) and corneal topography. Data from 42 eyes (13 males and 29 females) were analyzed in this study. The angle kappa was measured using Orbscan II and calculated with UBM and corneal topography. The angle kappa of the dominant eye was compared with measurements by Orbscan II. The mean patient age was 36.4 ± 13.8 years. The average angle kappa measured by Orbscan II was 3.98° ± 1.12°, while the average angle kappa calculated with UBM and corneal topography was 3.19° ± 1.15°. The difference in angle kappa measured by the two methods was statistically significant (p < 0.001). The two methods showed good reliability (intraclass correlation coefficient, 0.671; p < 0.001). Bland-Altman plots were used to demonstrate the agreement between the two methods. We designed a new method using UBM and corneal topography to calculate the angle kappa. This method is convenient to use and allows for measurement of the angle kappa without an expensive device.

  10. Non-Invasive Measurement of Pulsatile Intracranial Pressures Using Ultrasound

    NASA Technical Reports Server (NTRS)

    Ueno, Toshiaki; Ballard, Richard E.; Shuer, Lawrence M.; Cantrell, John H.; Cantrell, John H.; Hargens, Alan R.

    1997-01-01

    Early detection of elevated intracranial pressure (ICP) will aid clinical decision-making for head trauma, brain tumor and other cerebrovascular diseases. Conventional methods, however, require surgical procedures which take time and are accompanied by increased risk of infection. Accordingly we have developed and refined a new ultrasound device to measure skull movements which are known to occur in conjunction with altered ICP. The principle of this device is based upon pulse phase locked loop (PPLL), which enables us to detect changes in distance on the order of microns between an ultrasound transducer on one side of the skull and the opposite inner surface of the cranium. The present study was designed to verify this measurement technique in cadavera. Transcranial distance was increased in steps of 10 mmHg from zero to 50 mmHg by saline infusion into the lateral ventricle of two cadavera. In separate experiments, pulsations of ICP with the amplitudes of zero to 2 mmHg were generated by rhythmic injections of saline using a syringe. When the ICP was stepwise increased from zero to 50 mmHg, transcranial distance increased in proportion with the ICP increase (y=12 x - 76, r=0.938), where y is changes in transcranial distance in microns and x is ICP in mmHg. In the data recorded while ICP pulsations were generated, fast Fourier transform analysis demonstrated that cranial pulsations were clearly associated with ICP pulsations. The results indicate that changes in transcranial distance is linearly correlated with those in ICP, and also that the PPLL device has sufficient sensitivity to detect transcranial pulsations which occur in association with the cardiac cycle. By analyzing the magnitude of cranial pulsations, we may be able to estimate the pressure-volume index in the cranium. As a result, estimates of intracranial compliance may be possible by using the PPLL device. Further studies are necessary in normal subjects and patients.

  11. Non-Invasive Measurement of Pulsatile Intracranial Pressures Using Ultrasound

    NASA Technical Reports Server (NTRS)

    Ueno, Toshiaki; Ballard, Richard E.; Shuer, Lawrence M.; Cantrell, John H.; Cantrell, John H.; Hargens, Alan R.

    1997-01-01

    Early detection of elevated intracranial pressure (ICP) will aid clinical decision-making for head trauma, brain tumor and other cerebrovascular diseases. Conventional methods, however, require surgical procedures which take time and are accompanied by increased risk of infection. Accordingly we have developed and refined a new ultrasound device to measure skull movements which are known to occur in conjunction with altered ICP. The principle of this device is based upon pulse phase locked loop (PPLL), which enables us to detect changes in distance on the order of microns between an ultrasound transducer on one side of the skull and the opposite inner surface of the cranium. The present study was designed to verify this measurement technique in cadavera. Transcranial distance was increased in steps of 10 mmHg from zero to 50 mmHg by saline infusion into the lateral ventricle of two cadavera. In separate experiments, pulsations of ICP with the amplitudes of zero to 2 mmHg were generated by rhythmic injections of saline using a syringe. When the ICP was stepwise increased from zero to 50 mmHg, transcranial distance increased in proportion with the ICP increase (y=12 x - 76, r=0.938), where y is changes in transcranial distance in microns and x is ICP in mmHg. In the data recorded while ICP pulsations were generated, fast Fourier transform analysis demonstrated that cranial pulsations were clearly associated with ICP pulsations. The results indicate that changes in transcranial distance is linearly correlated with those in ICP, and also that the PPLL device has sufficient sensitivity to detect transcranial pulsations which occur in association with the cardiac cycle. By analyzing the magnitude of cranial pulsations, we may be able to estimate the pressure-volume index in the cranium. As a result, estimates of intracranial compliance may be possible by using the PPLL device. Further studies are necessary in normal subjects and patients.

  12. Ultrasound measured renal length versus low dose CT volume in predicting single kidney glomerular filtration rate.

    PubMed

    Widjaja, E; Oxtoby, J W; Hale, T L; Jones, P W; Harden, P N; McCall, I W

    2004-09-01

    Ultrasound measured renal length and CT measured renal volume are potential surrogate markers for single kidney glomerular filtration rate (SKGFR). The aims of this study are to determine: (1) the repeatability of ultrasound measured length and low radiation dose spiral CT measured volume; (2) the relationship between renal length and volume; and (3) whether length and/or volume is a predictor of SKGFR. 69 patients with suspected renal artery stenosis underwent ultrasound renal length measurement, CT evaluation of renal volume and assessment of SKGFR. 40 patients had ultrasound measurement of length and CT evaluation of volume performed twice on two separate visits. 25 patients also had ultrasound measured renal parenchymal thickness and area. The region of interest was drawn around the kidneys and a threshold set to subtract renal peripelvic fat and renal pelvis. The volume from each slice was summed to obtain the total volume for each kidney. The limits of agreement for ultrasound measured renal length were -1.6 cm to 1.52 cm and that for CT renal volume were -33 ml to 32 ml. There was significant correlation between ultrasound measured length and CT volume (r=0.74, p<0.01). Volume was a better predictor of SKGFR (r(2)=0.57) than length (r(2)=0.48). The combined parameters of ultrasound measured length, area and parenchymal thickness were a better predictor of volume (r(2)=0.81) and SKGFR (r(2)=0.58) than ultrasound measured length on its own. The low dose CT technique was reasonably reproducible and renal volume measurements correlate better with SKGFR than length. Ultrasound predictions of renal volume and SKGFR can be improved by incorporating cross-sectional area and parenchymal thickness. Further investigation is required to refine our low dose CT technique.

  13. Quantitative measurement of ultrasound pressure field by optical phase contrast method and acoustic holography

    NASA Astrophysics Data System (ADS)

    Oyama, Seiji; Yasuda, Jun; Hanayama, Hiroki; Yoshizawa, Shin; Umemura, Shin-ichiro

    2016-07-01

    A fast and accurate measurement of an ultrasound field with various exposure sequences is necessary to ensure the efficacy and safety of various ultrasound applications in medicine. The most common method used to measure an ultrasound pressure field, that is, hydrophone scanning, requires a long scanning time and potentially disturbs the field. This may limit the efficiency of developing applications of ultrasound. In this study, an optical phase contrast method enabling fast and noninterfering measurements is proposed. In this method, the modulated phase of light caused by the focused ultrasound pressure field is measured. Then, a computed tomography (CT) algorithm used to quantitatively reconstruct a three-dimensional (3D) pressure field is applied. For a high-intensity focused ultrasound field, a new approach that combines the optical phase contrast method and acoustic holography was attempted. First, the optical measurement of focused ultrasound was rapidly performed over the field near a transducer. Second, the nonlinear propagation of the measured ultrasound was simulated. The result of the new approach agreed well with that of the measurement using a hydrophone and was improved from that of the phase contrast method alone with phase unwrapping.

  14. Learning evaluation of ultrasound image segmentation using combined measures

    NASA Astrophysics Data System (ADS)

    Fang, Mengjie; Luo, Yongkang; Ding, Mingyue

    2016-03-01

    Objective evaluation of medical image segmentation is one of the important steps for proving its validity and clinical applicability. Although there are many researches presenting segmentation methods on medical image, while with few studying the evaluation methods on their results, this paper presents a learning evaluation method with combined measures to make it as close as possible to the clinicians' judgment. This evaluation method is more quantitative and precise for the clinical diagnose. In our experiment, the same data sets include 120 segmentation results of lumen-intima boundary (LIB) and media-adventitia boundary (MAB) of carotid ultrasound images respectively. And the 15 measures of goodness method and discrepancy method are used to evaluate the different segmentation results alone. Furthermore, the experimental results showed that compared with the discrepancy method, the accuracy with the measures of goodness method is poor. Then, by combining with the measures of two methods, the average accuracy and the area under the receiver operating characteristic (ROC) curve of 2 segmentation groups are higher than 93% and 0.9 respectively. And the results of MAB are better than LIB, which proved that this novel method can effectively evaluate the segmentation results. Moreover, it lays the foundation for the non-supervised segmentation evaluation system.

  15. Comparative Performance Assessment of Point-of-Care Testing Devices for Measuring Glucose and Ketones at the Patient Bedside

    PubMed Central

    Ceriotti, Ferruccio; Kaczmarek, Ewa; Guerra, Elena; Mastrantonio, Fabrizio; Lucarelli, Fausto; Valgimigli, Francesco; Mosca, Andrea

    2014-01-01

    Background: Point-of-care (POC) testing devices for monitoring glucose and ketones can play a key role in the management of dysglycemia in hospitalized diabetes patients. The accuracy of glucose devices can be influenced by biochemical changes that commonly occur in critically ill hospital patients and by the medication prescribed. Little is known about the influence of these factors on ketone POC measurements. The aim of this study was to assess the analytical performance of POC hospital whole-blood glucose and ketone meters and the extent of glucose interference factors on the design and accuracy of ketone results. Methods: StatStrip glucose/ketone, Optium FreeStyle glucose/ketone, and Accu-Chek Performa glucose were also assessed and results compared to a central laboratory reference method. The analytical evaluation was performed according to Clinical and Laboratory Standards Institute (CLSI) protocols for precision, linearity, method comparison, and interference. Results: The interferences assessed included acetoacetate, acetaminophen, ascorbic acid, galactose, maltose, uric acid, and sodium. The accuracies of both Optium ketone and glucose measurements were significantly influenced by varying levels of hematocrit and ascorbic acid. StatStrip ketone and glucose measurements were unaffected by the interferences tested with exception of ascorbic acid, which reduced the higher level ketone value. The accuracy of Accu-Chek glucose measurements was affected by hematocrit, by ascorbic acid, and significantly by galactose. The method correlation assessment indicated differences between the meters in compliance to ISO 15197 and CLSI 12-A3 performance criteria. Conclusions: Combined POC glucose/ketone methods are now available. The use of these devices in a hospital setting requires careful consideration with regard to the selection of instruments not sensitive to hematocrit variation and presence of interfering substances. PMID:25519295

  16. Comparative performance assessment of point-of-care testing devices for measuring glucose and ketones at the patient bedside.

    PubMed

    Ceriotti, Ferruccio; Kaczmarek, Ewa; Guerra, Elena; Mastrantonio, Fabrizio; Lucarelli, Fausto; Valgimigli, Francesco; Mosca, Andrea

    2015-03-01

    Point-of-care (POC) testing devices for monitoring glucose and ketones can play a key role in the management of dysglycemia in hospitalized diabetes patients. The accuracy of glucose devices can be influenced by biochemical changes that commonly occur in critically ill hospital patients and by the medication prescribed. Little is known about the influence of these factors on ketone POC measurements. The aim of this study was to assess the analytical performance of POC hospital whole-blood glucose and ketone meters and the extent of glucose interference factors on the design and accuracy of ketone results. StatStrip glucose/ketone, Optium FreeStyle glucose/ketone, and Accu-Chek Performa glucose were also assessed and results compared to a central laboratory reference method. The analytical evaluation was performed according to Clinical and Laboratory Standards Institute (CLSI) protocols for precision, linearity, method comparison, and interference. The interferences assessed included acetoacetate, acetaminophen, ascorbic acid, galactose, maltose, uric acid, and sodium. The accuracies of both Optium ketone and glucose measurements were significantly influenced by varying levels of hematocrit and ascorbic acid. StatStrip ketone and glucose measurements were unaffected by the interferences tested with exception of ascorbic acid, which reduced the higher level ketone value. The accuracy of Accu-Chek glucose measurements was affected by hematocrit, by ascorbic acid, and significantly by galactose. The method correlation assessment indicated differences between the meters in compliance to ISO 15197 and CLSI 12-A3 performance criteria. Combined POC glucose/ketone methods are now available. The use of these devices in a hospital setting requires careful consideration with regard to the selection of instruments not sensitive to hematocrit variation and presence of interfering substances. © 2014 Diabetes Technology Society.

  17. IGBT-based kilovoltage pulsers for ultrasound measurement applications.

    PubMed

    Gammell, Paul M; Harris, Gerald R

    2003-12-01

    Two high-voltage pulser designs are presented that offer advantages in some ultrasound measurement applications, such as driving thick ultrasonic source transducers used for broadband measurements of attenuation or hydrophone frequency response and directivity. The pulsers use integrated gate bipolar transistors (IGBTs) as the switching devices, and in one design an output voltage pulse is produced that has a peak amplitude nearly twice that of the supply voltage. The pulsers are inexpensive and relatively easy to construct. The power supply need only provide the average current to charge the capacitors, as opposed to the much higher peak pulse current. With a 1200 V supply and a pulse repetition frequency of 200 Hz, the nondoubling and doubling pulsers provided peak voltages of greater than 1100 V and 2200 V, respectively, into loads ranging from 50 omega to 500 omega. For a 50 omega load, slewing rates of 38 V/ns and 23 V/ns were measured for the nondoubling and doubling pulsers, respectively. For a 500 omega load these values were 56 V/ns and 36 V/ns.

  18. Pharmacogenomics: bench to bedside.

    PubMed

    Weinshilboum, Richard; Wang, Liewei

    2004-09-01

    Pharmacogenetics is the study of the role of inheritance in inter-individual variation in drug response. Since its origins in the mid-twentieth century, a major driving force in pharmacogenetics research has been the promise of individualized drug therapy to maximize drug efficacy and minimize drug toxicity. In recent years, the convergence of advances in pharmacogenetics with rapid developments in human genomics has resulted in the evolution of pharmacogenetics into pharmacogenomics, and led to increasing enthusiasm for the 'translation' of this evolving discipline into clinical practice. Here, we briefly summarize the development of pharmacogenetics and pharmacogenomics, and then discuss the key factors that have had an influence on - and will continue to affect - the translation of pharmacogenomics from the research bench to the bedside, highlighting the challenges that need to be addressed to achieve this goal.

  19. The Bedside Sherlock Holmes

    PubMed Central

    Fitzgerald, Faith T.; Tierney, Lawrence M.

    1982-01-01

    There are a multitude of diagnostic clues contained in clothing, jewelry, possessions and other extracorporeal attachments that each patient brings with him or her to a physician. Because of the emphasis of classic physical diagnosis on the body of a patient solely, and because of modern practices that may have patients stripped of these articles before the first encounter with their physician, these interesting and enlightening findings are often ignored or unavailable. Incorporation of these observations into the panoply of data obtained from the history and physical examination will enhance both the accuracy and adventure of differential diagnosis. Such exercises in observation, moreover, may increase general physical diagnostic skills as well as enliven bedside rounds. PMID:7135953

  20. The bedside Sherlock Holmes.

    PubMed

    Fitzgerald, F T; Tierney, L M

    1982-08-01

    There are a multitude of diagnostic clues contained in clothing, jewelry, possessions and other extracorporeal attachments that each patient brings with him or her to a physician. Because of the emphasis of classic physical diagnosis on the body of a patient solely, and because of modern practices that may have patients stripped of these articles before the first encounter with their physician, these interesting and enlightening findings are often ignored or unavailable. Incorporation of these observations into the panoply of data obtained from the history and physical examination will enhance both the accuracy and adventure of differential diagnosis. Such exercises in observation, moreover, may increase general physical diagnostic skills as well as enliven bedside rounds.

  1. Optical resonant ultrasound spectroscopy for fluid properties measurement.

    PubMed

    Hale, T; Asaki, T

    2001-07-01

    The properties of fluids are studied using unusually small containment spherical resonators. Proper identification of resonant fluid signatures allows determination of pressure and density of the internal gas with great accuracy using an appropriate equation of state (EOS). Low noise and high sensitivity detection of vibration are critical parameters to characterizing the contained gas when its pressure approaches 1 atm or less. The benefits of using spherical resonators to determine fluid properties are discussed, and some example calculations of sound speed are presented. In addition to measuring fluids, a comparative experimental approach is taken to explore and, eventually, to optimize vibration detection. In the experiments, two detection methods, a contact piezoelectric transducer (PZT) device and a non-contact optical device, are compared simultaneously and quantitatively. This is done in a unique manner without change in vibration coupling to the sample between tests. A commercially available resonant ultrasound spectroscopy system is used as the contact system, while another commercial device (used as the non-contact vibration detector) combined with the same excitation source (used in the contact system) comprises the other system. The non-contact detector is an optical interferometric receiver that provides adaptation to optically rough surfaces and high sensitivity to acoustic displacements through optical interference in photorefractive GaAs. Both vibration detection systems are compared with particular emphasis on displacement sensitivity, frequency response, and noise level. Furthermore, the results from comparing detection modalities are presented, and their effects on fluid properties measurement are discussed.

  2. Noninvasive measurement of pulsatile intracranial pressure using ultrasound

    NASA Technical Reports Server (NTRS)

    Ueno, T.; Ballard, R. E.; Shuer, L. M.; Cantrell, J. H.; Yost, W. T.; Hargens, A. R.

    1998-01-01

    The present study was designed to validate our noninvasive ultrasonic technique (pulse phase locked loop: PPLL) for measuring intracranial pressure (ICP) waveforms. The technique is based upon detecting skull movements which are known to occur in conjunction with altered intracranial pressure. In bench model studies, PPLL output was highly correlated with changes in the distance between a transducer and a reflecting target (R2 = 0.977). In cadaver studies, transcranial distance was measured while pulsations of ICP (amplitudes of zero to 10 mmHg) were generated by rhythmic injections of saline. Frequency analyses (fast Fourier transformation) clearly demonstrate the correspondence between the PPLL output and ICP pulse cycles. Although theoretically there is a slight possibility that changes in the PPLL output are caused by changes in the ultrasonic velocity of brain tissue, the decreased amplitudes of the PPLL output as the external compression of the head was increased indicates that the PPLL output represents substantial skull movement associated with altered ICP. In conclusion, the ultrasound device has sufficient sensitivity to detect transcranial pulsations which occur in association with the cardiac cycle. Our technique makes it possible to analyze ICP waveforms noninvasively and will be helpful for understanding intracranial compliance and cerebrovascular circulation.

  3. Thermoacoustic sensor for ultrasound power measurements and ultrasonic equipment calibration.

    PubMed

    Fay, B; Rinker, M; Lewin, P A

    1994-01-01

    This paper describes a thermoacoustic sensor developed for measurements of the acoustic power and calibration of ultrasonic transducers in the medical imaging and nondestructive testing frequency range. It is shown that the equilibrium temperature produced by ultrasound absorption in an absorbing material and detected by a copper-constantan thermocouple is proportional to the square of the current applied to the acoustic source. It is also demonstrated that the simultaneous measurement of this current and the corresponding equilibrium temperature at a given frequency allow the transmitting current sensitivity of the acoustic source to be calculated. The sensor thus provides a useful and low-cost alternative to the expensive calibration methods such as those based on the reciprocity technique, the planar scanning technique and the radiation force balance. The principles of the sensor's operation are outlined and its construction and characteristics are described. Experimental data in the frequency range of 1-8 MHz are presented and the advantages and disadvantages of the sensor are discussed.

  4. Transverse Ultrasound Measurements in 4He Single Crystals

    NASA Astrophysics Data System (ADS)

    Syshchenko, O.; Beamish, J.

    2008-02-01

    Recently, Kim and Chan (Science 305:1941, 2004; Phys. Rev. Lett. 97:115302, 2006) have reported an anomalous decoupling transition of solid 4He in a torsional oscillator measurement, and interpret their results as evidence for non-classical rotational inertia and a possible supersolid phase of 4He. The detailed nature and properties of such a “supersolid” state in 4He are still far from being clear, although there are clues from experiments involving 3He impurities, different sample cell geometries, annealing effects and grain boundary flow. Defects produced during crystal growth or deformation (e.g. dislocations) may affect supersolidity, or even produce it, and they are expected to have significant impact on the elastic properties of the solid. The supersolid fraction could also decouple from the lattice and produce a decrease in the transverse sound speed. We have begun the experiments in this laboratory to study such effects, measuring the velocity and attenuation of transverse ultrasound at 10 MHz in 4He single crystals grown at constant pressure.

  5. Measurement of a PAGAT gel dosimeter by ultrasound computed tomography

    NASA Astrophysics Data System (ADS)

    Khoei, S.; Trapp, J. V.; Langton, C. M.

    2013-06-01

    In this work we used a 3D quantitative CT ultrasound imaging system to characterise polymer gel dosimeters. The system comprised of two identical 5 MHz 128 element phased-array ultrasound transducers co-axially aligned and submerged in water as a coupling agent. Rotational and translational movement of the gel dosimeter sample between the transducers were performed using a robotic arm. Ultrasound signals were generated and received using an Olympus Omniscan unit. Dose sensitivity of attenuation and time of flight ultrasonic parameters were assessed using this system.

  6. Measurement of muscle architecture concurrently with muscle hardness using ultrasound strain elastography.

    PubMed

    Chino, Kentaro; Akagi, Ryota; Dohi, Michiko; Takahashi, Hideyuki

    2014-09-01

    The B-mode ultrasound image that can measure muscle architecture is displayed side by side with the ultrasound strain elastogram that can assess muscle hardness. Consequently, muscle architecture can be measured concurrently with muscle hardness using ultrasound strain elastography. To demonstrate the measurement of muscle architecture concurrently with muscle hardness using ultrasound strain elastography. Concurrent measurements of muscle architectural parameters (muscle thickness, pennation angle, and fascicle length) and muscle hardness of the medial gastrocnemius were performed with ultrasound strain elastography. Separate measurements of the muscle architectural parameters were also performed for use as reference values for the concurrent measurements. Both types of measurements were performed twice at 20° dorsiflexion, neutral position, and 30° plantar flexion. Coefficients of variance of the muscle architectural parameters obtained from the concurrent measurements (≤7.6%) were significantly higher than those obtained from the separate measurements (≤2.4%) (all P < 0.05). Intraclass correlation coefficients of the architectural parameters were lower in the concurrent measurements (≥0.74) than in the separate measurements (≥0.97). However, there were no significant differences in any muscle architectural parameters between the concurrent and separate measurements (all P > 0.05). The use of ultrasound strain elastography for the concurrent measurement of muscle architecture and muscle hardness is feasible. © The Foundation Acta Radiologica 2013 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

  7. Design of a Thermoacoustic Sensor for Low Intensity Ultrasound Measurements Based on an Artificial Neural Network

    PubMed Central

    Xing, Jida; Chen, Jie

    2015-01-01

    In therapeutic ultrasound applications, accurate ultrasound output intensities are crucial because the physiological effects of therapeutic ultrasound are very sensitive to the intensity and duration of these applications. Although radiation force balance is a benchmark technique for measuring ultrasound intensity and power, it is costly, difficult to operate, and compromised by noise vibration. To overcome these limitations, the development of a low-cost, easy to operate, and vibration-resistant alternative device is necessary for rapid ultrasound intensity measurement. Therefore, we proposed and validated a novel two-layer thermoacoustic sensor using an artificial neural network technique to accurately measure low ultrasound intensities between 30 and 120 mW/cm2. The first layer of the sensor design is a cylindrical absorber made of plexiglass, followed by a second layer composed of polyurethane rubber with a high attenuation coefficient to absorb extra ultrasound energy. The sensor determined ultrasound intensities according to a temperature elevation induced by heat converted from incident acoustic energy. Compared with our previous one-layer sensor design, the new two-layer sensor enhanced the ultrasound absorption efficiency to provide more rapid and reliable measurements. Using a three-dimensional model in the K-wave toolbox, our simulation of the ultrasound propagation process demonstrated that the two-layer design is more efficient than the single layer design. We also integrated an artificial neural network algorithm to compensate for the large measurement offset. After obtaining multiple parameters of the sensor characteristics through calibration, the artificial neural network is built to correct temperature drifts and increase the reliability of our thermoacoustic measurements through iterative training about ten seconds. The performance of the artificial neural network method was validated through a series of experiments. Compared to our previous

  8. Design of a Thermoacoustic Sensor for Low Intensity Ultrasound Measurements Based on an Artificial Neural Network.

    PubMed

    Xing, Jida; Chen, Jie

    2015-06-23

    In therapeutic ultrasound applications, accurate ultrasound output intensities are crucial because the physiological effects of therapeutic ultrasound are very sensitive to the intensity and duration of these applications. Although radiation force balance is a benchmark technique for measuring ultrasound intensity and power, it is costly, difficult to operate, and compromised by noise vibration. To overcome these limitations, the development of a low-cost, easy to operate, and vibration-resistant alternative device is necessary for rapid ultrasound intensity measurement. Therefore, we proposed and validated a novel two-layer thermoacoustic sensor using an artificial neural network technique to accurately measure low ultrasound intensities between 30 and 120 mW/cm2. The first layer of the sensor design is a cylindrical absorber made of plexiglass, followed by a second layer composed of polyurethane rubber with a high attenuation coefficient to absorb extra ultrasound energy. The sensor determined ultrasound intensities according to a temperature elevation induced by heat converted from incident acoustic energy. Compared with our previous one-layer sensor design, the new two-layer sensor enhanced the ultrasound absorption efficiency to provide more rapid and reliable measurements. Using a three-dimensional model in the K-wave toolbox, our simulation of the ultrasound propagation process demonstrated that the two-layer design is more efficient than the single layer design. We also integrated an artificial neural network algorithm to compensate for the large measurement offset. After obtaining multiple parameters of the sensor characteristics through calibration, the artificial neural network is built to correct temperature drifts and increase the reliability of our thermoacoustic measurements through iterative training about ten seconds. The performance of the artificial neural network method was validated through a series of experiments. Compared to our previous

  9. Comparison of portable and conventional ultrasound imaging in spinal curvature measurement

    NASA Astrophysics Data System (ADS)

    Yan, Christina; Tabanfar, Reza; Kempston, Michael; Borschneck, Daniel; Ungi, Tamas; Fichtinger, Gabor

    2016-03-01

    PURPOSE: In scoliosis monitoring, tracked ultrasound has been explored as a safer imaging alternative to traditional radiography. The use of ultrasound in spinal curvature measurement requires identification of vertebral landmarks, but bones have reduced visibility in ultrasound imaging and high quality ultrasound machines are often expensive and not portable. In this work, we investigate the image quality and measurement accuracy of a low cost and portable ultrasound machine in comparison to a standard ultrasound machine in scoliosis monitoring. METHODS: Two different kinds of ultrasound machines were tested on three human subjects, using the same position tracker and software. Spinal curves were measured in the same reference coordinate system using both ultrasound machines. Lines were defined by connecting two symmetric landmarks identified on the left and right transverse process of the same vertebrae, and spinal curvature was defined as the transverse process angle between two such lines, projected on the coronal plane. RESULTS: Three healthy volunteers were scanned by both ultrasound configurations. Three experienced observers localized transverse processes as skeletal landmarks and obtained transverse process angles in images obtained from both ultrasounds. The mean difference per transverse process angle measured was 3.00 +/-2.1°. 94% of transverse processes visualized in the Sonix Touch were also visible in the Telemed. Inter-observer error in the Telemed was 4.5° and 4.3° in the Sonix Touch. CONCLUSION: Price, convenience and accessibility suggest the Telemed to be a viable alternative in scoliosis monitoring, however further improvements in measurement protocol and image noise reduction must be completed before implementing the Telemed in the clinical setting.

  10. Damage Detection in Concrete Using Diffuse Ultrasound Measurements

    NASA Astrophysics Data System (ADS)

    Deroo, Frederik; Jacobs, Laurence J.; Kim, Jin-Yeon; Qu, Jianmin; Sabra, Karim

    2010-02-01

    Heterogeneities in concrete caused by the random distribution of aggregate in the cement-paste matrix lead to strong scattering of ultrasonic waves at wavelengths on the order of the aggregate. Use of these high frequencies is necessary to detect damage at an early stage, something that is not possible with conventional ultrasonic methods. The ultrasound energy density in that regime can be described by the diffusion equation. The objective of this research is to develop a quantitative understanding of the effects of additional scattering sources, such as small cracks in the cement-paste matrix, on the parameters of the diffusion equation; these parameters are the diffusion and the dissipation coefficients. Applying diffusion theory, the diffusivity and dissipation coefficients are experimentally determined as functions of frequency using ultrasonic waves. The cuboid shaped samples employed are made of a Portland cement-paste matrix and regular aggregate, such as gravel and sand. The results provide a basic understanding of repeatability and consistency of diffusion measurements, with an emphasis on the nondestructive evaluation of concrete.

  11. Improving nurse-physician teamwork through interprofessional bedside rounding.

    PubMed

    Henkin, Stanislav; Chon, Tony Y; Christopherson, Marie L; Halvorsen, Andrew J; Worden, Lindsey M; Ratelle, John T

    2016-01-01

    Teamwork between physicians and nurses has a positive association with patient satisfaction and outcomes, but perceptions of physician-nurse teamwork are often suboptimal. To improve nurse-physician teamwork in a general medicine inpatient teaching unit by increasing face-to-face communication through interprofessional bedside rounds. From July 2013 through October 2013, physicians (attendings and residents) and nurses from four general medicine teams in a single nursing unit participated in bedside rounding, which involved the inclusion of nurses in morning rounds with the medicine teams at the patients' bedside. Based on stakeholder analysis and feedback, a checklist for key patient care issues was created and utilized during bedside rounds. To assess the effect of bedside rounding on nurse-physician teamwork, a survey of selected items from the Safety Attitudes Questionnaire (SAQ) was administered to participants before and after the implementation of bedside rounds. The number of pages to the general medicine teams was also measured as a marker of physician-nurse communication. Participation rate in bedside rounds across the four medicine teams was 58%. SAQ response rates for attendings, residents, and nurses were 36/36 (100%), 73/73 (100%), and 32/73 (44%) prior to implementation of bedside rounding and 36 attendings (100%), 72 residents (100%), and 14 (19%) nurses after the implementation of bedside rounding, respectively. Prior to bedside rounding, nurses provided lower teamwork ratings (percent agree) than residents and attendings on all SAQ items; but after the intervention, the difference remained significant only on SAQ item 2 ("In this clinical area, it is not difficult to speak up if I perceive a problem with patient care", 64% for nurses vs 79% for residents vs 94% for attendings, P=0.02). Also, resident responses improved on SAQ item 1 ("Nurse input is well received in this area", 62% vs 82%, P=0.01). Increasing face-to-face communication through

  12. Voltammetric measurements of the transient and steady mass transport effects of ultrasound

    NASA Astrophysics Data System (ADS)

    Cooper, Evan Lloyd

    Ultrasound is useful in a variety of industrial and medical processes. Many studies have emphasized the phenomena of cavitation as the primary mechanism for the effects of ultrasound. Ultrasound gives rise to other effects such as acoustic streaming and field induced fluid motion, and these effects also create useful actions. This dissertation focuses upon understanding the basic nature of ultrasound as an interfacial mass transport mechanism. Electrochemistry provides an excellent set of methodologies for studying the interfacial effects of ultrasound. Electrochemical measurements are highly sensitive to mass transport effects at the solid electrode-liquid electrolyte interface. This study employs established techniques that probe mass transport in electrochemical systems, including dual electrode systems such as the ring-disk electrode and the interdigitated array electrode. A chemiluminescent probe molecule, luminol, 3- aminophthalhydrazide, is used to provide visual imaging of the ultrasonic field. This process has been previously used to examine the relative effects of ultrasonic cavitation in a reaction vessel, but the use of this probe molecule in a sonoelectrochemical reaction system is novel. The high transport rates possible with ultrasound enable precise electroanalytical measurements with limits of detection on the order of 10-7 mol/L. It is observed that the characteristically oscillating portion of the current signal in sonoelectrochemical measurements depends on the analyte concentration. This dependence arises from a modulated mass transport effect, and this study makes a heretofore unreported application of this modulation to an electroanalytical measurement. The effects of electrolyte viscosity, ultrasound intensity, and signal filtering on this modulated signal are reported. Cavitation is only one of the factors affecting interfacial mass transport by ultrasound. Collection efficiency and electrochemiluminescence studies show that acoustic

  13. Measuring Femoral Torsion In Vivo Using Freehand 3-D Ultrasound Imaging.

    PubMed

    Passmore, Elyse; Pandy, Marcus G; Graham, H Kerr; Sangeux, Morgan

    2016-02-01

    Despite variation in bone geometry, muscle and joint function is often investigated using generic musculoskeletal models. Patient-specific bone geometry can be obtained from computerised tomography, which involves ionising radiation, or magnetic resonance imaging (MRI), which is costly and time consuming. Freehand 3-D ultrasound provides an alternative to obtain bony geometry. The purpose of this study was to determine the accuracy and repeatability of 3-D ultrasound in measuring femoral torsion. Measurements of femoral torsion were performed on 10 healthy adults using MRI and 3-D ultrasound. Measurements of femoral torsion from 3-D ultrasound were, on average, smaller than those from MRI (mean difference = 1.8°; 95% confidence interval: -3.9°, 7.5°). MRI and 3-D ultrasound had Bland and Altman repeatability coefficients of 3.1° and 3.7°, respectively. Accurate measurements of femoral torsion were obtained with 3-D ultrasound offering the potential to acquire patient-specific bone geometry for musculoskeletal modelling. Three-dimensional ultrasound is non-invasive and relatively inexpensive and can be integrated into gait analysis.

  14. An automated in vitro model for the evaluation of ultrasound modalities measuring myocardial deformation

    PubMed Central

    2010-01-01

    Background Echocardiography is the method of choice when one wishes to examine myocardial function. Qualitative assessment of the 2D grey scale images obtained is subjective, and objective methods are required. Speckle Tracking Ultrasound is an emerging technology, offering an objective mean of quantifying left ventricular wall motion. However, before a new ultrasound technology can be adopted in the clinic, accuracy and reproducibility needs to be investigated. Aim It was hypothesized that the collection of ultrasound sample data from an in vitro model could be automated. The aim was to optimize an in vitro model to allow for efficient collection of sample data. Material & Methods A tissue-mimicking phantom was made from water, gelatin powder, psyllium fibers and a preservative. Sonomicrometry crystals were molded into the phantom. The solid phantom was mounted in a stable stand and cyclically compressed. Peak strain was then measured by Speckle Tracking Ultrasound and sonomicrometry. Results We succeeded in automating the acquisition and analysis of sample data. Sample data was collected at a rate of 200 measurement pairs in 30 minutes. We found good agreement between Speckle Tracking Ultrasound and sonomicrometry in the in vitro model. Best agreement was 0.83 ± 0.70%. Worst agreement was -1.13 ± 6.46%. Conclusions It has been shown possible to automate a model that can be used for evaluating the in vitro accuracy and precision of ultrasound modalities measuring deformation. Sonomicrometry and Speckle Tracking Ultrasound had acceptable agreement. PMID:20822532

  15. Ultrasound measurements of cavitation bubble radius for femtosecond laser-induced breakdown in water.

    PubMed

    Aglyamov, Salavat R; Karpiouk, Andrei B; Bourgeois, Frederic; Ben-Yakar, Adela; Emelianov, Stanislav Y

    2008-06-15

    A recently developed ultrasound technique is evaluated by measuring the behavior of a cavitation bubble that is induced in water by a femtosecond laser pulse. The passive acoustic emission during optical breakdown is used to estimate the location of the cavitation bubble's origin. In turn, the position of the bubble wall is defined based on the active ultrasonic pulse-echo signal. The results suggest that the developed ultrasound technique can be used for quantitative measurements of femtosecond laser-induced microbubbles.

  16. Combined Thoracic Ultrasound Assessment during a Successful Weaning Trial Predicts Postextubation Distress.

    PubMed

    Silva, Stein; Ait Aissa, Dalinda; Cocquet, Pierre; Hoarau, Lucille; Ruiz, Jean; Ferre, Fabrice; Rousset, David; Mora, Michel; Mari, Arnaud; Fourcade, Olivier; Riu, Béatrice; Jaber, Samir; Bataille, Bénoît

    2017-10-01

    Recent studies suggest that isolated sonographic assessment of the respiratory, cardiac, or neuromuscular functions in mechanically ventilated patients may assist in identifying patients at risk of postextubation distress. The aim of the present study was to prospectively investigate the value of an integrated thoracic ultrasound evaluation, encompassing bedside respiratory, cardiac, and diaphragm sonographic data in predicting postextubation distress. Longitudinal ultrasound data from 136 patients who were extubated after passing a trial of pressure support ventilation were measured immediately after the start and at the end of this trial. In case of postextubation distress (31 of 136 patients), an additional combined ultrasound assessment was performed while the patient was still in acute respiratory failure. We applied machine-learning methods to improve the accuracy of the related predictive assessments. Overall, integrated thoracic ultrasound models accurately predict postextubation distress when applied to thoracic ultrasound data immediately recorded before the start and at the end of the trial of pressure support ventilation (learning sample area under the curve: start, 0.921; end, 0.951; test sample area under the curve: start, 0.972; end, 0.920). Among integrated thoracic ultrasound data, the recognition of lung interstitial edema and the increased telediastolic left ventricular pressure were the most relevant predictive factors. In addition, the use of thoracic ultrasound appeared to be highly accurate in identifying the causes of postextubation distress. The decision to attempt extubation could be significantly assisted by an integrative, dynamic, and fully bedside ultrasonographic assessment of cardiac, lung, and diaphragm functions.

  17. An ergonomic, instrumented ultrasound probe for 6-axis force/torque measurement.

    PubMed

    Gilbertson, Matthew W; Anthony, Brian W

    2013-01-01

    An ergonomic, instrumented ultrasound probe has been developed for medical imaging applications. The device, which fits compactly in the hand of sonographers and permits rapid attachment & removal of the ultrasound probe, measures ultrasound probe-to-patient contact forces and torques in all six axes. The device was used to measure contact forces and torques applied by ten professional sonographers on five patients during thirty-six abdominal exams. Of the three contact forces, those applied along the probe axis were found to be largest, averaging 7.0N. Measurement noise was quantified for each axis, and found to be small compared with the axial force. Understanding the range of forces applied during ultrasound imaging enables the design of more accurate robotic imaging systems and could also improve understanding of the correlation between contact force and sonographer fatigue and injury.

  18. Comparison of central corneal thickness measurements using ultrasound pachymetry, ultrasound biomicroscopy, and the Artemis-2 VHF scanner in normal eyes

    PubMed Central

    Al-Farhan, Haya M; Al-Otaibi, Wafa’a Majed

    2012-01-01

    Purpose To compare the precision of central corneal thickness (CCT) measurements taken with the handheld ultrasound pachymeter (USP), ultrasound biomicroscopy (UBM), and the Artemis-2 very high frequency ultrasound scanner (VHFUS) on normal subjects. Design Prospective study. Methods One eye from each of 61 normal subjects was randomly selected for this study. The measurements of the CCT were taken with the USP, VHFUS, and UBM. Results were compared statistically using repeated-measures analysis of variance (ANOVA), Pearson’s correlation coefficient, and limits of agreement. Results The average CCT (± standard deviation) was 530.1 ± 30.5 μm, 554.9 ± 31.7 μm, and 559.5 ± 30.7 μm for UBM, VHFUS, and USP respectively. The intraobserver repeatability analyses of variance are not significant for USP, UBM, and VHFUS. P-values were 0.17, 0.19, and 0.37 respectively. Repeated-measures ANOVA showed a significant difference between the three different methods of measuring CCT (P = 0.0001). The ANOVA test revealed no statistically significant difference between USP and VHFUS (P > 0.05), yet statistical significant differences with UBM versus USP and UBM versus VHFUS (P < 0.001). There were high correlations between the three instruments (P < 0.0001). The mean differences (and upper/lower limits of agreement) for CCT measurements were 29.4 ± 14.3 (2.7/56), 4.6 ± 8.6 (−14.7/23.8), and −24.8 ± 13.1 (−50.4/0.8) for USP versus UBM, USP versus VHFUS, and UBM versus VHFUS, respectively. Conclusion The UBM produces CCT measurements that vary significantly from those returned by the USP and the VHFUS, suggesting that the UBM may not be used interchangeably with either equipment for monitoring the CCT in the clinical setting. PMID:22848145

  19. Comparison of central corneal thickness measurements using ultrasound pachymetry, ultrasound biomicroscopy, and the Artemis-2 VHF scanner in normal eyes.

    PubMed

    Al-Farhan, Haya M; Al-Otaibi, Wafa'a Majed

    2012-01-01

    To compare the precision of central corneal thickness (CCT) measurements taken with the handheld ultrasound pachymeter (USP), ultrasound biomicroscopy (UBM), and the Artemis-2 very high frequency ultrasound scanner (VHFUS) on normal subjects. Prospective study. One eye from each of 61 normal subjects was randomly selected for this study. The measurements of the CCT were taken with the USP, VHFUS, and UBM. Results were compared statistically using repeated-measures analysis of variance (ANOVA), Pearson's correlation coefficient, and limits of agreement. The average CCT (± standard deviation) was 530.1 ± 30.5 μm, 554.9 ± 31.7 μm, and 559.5 ± 30.7 μm for UBM, VHFUS, and USP respectively. The intraobserver repeatability analyses of variance are not significant for USP, UBM, and VHFUS. P-values were 0.17, 0.19, and 0.37 respectively. Repeated-measures ANOVA showed a significant difference between the three different methods of measuring CCT (P = 0.0001). The ANOVA test revealed no statistically significant difference between USP and VHFUS (P > 0.05), yet statistical significant differences with UBM versus USP and UBM versus VHFUS (P < 0.001). There were high correlations between the three instruments (P < 0.0001). The mean differences (and upper/lower limits of agreement) for CCT measurements were 29.4 ± 14.3 (2.7/56), 4.6 ± 8.6 (-14.7/23.8), and -24.8 ± 13.1 (-50.4/0.8) for USP versus UBM, USP versus VHFUS, and UBM versus VHFUS, respectively. The UBM produces CCT measurements that vary significantly from those returned by the USP and the VHFUS, suggesting that the UBM may not be used interchangeably with either equipment for monitoring the CCT in the clinical setting.

  20. [WHEN ULTRASOUND MEETS THE INTERNIST].

    PubMed

    Katz, David; Dadon, Ziv; Zalut, Todd; Avraham Alpert, Evan

    2017-06-01

    Point-of-care ultrasound (POCUS) is an important modality with many advantages. At the Shaare Zedek Medical Centre, we developed a case-based course to teach POCUS to internal medicine residents and attendings. The topics include: "Introduction to Point-of-Care Ultrasound", "Focused Assessment with Sonography of Trauma", "Basic Cardiac, Pulmonary and Vascular Ultrasound", "Rapid Ultrasound in Shock" and "Ultrasound Guided Central Lines". The use of POCUS should aid in rapid diagnosis, decrease complications associated with bed-side procedures, and ultimately improve patient care.

  1. Measurement of Thermal Effects of Doppler Ultrasound: An In Vitro Study

    PubMed Central

    Helmy, Samir; Bader, Yvonne; Koch, Marianne; Tiringer, Denise; Kollmann, Christian

    2015-01-01

    Objective Ultrasound is considered a safe imaging modality and is routinely applied during early pregnancy. However, reservations are expressed concerning the application of Doppler ultrasound in early pregnancy due to energy emission of the ultrasound probe and its conversion to heat. The objective of this study was to evaluate the thermal effects of emitted Doppler ultrasound of different ultrasound machines and probes by means of temperature increase of in-vitro test-media. Methods We investigated the energy-output of 5 vaginal and abdominal probes of 3 ultrasound machines (GE Healthcare, Siemens, Aloka). Two in-vitro test objects were developed at the Center for Medical Physics and Biomedical Engineering, Medical University Vienna (water bath and hydrogel bath). Temperature increase during Doppler ultrasound emission was measured via thermal sensors, which were placed inside the test objects or on the probes’ surface. Each probe was emitting for 5 minutes into the absorbing test object with 3 different TI/MI settings in Spectral Doppler mode. Results During water bath test, temperature increase varied between 0.1 and 1.0°C, depending on probe, setting and focus, and was found highest for spectral Doppler mode alone. Maximum temperature increase was found during the surface heating test, where values up to 2.4°C could be measured within 5 minutes of emission. Conclusions Activation of Doppler ultrasound in the waterbath model causes a significant increase of temperature within one minute. Thermally induced effects on the embryo cannot be excluded when using Doppler ultrasound in early pregnancy. PMID:26302465

  2. Measurement of Thermal Effects of Doppler Ultrasound: An In Vitro Study.

    PubMed

    Helmy, Samir; Bader, Yvonne; Koch, Marianne; Tiringer, Denise; Kollmann, Christian

    2015-01-01

    Ultrasound is considered a safe imaging modality and is routinely applied during early pregnancy. However, reservations are expressed concerning the application of Doppler ultrasound in early pregnancy due to energy emission of the ultrasound probe and its conversion to heat. The objective of this study was to evaluate the thermal effects of emitted Doppler ultrasound of different ultrasound machines and probes by means of temperature increase of in-vitro test-media. We investigated the energy-output of 5 vaginal and abdominal probes of 3 ultrasound machines (GE Healthcare, Siemens, Aloka). Two in-vitro test objects were developed at the Center for Medical Physics and Biomedical Engineering, Medical University Vienna (water bath and hydrogel bath). Temperature increase during Doppler ultrasound emission was measured via thermal sensors, which were placed inside the test objects or on the probes' surface. Each probe was emitting for 5 minutes into the absorbing test object with 3 different TI/MI settings in Spectral Doppler mode. During water bath test, temperature increase varied between 0.1 and 1.0°C, depending on probe, setting and focus, and was found highest for spectral Doppler mode alone. Maximum temperature increase was found during the surface heating test, where values up to 2.4°C could be measured within 5 minutes of emission. Activation of Doppler ultrasound in the waterbath model causes a significant increase of temperature within one minute. Thermally induced effects on the embryo cannot be excluded when using Doppler ultrasound in early pregnancy.

  3. Measurement of neonatal heart rate using handheld Doppler ultrasound.

    PubMed

    Dyson, Amanda; Jeffrey, Michele; Kluckow, Martin

    2017-03-01

    This pilot study aimed to determine whether handheld Doppler ultrasound is feasible and reliable for measuring neonatal heart rate (HR) when compared with ECG. Stable newborns were recruited from the neonatal intensive care unit and postnatal ward between July 2014 and January 2015 at Royal North Shore Hospital, Sydney, Australia. Each newborn had their HR recorded every 15 s over 145 s using four different modalities: ECG, counted audible Doppler (AD) over 10 s, pulse oximetry (PO) and the Doppler display (DD). The correlation and variation between each modality and ECG. 51 newborns with a median gestational age of 38 weeks (27-41) and a mean weight of 2.78 kg (0.82 to 4.76) with a median postnatal age of 3 days (0-87) were studied. There was a mean difference of 0.69 bpm (95% CI -2.9 to +1.5) between AD-HR and ECG-HR with good correlation between modalities (r=0.94, p<0.01). The median time to achieve AD-HR was 3 s (1-45). The mean difference between DD-HR and ECG-HR was 5.37 bpm (95% CI -12.8 to +2.1) with moderate correlation (r=0.37, p=0.04). The mean difference between PO-HR and ECG-HR was 0.49 bpm (95% CI -1.5 to +0.51) with good correlation (r=0.99, p<0.01). The variability between AD-HR and ECG-HR decreased with decreasing weight. AD-HR correlates well with ECG-HR. Further research in the delivery room is recommended before using AD-HR in this area. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

  4. Ultrasound -- Pelvis

    MedlinePlus Videos and Cool Tools

    ... needles are used to extract a sample of cells from organs for laboratory testing. Doppler ultrasound images ... ultrasound, measures the direction and speed of blood cells as they move through vessels. The movement of ...

  5. Ultrasound Elastography: The New Frontier in Direct Measurement of Muscle Stiffness

    PubMed Central

    Brandenburg, Joline E.; Eby, Sarah F.; Song, Pengfei; Zhao, Heng; Brault, Jeffrey S.; Chen, Shigao; An, Kai-Nan

    2014-01-01

    The use of brightness-mode ultrasound and Doppler ultrasound in physical medicine and rehabilitation has increased dramatically. The continuing evolution of ultrasound technology has also produced ultrasound elastography, a cutting-edge technology that can directly measure the mechanical properties of tissue, including muscle stiffness. Its real-time and direct measurements of muscle stiffness can aid the diagnosis and rehabilitation of acute musculoskeletal injuries and chronic myofascial pain. It can also help monitor outcomes of interventions affecting muscle in neuromuscular and musculoskeletal diseases, and it can better inform the functional prognosis. This technology has implications for even broader use of ultrasound in physical medicine and rehabilitation practice, but more knowledge about its uses and limitations is essential to its appropriate clinical implementation. In this review, we describe different ultrasound elastography techniques for studying muscle stiffness, including strain elastography, acoustic radiation force impulse imaging, and shear-wave elastography. We discuss the basic principles of these techniques, including the strengths and limitations of their measurement capabilities. We review the current muscle research, discuss physiatric clinical applications of these techniques, and note directions for future research. PMID:25064780

  6. Ultrasound elastography: the new frontier in direct measurement of muscle stiffness.

    PubMed

    Brandenburg, Joline E; Eby, Sarah F; Song, Pengfei; Zhao, Heng; Brault, Jeffrey S; Chen, Shigao; An, Kai-Nan

    2014-11-01

    The use of brightness-mode ultrasound and Doppler ultrasound in physical medicine and rehabilitation has increased dramatically. The continuing evolution of ultrasound technology has also produced ultrasound elastography, a cutting-edge technology that can directly measure the mechanical properties of tissue, including muscle stiffness. Its real-time and direct measurements of muscle stiffness can aid the diagnosis and rehabilitation of acute musculoskeletal injuries and chronic myofascial pain. It can also help monitor outcomes of interventions affecting muscle in neuromuscular and musculoskeletal diseases, and it can better inform the functional prognosis. This technology has implications for even broader use of ultrasound in physical medicine and rehabilitation practice, but more knowledge about its uses and limitations is essential to its appropriate clinical implementation. In this review, we describe different ultrasound elastography techniques for studying muscle stiffness, including strain elastography, acoustic radiation force impulse imaging, and shear-wave elastography. We discuss the basic principles of these techniques, including the strengths and limitations of their measurement capabilities. We review the current muscle research, discuss physiatric clinical applications of these techniques, and note directions for future research.

  7. Validation of nipple diameter and tongue movement measurements with B-mode ultrasound during breastfeeding.

    PubMed

    McClellan, Holly L; Sakalidis, Vanessa S; Hepworth, Anna R; Hartmann, Peter E; Geddes, Donna T

    2010-11-01

    Infant feeding problems are extremely common during breastfeeding establishment. To objectively assess infant sucking, consistent methods to analyze ultrasound images of the infant's oral cavity are required. We developed and assessed the reliability of an extensive ultrasound measurement protocol by measuring nipple diameter and placement. Midline submental ultrasound scans of 30 term breastfed infants were analyzed by two raters. Nipple diameter, nipple hard-soft palate junction distance and tongue hard-soft palate junction distance were measured on two frames: tongue-up and tongue-down. No evidence of measurement bias was found between raters and inter-rater agreement and consistency scores were high. The changes in nipple diameter and placement were consistent with previous descriptions; however, the diameter of the nipple was not consistent in either position. This method provides objective measurements representative of tongue movement, and further investigation is required to ensure usefulness when examining sucking difficulties.

  8. [Relationship between ultrasound measurements of the median nerve and electrophysiological severity in carpal tunnel syndrome].

    PubMed

    Bueno-Gracia, Elena; Tricás-Moreno, José Miguel; Fanlo-Mazas, Pablo; Malo-Urriés, Miguel; Haddad-Garay, María; Estébanez-de-Miguel, Elena; Hidalgo-García, César; Ruiz-de-Escudero Zapico, Alazne

    2015-11-16

    Ultrasonography is a tool that has advanced a great deal in the diagnosis of neural compressive pathologies, such as carpal tunnel syndrome (CTS). In order to plan the treatment it is important to establish the severity of the pathology, which means that it would be important to know the capacity of ultrasonography to determine the extent to which the median nerve is compromised at this level. To investigate the correlation between ultrasound measurements and electrophysiological severity in patients with CTS. Ultrasound measurements were performed with 59 subjects (97 wrists) who were referred to have an electroneurogram (ENG) due to suspected CTS. According to the ENG, the subjects were classified as healthy, mild, moderate or severe CTS. The relationship between the ultrasound measurements and the results of the ENG were later analysed in terms of their severity. The ROC (receiver operating characteristic) curves were calculated for the optimal cut-off values in each group, taking into account their severity. Both ultrasound measurements showed a correlation with the severity of the CTS determined by ENG. The cross-sectional area of the median nerve in the wrist (CSA-W) showed the highest correlation (r = 0.613). There is a relation between the ultrasound measurements of the median nerve, especially in the CSA-W, and the severity of CTS in the clinical context. These measurements could be used as complementary data to diagnose CTS and to determine its severity.

  9. Validity of Measurement of Shear Modulus by Ultrasound Shear Wave Elastography in Human Pennate Muscle

    PubMed Central

    Miyamoto, Naokazu; Hirata, Kosuke; Kanehisa, Hiroaki; Yoshitake, Yasuhide

    2015-01-01

    Ultrasound shear wave elastography is becoming a valuable tool for measuring mechanical properties of individual muscles. Since ultrasound shear wave elastography measures shear modulus along the principal axis of the probe (i.e., along the transverse axis of the imaging plane), the measured shear modulus most accurately represents the mechanical property of the muscle along the fascicle direction when the probe’s principal axis is parallel to the fascicle direction in the plane of the ultrasound image. However, it is unclear how the measured shear modulus is affected by the probe angle relative to the fascicle direction in the same plane. The purpose of the present study was therefore to examine whether the angle between the principal axis of the probe and the fascicle direction in the same plane affects the measured shear modulus. Shear modulus in seven specially-designed tissue-mimicking phantoms, and in eleven human in-vivo biceps brachii and medial gastrocnemius were determined by using ultrasound shear wave elastography. The probe was positioned parallel or 20° obliquely to the fascicle across the B-mode images. The reproducibility of shear modulus measurements was high for both parallel and oblique conditions. Although there was a significant effect of the probe angle relative to the fascicle on the shear modulus in human experiment, the magnitude was negligibly small. These findings indicate that the ultrasound shear wave elastography is a valid tool for evaluating the mechanical property of pennate muscles along the fascicle direction. PMID:25853777

  10. The measurements of ultrasound parameters on calcaneus by two-sided interrogation techniques

    NASA Astrophysics Data System (ADS)

    Chen, Pei-Jarn; Chen, Tainsong; Lu, Ming-Chang; Yao, Wei-Jen

    2005-06-01

    Recently, ultrasound techniques have become an important alternative in the assessment of osteoporosis. The speed of sound (SOS) and broadband ultrasound attenuation (BUA) on calcaneus are commonly used in an ultrasound densitometer for osteoporosis evaluation. However, the quantitative ultrasound (QUS) parameters provided by a densitometer using most commercial ultrasound instruments are based on the assumption of a fixed bone thickness. Information on bone thickness is a critical factor for accurate estimation of SOS through conventional approaches; yet, the thickness of bone tissue is not available through in vivo measurements and it is almost impossible to obtain the thickness of bone tissue via conventional approaches. Therefore, the SOS measurements will be incorrect. The purpose of this work is to develop a two-sided interrogation technique for the SOS measurements that is less susceptible to bone thickness. The results show that this proposed technique can obtain a better SOS estimation on bone tissue. Using bone phantoms that mimic actual tissue, the validity of the approach is confirmed with measurements showing high accuracy (>99%) and low standard deviation (<0.5%). Finally, the measurements of 14 healthy subjects are also reported. The results show that this technique can provide the bone thickness information to reduce the SOS estimation errors compared with the fixed bone thickness assumption.

  11. A multidimensional investigation of children's /r/ productions: perceptual, ultrasound, and acoustic measures.

    PubMed

    Klein, Harriet B; McAllister Byun, Tara; Davidson, Lisa; Grigos, Maria I

    2013-08-01

    This study explored relationships among perceptual, ultrasound, and acoustic measurements of children's correct and misarticulated /r/ sounds. Longitudinal data documenting changes across these parameters were collected from 2 children who acquired /r/ over a period of intervention and were compared with data from children with typical speech. Participants were 3 children with typical speech, recorded once, and 2 children with /r/ misarticulation, recorded over 7-8 months. The following data from /r/ produced in nonwords were collected: perceptually rated accuracy, ultrasound measures of tongue shape, and F3 - F2 distance. Regression models revealed significant associations among perceptual, ultrasound, and acoustic measures of /r/ accuracy. The inclusion of quantitative tongue-shape measurements improved the match between the ultrasound and perceptual/acoustic data. Perceptually incorrect /r/ productions were found to feature posteriorly located peaked tongue shapes. Of the children who were seen longitudinally, 1 developed a bunched /r/ and 1 demonstrated retroflexion. The children with typical speech also differed in their tongue shapes. Results support the validity of using qualitative and quantitative ultrasound measures to characterize the accuracy of children's /r/ sounds. Clinically, findings suggest that it is important to encourage pharyngeal constriction while allowing children to find the /r/ tongue shape that best fits their individual vocal tract.

  12. A Multidimensional Investigation of Children’s /r/ Productions: Perceptual, Ultrasound, and Acoustic Measures

    PubMed Central

    Klein, Harriet B.; Byun, Tara McAllister; Davidson, Lisa; Grigos, Maria I.

    2014-01-01

    Purpose This study explored relationships among perceptual, ultrasound, and acoustic measurements of children’s correct and misarticulated /r/ sounds. Longitudinal data documenting changes across these parameters were collected from 2 children who acquired /r/ over a period of intervention and were compared with data from children with typical speech. Method Participants were 3 children with typical speech, recorded once, and 2 children with /r/ misarticulation, recorded over 7–8 months. The following data from /r/ produced in nonwords were collected: perceptually rated accuracy, ultrasound measures of tongue shape, and F3 – F2 distance. Results Regression models revealed significant associations among perceptual, ultrasound, and acoustic measures of /r/ accuracy. The inclusion of quantitative tongue-shape measurements improved the match between the ultrasound and perceptual/acoustic data. Perceptually incorrect /r/ productions were found to feature posteriorly located peaked tongue shapes. Of the children who were seen longitudinally, 1 developed a bunched /r/ and 1 demonstrated retroflexion. The children with typical speech also differed in their tongue shapes. Conclusion Results support the validity of using qualitative and quantitative ultrasound measures to characterize the accuracy of children’s /r/ sounds. Clinically, findings suggest that it is important to encourage pharyngeal constriction while allowing children to find the /r/ tongue shape that best fits their individual vocal tract. PMID:23813195

  13. Narrowed beam width in newer ultrasound machines shortens measurements in the lateral direction: fetal measurement charts may be obsolete.

    PubMed

    Økland, I; Bjåstad, T G; Johansen, T F; Gjessing, H K; Grøttum, P; Eik-Nes, S H

    2011-07-01

    Fetal ultrasound measurements are made in axial, lateral and oblique directions. Lateral resolution is influenced by the beam width of the ultrasound system. To improve lateral resolution and image quality, the beam width has been made narrower; consequently, measurements in the lateral direction are affected and apparently made shorter, approaching the true length. The aims of this study were to explore our database to reveal time-dependent shortening of ultrasound measurements made in the lateral direction, and to assess the extent of beam-width changes by comparing beam-width measurements made on old and new ultrasound machines. A total of 41,941 femur length measurements, collected during the time-period 1987-2005, were analyzed, with time as a covariate. Using three ultrasound machines from the 1990s and three newer machines from 2007, we performed 25 series of blinded beam-width measurements on a tissue-mimicking phantom, measuring at depths of 3-8 cm with a 5-MHz transducer. Regression analysis showed time to be a significant covariate. At the same gestational age, femur length measurement was 1.15 (95% CI, 1.08-1.23) mm shorter in the time-period 1999-2005 than in the time-period 1987-1992. Overall, the beam width was 1.08 (95% CI, 0.50-1.65) mm narrower with the new machines than with the old machines. Technical improvements in modern ultrasound machines that have reduced the beam width affect fetal measurements in the lateral direction. This has clinical implications and new measurement charts are needed. Copyright © 2011 ISUOG. Published by John Wiley & Sons, Ltd.

  14. Accuracy of Bedside Paediatric Early Warning System (BedsidePEWS) in a Pediatric Stem Cell Transplant Unit.

    PubMed

    Gawronski, Orsola; Ciofi Degli Atti, Marta L; Di Ciommo, Vincenzo; Cecchetti, Corrado; Bertaina, Alice; Tiozzo, Emanuela; Raponi, Massimiliano

    2016-07-01

    Hospital mortality in children who undergo stem cell transplant (SCT) is high. Early warning scores aim at identifying deteriorating patients and at preventing adverse outcomes. The bedside pediatric early warning system (BedsidePEWS) is a pediatric early warning score based on 7 clinical indicators, ranging from 0 (all indicators within normal ranges for age) to 26. The aim of this case-control study was to assess the performance of BedsidePEWS in identifying clinical deterioration events among children admitted to an SCT unit. Cases were defined as clinical deterioration events; controls were all the other patients hospitalized on the same ward at the time of case occurrence. BedsidePEWS was retrospectively measured at 4-hour intervals in cases and controls 24 hours before an event (T4-T24). We studied 19 cases and 80 controls. The score significantly increased in cases from a median of 4 at T24 to a median of 14 at T4. The proportion of correctly classified cases and controls was >90% since T8. The area under the curve receiver operating characteristic was 0.9. BedsidePEWS is an accurate screening tool to predict clinical deterioration in SCT patients. © 2015 by Association of Pediatric Hematology/Oncology Nurses.

  15. Are portable bladder scanning and real-time ultrasound accurate measures of bladder volume in postnatal women?

    PubMed

    Mathew, S; Horne, A W; Murray, L S; Tydeman, G; McKinley, C A

    2007-08-01

    Real-time ultrasound and portable bladder scanners are commonly used instead of catheterisation to determine bladder volumes in postnatal women but it is not known whether these are accurate. Change in bladder volumes measured by ultrasound and portable scanners were compared with actual voided volume (VV) in 100 postnatal women. The VV was on average 41 ml (CI 29 - 54 ml) higher than that measured by ultrasound, and 33 ml (CI 17 - 48 ml) higher than that measured by portable scanners. Portable scanner volumes were 9 ml (CI -8 - 26 ml) higher than those measured by ultrasound. Neither method is an accurate tool for detecting bladder volume in postnatal women.

  16. Clinical agreement between automated and calculated ultrasound measurements of bladder volume.

    PubMed

    Dudley, N J; Kirkland, M; Lovett, J; Watson, A R

    2003-11-01

    Non-invasive urine volume measurement is an important tool in the management of dysfunctional and neuropathic bladders in children. Ultrasound imaging devices have been used for many years for this purpose. An automated scanner (Bladderscan) is now available and has been recommended by a number of authors, but there is conflicting evidence in the literature regarding the accuracy and appropriate clinical application of the device. We aimed to assess the level of clinical agreement between the two methods. 36 urine volume measurements were made on 11 children using both instruments. Although there was a good correlation between the methods (r=0.97), the clinical agreement was poor (limits of agreement +/-77 ml). 13 voided volumes were directly measured and compared with the difference between pre- and post-void ultrasound measurements. The systematic errors were small but the mean absolute errors were 54 ml and 23 ml, respectively, for the automated and ultrasound imaging methods. If used correctly, ultrasound imaging provides more accurate results and can compete with the cost, convenience and ease of use of the automated method. Low cost, highly portable ultrasound imaging devices are now available and should be used in preference to the Bladderscan.

  17. The use of 2D ultrasound elastography for measuring tendon motion and strain.

    PubMed

    Chernak Slane, Laura; Thelen, Darryl G

    2014-02-07

    The goal of the current study was to investigate the fidelity of a 2D ultrasound elastography method for the measurement of tendon motion and strain. Ultrasound phantoms and ex vivo porcine flexor tendons were cyclically stretched to 4% strain while cine ultrasound radiofrequency (RF) data and video data were simultaneously collected. 2D ultrasound elastography was used to estimate tissue motion and strain from RF data, and surface tissue motion and strain were separately estimated using digital image correlation (DIC). There were strong correlations (R(2)>0.97) between DIC and RF measurements of phantom displacement and strain, and good agreement in estimates of peak phantom strain (DIC: 3.5±0.2%; RF: 3.7±0.1%). For tendon, elastographic estimates of displacement profiles also correlated well with DIC measurements (R(2)>0.92), and exhibited similar estimated peak tendon strain (DIC: 2.6±1.4%; RF: 2.2±1.3%). Elastographic tracking with B-Mode images tended to under-predict peak strain for both the phantom and tendon. This study demonstrates the capacity to use quantitative elastographic techniques to measure tendon displacement and strain within an ultrasound image window. The approach may be extendible to in vivo use on humans, which would allow for the non-invasive analysis of tendon deformation in both normal and pathological states. © 2013 Elsevier Ltd. All rights reserved.

  18. The Use of 2D Ultrasound Elastography for Measuring Tendon Motion and Strain

    PubMed Central

    Slane, Laura Chernak; Thelen, Darryl G.

    2014-01-01

    The goal of the current study was to investigate the fidelity of a 2D ultrasound elastography method for the measurement of tendon motion and strain. Ultrasound phantoms and ex vivo porcine flexor tendons were cyclically stretched to 4% strain while cine ultrasound radiofrequency (RF) data and video data were simultaneously collected. 2D ultrasound elastography was used to estimate tissue motion and strain from RF data, and surface tissue motion and strain were separately estimated using digital image correlation (DIC). There were strong correlations (R2 > 0.97) between DIC and RF measurements of phantom displacement and strain, and good agreement in estimates of peak phantom strain (DIC: 3.5 ± 0.2%; RF: 3.7 ± 0.1%). For tendon, elastographic estimates of displacement profiles also correlated well with DIC measurements (R2 > 0.92), and exhibited similar estimated peak tendon strain (DIC: 2.6 ± 1.4%; RF: 2.2 ± 1.3%). Elastographic tracking with B-Mode images tended to under-predict peak strain for both the phantom and tendon. This study demonstrates the capacity to use quantitative elastographic techniques to measure tendon displacement and strain within an ultrasound image window. The approach may be extendible to in vivo use on humans, which would allow for the non-invasive analysis of tendon deformation in both normal and pathological states. PMID:24388164

  19. Transvaginal ultrasound

    MedlinePlus

    ... Uterine bleeding - transvaginal ultrasound; Menstrual bleeding - transvaginal ultrasound; Infertility - transvaginal ultrasound; Ovarian - transvaginal ultrasound; Abscess - transvaginal ultrasound

  20. Ultrasound pregnancy

    MedlinePlus

    Pregnancy sonogram; Obstetric ultrasonography; Obstetric sonogram; Ultrasound - pregnancy; IUGR - ultrasound; Intrauterine growth - ultrasound; Polyhydramnios - ultrasound; Oligohydramnios - ultrasound; ...

  1. Quantitative Measurement of Highly Focused Ultrasound Pressure Field by Optical Shadowgraph

    NASA Astrophysics Data System (ADS)

    Miyasaka, R.; Harigane, S.; Yoshizawa, S.; Umemura, S.

    2014-06-01

    In the development of medical ultrasound techniques, fast and accurate pressure field measurement is important. The most common method to measure an ultrasound pressure field is mechanically scanning a hydrophone, which takes a long time and might disturb the acoustic field. In this study, we used an optical shadowgraph method. To perform this method quantitatively, it is important to define the optical propagation length precisely. For this purpose, a holographic diffuser was used as the imaging screen. Combined with a computed tomography (CT) algorithm, a pressure field was reconstructed, and the result was compared with that of hydrophone measurement. By using two shadowgraph data from short and long propagation lengths, the pressure field was successfully reconstructed even at a pressure level for high intensity focused ultrasound (HIFU) treatment.

  2. Use of serial ultrasound measures in the study of growth- and breed-related changes of ultrasonic measurements and relationship with carcass measurements in lean cattle breeds.

    PubMed

    Peña, F; Molina, A; Juárez, M; Requena, F; Avilés, C; Santos, R; Domenech, V; Horcada, A

    2014-01-01

    The growth and breed-related changes of rib and rump characteristics in lean beef cattle and the ability of ultrasound to predict carcass traits were investigated. Three hundred bulls from three breeds were scanned monthly (6-7 times) using real-time ultrasound with final scans taken <7 days prior to harvest. The rib and rump ultrasound measurements, except intramuscular fat content, increased (P<0.05) with live weight. Breed affected most of traits. The 12th rib ultrasound measurements showed a weak to high positive correlation (0.131 to 0.976, P>0.05 to P<0.001) with 12th rib measurements in the carcass. Regression equations developed with the ultrasound measurements, explained 97% of the variation in longissimus muscle area, 88% of the variation in fat thickness and 57% of the variation in intramuscular fat content. When last ultrasound scan measurements were excluded from prediction equations, the R(2) significantly decreased. Ultrasound measures "in vivo" are viable options for assessing carcass attributes of lean cattle.

  3. Ultrasound and histological measurements of dividing membrane thickness in twin gestations.

    PubMed

    Bracero, L A; Huff, C; Blitz, M J; Plata, M J; Seybold, D J; Broce, M

    2016-10-27

    To determine how prenatal ultrasound measurements of dividing membrane thickness correlate with postnatal histological measurements and chorionicity in twin gestations. This was a prospective, longitudinal cohort study of twin gestations. Dividing membrane thickness was measured by transabdominal ultrasound, with the insonation beam both parallel and perpendicular to the membrane, in the second or third trimester, depending on when care was established. Ultrasound examinations were performed every 4 weeks following initial assessment until delivery. Measurements of membrane thickness from the first ultrasound examination were compared with histological measurements after delivery. A total of 45 twin pregnancies (32 dichorionic, 13 monochorionic) were included. Mean gestational age at initial ultrasound examination was 24.1 ± 7.3 weeks. Parallel ultrasound measurements of membrane thickness were 1.6 ± 0.8 mm for monochorionic and 2.5 ± 0.9 mm for dichorionic gestations (P = 0.001). Perpendicular ultrasound measurements were 1.6 ± 0.3 mm for monochorionic and 2.2 ± 0.8 mm for dichorionic gestations (P = 0.009). Inter- and intraobserver reliability of ultrasound measurements were 0.847 and 0.950, respectively. Parallel and perpendicular ultrasound measurements correlated better with each other (R = 0.807, P < 0.001) than with histological measurements of membrane thickness (Rparallel  = 0.538, P < 0.001; Rperpendicular  = 0.529, P < 0.001). Receiver-operating characteristics curve analyses to predict histological membrane thickness > 50(th) percentile resulted in an area under the curve (AUC) of 0.828 for parallel (P < 0.001) and 0.874 for perpendicular (P < 0.001) measurements with a cut-off value of 1.9 mm for both approaches. The AUCs for parallel and perpendicular measurements to predict dichorionicity were 0.892 (P < 0.001) and 0.823 (P < 0.001) with cut-off values of 1

  4. A Preponderance of Elastic Properties of Alpha Plutonium Measured Via Resonant Ultrasound Spectroscopy

    SciTech Connect

    Saleh, Tarik A.; Farrow, Adam M.; Freibert, Franz J.

    2012-06-06

    Samples of {alpha} plutonium were fabricated at the Los Alamos National Laboratory's Plutonium Facility. Cylindrical samples were machined from cast pucks. Precision immersion density and resonant ultrasound spectroscopy (RUS) measurements were completed on 27 new samples, yielding elastic moduli measurements. Mechanical tests were performed in compression yielding stress-strain curves as a function of rate, temperature and phase.

  5. Practical experience of using ultrasound flowmeters at the measurement associated petroleum gas

    NASA Astrophysics Data System (ADS)

    Fazlyyyakhmatov, M. G.; Kashapov, N. F.; Khayritonov, Kh A.; Lazarev, D. K.; Lazarev, V. K.

    2015-06-01

    The results of field tests of several ultrasound flowmeters at existing oil and gas extraction objects are given in the paper. Measured medium - associated petroleum gas. This work aims to create a unified system for measuring the amount and parameters of APG in order to reduce operating costs.

  6. Feasibility of Quantitative Ultrasound Measurement of the Heel Bone in People with Intellectual Disabilities

    ERIC Educational Resources Information Center

    Mergler, S.; Lobker, B.; Evenhuis, H. M.; Penning, C.

    2010-01-01

    Low bone mineral density (BMD) and fractures are common in people with intellectual disabilities (ID). Reduced mobility in case of motor impairment and the use of anti-epileptic drugs contribute to the development of low BMD. Quantitative ultrasound (QUS) measurement of the heel bone is a non-invasive and radiation-free method for measuring bone…

  7. Feasibility of Quantitative Ultrasound Measurement of the Heel Bone in People with Intellectual Disabilities

    ERIC Educational Resources Information Center

    Mergler, S.; Lobker, B.; Evenhuis, H. M.; Penning, C.

    2010-01-01

    Low bone mineral density (BMD) and fractures are common in people with intellectual disabilities (ID). Reduced mobility in case of motor impairment and the use of anti-epileptic drugs contribute to the development of low BMD. Quantitative ultrasound (QUS) measurement of the heel bone is a non-invasive and radiation-free method for measuring bone…

  8. The Use of B-Mode Ultrasound for Measuring Subcutaneous Fat Thickness on the Upper Arms.

    ERIC Educational Resources Information Center

    Weiss, Lawrence W.; Clark, Frank C.

    1985-01-01

    A study was carried out to investigate the potential use of B-mode ultrasound for measuring subcutaneous fat thickness at two arm sites. B-mode sonograms and skinfold measurements were found to be highly correlated for both men and women. (Author/MT)

  9. Direct Measurement of Basilar Membrane Motion Using Pulsed-Wave Doppler High-Frequency Ultrasound

    NASA Astrophysics Data System (ADS)

    Torbatian, Z.; Garland, P.; Adamson, R. B. A.; Bance, M.; Brown, J. A.

    2011-11-01

    We present a preliminary report on the use of a new technique for measuring the motion of the basilar membrane, high-frequency ultrasound Doppler vibrometry. Using a custom-built, 1 mm diameter probe, we collected ultrasonic reflections from intracochlear structures and applied pulsed-wave Doppler vibrometry to measure the basilar membrane response to pressure applied in the ear canal.

  10. Mechanism modeling for phase fraction measurement with ultrasound attenuation in oil–water two-phase flow

    NASA Astrophysics Data System (ADS)

    Su, Qian; Tan, Chao; Dong, Feng

    2017-03-01

    When measuring the phase fraction of oil–water two-phase flow with the ultrasound attenuation, the phase distribution and fraction have direct influence on the attenuation coefficient. Therefore, the ultrasound propagation at various phase fractions and distributions were investigated. Mechanism models describing phase fraction with the ultrasound attenuation coefficient were established by analyzing the interaction between ultrasound and two-phase flow by considering the scattering, absorption and diffusion effect. Experiments were performed to verify the theoretical analysis, and the test results gave good agreement with the theoretical analysis. When the dispersed phase fraction is low, the relationship between ultrasound attenuation coefficient and phase fraction is of monotonic linearity; at higher dispersed phase fraction, ultrasound attenuation coefficient presents an irregular response to the dispersed phase fraction. The presented mechanism models give reasonable explanations about the trend of ultrasound attenuation.

  11. Optical Scattering Measurement of Microbubble Cloud Dynamics in Ultrasound

    NASA Astrophysics Data System (ADS)

    Takashi Miwa,; Yoshiki Yamakoshi,; Tomoharu Mashiyama,

    2010-07-01

    The manipulation of microbubbles by ultrasonic waves has the potential to be a useful technique in therapeutic ultrasound, such as for drug delivery systems and gene delivery systems. The Bjerknes force, which is an acoustic radiation force produced by microbubbles, acts as a driving force on the microbubbles; however, the two types of Bjerknes force make the resultant bubble movement very complex. In this paper, the evaluation of microbubble dynamics under ultrasonic wave radiation based on a laser diffraction method is proposed. The relationship between the microbubble spatial distribution and the diffracted light intensity is discussed on the basis of both theoretical analysis and numerical simulations. Experiments are carried out using ultrasonic wave contrast agent as microbubbles.

  12. Challenges and regulatory considerations in the acoustic measurement of high-frequency (>20 MHz) ultrasound.

    PubMed

    Nagle, Samuel M; Sundar, Guru; Schafer, Mark E; Harris, Gerald R; Vaezy, Shahram; Gessert, James M; Howard, Samuel M; Moore, Mary K; Eaton, Richard M

    2013-11-01

    This article examines the challenges associated with making acoustic output measurements at high ultrasound frequencies (>20 MHz) in the context of regulatory considerations contained in the US Food and Drug Administration industry guidance document for diagnostic ultrasound devices. Error sources in the acoustic measurement, including hydrophone calibration and spatial averaging, nonlinear distortion, and mechanical alignment, are evaluated, and the limitations of currently available acoustic measurement instruments are discussed. An uncertainty analysis of acoustic intensity and power measurements is presented, and an example uncertainty calculation is done on a hypothetical 30-MHz high-frequency ultrasound system. This analysis concludes that the estimated measurement uncertainty of the acoustic intensity is +73%/-86%, and the uncertainty in the mechanical index is +37%/-43%. These values exceed the respective levels in the Food and Drug Administration guidance document of 30% and 15%, respectively, which are more representative of the measurement uncertainty associated with characterizing lower-frequency ultrasound systems. Recommendations made for minimizing the measurement uncertainty include implementing a mechanical positioning system that has sufficient repeatability and precision, reconstructing the time-pressure waveform via deconvolution using the hydrophone frequency response, and correcting for hydrophone spatial averaging.

  13. Force-controlled ultrasound to measure passive mechanical properties of muscle in Duchenne muscular dystrophy.

    PubMed

    Pigula, Anne J; Wu, Jim S; Gilbertson, Matthew W; Darras, Basil T; Rutkove, Seward B; Anthony, Brian W

    2016-08-01

    The purpose of this study is to assess differences in skeletal muscle compressibility between patients with Duchenne muscular dystrophy (DMD) and normal subjects. The transverse passive mechanical properties of muscle, particularly those related to stiffness and elasticity, can be measured using force-controlled ultrasound. We acquired ultrasound videos of muscle compression under known pressures in the biceps and quadriceps in 23 boys with DMD and 20 age-matched healthy controls. We calculated the bulk linear spring constant, nonlinear stress-strain response, and average Young's modulus for each. Young's modulus was found to be significantly higher in the DMD population in both the biceps (normal: 33 ± 6 kPa, DMD: 45 ± 14, p <; .01) and quadriceps (normal: 42 ± 6, DMD: 58 ± 14, p <; .0001). Muscle compressibility measured by force-controlled ultrasound is an objective and robust technique to quantitatively monitor the effects of DMD and distinguish from normal subjects.

  14. Localization of the transverse processes in ultrasound for spinal curvature measurement

    NASA Astrophysics Data System (ADS)

    Kamali, Shahrokh; Ungi, Tamas; Lasso, Andras; Yan, Christina; Lougheed, Matthew; Fichtinger, Gabor

    2017-03-01

    PURPOSE: In scoliosis monitoring, tracked ultrasound has been explored as a safer imaging alternative to traditional radiography. The use of ultrasound in spinal curvature measurement requires identification of vertebral landmarks such as transverse processes, but as bones have reduced visibility in ultrasound imaging, skeletal landmarks are typically segmented manually, which is an exceedingly laborious and long process. We propose an automatic algorithm to segment and localize the surface of bony areas in the transverse process for scoliosis in ultrasound. METHODS: The algorithm uses cascade of filters to remove low intensity pixels, smooth the image and detect bony edges. By applying first differentiation, candidate bony areas are classified. The average intensity under each area has a correlation with the possibility of a shadow, and areas with strong shadow are kept for bone segmentation. The segmented images are used to reconstruct a 3-D volume to represent the whole spinal structure around the transverse processes. RESULTS: A comparison between the manual ground truth segmentation and the automatic algorithm in 50 images showed 0.17 mm average difference. The time to process all 1,938 images was about 37 Sec. (0.0191 Sec. / Image), including reading the original sequence file. CONCLUSION: Initial experiments showed the algorithm to be sufficiently accurate and fast for segmentation transverse processes in ultrasound for spinal curvature measurement. An extensive evaluation of the method is currently underway on images from a larger patient cohort and using multiple observers in producing ground truth segmentation.

  15. A comparison of fetal organ measurements by echo-planar magnetic resonance imaging and ultrasound.

    PubMed

    Duncan, Keith R; Issa, Bashar; Moore, Rachel; Baker, Philip N; Johnson, Ian R; Gowland, Penny A

    2005-01-01

    To compare fetal organ size measured using echo-planar magnetic resonance imaging and 2D ultrasound. To determine the relative accuracy with which each technique can predict fetal growth restriction. A cross sectional, observational study comparing two different measurement techniques against a gold standard, in a normal clinical population and an abnormal population. Seventy-four pregnant women (33 who were ultimately found to be normal and 37 with fetal growth restricted fetuses) were recruited from the City Hospital Nottingham UK to be scanned once (at various gestations). Each fetus had a standard ultrasound biometry assessment followed by magnetic resonance imaging measurement of organ volumes. For each measurement for both techniques, the normal population was plotted with 90% confidence intervals. Fetal growth restricted subjects were compared with the normal population using this plot; 2 x 2 tables were created for each measurement. This was used to calculate the relative sensitivities and positive predictive value of the different measurements. A Bland-Altman plot was used to compare the ultrasound and magnetic resonance imaging measurements of fetal weight. Brain sparing was seen in ultrasonic head circumference measurements, but an overall reduction in fetal growth restriction brain volume was apparent using magnetic resonance imaging at late gestations. Across the whole range of gestational ages, ultrasound assessment of fetal weight was the best predictor of fetal growth restriction. Ultrasound fetal weight assessment appears to identify more fetuses with fetal growth restriction than abdominal circumference. The brain sparing apparent in ultrasonic head circumference measurements of fetuses with fetal growth restriction masks a reduction in brain volume observed with magnetic resonance imaging.

  16. Ultrasound stylet for non-image-guided ventricular catheterization.

    PubMed

    Coulson, Nathaniel K; Chiarelli, Peter A; Su, David K; Chang, Jason J; MacConaghy, Brian; Murthy, Revathi; Toms, Peter; Robb, Terrence L; Ellenbogen, Richard G; Browd, Samuel R; Mourad, Pierre D

    2015-10-01

    OBJECT Urgent ventriculostomy placement can be a lifesaving procedure in the setting of hydrocephalus or elevated intracranial pressure. While external ventricular drain (EVD) insertion is common, there remains a high rate of suboptimal drain placement. Here, the authors seek to demonstrate the feasibility of an ultrasound-based guidance system that can be inserted into an existing EVD catheter to provide a linear ultrasound trace that guides the user toward the ventricle. METHODS The ultrasound stylet was constructed as a thin metal tube, with dimensions equivalent to standard catheter stylets, bearing a single-element, ceramic ultrasound transducer at the tip. Ultrasound backscatter signals from the porcine ventricle were processed by custom electronics to offer real-time information about ventricular location relative to the catheter. Data collected from the prototype device were compared with reference measurements obtained using standard clinical ultrasound imaging. RESULTS A study of porcine ventricular catheterization using the experimental device yielded a high rate of successful catheter placement after a single pass (10 of 12 trials), despite the small size of pig ventricles and the lack of prior instruction on porcine ventricular architecture. A characteristic double-peak signal was identified, which originated from ultrasound reflections off of the near and far ventricular walls. Ventricular dimensions, as obtained from the width between peaks, were in agreement with standard ultrasound reference measurements (p < 0.05). Furthermore, linear ultrasound backscatter data permitted in situ measurement of the stylet distance to the ventricular wall (p < 0.05), which assisted in catheter guidance. CONCLUSIONS The authors have demonstrated the ability of the prototype ultrasound stylet to guide ventricular access in the porcine brain. The alternative design of the device makes it potentially easy to integrate into the standard workflow for bedside EVD

  17. The effect of dead elements on the accuracy of Doppler ultrasound measurements.

    PubMed

    Vachutka, Jaromir; Dolezal, Ladislav; Kollmann, Christian; Klein, Jakob

    2014-01-01

    The objective of this study is to investigate the effect of multiple dead elements in an ultrasound probe on the accuracy of Doppler ultrasound measurements. For this work, we used a specially designed ultrasound imaging system, the Ultrasonix Sonix RP, that provides the user with the ability to disable selected elements in the probe. Using fully functional convex, linear, and phased array probes, we established a performance baseline by measuring the parameters of a laminar parabolic flow profile. These same parameters were then measured using probes with 1 to 10 disabled elements. The acquired velocity spectra from the functional probes and the probes with disabled elements were then analyzed to determine the overall Doppler power, maximum flow velocity, and average flow velocity. Color Flow Doppler images were also evaluated in a similar manner. The analysis of the Doppler spectra indicates that the overall Doppler power as well as the detected maximum and average velocities decrease with the increasing number of disabled elements. With multiple disabled elements, decreases in the detected maximum and average velocities greater than 20% were recorded. Similar results were also observed with Color Flow Doppler measurements. Our results confirmed that the degradation of the ultrasound probe through the loss of viable elements will negatively affect the quality of the Doppler-derived diagnostic information. We conclude that the results of Doppler measurements cannot be considered accurate or reliable if there are four or more contiguous dead elements in any given probe.

  18. Instrumentation for bedside analysis of swallowing disorders.

    PubMed

    Greco, Catiuscia S S; Nunes, Luiz G Q; Melo, Pedro L

    2010-01-01

    Disordered swallowing, or dysphagia, is a common problem seen in patients undergoing treatment for cancer, stroke and neurodegenerative illnesses. This disease is associated with aspiration-induced chest infections. The methods currently used for diagnosis, however, are qualitative or based on expensive equipment. Swallowing accelerometry is a promising low-cost, quantitative and noninvasive tool for the evaluation of swallowing. This work describes the design and application of a bedside instrument able to evaluate swallowing mechanisms and to identify patients at risk of aspiration. Three-axis swallowing accelerometry was used to measure the neck vibrations associated with deglutition, providing analog signals to a virtual instrument developed in LabVIEW environment. In vivo tests in normal subjects as well as tests with disphagic patients showed that the system was able to easily and non-invasively detect changes in the swallowing acceleration pattern associated with increasing values of water volume (p < 0.02) and disphagia. We concluded that the developed system could be a useful tool for the objective bedside evaluation of patients at risk of aspiration.

  19. Visualizing and measuring the temperature field produced by medical diagnostic ultrasound using thermography

    NASA Astrophysics Data System (ADS)

    Vachutka, J.; Grec, P.; Mornstein, V.; Caruana, C. J.

    2008-11-01

    The heating of tissues by diagnostic ultrasound can pose a significant hazard particularly in the imaging of the unborn child. The demonstration of the temperature field in tissue is therefore an important objective in the teaching of biomedical physics to healthcare professionals. The temperature field in a soft tissue model was made visible and measured using thermography. Temperature data from the images were used to investigate the dependence of temperature increase within the model on ultrasound exposure time and distance from the transducer. The experiment will be used within a multi-professional biomedical physics teaching laboratory for enhancing learning regarding the principles of thermography and the thermal effects of ultrasound to medical and healthcare students and also for demonstrating the quantitative use of thermographic imaging to students of biophysics, medical physics and medical technology.

  20. Preterm neonatal lateral ventricle volume from three-dimensional ultrasound is not strongly correlated to two-dimensional ultrasound measurements.

    PubMed

    Kishimoto, Jessica; de Ribaupierre, Sandrine; Salehi, Fateme; Romano, Walter; Lee, David S C; Fenster, Aaron

    2016-10-01

    The aim of this study is to compare longitudinal two-dimensional (2-D) and three-dimensional (3-D) ultrasound (US) estimates of ventricle size in preterm neonates with posthemorrhagic ventricular dilatation (PHVD) using quantitative measurements of the lateral ventricles. Cranial 2-D US and 3-D US images were acquired from neonatal patients with diagnosed PHVD within 10 min of each other one to two times per week and analyzed offline. Ventricle index, anterior horn width, third ventricle width, and thalamo-occipital distance were measured on the 2-D images and ventricle volume (VV) was measured from 3-D US images. Changes in the measurements between successive image sets were also recorded. No strong correlations were found between VV and 2-D US measurements ([Formula: see text] between 0.69 and 0.36). Additionally, weak correlations were found between changes in 2-D US measurements and 3-D US VV ([Formula: see text] between 0.13 and 0.02). A trend was found between increasing 2-D US measurements and 3-D US-based VV, but this was not the case when comparing changes between 3-D US VV and 2-D US measurements. If 3-D US-based VV provides a more accurate estimate of ventricle size than 2-D US measurements, moderate-weak correlations with 3-D US suggest that monitoring preterm patients with PHVD using 2-D US measurements alone might not accurately represent whether the ventricles are progressively dilating. A volumetric measure (3-D US or MRI) could be used instead to more accurately represent changes.

  1. Submental ultrasound measurement of dynamic tongue base thickness in patients with obstructive sleep apnea.

    PubMed

    Chen, Jeng-Wen; Chang, Chun-Hsiang; Wang, Shou-Jen; Chang, Yen-Teh; Huang, Chih-Chung

    2014-11-01

    Dynamic tongue base thickness (TBT) may be an important anatomic factor in airway narrowing in patients with obstructive sleep apnea (OSA). The development of an accurate clinical assessment of the retroglossal airway in patients with OSA is still evolving. Submental ultrasound was used to investigate the association between measurements of TBT in response to negative airway pressure and the existence of OSA. Twenty OSA patients and 20 control participants underwent ultrasound measurement of TBT on eupneic breathing and with the Mueller maneuver, as well as clinical and polysomnographic assessments. Logistic regression analyses indicated that after adjustment for confounding factors, independent predictors of OSA included TBT in response to negative airway pressure, as measured by submental ultrasound with the Mueller maneuver (odds ratio: 2.11, 95% confidence interval: 1.15-3.87, p < 0.05), and the difference between TBT with the Muller maneuver and that without the Mueller maneuver (odds ratio: 2.47, 95% confidence interval: 1.09-5.58, p < 0.05). Ultrasound measurement of TBT during the Mueller maneuver provides a quantitative assessment of the retroglossal airway in OSA patients with minimal invasiveness and easy accessibility.

  2. A Multidimensional Investigation of Children's /r/ Productions: Perceptual, Ultrasound, and Acoustic Measures

    ERIC Educational Resources Information Center

    Klein, Harriet B.; McAllister Byun, Tara; Davidson, Lisa; Grigos, Maria I.

    2013-01-01

    Purpose: This study explored relationships among perceptual, ultrasound, and acoustic measurements of children's correct and misarticulated /r/ sounds. Longitudinal data documenting changes across these parameters were collected from 2 children who acquired /r/ over a period of intervention and were compared with data from children with typical…

  3. A Multidimensional Investigation of Children's /r/ Productions: Perceptual, Ultrasound, and Acoustic Measures

    ERIC Educational Resources Information Center

    Klein, Harriet B.; McAllister Byun, Tara; Davidson, Lisa; Grigos, Maria I.

    2013-01-01

    Purpose: This study explored relationships among perceptual, ultrasound, and acoustic measurements of children's correct and misarticulated /r/ sounds. Longitudinal data documenting changes across these parameters were collected from 2 children who acquired /r/ over a period of intervention and were compared with data from children with typical…

  4. Easy Pulsatile Phantom for Teaching and Validation of Flow Measurements in Ultrasound

    PubMed Central

    Rominger, M. B.; Müller-Stuler, E.-M.; Pinto, M.; Becker, A. S.; Martini, K.; Frauenfelder, T.; Klingmüller, V.

    2016-01-01

    Purpose: To build a simple model to teach and validate non-pulsatile and pulsatile flow quantification in ultrasound. Materials and Methods: The setting consists of the following connected components: (1) medical syringe pump producing an adjustable constant flow (ml/min), (2) modulator modifying constant flow to a reproducible pulsatile flow, (3) water tank containing a diagonal running silicone tube (0.5 mm inner diameter), and (4) a fixated ultrasound probe (L9 Linear Array 9 MHz, GE Logiq E9) measuring the flow inside the tube. Commercially available microbubbles suspended with physiological saline solution were used for ultrasonic visibility. Spectral Doppler of different flow profiles is performed. Results: The syringe pump produces an adjustable, constant flow and serves as the reference standard. The filling volume of the tube system is 1.2 ml. Microbubbles are very well detected by ultrasound and can be used as an easy and clean blood mimicking substance. The modulator generates different physiological and pathological flow profiles. Velocities are similar to those found within human blood vessels. Thus, it is possible to train and validate flow measurements in ultrasound. Conclusion: The model produces non-pulsatile and various pulsatile flow profiles and allows validation of flow measurements. The compact size permits easy and economic setup for flow measurements in research, skills lab and continuing education. PMID:27689183

  5. A novel noncontact ultrasound indentation system for measurement of tissue material properties using water jet compression.

    PubMed

    Lu, M H; Zheng, Y P; Huang, Q H

    2005-06-01

    This study is aimed to develop a novel noncontact ultrasonic indentation system for measuring quantitative mechanical properties of soft tissues, which are increasingly important for tissue assessment and characterization. The key idea of this method is to use a water jet as an indenter to compress the soft tissue while at the same time as a medium for an ultrasound beam to propagate through. The use of water jet indentation does not require a rigid compressor in front of the focused high frequency ultrasound transducer to compress the tissue, so that the additional attenuation caused by the rigid compressor and the strong echoes reflected from its surfaces can be avoided. The indentation deformation was estimated from the ultrasound echoes using a cross-correlation algorithm and the indentation force was calculated from the water pressure measured inside the water pipe. Experiments were performed on uniform tissue-mimicking phantoms with different stiffness. The Young's moduli and Poisson's ratios of these phantoms were measured using a uniaxial ultrasound compression system. The ratio of the indentation pressure to the tissue relative deformation was obtained from the water indentation. This ratio was well correlated with the Young's modulus (r = 0.87). The results also demonstrated that the water indentation approach could differentiate materials with different stiffness in a combined phantom (288 kPa and 433 kPa). This novel noncontact water indentation approach could be potentially used for the measurement of the elasticity of small samples and with a fast scanning speed.

  6. Exploration Analysis of Carbon Dioxide Levels and Ultrasound Measures of the Eye During ISS Missions

    NASA Technical Reports Server (NTRS)

    Young, M.; Mason, S.; Schaefer, C.; Wear, M. L.; Sargsyan, A.; Garcia, K.; Coble, C.; Gruschkus, S.; Law, J.; Alexander, D.; hide

    2016-01-01

    Enhanced screening for the Visual Impairment/Intracranial Pressure (VIIP) Syndrome, including in-flight ultrasound, was implemented in 2010 to better characterize the changes in vision observed in some long-duration crewmembers. Suggested possible risk factors for VIIP include cardiovascular changes, diet, anatomical and genetic factors, and environmental conditions. As a potent vasodilator, carbon dioxide (CO (sub 2)), which is chronically elevated on the International Space Station (ISS) relative to typical indoor and outdoor ambient levels on Earth, seems a plausible contributor to VIIP. In an effort to understand the possible associations between CO (sub 2) and VIIP, this study analyzes the relationship between ambient CO (sub 2) levels on ISS and ultrasound measures of the eye obtained from ISS fliers. CO (sub 2) measurements will be pulled directly from Operational Data Reduction Complex for the Lab and Node 3 major constituent analyzers (MCAs) on ISS or from sensors located in the European Columbus module, as available. CO (sub 2) measures between ultrasound sessions will be summarized using standard time series class metrics in MATLAB including time-weighted means and variances. Cumulative CO (sub 2) exposure metrics will also be developed. Regression analyses will be used to quantify the relationships between the CO (sub 2) metrics and specific ultrasound measures. Generalized estimating equations will adjust for the repeated measures within individuals. Multiple imputation techniques will be used to adjust for any possible biases in missing data for either CO (sub 2) or ultrasound measures. These analyses will elucidate the possible relationship between CO (sub 2) and changes in vision and also inform future analysis of inflight VIIP data.

  7. Bedside Reporting: Protocols for Improving Patient Care.

    PubMed

    Ferguson, Teresa D; Howell, Teresa L

    2015-12-01

    Bedside reporting continues to gain much attention and is being investigated to support the premise that "hand-off" communications enhance efficacy in delivery of patient care. Patient inclusion in shift reports enhances good patient outcomes, increased satisfaction with care delivery, enhanced accountability for nursing professionals, and improved communications between patients and their direct care providers. This article discusses the multiple benefits of dynamic dialogue between patients and the health care team, challenges often associated with bedside reporting, and protocols for managing bedside reporting with the major aim of improving patient care. Nursing research supporting the concept of bedside reporting is examined.

  8. System and method for improving ultrasound image acquisition and replication for repeatable measurements of vascular structures

    NASA Technical Reports Server (NTRS)

    Selzer, Robert H. (Inventor); Hodis, Howard N. (Inventor)

    2006-01-01

    High resolution B-mode ultrasound images of the common carotid artery are obtained with an ultrasound transducer using a standardized methodology. Subjects are supine with the head counter-rotated 45 degrees using a head pillow. The jugular vein and carotid artery are located and positioned in a vertical stacked orientation. The transducer is rotated 90 degrees around the centerline of the transverse image of the stacked structure to obtain a longitudinal image while maintaining the vessels in a stacked position. A computerized methodology assists operators to accurately replicate images obtained over several spaced-apart examinations. The methodology utilizes a split-screen display in which the arterial ultrasound image from an earlier examination is displayed on one side of the screen while a real-time live ultrasound image from a current examination is displayed next to the earlier image on the opposite side of the screen. By viewing both images, whether simultaneously or alternately, while manually adjusting the ultrasound transducer, an operator is able to bring into view the real-time image that best matches a selected image from the earlier ultrasound examination. Utilizing this methodology, measurement of vascular dimensions such as carotid arterial IMT and diameter, the coefficient of variation is substantially reduced to values approximating from about 1.0% to about 1.25%. All images contain anatomical landmarks for reproducing probe angulation, including visualization of the carotid bulb, stacking of the jugular vein above the carotid artery, and initial instrumentation settings, used at a baseline measurement are maintained during all follow-up examinations.

  9. Reproducibility and validity of ultrasound for the measurement of visceral and subcutaneous adipose tissues.

    PubMed

    Schlecht, Inga; Wiggermann, Philipp; Behrens, Gundula; Fischer, Beate; Koch, Manja; Freese, Johanna; Rubin, Diana; Nöthlings, Ute; Stroszczynski, Christian; Leitzmann, Michael F

    2014-12-01

    Ultrasound represents a low-cost and widely available field method for assessing visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) but its measurement properties are uncertain. The aim of the current study was to examine the reproducibility and validity of ultrasound to quantify abdominal fat compartments. In two study centers, VAT and SAT thicknesses were quantified by ultrasound two times by two observers each among 127 adults aged 20-70 years. In a separate sample of 30 adults, the ultrasound method was validated by comparing VAT and SAT thicknesses with VAT and SAT areas at vertebrae L2/L3 as obtained by a single magnetic resonance imaging (MRI) slice. For VAT, the intra-rater reproducibility values for observers 1 and 2 were r=0.996 (95% CI=0.994-0.997) and r=0.999 (95% CI=0.999-0.999), respectively. For SAT, the intra-rater reproducibility values were r=0.992 (95% CI=0.989-0.994) and r=0.993 (95% CI=0.990-0.995), respectively. The inter-rater reproducibility values for VAT and SAT were r=0.998 (95% CI=0.997-0.999) and r=0.990 (95% CI=0.986-0.993), respectively. For VAT and SAT, the correlation coefficients between ultrasound and MRI measurements were r=0.898 (P<0.001) and r=0.705 (P<0.001), respectively. Ultrasound provides reproducible and valid estimates of VAT and SAT and represents a useful method to assess abdominal fat in large scale epidemiologic studies. Copyright © 2014 Elsevier Inc. All rights reserved.

  10. Pleural ultrasound for clinicians.

    PubMed

    Porcel, J M

    2016-11-01

    Pleural ultrasonography is useful for identifying and characterising pleural effusions, solid pleural lesions (nodules, masses, swellings) and pneumothorax. Pleural ultrasonography is also considered the standard care for guiding interventionist procedures on the pleura at the patient's bedside (thoracentesis, drainage tubes, pleural biopsies and pleuroscopy). Hospitals should promote the acquisition of portable ultrasound equipment to increase the patient's safety. Copyright © 2016 Elsevier España, S.L.U. and Sociedad Española de Medicina Interna (SEMI). All rights reserved.

  11. An Improved Tumour Temperature Measurement and Control Method for Superficial Tumour Ultrasound Hyperthermia Therapeutic System

    NASA Astrophysics Data System (ADS)

    Shen1, G. F.; Chen, Y. Z.; Ren, G. X.

    2006-10-01

    In tumour hyperthermia therapy, the research on measurement and control of tumour temperature is very important. Based on the hardware platform of superficial tumour ultrasound hyperthermia therapeutic system, an improved tumour temperature measurement and control method is presented in this paper. The experiment process, data and results are discussed in detail. The improved method will greatly reduce the pain and dread of the patients during the therapy period on the tumour temperature measurement and control by using the pinhead sensor.

  12. Optical bedside monitoring of cerebral blood flow in acute ischemic stroke patients during head-of-bed manipulation.

    PubMed

    Favilla, Christopher G; Mesquita, Rickson C; Mullen, Michael; Durduran, Turgut; Lu, Xiangping; Kim, Meeri N; Minkoff, David L; Kasner, Scott E; Greenberg, Joel H; Yodh, Arjun G; Detre, John A

    2014-05-01

    A primary goal of acute ischemic stroke (AIS) management is to maximize perfusion in the affected region and surrounding ischemic penumbra. However, interventions to maximize perfusion, such as flat head-of-bed (HOB) positioning, are currently prescribed empirically. Bedside monitoring of cerebral blood flow (CBF) allows the effects of interventions such as flat HOB to be monitored and may ultimately be used to guide clinical management. Cerebral perfusion was measured during HOB manipulations in 17 patients with unilateral AIS affecting large cortical territories in the anterior circulation. Simultaneous measurements of frontal CBF and arterial flow velocity were performed with diffuse correlation spectroscopy and transcranial Doppler ultrasound, respectively. Results were analyzed in the context of available clinical data and a previous study. Frontal CBF, averaged over the patient cohort, decreased by 17% (P=0.034) and 15% (P=0.011) in the ipsilesional and contralesional hemispheres, respectively, when HOB was changed from flat to 30°. Significant (cohort-averaged) changes in blood velocity were not observed. Individually, varying responses to HOB manipulation were observed, including paradoxical increases in CBF with increasing HOB angle. Clinical features, stroke volume, and distance to the optical probe could not explain this paradoxical response. A lower HOB angle results in an increase in cortical CBF without a significant change in arterial flow velocity in AIS, but there is variability across patients in this response. Bedside CBF monitoring with diffuse correlation spectroscopy provides a potential means to individualize interventions designed to optimize CBF in AIS.

  13. A comparison of portable ultrasound and fully-equipped clinical ultrasound unit in the thyroid size measurement of the Indo-Pacific bottlenose dolphin.

    PubMed

    Kot, Brian C W; Ying, Michael T C; Brook, Fiona M

    2012-01-01

    Measurement of thyroid size and volume is a useful clinical parameter in both human and veterinary medicine, particularly for diagnosing thyroid diseases and guiding corrective therapy. Procuring a fully-equipped clinical ultrasound unit (FCUS) may be difficult in most veterinary settings. The present study evaluated the inter-equipment variability in dolphin thyroid ultrasound measurements between a portable ultrasound unit (PUS) and a FCUS; for both units, repeatability was also assessed. Thyroid ultrasound examinations were performed on 15 apparently healthy bottlenose dolphins with both PUS and FCUS under identical scanning conditions. There was a high level of agreement between the two ultrasound units in dolphin thyroid measurements (ICC = 0.859-0.976). A high intra-operator repeatability in thyroid measurements was found (PUS: ICC = 0.854-0.984, FCUS: ICC = 0.709-0.954). As a conclusion, no substantial inter-equipment variability was found between PUS and FCUS in dolphin thyroid size measurements under identical scanning conditions, supporting further application of PUS for quantitative analyses of dolphin thyroid gland in both research and clinical practices at aquarium settings.

  14. Effects of non-optimal focusing on dual-frequency ultrasound measurements of bone.

    PubMed

    Malo, Markus K H; Karjalainen, Janne P; Riekkinen, Ossi; Isaksson, Hanna; Jurvelin, Jukka S; Töyräs, Juha

    2011-06-01

    In pulse-echo (PE) ultrasound measurements, the use of focused transducers is desirable for quantitative assessment of bone characteristics because of the attenuation in the overlying soft tissues. However, the variable thickness and composition of the soft tissue overlying bone affect the focal depth of the ultrasound beam and induce errors into the measurements. To compensate for the attenuation-related effects caused by the interfering soft tissue (i.e., fat and lean tissue), a dual-frequency ultrasound (DFUS) technique was recently introduced. The aim of this study was to investigate the effect of non-optimal focal depth of the ultrasound beam on the determination of the integrated reflection coefficient (IRC) of bone when overlaid by an interfering layer composed of oil and water. The feasibility of the DFUS-based correction of the IRC was evaluated through numerical simulations and experimental measurements. Even when the interfering layer-bone interface was out of focus, the total thickness of the interfering layer could be accurately determined with the technique. However, based on the simulations, the errors in the determination of the composition of the interfering layer increased (0.004 to 113.8%) with the increase in distance between the interfering layer-bone interface and the focus of the ultrasound beam. Attenuation compensation, based on the true composition of the interfering layer, resulted in an average relative error of 22.3% in the IRC values calculated from the simulations. Interestingly, the attenuation compensation with the interfering layer composition estimated using the DFUS technique resulted in a smaller average relative error of 14.9% in the IRC values. The simulations suggest that DFUS can reduce the errors induced by soft tissue in bone PE ultrasound measurements. The experimental measurements indicate that the accuracy of the IRC measurements is rather similar when using DFUS correction or correction based on the true composition of

  15. Validity Study of Vertebral Rotation Measurement Using 3-D Ultrasound in Adolescent Idiopathic Scoliosis.

    PubMed

    Wang, Qian; Li, Meng; Lou, Edmond H M; Chu, Winnie C W; Lam, Tsz-Ping; Cheng, Jack C Y; Wong, Man-Sang

    2016-07-01

    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.

  16. Measurement of the quadriceps femoris muscle using magnetic resonance and ultrasound imaging.

    PubMed Central

    Walton, J M; Roberts, N; Whitehouse, G H

    1997-01-01

    OBJECTIVES: To define a method for measurement of the cross sectional area and volume of the quadriceps femoris muscle using magnetic resonance imaging (MRI) in conjunction with stereology, and to compare the results of measurements obtained by the MRI method with those obtained by the conventional method of static B-mode ultrasound in order to evaluate whether MRI is a reliable alternative to ultrasound. METHODS: A preliminary MRI study was undertaken on a single female volunteer in order to optimise the scanning technique and sampling design for estimating the muscle volume using the Cavalieri method. Ten healthy volunteers participated in the method comparison study. Each volunteer underwent static B-mode ultrasonography, immediately followed by MRI. The cross sectional area of the quadriceps femoris was estimated at the junction of the proximal one third and distal two thirds of the thigh, and seven systematic sections of the thigh were obtained in order to estimate muscle volume by both modalities. RESULTS: Seven sections through the muscle are required to achieve a coefficient of error of 4-5%. There was no significant difference in the cross sectional area estimates or volume estimates when ultrasound and MRI were compared. CONCLUSION: Muscle cross sectional area and volume can be measured without bias by MRI in conjunction with stereological methods and the method is a reliable alternative to static B-mode ultrasound for this purpose. Images Figure 1 Figure 4 Figure 5 PMID:9132215

  17. Development of distance accuracy measurement program for quality control of diagnostic ultrasound system

    NASA Astrophysics Data System (ADS)

    Kim, Yon-Min; Kim, Moon-Chan; Han, Dong-Kyoon; Cho, Jae-Hwan; Kim, Sang-Hyun

    2013-12-01

    Evaluating the performance of a diagnostic ultrasound system is important. Above all, establishing standards for such evaluations in an objective and systematic way is critical. However, quality control is currently measured based on subjective judgment of an observer. Against this background, this study intended to suggest quantified and objective data that would enable inter-observer variation to be overcome. Five radiological technologists used an ATS-539 multi-purpose ultrasound phantom to conduct measurements in the predetermined method. A digital imaging and communications in medicine (DICOM) standard image was obtained in an ultrasound system by using a self-developed software to measure the accuracy of the distance before the 95% confidence interval was calculated. In order to examine the accuracy of the distance in longitudinal and transverse measurements, we conducted t-tests to evaluate the significance for the results of quality control that was performed manually for the past one year and for the results of quality control that was performed by using software with the same equipment. For the longitudinal and the transverse measurements, the 95% confidence intervals were 100.96-101.29 mm and 83.18-84.26 mm, respectively. The computerized longitudinal measurement showed no significant difference from the manual measurement ( p > 0.05). The results of measurements using of software showed a higher reproducibility.

  18. Development and Validation of a Method to Measure Lumbosacral Motion Using Ultrasound Imaging.

    PubMed

    van den Hoorn, Wolbert; Coppieters, Michel W; van Dieën, Jaap H; Hodges, Paul W

    2016-05-01

    The study aim was to validate an ultrasound imaging technique to measure sagittal plane lumbosacral motion. Direct and indirect measures of lumbosacral angle change were developed and validated. Lumbosacral angle was estimated by the angle between lines through two landmarks on the sacrum and lowest lumbar vertebrae. Distance measure was made between the sacrum and lumbar vertebrae, and angle was estimated after distance was calibrated to angle. This method was tested in an in vitro spine and an in vivo porcine spine and validated to video and fluoroscopy measures, respectively. R(2), regression coefficients and mean absolute differences between ultrasound measures and validation measures were, respectively: 0.77, 0.982, 0.67° (in vitro, angle); 0.97, 0.992, 0.82° (in vitro, distance); 0.94, 0.995, 2.1° (in vivo, angle); and 0.95, 0.997, 1.7° (in vivo, distance). Lumbosacral motion can be accurately measured with ultrasound. This provides a basis to develop measurements for use in humans.

  19. Interobserver agreement in perineal ultrasound measurement of the anovaginal distance: a methodological study.

    PubMed

    Pihl, Sofia; Uustal, Eva; Hjertberg, Linda; Blomberg, Marie

    2017-06-17

    Objective outcome measures of the extent of laceration at delivery are needed. In this study we evaluated and describe here a method for learning perineal ultrasound measurement of the anovaginal distance (AVD). The learning period needed for examiners proficient in vaginal ultrasound examination and the interobserver agreement after reaching proficiency in AVD measurement were determined. The hypothesis was that the method is feasible to learn and reproducible for use in further research. The method was taught by an examiner experienced in perineal ultrasonography. The distance between the mucosal margin of the internal anal sphincter was measured with a vaginal probe. The studied examiners measured the AVD until similar results (±5 mm) were achieved. The AVD in 40 women was then measured and documented by two examiners who were blinded to each other's results. Interobserver agreement was calculated using the kappa score. Examiners with previous experience in vaginal ultrasonography had learned the method after performing five sets of comeasurements. The AVD measurements after the learning period showed almost perfect agreement (κ = 0.87) between the examiners. The method for perineal ultrasound measurement of AVD was learned quickly with high interobserver agreement. The method is feasible to learn and reproducible for use in further research.

  20. A Comparative Study on the Influence of Probe Placement on Quality Assurance Measurements in B-mode Ultrasound by Means of Ultrasound Phantoms

    PubMed Central

    Scorza, A; Conforto, S; D'Anna, C; Sciuto, S.A

    2015-01-01

    To check or to prevent failures in ultrasound medical systems, some tests should be scheduled for both clinical suitability and technical functionality evaluation: among them, image quality assurance tests performed by technicians through ultrasound phantoms are widespread today and their results depend on issues related to scanner settings as well as phantom features and operator experience. In the present study variations on some features of the B-mode image were measured when the ultrasound probe is handled by the technician in a routine image quality test: ultrasound phantom images from two array transducers are processed to evaluate measurement dispersion in distance accuracy, high contrast spatial resolution and penetration depth when probe is handled by the operator. All measurements are done by means of an in-house image analysis software that minimizes errors due to operator’s visual acuity and subjective judgment while influences of ultrasound transducer position on quality assurance test results are estimated as expanded uncertainties on parameters above (measurement reproducibility at 95 percent confidence level): depending on the probe model, they ranged from ±0.1 to ±1.9 mm in high contrast spatial resolution, from ±0.1 to ±5.5 percent in distance measurements error and from ±1 to ±10 mm in maximum depth of signal visualization. Although numerical results are limited to the two examined probes, they confirm some predictions based on general working principles of diagnostic ultrasound systems: (a) measurements strongly depend on settings as well on phantoms features, probes and parameters investigated; (b) relative uncertainty due to probe manipulation on spatial resolution can be very high, i.e. from 10 to more than 30 percent; (c) Field of View settings must be taken into account for measurement reproducibility as well as Dynamic Range compression and phantom attenuation. PMID:26312078

  1. Accurate evaluation of viscoelasticity of radial artery wall during flow-mediated dilation in ultrasound measurement

    NASA Astrophysics Data System (ADS)

    Sakai, Yasumasa; Taki, Hirofumi; Kanai, Hiroshi

    2016-07-01

    In our previous study, the viscoelasticity of the radial artery wall was estimated to diagnose endothelial dysfunction using a high-frequency (22 MHz) ultrasound device. In the present study, we employed a commercial ultrasound device (7.5 MHz) and estimated the viscoelasticity using arterial pressure and diameter, both of which were measured at the same position. In a phantom experiment, the proposed method successfully estimated the elasticity and viscosity of the phantom with errors of 1.8 and 30.3%, respectively. In an in vivo measurement, the transient change in the viscoelasticity was measured for three healthy subjects during flow-mediated dilation (FMD). The proposed method revealed the softening of the arterial wall originating from the FMD reaction within 100 s after avascularization. These results indicate the high performance of the proposed method in evaluating vascular endothelial function just after avascularization, where the function is difficult to be estimated by a conventional FMD measurement.

  2. Measuring submicrometer displacement vectors using high-frame-rate ultrasound imaging.

    PubMed

    Kruizinga, Pieter; Mastik, Frits; Bosch, Johan G; de Jong, Nico; van der Steen, Anton F W; van Soest, Gijs

    2015-10-01

    Measuring the magnitude and direction of tissue displacement provides the basis for the assessment of tissue motion or tissue stiffness. Using conventional displacement tracking by ultrasound delay estimation, only one direction of tissue displacement can be estimated reliably. In this paper, we describe a new technique for estimating the complete two-dimensional displacement vector using high-frame-rate ultrasound imaging. We compute the displacement vector using phase delays that can be measured between pairs of elements within an array. By combining multiple element-pair solutions, we find a new robust estimate for the displacement vector. In this paper, we provide experimental proof that this method permits measurement of the displacement vector for isolated scatterers and diffuse scatterers with high (submicrometer) precision, without the need for beam steering. We also show that we can measure the axial and lateral distension of a carotid artery in a transverse view.

  3. Measurement of temperature decrease caused by blood flow in focused ultrasound irradiation by thermal imaging method

    NASA Astrophysics Data System (ADS)

    Tsuchiya, Takenobu; Hatano, Yuichi; Mori, Yashunori; Shen, Rakushin; Endoh, Nobuyuki

    2016-07-01

    In this study, to estimate the local temperature changes caused by a thick blood vessel, the temperature distribution in a tissue phantom with a thick blood vessel during focused ultrasound irradiation was measured by a thermal imaging method. The blood flow rate in the simulated blood vessel was varied and the relationship between flow rate and temperature decrease was examined. The phantom using the thermal imaging method is divided into two parts, and the increases in temperature distribution as a function of blood flow rate are measured using a thermocamera under constant ultrasound irradiation. The irradiation conditions of ultrasound waves were a central frequency of 1 MHz, a wave number length of 200 cycles, and a duty ratio of 0.2. The irradiation duration was 5 min, and the ultrasound intensity I SPTA was 36 W/cm2. The amount of temperature decrease caused by the cooling effect of blood flow increased with the blood flow rate and it became constant at a certain threshold of blood flow rate. The threshold of blood flow rate is about 250 ml/min.

  4. Measurement of Central Corneal Thickness Using Ultrasound Pachymetry and Orbscan II in Normal Eyes.

    PubMed

    Sadoughi, Mohammad Mehdi; Einollahi, Bahram; Einollahi, Neda; Rezaei, Javad; Roshandel, Danial; Feizi, Sepehr

    2015-01-01

    To compare ultrasound pachymetry and Orbscan II for measurement of central corneal thickness (CCT) in normal eyes. The current study was performed at Labbafinejad Medical Center (LMC), Tehran, Iran. Three hundred eyes from 150 healthy individuals referred for keratorefractive surgery were assessed first by Orbscan II and then by ultrasound pachymetry, and CCT values were recorded and compared. Overall, Orbscan II overestimated CCT as compared to ultrasound pachymetry by about 2.4% (mean values 547.6 ± 34.7 versus 534.8 ± 34.7, respectively, P < 0.001). The difference was more significant when CCT was less than 500 microns (mean values 493.2 ± 16.9 versus 479.9 ± 15.6, mean overestimation: 2.6%, P < 0.001). There was good linear correlation between the two methods (Pearson's correlation r = 0.968, P < 0.0001). Orbscan II has good correlation with ultrasound pachymetry for measurement of CCT in normal eyes; however Orbscan II should not be used to evaluate corneal thickness before keratorefractive surgeries, as it tends to overestimate corneal thickness and may result in undesirable, low residual stromal thickness.

  5. Time-resolved measurement of bubble cavitation by using power Doppler ultrasound image

    NASA Astrophysics Data System (ADS)

    Koda, Ren; Izumi, Yosuke; Nagai, Hayato; Yamakoshi, Yoshiki

    2017-04-01

    In this study, a novel measurement method for a secondary ultrasound wave irradiated by microbubble cavitation is proposed. High-intensity ultrasound (h-US, 1.0-1.5 MPa), which produces bubble cavitation, is irradiated with a fixed time delay after introducing imaging US, whose frequency is different from that of the h-US. The bubble cavitation signal (BCS) is detected by the signal-processing unit of an ultrasound power Doppler imaging instrument. By this method, both a spatially resolved bubble image (S-image) and the temporal transition of the BCS (T-image) are monitored simultaneously. A feature of the method is that the BCS is observed in situ with sub-µs time resolution. The accuracy of the method is evaluated and it is found that the maximum deviation of the amplitude of the simulated BCS is 4.80%. This method is applied to measure the BCS of ultrasound contrast agent microbubbles. As a result, the dependence of the inherent temporal transition of the BCS on the sound pressure of the h-US (0.6-1.2 MPa) is observed.

  6. Sonochemotherapy: from bench to bedside

    PubMed Central

    Lammertink, Bart H. A.; Bos, Clemens; Deckers, Roel; Storm, Gert; Moonen, Chrit T. W.; Escoffre, Jean-Michel

    2015-01-01

    The combination of microbubbles and ultrasound has emerged as a promising method for local drug delivery. Microbubbles can be locally activated by a targeted ultrasound beam, which can result in several bio-effects. For drug delivery, microbubble-assisted ultrasound is used to increase vascular- and plasma membrane permeability for facilitating drug extravasation and the cellular uptake of drugs in the treated region, respectively. In the case of drug-loaded microbubbles, these two mechanisms can be combined with local release of the drug following destruction of the microbubble. The use of microbubble-assisted ultrasound to deliver chemotherapeutic agents is also referred to as sonochemotherapy. In this review, the basic principles of sonochemotherapy are discussed, including aspects such as the type of (drug-loaded) microbubbles used, the routes of administration used in vivo, ultrasound devices and parameters, treatment schedules and safety issues. Finally, the clinical translation of sonochemotherapy is discussed, including the first clinical study using sonochemotherapy. PMID:26217226

  7. Ultrasound Accuracy of Liver Length Measurement with Cadaveric Specimens.

    PubMed

    Riestra-Candelaria, Bárbara L; Rodríguez-Mojica, Wilma; Vázquez-Quiñones, Luis E; Jorge, Juan Carlos

    2016-01-01

    The liver is one of the principal organs of our body involved in over 500 physiological functions related to metabolism, digestion, immunity, and storage of nutrients, which makes it an essential organ to preserve life. Given that there are a number of approaches to measure liver length through diagnostic 2D sonography, this work aims to determine the most accurate measurement of this organ. Cadaveric specimens (n = 21) were employed to assess measurements in midclavicular line (MCL) and midaxillary line (MAL). Each measurement was calculated in anteroposterior (AP) and craniocaudal (CC) planes. In addition, in situ measurements were obtained by accessing the organ through the anterior thoracoabdominal wall. Statistical differences were detected between MCL and MAL measurements (p < 0.05), a positive correlation between MAL CC and in situ anterior measurements were noted (r = 0.97). Liver size, as assessed through in situ measurements, varied as a funtion of BMI and waist circumference (p < 0.05). It is concluded that CC measurement of the RLL in MAL from the uppermost right hemi-diaphragm to the inferior tip of the right lobe through a horizontal line parallel to the anterior liver wall is the most accurate measurement of the organ by sonography.

  8. Essential tremor: from bedside to bench and back to bedside.

    PubMed

    Louis, Elan D

    2014-08-01

    The last several years have witnessed a remarkable increase in research on essential tremor, with consequent advances in our understanding of this entity. An attempt to both summarize and frame this work has not been undertaken. Here, I show that observations on essential tremor arising from clinical practice/clinical studies have guided scientific studies of this disorder. In turn, the results of scientific studies are beginning to be translated back to the bedside to improve treatment. Recent essential tremor research has given rise to several novel and intriguing ideas about the disease. These include the following: essential tremor may represent a family of diseases rather than a single disease; essential tremor seems to be a disease of the cerebellum or cerebellar system; essential tremor may be neurodegenerative; low gamma aminobutyric acid tone seems to be a central feature of essential tremor. As with many emerging ideas, there is significant discussion and debate over these emerging ideas, and this fuels additional scientific studies. The flow of ideas from clinical observations about essential tremor, to their translation into scientific studies, and their translation back to the bedside, is expected to eventually lead to improvements at the patient interface.

  9. The age-related advancement of arterial disease measured by Doppler ultrasound diastolic flow analysis.

    PubMed

    Terenzi, T; Gallagher, D; DeMeersman, R; Beadle, E; Muller, D

    1993-10-01

    To quantify by A-mode Doppler sonography the age-related progression of arterial disease so that age dependent normal values may be established for the screening Doppler peripheral arterial exam. Arterial distensibility was assessed by A-mode Doppler diastolic flow analysis as a measure of atherogenesis. These values will increase the sensitivity and decrease the incidence of false-positive results when the Doppler exam is utilized to differentially diagnosis vascular and sciatic neurogenic claudication. The relationship between age and results from the standard ankle/arm index ultrasound pneumatic cuff examination was also analyzed. A two by three analysis of variance with orthogonal Helmert contrast codes and simple linear regression analysis was utilized for this cross-sectionally designed investigation. The dependent measures of diastolic flow analysis and ankle/arm pressure index were obtained within three nested successively increasing age groups. Chiropractic office. Studied were a total of 90 sedentary nonsmoking subjects, aged 23-79 yr, all of whom had normally accepted levels of serum glucose, cholesterol and blood pressure. Subjects were screened for evidence of aortic coarctation, myocardial infarction, tachyarrhythmia, aortic valve stenosis, mitral prolapse, hypertension, hypercholesterolemia, diabetes and peripheral occlusive arterial disease. Anthropometric measurements and percent body fat were obtained. A predictive oxygen consumption bike ergometer test was performed to obtain aerobic capacity. The commonly utilized standard ankle/arm index ultrasound pneumatic cuff examination and arterial diastolic flow analysis were performed with A-mode Doppler ultrasound on all subjects. These results demonstrate that a significant inverse linear relationship exists between aging and arterial compliance (p < .0001) in our population. Diastolic flow analysis had a greater sensitivity to arterial disease than the standard ankle/arm index ultrasound pneumatic

  10. Noncontact Measurement of Humidity and Temperature Using Airborne Ultrasound

    NASA Astrophysics Data System (ADS)

    Akihiko Kon,; Koichi Mizutani,; Naoto Wakatsuki,

    2010-04-01

    We describe a noncontact method for measuring humidity and dry-bulb temperature. Conventional humidity sensors are single-point measurement devices, so that a noncontact method for measuring the relative humidity is required. Ultrasonic temperature sensors are noncontact measurement sensors. Because water vapor in the air increases sound velocity, conventional ultrasonic temperature sensors measure virtual temperature, which is higher than dry-bulb temperature. We performed experiments using an ultrasonic delay line, an atmospheric pressure sensor, and either a thermometer or a relative humidity sensor to confirm the validity of our measurement method at relative humidities of 30, 50, 75, and 100% and at temperatures of 283.15, 293.15, 308.15, and 323.15 K. The results show that the proposed method measures relative humidity with an error rate of less than 16.4% and dry-bulb temperature with an error of less than 0.7 K. Adaptations of the measurement method for use in air-conditioning control systems are discussed.

  11. Mantra meditation as a bedside spiritual intervention.

    PubMed

    Chan, Roxane Raffin

    2014-01-01

    The increased acceptance of integrative care allows nurses to investigate their role as active providers of spiritual care at the bedside. Lack of clear role expectations and interventions support the need for a simple, flexible spiritual bedside intervention. The use of a meditation mantra is discussed.

  12. Measurement of the Doppler power of flowing blood using ultrasound Doppler devices.

    PubMed

    Huang, Chih-Chung; Chou, Hung-Lung; Chen, Pay-Yu

    2015-02-01

    Measurement of the Doppler power of signals backscattered from flowing blood (henceforth referred to as the Doppler power of flowing blood) and the echogenicity of flowing blood have been used widely to assess the degree of red blood cell (RBC) aggregation for more than 20 y. Many studies have used Doppler flowmeters based on an analogue circuit design to obtain the Doppler shifts in the signals backscattered from flowing blood; however, some recent studies have mentioned that the analogue Doppler flowmeter exhibits a frequency-response problem whereby the backscattered energy is lost at higher Doppler shift frequencies. Therefore, the measured Doppler power of flowing blood and evaluations of RBC aggregation obtained using an analogue Doppler device may be inaccurate. To overcome this problem, the present study implemented a field-programmable gate array-based digital pulsed-wave Doppler flowmeter to measure the Doppler power of flowing blood, in the aim of providing more accurate assessments of RBC aggregation. A clinical duplex ultrasound imaging system that can acquire pulsed-wave Doppler spectrograms is now available, but its usefulness for estimating the ultrasound scattering properties of blood is still in doubt. Therefore, the echogenicity and Doppler power of flowing blood under the same flow conditions were measured using a laboratory pulser-receiver system and a clinical ultrasound system, respectively, for comparisons. The experiments were carried out using porcine blood under steady laminar flow with both RBC suspensions and whole blood. The experimental results indicated that a clinical ultrasound system used to measure the Doppler spectrograms is not suitable for quantifying Doppler power. However, the Doppler power measured using a digital Doppler flowmeter can reveal the relationship between backscattering signals and the properties of blood cells because the effects of frequency response are eliminated. The measurements of the Doppler power and

  13. Validation of an ultrasound dilution technology for cardiac output measurement and shunt detection in infants and children.

    PubMed

    Lindberg, Lars; Johansson, Sune; Perez-de-Sa, Valeria

    2014-02-01

    To validate cardiac output measurements by ultrasound dilution technology (COstatus monitor) against those obtained by a transit-time ultrasound technology with a perivascular flow probe and to investigate ultrasound dilution ability to estimate pulmonary to systemic blood flow ratio in children. Prospective observational clinical trial. Pediatric cardiac operating theater in a university hospital. In 21 children (6.1 ± 2.6 kg, mean ± SD) undergoing heart surgery, cardiac output was simultaneously recorded by ultrasound dilution (extracorporeal arteriovenous loop connected to existing arterial and central venous catheters) and a transit-time ultrasound probe applied to the ascending aorta, and when possible, the main pulmonary artery. The pulmonary to systemic blood flow ratio estimated from ultrasound dilution curve analysis was compared with that estimated from transit-time ultrasound technology. Bland-Altman analysis of the whole cohort (90 pairs, before and after surgery) showed a bias between transit-time ultrasound (1.01 ± 0.47 L/min) and ultrasound dilution technology (1.03 ± 0.51 L/min) of -0.02 L/min, limits of agreement -0.3 to 0.3 L/min, and percentage error of 31%. In children with no residual shunts, the bias was -0.04 L/min, limits of agreement -0.28 to 0.2 L/min, and percentage error 19%. The pooled co efficient of variation was for the whole cohort 3.5% (transit-time ultrasound) and 6.3% (ultrasound dilution), and in children without shunt, it was 2.9% (transit-time ultrasound) and 4% (ultrasound dilution), respectively. Ultrasound dilution identified the presence of shunts (pulmonary to systemic blood flow ≠ 1) with a sensitivity of 100% and a specificity of 92%. Mean pulmonary to systemic blood flow ratio by transit-time ultrasound was 2.6 ± 1.0 and by ultrasound dilution 2.2 ± 0.7 (not significant). The COstatus monitor is a reliable technique to measure cardiac output in children with high sensitivity and specificity for detecting the

  14. The influence of dairy consumption and physical activity on ultrasound bone measurements in Flemish children.

    PubMed

    De Smet, Stephanie; Michels, Nathalie; Polfliet, Carolien; D'Haese, Sara; Roggen, Inge; De Henauw, Stefaan; Sioen, Isabelle

    2015-03-01

    The study's aim was to analyse whether children's bone status, assessed by calcaneal ultrasound measurements, is influenced by dairy consumption and objectively measured physical activity (PA). Moreover, the interaction between dairy consumption and PA on bone mass was studied. Participants of this cross-sectional study were 306 Flemish children (6-12 years). Body composition was measured with air displacement plethysmography (BodPod), dairy consumption with a Food Frequency Questionnaire, PA with an accelerometer (only in 234 of the 306 children) and bone mass with quantitative ultrasound, quantifying speed of sound (SOS), broadband ultrasound attenuation (BUA) and Stiffness Index (SI). Regression analyses were used to study the associations between dairy consumption, PA, SOS, BUA and SI. Total dairy consumption and non-cheese dairy consumption were positively associated with SOS and SI, but no significant association could be demonstrated with BUA. In contrast, milk consumption, disregarding other dairy products, had no significant effect on calcaneal bone measurements. PA [vigorous PA, moderate to vigorous physical activity (MVPA) and counts per minute] was positively associated and sedentary time was negatively associated with BUA and SI, but no significant influence on SOS could be detected. Dairy consumption and PA (sedentary time and MVPA) did not show any interaction influencing bone measurements. In conclusion, even at young age, PA and dairy consumption positively influence bone mass. Promoting PA and dairy consumption in young children may, therefore, maximize peak bone mass, an important protective factor against osteoporosis later in life.

  15. Ultrasound lineal measurements predict ventricular volume in posthaemorrhagic ventricular dilatation in preterm infants.

    PubMed

    Benavente-Fernandez, Isabel; Lubián-Gutierrez, Manuel; Jimenez-Gomez, Gema; Lechuga-Sancho, Alfonso M; Lubián-López, Simon P

    2017-02-01

    Posthaemorrhagic ventricular dilatation (PHVD) is monitored by conventional two-dimensional ultrasound (2DUS). The aims of this study were to determine the volume of the lateral ventricles using three-dimensional ultrasound (3DUS) in preterm infants with PHVD and to evaluate the relationship between volume and linear measurements. Serial 2DUSs and 3DUSs were performed on preterm infants with PHVD admitted to the neonatal intensive care unit at Puerta del Mar Hospital, Cádiz, Spain, from January 2013 to December 2014. The ventricular index, anterior horn width and thalamo-occipital distance were used as ventricular lineal measurements. Ventricular volume was calculated offline. Serial ultrasounds from seven preterm infants were measured. Each linear measurement was significantly associated with volume, and an equation was obtained through a significant multilevel mixed-effects lineal regression model: ventricular volume (cm(3) ) = -11.02 + 0.668*VI + 0.817*AHW + 0.256*TOD. Intra-observer and interobserver agreement was excellent with an intraclass correlation coefficient of 0.99. Lateral ventricular volumes of preterm infants with PHVD could be reliably determined using 3DUS. Ventricular volume could be accurately estimated using three lineal measurements. More studies are needed to address the importance of volume determination in PHVD. ©2016 Foundation Acta Paediatrica. Published by John Wiley & Sons Ltd.

  16. Comparison between body fat measurements obtained by portable ultrasound and caliper in young adults.

    PubMed

    Ulbricht, L; Neves, E B; Ripka, W L; Romaneli, E F R

    2012-01-01

    The objective of this study was to compare and correlate the Portable Ultra Sound (US) measuring technique to the skinfold measuring technique (SF) to estimate body fat percentage (%F) in young adults. Sixty military were evaluated, all males, divided in two groups: Group 1 (normal) composed by 30 military with Body Mass Index (BMI) until 24.99 kg/m(2) and Group 2 (overweight) composed by 30 military with BMI > 25 kg/m(2). Weight, height, skinfolds and ultrasound were measured in 9 points (triceps, subscapular, biceps, chest, medium axillary, abdominal, suprailiac, thigh and calf). Body fat average values obtained by skinfold thickness and ultrasound measurements were 13.25 ± 6.32 % and 12.73 ± 5.95 % respectively. Despite significant differences in measurements of each anatomical site, it was possible to verify that the total final body fat percentage calculated by both techniques did not present significant differences and that overweight group presented greater similarity between the values obtained using caliper and ultrasound equipment.

  17. Simultaneous measurement of red blood cell aggregation and whole blood coagulation using high-frequency ultrasound.

    PubMed

    Nam, Kweon-Ho; Yeom, Eunseop; Ha, Hojin; Lee, Sang Joon

    2012-03-01

    This study aims to investigate the feasibility of using high-frequency ultrasound (HFUS) for simultaneous monitoring of blood coagulation and red blood cell (RBC) aggregation. Using a 35-MHz ultrasound scanner, ultrasound speckle data were acquired from whole blood samples of three experimental groups of rats, including 4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid (DIDS)-treated, noncoagulation and normal control groups. The variations of blood echogenicity, the shape parameters of probability distribution of speckle intensity (skewness and kurtosis) and the correlation coefficient between two consecutive speckle data were calculated as a function of time starting from immediately after taking blood. The blood echogenicity increases rapidly to plateaus at the early stage of measurement for all the experimental groups caused by the formation of RBC aggregates. The DIDS-treated group exhibits the lowest echogenicity level due to the inhibitory effect of DIDS on RBC aggregation. The correlation analysis between consecutive speckle patterns seems to be useful to examine the variation of blood fluidity and the progress of clot formation. Whole blood coagulation is observed to be accelerated by DIDS treatment. In addition, the results of skewness and kurtosis analysis indicated that RBC aggregates may be disrupted during blood coagulation. The present study suggests that HFUS has good potential for simultaneous monitoring of RBC aggregation and blood coagulation to examine the relationship between them. Copyright © 2012 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

  18. Reliability of ultrasound to measure morphology of the toe flexor muscles

    PubMed Central

    2013-01-01

    Background Measuring the strength of individual foot muscles is very challenging; however, measuring muscle morphology has been shown to be associated with strength. A reliable method of assessing foot muscle atrophy and hypertrophy would therefore be beneficial to researchers and clinicians. Thus, the aim of this study was to evaluate the test-retest intra-observer reliability of ultrasound to measure the morphology of the primary toe flexor muscles. Method The abductor hallucis, flexor hallucis brevis, flexor digitorum brevis, quadratus plantae and abductor digiti minimi muscles in the foot, and the flexor digitorum longus and flexor hallucis longus muscles in the shank were assessed in five males and five females (mean age = 32.1 ± 10.1 years). Muscles were imaged using a GE Venue 40 ultrasound (6-9 or 7.6-10.7 MHz transducer) in a random order, and on two occasions 1-6 days apart. Muscle thickness and cross-sectional area were measured using Image J software with the assessor blinded to muscle and day of scan. Intraclass correlation coefficients (ICC) and limits of agreement were calculated to assess day-to-day repeatability of the measurements. Results The method was found to have good reliability (ICC = 0.89-0.99) with limits of agreement between 8-28% of the relative muscle size. Conclusion The protocol described in this paper showed that ultrasound is a reliable method to measure morphology of the toe flexor muscles. The portability and advantages of ultrasound make it a useful tool for clinical and research settings. PMID:23557252

  19. Third trimester ultrasound soft-tissue measurements accurately predicts macrosomia.

    PubMed

    Maruotti, Giuseppe Maria; Saccone, Gabriele; Martinelli, Pasquale

    2017-04-01

    To evaluate the accuracy of sonographic measurements of fetal soft tissue in the prediction of macrosomia. Electronic databases were searched from their inception until September 2015 with no limit for language. We included only studies assessing the accuracy of sonographic measurements of fetal soft tissue in the abdomen or thigh in the prediction of macrosomia  ≥34 weeks of gestation. The primary outcome was the accuracy of sonographic measurements of fetal soft tissue in the prediction of macrosomia. We generated the forest plot for the pooled sensitivity and specificity with 95% confidence interval (CI). Additionally, summary receiver-operating characteristics (ROC) curves were plotted and the area under the curve (AUC) was also computed to evaluate the overall performance of the diagnostic test accuracy. Three studies, including 287 singleton gestations, were analyzed. The pooled sensitivity of sonographic measurements of abdominal or thigh fetal soft tissue in the prediction of macrosomia was 80% (95% CI: 66-89%) and the pooled specificity was 95% (95% CI: 91-97%). The AUC for diagnostic accuracy of sonographic measurements of fetal soft tissue in the prediction of macrosomia was 0.92 and suggested high diagnostic accuracy. Third-trimester sonographic measurements of fetal soft tissue after 34 weeks may help to detect macrosomia with a high degree of accuracy. The pooled detection rate was 80%. A standardization of measurements criteria, reproducibility, building reference charts of fetal subcutaneous tissue and large studies to assess the optimal cutoff of fetal adipose thickness are necessary before the introduction of fetal soft-tissue markers in the clinical practice.

  20. Backfat thickness and longissimus dorsi real-time ultrasound measurements in light lambs.

    PubMed

    Esquivelzeta, C; Casellas, J; Fina, M; Piedrafita, J

    2012-12-01

    The aim of this study was to assess the accuracy of ultrasound measurements for predicting carcass traits in 124 Spanish pascual-type lambs (13 to 16 kg carcass weight). Ultrasound images were taken transversal and longitudinal to the vertebral column and at thoracic (TV; between 12th and 13th ribs) and lumbar (LV; between first and second lumbar vertebrae) locations. Skin thickness, subcutaneous backfat thickness (BFT), and depth (DLD), width (WLD), and area (ALD) of longissimus dorsi were obtained with ImageJ 1.42q software. After slaughter, BFT (TV, 2.30 ± 0.06 mm; LV, 2.46 ± 0.06 mm), DLD (TV, 2.47 ± 0.03 cm; LV, 2.48 ± 0.03 cm), WLD (TV, 4.50 ± 0.04 cm; LV, 4.60 ± 0.04 cm), and ALD (TV, 9.96 ± 0.12 cm(2); LV, 10.19 ± 0.13 cm(2)) were directly measured on the lamb carcass. Correlations between ultrasound and direct carcass measurements were greater than 0.61 for DLD, WLD, and ALD (P < 0.05) whereas they fluctuated between 0.32 and 0.60 for BFT (P < 0.05); moreover, correlations were significantly (P < 0.05) greater for transversal than for longitudinal views. In a similar way, linear regression analyses suggested a moderate underestimation for BFT and lumbar DLD when using real-time ultrasound technologies whereas WLD, ALD, and thoracic DLD suffered from under- and overestimation for small and large values of carcass traits, respectively. After decomposing the mean square prediction error (MSPE) for the different ultrasound measurements, we found that the error due to disturbance contributed most to the MSPE followed by the error of central tendency and the error due to regression. The SE of prediction (SEP) was also calculated as an additional precision indicator, obtaining estimates less than that in previous studies with larger lambs. In conclusion, transversal ultrasound measurements at the thoracic and lumbar levels could be a useful tool for predicting DLD, WLD, and ALD in light lambs, perhaps suffering from worse prediction properties when

  1. Noninvasive Intracranial Volume and Pressure Measurements Using Ultrasound

    NASA Technical Reports Server (NTRS)

    Hargens, A. R.

    1998-01-01

    Prevention of secondary brain injuries following head can be accomplished most easily when intracranial pressure (ICP) is monitored. However, current measurement techniques are invasive and thus not practical in the combat environment. The Pulsed Phase Lock Loop (PPLL) devise, which was developed and patented, uses a unique, noninvasive ultrasonic phase comparison method to measure slight changes in cranial volume which occur with changes in ICP. Year one studies involved instrument improvements and measurement of altered intracranial distance with altered ICP in fresh cadavera. Our software was improved to facilitate future studies of normal subjects and trauma patients. Our bench studies proved that PPLL output correlated highly with changes in path length across a model cranium. Cadaveric studies demonstrated excellent compact, noninvasive devise for monitoring changes in intracranial distance may aid in the early detection of elevated ICP, decreasing risk of secondary brain injury and infection, and returning head-injured patients to duty.

  2. Ultrasound cervical length measurement in prediction of labor induction outcome.

    PubMed

    Kehila, M; Abouda, H S; Sahbi, K; Cheour, H; Chanoufi, M Badis

    2016-05-17

    Induction of labor is one of the most common procedures in modern obstetrics, with an incidence of approximately 20% of all deliveries. Not all of these inductions result in vaginal delivery; some lead to cesarean sections, either for emergency reasons or for failed induction. That's why, It seems necessary to outline strategies for the improvement of the success rate of induced deliveries. Traditionally, the identification of women in whom labor induction is more likely to be successful is based on the Bishop score. However, several studies have shown it to be subjective, with high variation and a poor predictor of the outcome of labor induction. Transvaginal sonography for cervical measurement can be a more objective criterion in assessing the success of labor induction. Many studies have been done recently to compare cervical measurement and Bishop Score in labor induction.This paper reviewed the literature that evaluated sonographic cervical length measurement to predict induction of labor outcome.

  3. Direct and Doppler angle-independent measurement of blood flow velocity in small-diameter vessels using ultrasound microbubbles.

    PubMed

    Roy, Homagni Sikha; Zuo, Guoqing; Luo, Zhengchun; Wu, Hanping; Krupka, Tianyi M; Ran, Haitao; Li, Pan; Sun, Youping; Wang, Zhigang; Zheng, Yuanyi

    2012-01-01

    This article represents an initial attempt to demonstrate the feasibility of a novel method for measuring flow velocity in small vessels, which is a direct, noninvasive, ultrasound-guided, and Doppler angle-independent method. In vitro, experiments were designed to mimic blood flow inside tubes. Harmonic ultrasound imaging was used to track the movement of microbubbles, and the mean flow velocity was calculated. In vivo, the flow velocities were measured in the central arteries of rabbit ears. This method can be used whenever the Doppler ultrasound cannot measure the velocity in small vessels because of either low sensitivity or Doppler angle limitation. Copyright © 2012 Elsevier Inc. All rights reserved.

  4. Crack depth measurement in concrete using diffuse ultrasound

    NASA Astrophysics Data System (ADS)

    In, Chi Won; Kim, Jin-Yeon; Jacobs, Laurence L.; Kurtis, Kimberly

    2012-05-01

    Cracking in concrete structures is problematic because these cracks can significantly influence the stability of a concrete structure and compromise its durability. The first step to evaluate the serviceability of an in-field concrete structure is to have accurate information on existing crack depth. It is thus of paramount importance to be able to accurately determine the depth of cracks in these concrete structures. This research employs a diffusive ultrasonic technique to measure the depth of surface cracks in concrete. Ultrasonic measurements on a 25.4 × 33 × 60.96 cm3 concrete block containing an artificial crack with varying depths from 2.54 to 10.16 cm are conducted. Contact transducers with one transmitting and the other receiving the ultrasonic signals are mounted on the concrete surface on opposite sides of the crack. A pulse signal with the duration of 2μs is transmitted. In this frequency regime, wavelengths are sufficiently short (comparable with the aggregate size) so that a diffuse ultrasonic signal is detected. The arrival of the diffuse ultrasonic energy at the receiver is delayed by the existence of the crack. This lag-time and the diffusivity of the concrete sample are measured, and a finite element model is employed to solve the inverse problem to determine the crack depth from these measured diffuse ultrasonic parameters.

  5. Ultrasound power measurements of HITU transducer with a more stable radiation force balance

    NASA Astrophysics Data System (ADS)

    Karaböce, B.; Sadikoǧlu, E.; Bilgiç, E.

    2011-02-01

    A new radiation force balance (RFB) system was established at Turkish National Metrology Institute (UME) Ultrasonics Laboratory for High intensity therapeutic ultrasound (HITU) power measurements. The new system is highly stable at high power levels up to 500 Watts. The measurement system consists of a Plexiglas cylindrical balance arm, target mounting scale disks, conical reflecting and absorbing targets, adjustment nuts, and a hanging wire. Both of the two sides of balance were mounted similar size and weight targets. The equilibrium of the balance arm can be adjusted with nuts on screws located at both sides of the balance arm. Transducer was mounted to bottom of water tank. Absorbers in the bottom and the near walls of the tank were used for reflecting target case. Ultrasound power was applied to one scale of the balance where the reflecting/absorbing target was mounted and corresponding force was measured on the other scale of balance where was connected to a balance with a thin wire while the thin rest standing on a support. Ultrasound power of two HITU transducers at frequencies 0.93 MHz, 1.1 MHz and 3.3 MHz were measured with conventional and new system, the values were compared and uncertainty components were assessed in this paper.

  6. Correlation of pre-operative MRI and intra-operative 3D ultrasound to measure brain tissue shift

    NASA Astrophysics Data System (ADS)

    Gobbi, David G.; Comeau, Roch M.; Lee, Belinda K. H.; Peters, Terence M.

    2000-04-01

    The usefulness of stereotactic neurosurgery performed via a craniotomy is limited because the craniotomy leads to a brain tissue shift of 10 mm on average. We have recently completed an examination of 2D intra-operative ultrasound as a means of visualization and measurement of brain shift. A commercial 3D tracking system was used for real-time registration of the ultrasound video to pre-operative MR images, and annotation of the images was used to measure the shift. More than 15 surgical cases have been performed thus far with the 2D system. We are now undertaking phantom studies with tracked 3D ultrasound, and have developed sophisticated tools for real- time overlay of ultrasound and MRI volumes. These tools include a virtual-reality view of the ultrasound probe with live ultrasound video superimposed over a 3D -rendered MRI of the brain, as well as 3D ultrasound/MRI transparency overlay views. Algorithms to automatically extract landmarks from MRI and 3D ultrasound images are under development. We aim to use these landmarks to automatically generate nonlinear warp transformations to correct the pre-operative MRI as well as surgical target coordinates for brain shift. Portions of the C++ code developed for this project have been contributed to the open-source Visualization Toolkit (VTK).

  7. Scientific basis for standardization of fetal head measurements by ultrasound: a reproducibility study.

    PubMed

    Napolitano, R; Donadono, V; Ohuma, E O; Knight, C L; Wanyonyi, S Z; Kemp, B; Norris, T; Papageorghiou, A T

    2016-07-01

    To compare the standard methods for ultrasound measurement of fetal head circumference (HC) and biparietal diameter (BPD) (outer-to-outer (BPDoo) vs outer-to-inner (BPDoi) caliper placement), and compare acquisition of these measurements in transthalamic (TT) vs transventricular (TV) planes. This study utilized ultrasound images acquired from women participating in the Oxford arm of the INTERGROWTH-21(st) Project. In the first phase of the study, BPDoo and BPDoi were measured on stored images. In the second phase, real-time measurements of BPD, occipitofrontal diameter (OFD) and HC in TT and TV planes were obtained by pairs of sonographers. Reproducibility of measurements made by the same (intraobserver) and by different (interobserver) sonographers, as well as the reproducibility of caliper placement and measurements obtained in different planes, was assessed using Bland-Altman plots. In Phase I, we analyzed ultrasound images of 108 singleton fetuses. The mean intraobserver and interobserver differences were < 2% (1.34 mm) and the 95% limits of agreement were < 5% (3 mm) for both BPDoo and BPDoi. Neither method for measuring BPD showed consistently better reproducibility. In Phase II, we analyzed ultrasound images of 100 different singleton fetuses. The mean intraobserver and interobserver differences were < 1% (2.26 mm) and the 95% limits of agreement were < 8% (14.45 mm) for all fetal head measurements obtained in TV and TT planes. Neither plane for measuring fetal head showed consistently better reproducibility. Measurement of HC using the ellipse facility was as reproducible as HC calculated from BPD and OFD. OFD by itself was the least reproducible of all fetal head measurements. Measurements of BPDoi and BPDoo are equally reproducible; however, we believe BPDoo should be used in clinical practice as it allows fetal HC to be measured and compared with neonatal HC. For all head measurements, TV and TT planes provide equally reproducible

  8. Limited Accuracy of Colour Doppler Ultrasound Dynamic Tissue Perfusion Measurement in Diabetic Adults

    PubMed Central

    Stoperka, Felix; Karger, Claudia

    2016-01-01

    Dynamic tissue perfusion measurement (DTPM) is a pre-described and available method in pediatric ultrasound to quantify tissue perfusion in renal Doppler ultrasound by particular video analysis software. This study evaluates DTPM during single and between repeated visits after 6 months, calibrates repeated DTPM within different region of interest (ROI) and compares DTPM with kidney function markers in adult patients with early diabetic nephropathy (n = 17). During repeated measurements, no association of readings at the same patients in the same (n = 3 readings) as well as repeated visit (n = 2 visits) could be retrieved. No association between DTPM, MDRD-GFR, albuminuria, age and duration of diabetes was observed. These negative results are presumably related to inconsistency of DTPM due to non-fixed ROI position as could be shown in calibrating series. Further development of the method should be performed to enable reproducible DTPM readings in adults. PMID:28033403

  9. Carotid artery segmentation in ultrasound images and measurement of intima-media thickness.

    PubMed

    Naik, Vaishali; Gamad, R S; Bansod, P P

    2013-01-01

    The segmentation of the common carotid artery (CCA) wall is imperative for the determination of the intima-media thickness (IMT) on B-mode ultrasound (US) images. The IMT is considered an important indicator in the evaluation of the risk for the development of atherosclerosis. In this paper, authors have discussed the relevance of measurements in clinical practices and the challenges that one has to face while approaching the segmentation of carotid artery on ultrasound images. The paper presents an overall review of commonly used methods for the CCA segmentation and IMT measurement along with the different performance metrics that have been proposed and used for performance validation. Summary and future directions are given in the conclusion.

  10. Doppler ultrasound in the measurement of pulse wave velocity: agreement with the Complior method

    PubMed Central

    2011-01-01

    Aortic stiffness is an independent predictor factor for cardiovascular risk. Different methods for determining pulse wave velocity (PWV) are used, among which the most common are mechanical methods such as SphygmoCor or Complior, which require specific devices and are limited by technical difficulty in obtaining measurements. Doppler guided by 2D ultrasound is a good alternative to these methods. We studied 40 patients (29 male, aged 21 to 82 years) comparing the Complior method with Doppler. Agreement of both devices was high (R = 0.91, 0.84-0.95, 95% CI). The reproducibility analysis revealed no intra-nor interobserver differences. Based on these results, we conclude that Doppler ultrasound is a reliable and reproducible alternative to other established methods for the measurement of aortic PWV. PMID:21496271

  11. Accurate acoustic power measurement for low-intensity focused ultrasound using focal axial vibration velocity

    NASA Astrophysics Data System (ADS)

    Tao, Chenyang; Guo, Gepu; Ma, Qingyu; Tu, Juan; Zhang, Dong; Hu, Jimin

    2017-07-01

    Low-intensity focused ultrasound is a form of therapy that can have reversible acoustothermal effects on biological tissue, depending on the exposure parameters. The acoustic power (AP) should be chosen with caution for the sake of safety. To recover the energy of counteracted radial vibrations at the focal point, an accurate AP measurement method using the focal axial vibration velocity (FAVV) is proposed in explicit formulae and is demonstrated experimentally using a laser vibrometer. The experimental APs for two transducers agree well with theoretical calculations and numerical simulations, showing that AP is proportional to the square of the FAVV, with a fixed power gain determined by the physical parameters of the transducers. The favorable results suggest that the FAVV can be used as a valuable parameter for non-contact AP measurement, providing a new strategy for accurate power control for low-intensity focused ultrasound in biomedical engineering.

  12. Ultrasound NDE of Adhesive Bond Integrity: A Quantitative Measure

    DTIC Science & Technology

    1992-02-28

    Patriot rocket requires adhesive attachment of the ceramic-dome to the Kevlar ring . Similarly, titanium components must be bonded to phenolic-based...R. Ludwig, R. Anustasi, and G. Charron , "Comparison of Adhesive Bond Thick- ness Measurements using Experimental and Numerical Ultrasonic NDE Systems...voids that are off of the centerline which are modeled as circular rings . If the emphasis of the analysis is on the wave interaction between layered

  13. Cranial Ultrasound/Head Ultrasound

    MedlinePlus

    ... sickle cell disease. It is also used to measure conditions affecting blood flow to and within the brain, such as: Stenosis : ... saved. Doppler ultrasound, a special application of ultrasound, measures ... represent the flow of blood through the blood vessels. top of ...

  14. Development of Ultrasound to Measure In-vivo Dynamic Cervical Spine Intervertebral Disc Mechanics

    DTIC Science & Technology

    2015-01-01

    The capability of dual US to measure C-spine properties in-vivo in simulation environment is currently being tested. Biomechanics finite element(FE...and Integrity -9- 3.3 In-vivo Ultrasound Test in Simulated Environment -12- 3.4 FE Model Validaition and Modification and Simulate Operation...C-spine elastic and viscoelastic properties in-vivo under conditions simulating vibrations over a range of frequencies and amplitudes is currently

  15. Exploratory Analysis of Carbon Dioxide Levels and Ultrasound Measures of the Eye During ISS Missions

    NASA Technical Reports Server (NTRS)

    Schaefer, C.; Young, M.; Mason, S.; Coble, C.; Wear, M. L.; Sargsyan, A.; Garcia, K.; Law. J.; Alexander, D.; Ryder, V. Myers; hide

    2016-01-01

    Carbon dioxide (CO2) levels on ISS have typically averaged 2.3 to 5.3mm Hg, with large fluctuations occurring over periods of hours and days. CO2 has effects on cerebral vascular tone, resulting in vasodilation and alteration of cerebral blood flow(CBF). Increased CBF leads to elevated intracranial pressure(ICP), which is a factor leading to visual disturbance, headaches, and other central nervous system symptoms. Ultrasound of the optic nerve provides a surrogate measurement of ICP. Inflight ultrasounds were implemented as an enhanced screening tool for the Visual Impairment/Intracranial Pressure (VIIP) Syndrome. This analysis examines the relationships between ambient CO2 levels on ISS and ultrasound measures of the eye in an effort to understand how CO2 may be associated with VIIP and to inform future analysis of inflight VIIP data. Results as shown in Figure2, there was a large timeframe where CO2 readings were removed due to sensor fault errors(see Limitations), from June 2011 to January 2012. After extensive cleaning of the CO2 data, metrics for all of the data were calculated (Table2). Preliminary analyses showed possible associations between variability measures of CO2 and AP diameter (Figure3),and average CO2 exposure and ONSD(Figure4). Adjustments for multiple comparisons were not made due to the exploratory nature of the analysis.

  16. Reliability of measurements of rat lateral gastrocnemius architectural parameters obtained from ultrasound biomicroscopic images.

    PubMed

    Peixinho, Carolina Carneiro; Martins, Natália Santos da Fonseca; de Oliveira, Liliam Fernandes; Machado, João Carlos

    2014-01-01

    This study used ultrasound biomicroscopy (UBM) to quantify the pennation angle (PA) and muscle thickness (MT) of rat skeletal muscle and evaluated the reliability and reproducibility of the method by statistical analysis, determining the coefficient of variation (CV), intraclass correlation coefficient (ICC) and typical error of measurement. A UBM system with a center frequency of 40 MHz was used to acquire images of the right lateral gastrocnemius of ten male Wistar rats on two different days and with two ankle positions (90° or 150°). Two independent measurements of the PA and MT were randomly performed in each of three picture frames. The analysis resulted in CVs of 10.47% and 4.81% for the PA and the MT, respectively, for the ankle at 90° and 9.24% and 5.98% for the ankle at 150°. Additionally, the ICC values ranged from 0.75 to 0.92 for the PA and 0.57 to 0.99 for the MT. Statistically significant differences between the ankle positions were observed for the PA (p = 0.00013). The reliability of the PA and MT measurements for the rat right lateral gastrocnemius, determined from the ultrasound biomicroscopy images, was high (>0.90) for the methodology proposed. This finding indicates the potential of ultrasound biomicroscopy for quantitative muscle characterization and the longitudinal examination of tissue adaptation to different conditions of use, disease and rehabilitation.

  17. Reliability of Measurements of Rat Lateral Gastrocnemius Architectural Parameters Obtained from Ultrasound Biomicroscopic Images

    PubMed Central

    Peixinho, Carolina Carneiro; Martins, Natália Santos da Fonseca; de Oliveira, Liliam Fernandes; Machado, João Carlos

    2014-01-01

    This study used ultrasound biomicroscopy (UBM) to quantify the pennation angle (PA) and muscle thickness (MT) of rat skeletal muscle and evaluated the reliability and reproducibility of the method by statistical analysis, determining the coefficient of variation (CV), intraclass correlation coefficient (ICC) and typical error of measurement. A UBM system with a center frequency of 40 MHz was used to acquire images of the right lateral gastrocnemius of ten male Wistar rats on two different days and with two ankle positions (90° or 150°). Two independent measurements of the PA and MT were randomly performed in each of three picture frames. The analysis resulted in CVs of 10.47% and 4.81% for the PA and the MT, respectively, for the ankle at 90° and 9.24% and 5.98% for the ankle at 150°. Additionally, the ICC values ranged from 0.75 to 0.92 for the PA and 0.57 to 0.99 for the MT. Statistically significant differences between the ankle positions were observed for the PA (p = 0.00013). The reliability of the PA and MT measurements for the rat right lateral gastrocnemius, determined from the ultrasound biomicroscopy images, was high (>0.90) for the methodology proposed. This finding indicates the potential of ultrasound biomicroscopy for quantitative muscle characterization and the longitudinal examination of tissue adaptation to different conditions of use, disease and rehabilitation. PMID:24505306

  18. Ultrasound Measurement of the Temperature Field in Thermal Convection of a Liquid Metal

    NASA Astrophysics Data System (ADS)

    Xu, Hongzhou; Fife, Sean; Andereck, C. David

    2002-11-01

    We exploit the temperature dependence of sound velocity and the ease of propagation of ultrasound through fluids and solids to non-intrusively probe the thermal field of a convecting liquid metal. The technique has been validated previously with Rayleigh-Bénard convection of glycerol in a transparent chamber by comparing simultaneous ultrasound temperature measurements with visualization using a suspension in the glycerol of thermochromic liquid crystals. We subsequently constructed a movable 1D array of ultrasound transducers and have used it to measure 2D temperature distributions over the cross section of a stainless steel cell filled with mercury also undergoing Rayleigh-Bénard convection. The data clearly reveal the formation of a cellular flow pattern as the temperature difference between the bottom and top plates was slowly increased. Measurements of cell wavelength and growth, and of the critical Rayleigh number, are close to the theoretically predicted values. Details of this and related experiments, and more on the technique itself, including its limitations and potential improvements, will be described.

  19. Quantification of ultrasound correlation-based flow velocity mapping and edge velocity gradient measurement.

    PubMed

    Park, Dae Woo; Kruger, Grant H; Rubin, Jonathan M; Hamilton, James; Gottschalk, Paul; Dodde, Robert E; Shih, Albert J; Weitzel, William F

    2013-10-01

    This study investigated the use of ultrasound speckle decorrelation- and correlation-based lateral speckle-tracking methods for transverse and longitudinal blood velocity profile measurement, respectively. By studying the blood velocity gradient at the vessel wall, vascular wall shear stress, which is important in vascular physiology as well as the pathophysiologic mechanisms of vascular diseases, can be obtained. Decorrelation-based blood velocity profile measurement transverse to the flow direction is a novel approach, which provides advantages for vascular wall shear stress measurement over longitudinal blood velocity measurement methods. Blood flow velocity profiles are obtained from measurements of frame-to-frame decorrelation. In this research, both decorrelation and lateral speckle-tracking flow estimation methods were compared with Poiseuille theory over physiologic flows ranging from 50 to 1000 mm/s. The decorrelation flow velocity measurement method demonstrated more accurate prediction of the flow velocity gradient at the wall edge than the correlation-based lateral speckle-tracking method. The novelty of this study is that speckle decorrelation-based flow velocity measurements determine the blood velocity across a vessel. In addition, speckle decorrelation-based flow velocity measurements have higher axial spatial resolution than Doppler ultrasound measurements to enable more accurate measurement of blood velocity near a vessel wall and determine the physiologically important wall shear.

  20. Venous elastography: validation of a novel high-resolution ultrasound method for measuring vein compliance using finite element analysis.

    PubMed

    Biswas, Rohan; Patel, Prashant; Park, Dae W; Cichonski, Thomas J; Richards, Michael S; Rubin, Jonathan M; Hamilton, James; Weitzel, William F

    2010-01-01

    Ultrasonography for the noninvasive assessment of tissue properties has enjoyed widespread success. With the growing emphasis in recent years on arteriovenous fistulae (AVFs) for dialysis vascular access in patients with end-stage renal disease, and on reducing AVF failures, there is increasing interest in ultrasound for the preoperative evaluation of the mechanical and elastic properties of arteries and veins. This study used high-resolution ultrasound with phase-sensitive speckle tracking to obtain in vivo vein elasticity measurements during dilation. The results of this novel ultrasound technique were then compared to a computer model of venous strain. The computer model and ultrasound analysis of the vessel wall demonstrated internally consistent positive and negative longitudinal strain values as the vein wall underwent dilation. These results support further investigation of the use of phase-sensitive speckle tracking for ultrasound venous mapping for preoperative vascular access evaluation.

  1. Inter-Rectus Distance Measurement Using Ultrasound Imaging: Does the Rater Matter?

    PubMed

    Keshwani, Nadia; Hills, Nicole; McLean, Linda

    2016-01-01

    Purpose: To investigate the interrater reliability of inter-rectus distance (IRD) measured from ultrasound images acquired at rest and during a head-lift task in parous women and to establish the standard error of measurement (SEM) and minimal detectable change (MDC) between two raters. Methods: Two physiotherapists independently acquired ultrasound images of the anterior abdominal wall from 17 parous women and measured IRD at four locations along the linea alba: at the superior border of the umbilicus, at 3 cm and 5 cm above the superior border of the umbilicus, and at 3 cm below the inferior border of the umbilicus. The interrater reliability of the IRD measurements was determined using intra-class correlation coefficients (ICCs). Bland-Altman analyses were used to detect bias between the raters, and SEM and MDC values were established for each measurement site. Results: When the two raters performed their own image acquisition and processing, ICCs(3,5) ranged from 0.72 to 0.91 at rest and from 0.63 to 0.96 during head lift, depending on the anatomical measurement site. Bland-Altman analyses revealed no systematic bias between the raters. SEM values ranged from 0.23 cm to 0.71 cm, and MDC values ranged from 0.64 cm to 1.97 cm. Conclusion: When using ultrasound imaging to measure IRD in women, it is acceptable for different therapists to compare IRDs between patients and within patients over time if IRD is measured above or below the umbilicus. Interrater reliability of IRD measurement is poorest at the level of the superior border of the umbilicus.

  2. A nondestructive diagnostic method based on swept-frequency ultrasound transmission-reflection measurements

    NASA Astrophysics Data System (ADS)

    Bramanti, Mauro

    1992-08-01

    A nondestructive diagnostic technique is proposed to measure depth and thickness of unwanted inclusions inside laminate-type materials (gaps, delaminations, and cracks, for example). The method is based on the frequency-domain analysis of transmission and reflection coefficient measured on the material under test when it is irradiated by a CW ultrasound beam whose frequency varies over a suitable frequency range. By measuring the frequency distance between two adjacent minima in the attenuation and reflection coefficients the thickness and depth of the inclusion can be obtained. A practical implementation of the technique is suggested, and the first experimental results obtained by a laboratory setup are reported.

  3. Measurement of shear-wave velocity by ultrasound critical-angle reflectometry (UCR)

    NASA Technical Reports Server (NTRS)

    Mehta, S.; Antich, P.; Blomqvist, C. G. (Principal Investigator)

    1997-01-01

    There exists a growing body of research that relates the measurement of pressure-wave velocity in bone to different physiological conditions and treatment modalities. The shear-wave velocity has been less studied, although it is necessary for a more complete understanding of the mechanical properties of bone. Ultrasound critical-angle reflectometry (UCR) is a noninvasive and nondestructive technique previously used to measure pressure-wave velocities both in vitro and in vivo. This note describes its application to the measurement of shear-wave velocity in bone, whether directly accessible or covered by soft tissue.

  4. A high-performance measurement method for artery intimamedia thickness in medical ultrasound images

    NASA Astrophysics Data System (ADS)

    Jin, Jing; Wang, Yan; Gao, Xin; Wang, Qi

    2010-11-01

    A high-performance measurement method for the artery intima-media thickness (IMT) in medical ultrasound images is proposed. The scheme mainly consists of two parts. The first part is the detection process, including adaptive gray stretching for image enhancing, gradient transforming to restrain the over-segmentation, and the watershed algorithm for edge extraction. The intima can be detected automatically and exactly. The second part, combined with regional positioning and boundary fitting stages, is used to measure the IMT. Experimental results show that the proposed scheme can yield a good measurement result, and the calculation time can satisfy the practical requirement.

  5. Heritability of calcaneal quantitative ultrasound measures in healthy adults from the Fels Longitudinal Study.

    PubMed

    Lee, Miryoung; Czerwinski, Stefan A; Choh, Audrey C; Towne, Bradford; Demerath, Ellen W; Chumlea, Wm Cameron; Sun, Shumei S; Siervogel, Roger M

    2004-11-01

    Quantitative ultrasound (QUS) measurements of bone have been reported to predict osteoporotic fracture risk in postmenopausal women and older men. Although many studies have examined the heritability of bone mineral density (BMD), few studies have estimated the heritability of calcaneal QUS phenotypes. In the present study, we examined the genetic regulation of calcaneal QUS parameters in individuals from nuclear and extended families. The study population includes 260 men and 295 women aged 18-91 years (mean+/-SD: 46+/-16 years) who belong to 111 pedigrees in the Fels Longitudinal Study. Three measures of calcaneal structure were collected from both the right and left heel using the Sahara bone sonometer. These measures included broadband ultrasound attenuation (BUA), speed of sound (SOS), and the quantitative ultrasound index (QUI). We used a variance components based maximum likelihood method to estimate the heritability of QUS parameters while simultaneously adjusting for covariate effects. Additionally, we used bivariate extensions of these methods to calculate additive genetic and random environmental correlations among QUS measures. All phenotypes demonstrated statistically significant heritabilities (P<0.0000001). Heritabilities in the right heel (h2+/-SE) were h2=0.59+/-0.10 for BUA, h2=0.73+/-0.09 for SOS, and h2=0.72+/-0.09 for QUI. Similarly, heritabilities for the left heel were h2=0.52+/-0.10, h2=0.75+/-0.10, and h2=0.70+/0.10, respectively. There was evidence for significant genetic and environmental correlations among these six QUS measures. Combinations of QUS measures in the right and left heel demonstrated genetic correlations of 0.94-0.99 and all were significantly different from one indicating at least a partially unique genetic architecture for each of these measures. This study demonstrates that QUS measures of the calcaneus among healthy men and women are heritable, and there are large shared additive genetic effects among all of the traits

  6. Discriminative and reliability analyses of ultrasound measurement of abdominal muscles recruitment.

    PubMed

    Ferreira, Paulo H; Ferreira, Manuela L; Nascimento, Dafne P; Pinto, Rafael Z; Franco, Marcia R; Hodges, Paul W

    2011-10-01

    Rehabilitative ultrasound imaging has a great potential to be used as a tool in the assessment of trunk muscle function in patients with low back pain (LBP). However, a further investigation of the discriminative ability of this tool as well as the effect of operators' levels of training on reliability is warranted. Discriminative analysis of ultrasound and electromyography (EMG) measurements of transversus abdominus (TrA), obliquus internus (OI), and obliquus externus (OE) muscles function between people with and without LBP and the effect of operator's training on reliability of TrA muscle function of chronic LBP patients were conducted. For the discriminative study, measurements were collected from 10 subjects with LBP and 10 matched controls during isometric low load tasks with their limbs suspended. For the reliability study, in stage 1 the reliability of single ultrasonographic static images involved 4 operators (1 trained and 3 non-trained), whereas, in stage 2, two operators (1 trained and 1 non-trained) were used to determine the reliability of TrA thickness change. Methods used in the statistical analysis were pearson correlation and receiver operating characteristic curve for the discriminative study and intraclass correlation coefficient (ICC) for the reliability study. While ultrasound measures of OE muscle function showed poor association with EMG (r = 0.28, p = 0.22), TrA and OI function showed moderate to excellent association (TrA: r = 0.74, p < 0.000; OI: r = 0.85, p < 0.000). Ultrasound and EMG measures of TrA and OI function discriminated LBP patients from controls. Reliability of the assessment of TrA function with a trained operator (ICC = 0.92; 95% CI: 0.81-0.97) was substantially higher than a non-trained one (ICC = 0.44; 95% CI: -0.41-0.78). In conclusion, ultrasound measures of deep trunk function is a valid discriminative tool in LBP but highly dependent on operator's level of training. Copyright © 2011 Elsevier Ltd. All rights reserved.

  7. Agreement of clinical measurements of liver size with ultrasound when performed by medical students.

    PubMed

    Hunter, Selena A; Brimble, Justin; Weatherall, Mark; Galletly, Duncan C

    2014-11-07

    The accuracy of physical examination techniques in detecting liver disease is unclear. We sought to determine the perceived location of the lower liver border via scratch, percussion, palpation and ballottement with novice medical student examiners, compared with ultrasound localisation. Five novice medical students learnt four liver examination techniques and measured the lower liver border in 19 healthy volunteers. The difference between the examination technique and ultrasound (bias) and limits of agreement of each method were estimated by mixed linear models and shown using Bland-Altman- like plots. All techniques had similar bias for the lower liver border, between 1.6 and 1.9 cm superior to the ultrasound measurement. Percussion had the smallest variability with increasing liver size. Limits of agreement were wide for all techniques, smallest for palpation (6.04 cm) and largest for scratch (7.2 cm) compared to the mean liver distance of 8 cm. Conclusion There was no difference in bias between the scratch, percussion, palpation and ballottement techniques regarding the lower liver border. All techniques had very wide limits of agreement, although palpation had the smallest. Liver size examination by novice medical students in healthy subjects is unreliable. Further research is needed using examiners with a different level of expertise and participants of varying body habitus and confirmed liver disease.

  8. Laser-based ultrasound measurements of optical absorption depth in epoxy resins

    NASA Astrophysics Data System (ADS)

    Stratoudaki, Theodosia; Edwards, Christopher; Dixon, Stephen; Palmer, Stuart B.

    2002-09-01

    Pulsed lasers can generate ultrasound from stresses due to rapid thermal expansion. In this low power thermoelastic regime the material is not damaged. This paper concentrates on epoxy resins and aims to relate the observed amplitude of the longitudinal wave to the optical absorption depth of the epoxy. The ultrasound is generated using a high power pulsed laser and the absolute amplitude of the ultrasound is measured with a Michelson interferometer. In the thermoelastic regime, the laser beam is focused onto the sample, causing rapid expansion in times that are comparable to the rise time of the laser pulse. In metals, the laser radiation is absorbed in the thin electromagnetic skin depth but in non-metals the phenomenon is dominated by the optical absorption depth. The latter can vary from a few microns to several millimetres for materials such as epoxy resins. As a consequence, a bigger volume of the material is affected, the temperature rise is less and the amplitude of the longitudinal wave is greater. This condition is referred to as "a buried thermoelastic source". Two lasers were used in this study: a TEA CO2 and a XeCl excimer laser. The results are compared with optical transmission measurements.

  9. On the measurement of ultrasound transmission through a penetrable acoustic cone

    NASA Astrophysics Data System (ADS)

    Huthwaite, P.; Simonetti, F.

    2011-03-01

    Breast ultrasound tomography (BUST) is currently being developed for the early detection of cancer. Images of mechanical properties across the breast are formed using ultrasonic signals transmitted through the breast immersed in water. This is possible because the perturbation to the free propagation of ultrasound induced by the presence of the breast encodes information about the material properties of the breast. To achieve high sensitivity with BUST it is therefore crucial that the perturbation is most sensitive to the internal lesions inside the breast. However, the perturbation is also affected by the shape of the breast which can cause significant and undesired refraction effects. To understand the effect of breast shape on the transmission of ultrasound, this paper investigates transmission through a cone with properties similar to that of breast tissue. We show that it is possible to identify two regimes of transmission depending on the physical properties of the cone and transducers. While the first regime is suitable for BUST measurements, the second regime is highly affected by the breast shape and measurements are not reliable for accurate reconstructions. We provide a physical approximation that describes transmission in the first regime and which will aid the design of future BUST systems.

  10. Ultrasound modulated light blood flow measurement using intensity autocorrelation function: a Monte-Carlo simulation

    NASA Astrophysics Data System (ADS)

    Tsalach, A.; Metzger, Y.; Breskin, I.; Zeitak, R.; Shechter, R.

    2014-03-01

    Development of techniques for continuous measurement of regional blood flow, and in particular cerebral blood flow (CBF), is essential for monitoring critical care patients. Recently, a novel technique, based on ultrasound modulation of light was developed for non-invasive, continuous CBF monitoring (termed ultrasound-tagged light (UTL or UT-NIRS)), and shown to correlate with readings of 133 Xe SPECT1 and laser Doppler2. Coherent light is introduced into the tissue concurrently with an Ultrasound (US) field. Displacement of scattering centers within the sampled volume induced by Brownian motion, blood flow and the US field affects the photons' temporal correlation. Hence, the temporal fluctuations of the obtained speckle pattern provide dynamic information about the blood flow. We developed a comprehensive simulation, combining the effects of Brownian motion, US and flow on the obtained speckle pattern. Photons trajectories within the tissue are generated using a Monte-Carlo based model. Then, the temporal changes in the optical path due to displacement of scattering centers are determined, and the corresponding interference pattern over time is derived. Finally, the light intensity autocorrelation function of a single speckle is calculated, from which the tissue decorrelation time is determined. The simulation's results are compared with in-vitro experiments, using a digital correlator, demonstrating decorrelation time prediction within the 95% confidence interval. This model may assist in the development of optical based methods for blood flow measurements and particularly, in methods using the acousto-optic effect.

  11. Ultrasound measurements of temperature profiles in Rayleigh-Bénard convection

    NASA Astrophysics Data System (ADS)

    Rahal, Samir; Andereck, C. David

    1999-11-01

    Sound velocity in a fluid is a function of the temperature of the fluid along the path of the sound propagation. We have exploited this fact in developing an experimental technique for the measurement of temperature profiles in fluids using ultrasound. As a first step in testing this concept we have set up a narrow rectangular test cell containing a transparent fluid. The fluid layer is heated from below and cooled above, resulting in a periodic Rayleigh-Bénard roll pattern forming above convective onset. An ultrasound transducer operating in pulse/echo mode is moved systematically from one location to another along the test cell. At each location the time-of-flight across the cell (parallel with the convection roll axes) of the ultrasound pulses is measured. Each time-of-flight is converted to a local temperature, averaged across the cell, using the known relationship between the time-of-flight, the sound speed and the fluid temperature. From these data a temperature profile is produced. The system has a temperature resolution of ~ 0.1C. The patterns have also been visualized using thermochromic liquid crystals and we find qualitative agreement between the two independent approaches.

  12. Bedside handover: quality improvement strategy to "transform care at the bedside".

    PubMed

    Chaboyer, Wendy; McMurray, Anne; Johnson, Joanne; Hardy, Linda; Wallis, Marianne; Sylvia Chu, Fang Ying

    2009-01-01

    This quality improvement project implemented bedside handover in nursing. Using Lewin's 3-Step Model for Change, 3 wards in an Australian hospital changed from verbal reporting in an isolated room to bedside handover. Practice guidelines and a competency standard were developed. The change was received positively by both staff and patients. Staff members reported that bedside handover improved safety, efficiency, teamwork, and the level of support from senior staff members.

  13. Ultrasound spectroscopy

    NASA Astrophysics Data System (ADS)

    Giles, C. L.

    An ultrasound spectrometer was designed, constructed and used to measure the frequency dependence of forward scattered ultrasound from biological specimens. A piezoelectric transducer was continuously tuned through the frequency range of 150 to 400 MHz, producing ultrasound of the same frequency. Pulse modulation of the input signal permitted a frequency resolution of 2 MHz. The received pulse was detected at various temporal positions of its amplitude, thereby allowing measurement of the interference of the scattered and unscattered ultrasound radiation. Because of system nonlinearities all received signals were calibrated with respect to the attenuation of ultrasound in water over the system frequency range. The attenuation of water over the frequency range of 150 to 400 MHz was measured. Forward scattering experiments were performed with both physical objects and biological specimens. Sapphire spheres and plastic cylinders exhibited the expected Mie scattering resonant structure.

  14. Body Mass Normalization for Ultrasound Measurements of Adolescent Lateral Abdominal Muscle Thickness.

    PubMed

    Linek, Pawel; Saulicz, Edward; Wolny, Tomasz; Myśliwiec, Andrzej

    2017-04-01

    The purpose of this study was to determine the value of the allometric parameter for ultrasound measurements of the thickness of the oblique external (OE), internal (OI), and transversus abdominis (TrA) muscles in the adolescent population. The allometric parameter is the slope of the linear regression line between the log transformed body mass and log transformed muscle size measurement. The study included 321 adolescents between the ages of 10 and 17, consisting of 160 boys and 161 girls. The participants were recruited from local schools and attended regular school classes at normal grade levels. All individuals with no signs of scoliosis (screening with use of a scoliometer), and no surgical procedures performed on the trunk area were included. A real-time ultrasound B-scanner with a linear array transducer was used to obtain images of the lateral abdominal muscles from both sides of the body. The correlation between body mass and the OE muscle was r = 0.69; the OI muscle r = 0.68; and the TrA muscle r = 0.53 (in all cases, P < .0001). The allometric parameter for the OE was 0.88296; the OI 0.718756; and the TrA 0.60986. Using these parameters, no significant correlations were found between body mass and the allometric-scaled thickness of the lateral abdominal muscles. Significant positive correlations exist between body mass and lateral abdominal muscle thickness assessed by ultrasound imaging. Therefore, it is reasonable to advise that the values of the allometric parameters for OE, OI, and TrA obtained in this study should be used in other studies performed on adolescents. © 2016 by the American Institute of Ultrasound in Medicine.

  15. Ultrasound palpation sensor for tissue thickness and elasticity measurement--assessment of transverse carpal ligament.

    PubMed

    Zheng, Y P; Li, Z M; Choi, A P C; Lu, M H; Chen, X; Huang, Q H

    2006-12-22

    Palpation is a traditional diagnostic procedure for health care professionals to use their fingers to touch and feel the body soft tissues. It is a common clinical approach, though it is rather subjective and qualitative and the palpation results may vary among different people. Tissue ultrasound palpation sensor (TUPS) provides a feasible solution that makes the palpation of soft tissues not subjective feeling any more. It is comprised of an ultrasound transducer together with a load cell to form the finger-sized probe. The probe is used to push against the soft tissue surface to measure the thickness and elasticity of the soft tissues. TUPS has been successfully applied to the assessment of various human tissues. Recently, we have improved TUPS, which can now be linked to personal computer (PC) via universal serial bus (USB) and provide a better user-interface. The information of ultrasound signal and indentation force is displayed on PC in real time during measurement. In this paper, we introduce the recent application of TUPS for the assessment of the transverse carpal ligament. The tissues at the carpal tunnel regions of five normal male subjects were tested using TUPS. The results showed that the average thickness of the tissues covering the carpal tunnel ligament and the tunnel region was 7.98+/-1.05 mm and 9.59+/-1.12 mm, respectively. Under a compression force of 20 N applied by a cylindrical ultrasound indentor with a diameter of 9 mm, the stiffness of the soft tissue layer and the tunnel region was 6.72+/-2.10 N/mm and 15.63+/-8.42 N/mm, respectively. It is expected that TUPS can be a potential tool for non-invasive assessment of carpal tunnel syndrome.

  16. Measuring the volume of uterine fibroids using 2- and 3-dimensional ultrasound and comparison with histopathology.

    PubMed

    Zivković, Nikica; Zivković, Kreiimir; Despot, Albert; Paić, Josip; Zelić, Ana

    2012-12-01

    The aim of this study was clinical testing of the reliability and usability of three-dimensional (3D) and two-dimensional (2D) ultrasound (US) technology. The ultimate aim and purpose of this study was to establish ultrasound methods, standards and protocols for determining the volume of any gynecologic organ or tumor. The study included 31 women in reproductive age and postmenopause. All patients were examined with a RIC 5-9 3D-endovaginal probe (4.3-7.5 MHz) on a Voluson 730 Pro ultrasound device. The volume of myomas was measured by using the existing 2D and 3D ultrasound methods on the above mentioned device. All patients underwent myomectomy or hysterectomy due to clinically and ultrasonographically diagnosed uterine myomas indicating operative intervention. After the operation, the pathologist determined the volume of removed myomas by measuring them in a gauge bowl containing water, i.e. using Archimedes' principle (lift), serving as the control group with histopathologic diagnosis. A total of 155 myoma volumes were processed on 2D display, 31 myoma volumes were preoperatively measured on 3D display and 31 myoma volumes were measured by the pathologist. The values of US measurements for each US method were expressed as mean value of all measurements of myoma volumes. Statistical processing of the results and Student's t-test for independent samples revealed that the 2nd examined US method (measuring of myoma by using an ellipse and the longer tumor diameter) and 4th examined US method (measuring of myoma by using the longer and shorter tumor diameters together with establishing their mean values) in 2D US technique, as well as the 6th examined US method in 3D US technique showed no significant measurement differences in comparison with control measurement in a gauge bowl containing water (p < 0.05), indicating acceptability of the US methods for verifying tumor volumes. The standard error in determining the volume of myomas by the above US methods varied

  17. Comparing portable computers with bedside computers when administering medications using bedside medication verification.

    PubMed

    Ludwig-Beymer, Patti; Williams, Phillip; Stimac, Ellen

    2012-01-01

    This research examined bedside medication verification administration in 2 adult critical care units, using portable computers and permanent bedside computers. There were no differences in the number of near-miss errors, the time to administer the medications, or nurse perception of ease of medication administration, care of patients, or reliability of technology. The percentage of medications scanned was significantly higher with the use of permanent bedside computers, and nurses using permanent bedside computers were more likely to agree that the computer was always available.

  18. Numerical investigation of ultrasound reflection and backscatter measurements in cancellous bone on various receiving areas.

    PubMed

    Hosokawa, Atsushi

    2014-07-01

    In this study, new ultrasound reflection and backscatter measurements in cancellous bone using a membrane-type hydrophone are proposed. A membrane hydrophone made of a piezoelectric polymer film mounted on an annular frame allows an incident ultrasound wave to pass through its aperture because it has no backing material. Therefore, in measurements using the membrane hydrophone, the receiving area could be located independently from the transmitting area. In addition, the size and shape of the receiving area, which corresponded to those of the electrode deposited on the piezoelectric film, could be arranged in various ways. To investigate the validity of the proposed measurements, before bench-top experiments, the reflected and backscattered waves from cancellous bone were numerically simulated using a finite-difference time-domain method. The reflection and backscatter parameters were measured on various receiving areas, and their correlation coefficients with the structural parameters in the cancellous bone were derived. The simulated results suggested that appropriate receiving areas for the reflection and backscatter measurements could exist and that the proposed measurements could be more effective for evaluating bone properties than conventional measurements.

  19. Attenuation measurements of ultrasound in a kaolin-water slurry. A linear dependence upon frequency

    SciTech Connect

    Greenwood, M.S.; Mai, J.L.; Good, M.S. )

    1993-08-01

    The attenuation of ultrasound through a kaolin-water slurry was measured for frequencies ranging from 0.5 to 3.0 MHz. The maximum concentration of the slurry was for a weight percentage of 44% (or a volume fraction of 0.24). The goal of these measurements was to assess the feasibility of using ultrasonic attenuation to determine the concentration of a slurry of known composition. The measurements were obtained by consecutively adding kaolin to the slurry and measuring the attenuation at each concentration. After reaching a maximum concentration a dilution technique was used, in which an amount of slurry was removed and water was added, to obtain the attenuation as a function of the concentration. The dilution technique was the more effective method to obtain calibration data. These measurements were carried out using two transducers, having a center frequency of 2.25 MHz, separated by 0.1016m (4.0 in.). The maximum attenuation measured in these experiments was about 100Np/m, but the experimental apparatus has the capability of measuring a larger attenuation if the distance between the two transducers is decreased. For a given frequency, the data show that ln V/V[sub 0] depends linearly upon the volume fraction (V is the received voltage for the slurry and V[sub 0] is that obtained for water). This indicated that each particle acts independently in attenuating ultrasound. 12 refs., 7 figs., 3 tabs.

  20. Measurement of the contrast agent intrinsic and native harmonic response with single transducer pulse waved ultrasound systems.

    PubMed

    Verbeek, X A; Willigers, J M; Brands, P J; Ledoux, L A; Hoeks, A P

    1999-01-01

    Ultrasound contrast agents, i.e., small gas filled microbubbles, enhance the echogenicity of blood and have the potential to be used for tissue perfusion assessment. The contrast agents scatter ultrasound in a nonlinear manner and thereby introduce harmonics in the ultrasound signal. This property is exploited in new ultrasound techniques like harmonic imaging, which aims to display only the contrast agent presence. Much attention has already been given to the physical properties of the contrast agent. The present study focuses on practical aspects of the measurement of the intrinsic harmonic response of ultrasound contrast agents with single transducer pulse waved ultrasound systems. Furthermore, the consequences of two other sources of harmonics are discussed. These sources are the nonlinear distortion of ultrasound in a medium generating native harmonics, and the emitted signal itself which might contain contaminating harmonics. It is demonstrated conceptually and by experiments that optimization of the contrast agent harmonic response measured with a single transducer is governed by the transducer spectral sensitivity distribution rather than the resonance properties of the contrast agent. Both native and contaminating harmonics may be of considerable strength and can be misinterpreted as intrinsic harmonics of the contrast agent. Practical difficulties to filter out the harmonic component selectively, without deteriorating the image, may cause misinterpretation of the fundamental as a harmonic.

  1. Quantitative measurement of high intensity focused ultrasound pressure field by optical phase contrast method applying non-continuous phase unwrapping algorithm

    NASA Astrophysics Data System (ADS)

    Syahid, Mohd; Oyama, Seiji; Yasuda, Jun; Yoshizawa, Shin; Umemura, Shin-ichiro

    2015-07-01

    A fast and accurate ultrasound pressure field measurement is necessary for the progress of ultrasound application in medicine. In general, a hydrophone is used to measure the ultrasound field, which takes a long measurement time and might disturb the ultrasound field. Hence, we proposed a new method categorized in an optical method called Phase Contrast method to overcome the drawback in the hydrophone method. The proposed method makes use of the spatial DC spectrum formed in the focal plane to measure the modulated optical phase induced by ultrasound propagation in water. In this study, we take into account the decreased intensity of the DC spectrum at high ultrasound intensity to increase the measurement accuracy of the modulated optical phase. Then, we apply a non-continuous phase unwrapping algorithm to unwrap the modulated optical phase at high ultrasound intensity. From, the unwrapped result, we evaluate the quantitativeness of the proposed method.

  2. Can Anatomists Teach Living Anatomy Using Ultrasound as a Teaching Tool?

    ERIC Educational Resources Information Center

    Jurjus, Rosalyn A.; Dimorier, Kathryn; Brown, Kirsten; Slaby, Frank; Shokoohi, Hamid; Boniface, Keith; Liu, Yiju Teresa

    2014-01-01

    The utilization of bedside ultrasound by an increasing number of medical specialties has created the need for more ultrasound exposure and teaching in medical school. Although there is a widespread support for more vertical integration of ultrasound teaching throughout the undergraduate curriculum, little is known about whether the quality of…

  3. Can Anatomists Teach Living Anatomy Using Ultrasound as a Teaching Tool?

    ERIC Educational Resources Information Center

    Jurjus, Rosalyn A.; Dimorier, Kathryn; Brown, Kirsten; Slaby, Frank; Shokoohi, Hamid; Boniface, Keith; Liu, Yiju Teresa

    2014-01-01

    The utilization of bedside ultrasound by an increasing number of medical specialties has created the need for more ultrasound exposure and teaching in medical school. Although there is a widespread support for more vertical integration of ultrasound teaching throughout the undergraduate curriculum, little is known about whether the quality of…

  4. Ultrasound Velocity Measurements in High-Chromium Steel Under Plastic Deformation

    NASA Astrophysics Data System (ADS)

    Lunev, Aleksey; Bochkareva, Anna; Barannikova, Svetlana; Zuev, Lev

    2016-04-01

    In the present study, the variation of the propagation velocity of ultrasound in the plastic deformation of corrosion-resistant high-chromium steel 40X13 with ferrite-carbide (delivery status), martensitic (quenched) and sorbitol (after high-temperature tempering) structures have beem studied/ It is found that each state shows its view of the loading curve. In the delivery state diagram loading is substantially parabolic throughout, while in the martensitic state contains only linear strain hardening step and in the sorbitol state the plastic flow curve is three-step. The velocity of ultrasonic surface waves (Rayleigh waves) was measured simultaneously with the registration of the loading curve in the investigated steel in tension. It is shown that the dependence of the velocity of ultrasound in active loading is determined by the law of plastic flow, that is, the staging of the corresponding diagram of loading. Structural state of the investigated steel is not only changing the type of the deformation curve under uniaxial tension, but also changes the nature of ultrasound speed of deformation.

  5. Three-dimensional simulation of ultrasound propagation through trabecular bone structures measured by synchrotron microtomography.

    PubMed

    Bossy, Emmanuel; Padilla, Frédéric; Peyrin, Françoise; Laugier, Pascal

    2005-12-07

    Three-dimensional numerical simulations of ultrasound transmission were performed through 31 trabecular bone samples measured by synchrotron microtomography. The synchrotron microtomography provided high resolution 3D mappings of bone structures, which were used as the input geometry in the simulation software developed in our laboratory. While absorption (i.e. the absorption of ultrasound through dissipative mechanisms) was not taken into account in the algorithm, the simulations reproduced major phenomena observed in real through-transmission experiments in trabecular bone. The simulated attenuation (i.e. the decrease of the transmitted ultrasonic energy) varies linearly with frequency in the MHz frequency range. Both the speed of sound (SOS) and the slope of the normalized frequency-dependent attenuation (nBUA) increase with the bone volume fraction. Twenty-five out of the thirty-one samples exhibited negative velocity dispersion. One sample was rotated to align the main orientation of the trabecular structure with the direction of ultrasonic propagation, leading to the observation of a fast and a slow wave. Coupling numerical simulation with real bone architecture therefore provides a powerful tool to investigate the physics of ultrasound propagation in trabecular structures. As an illustration, comparison between results obtained on bone modelled either as a fluid or a solid structure suggested the major role of mode conversion of the incident acoustic wave to shear waves in bone to explain the large contribution of scattering to the overall attenuation.

  6. Three-dimensional simulation of ultrasound propagation through trabecular bone structures measured by synchrotron microtomography

    NASA Astrophysics Data System (ADS)

    Bossy, Emmanuel; Padilla, Frédéric; Peyrin, Françoise; Laugier, Pascal

    2005-12-01

    Three-dimensional numerical simulations of ultrasound transmission were performed through 31 trabecular bone samples measured by synchrotron microtomography. The synchrotron microtomography provided high resolution 3D mappings of bone structures, which were used as the input geometry in the simulation software developed in our laboratory. While absorption (i.e. the absorption of ultrasound through dissipative mechanisms) was not taken into account in the algorithm, the simulations reproduced major phenomena observed in real through-transmission experiments in trabecular bone. The simulated attenuation (i.e. the decrease of the transmitted ultrasonic energy) varies linearly with frequency in the MHz frequency range. Both the speed of sound (SOS) and the slope of the normalized frequency-dependent attenuation (nBUA) increase with the bone volume fraction. Twenty-five out of the thirty-one samples exhibited negative velocity dispersion. One sample was rotated to align the main orientation of the trabecular structure with the direction of ultrasonic propagation, leading to the observation of a fast and a slow wave. Coupling numerical simulation with real bone architecture therefore provides a powerful tool to investigate the physics of ultrasound propagation in trabecular structures. As an illustration, comparison between results obtained on bone modelled either as a fluid or a solid structure suggested the major role of mode conversion of the incident acoustic wave to shear waves in bone to explain the large contribution of scattering to the overall attenuation.

  7. Toward predicting tensile strength of pharmaceutical tablets by ultrasound measurement in continuous manufacturing.

    PubMed

    Razavi, Sonia M; Callegari, Gerardo; Drazer, German; Cuitiño, Alberto M

    2016-06-30

    An ultrasound measurement system was employed as a non-destructive method to evaluate its reliability in predicting the tensile strength of tablets and investigate the benefits of incorporating it in a continuous line, manufacturing solid dosage forms. Tablets containing lactose, acetaminophen, and magnesium stearate were manufactured continuously and in batches. The effect of two processing parameters, compaction force and level of shear strain were examined. Young's modulus and tensile strength of tablets were obtained by ultrasound and diametrical mechanical testing, respectively. It was found that as the blend was exposed to increasing levels of shear strain, the speed of sound in the tablets decreased and the tablets became both softer and mechanically weaker. Moreover, the results indicate that two separate tablet material properties (e.g., relative density and Young's modulus) are necessary in order to predict tensile strength. A strategy for hardness prediction is proposed that uses the existing models for Young's modulus and tensile strength of porous materials. Ultrasound testing was found to be very sensitive in differentiating tablets with similar formulation but produced under different processing conditions (e.g., different level of shear strain), thus, providing a fast, and non-destructive method for hardness prediction that could be incorporated to a continuous manufacturing process. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. Quantitative muscle ultrasound measures rapid declines over time in children with SMA type 1.

    PubMed

    Ng, Kay W; Connolly, Anne M; Zaidman, Craig M

    2015-11-15

    Muscles are small in spinal muscular atrophy (SMA). It is not known if muscle size changes over time in SMA type 1. We quantified changes over time in muscle size and echointensity during two repeated ultrasound examinations of unilateral proximal (biceps brachii/brachialis and quadriceps) and distal (anterior forearm flexors and tibialis anterior) muscles in three children with SMA type 1. We compared muscle thickness (MT) to body weight-dependent normal reference values. Children were 1, 6, and 11months old at baseline and had 2, 2 and 4 months between ultrasound examinations, respectively. At baseline, MT was normal for weight in all muscles except an atrophic quadriceps in the oldest child. MT decreased and echointensity increased (worsened) over time. At follow up, MT was below normal for weight in the quadriceps in all three children, in the biceps/brachioradialis in two, and in the anterior forearm in one. Tibialis anterior MT remained normal for weight in all three children. Muscle echointensity increased over time in all muscles and, on average, more than doubled in two children. In children with SMA type 1, muscle atrophies and becomes hyperechoic over time. Quantitative muscle ultrasound measures disease progression in SMA type 1 that warrants additional study in more children. Copyright © 2015. Published by Elsevier B.V.

  9. Direct measurement of speed of sound in cartilage in situ using ultrasound and magnetic resonance images.

    PubMed

    Nitta, N; Aoki, T; Hyodo, K; Misawa, M; Homma, K

    2013-01-01

    This study verified the accuracy of the speed of sound (SOS) measured by the combination method, which calculates the ratio between the thickness values of cartilage measured by using the magnetic resonance imaging (MRI) and the ultrasonic pulse-echo imaging, and investigated in vivo application of this method. SOS specific to an ultrasound imaging device was used as a reference value to calculate the actual SOS from the ratio of cartilage thicknesses obtained from MR and ultrasound images. The accuracy of the thickness measurement was verified by comparing results obtained using MRI and a non-contact laser, and the accuracy of the calculated SOS was confirmed by comparing results of the pulse-echo and transmission methods in vitro. The difference between laser and MRI measurements was 0.05 ± 0.22 mm. SOS values in a human knee measured by the combination method in the medial and lateral femoral condyles were 1650 ± 79 and 1642 ± 78 m/s, respectively (p < 0.05). The results revealed the feasibility of in situ SOS measurement using the combination method.

  10. Absolute and relative reliability of lumbar interspinous process ultrasound imaging measurements

    PubMed Central

    Tozawa, Ryosuke; Katoh, Munenori; Aramaki, Hidefumi; Kawasaki, Tsubasa; Nishikawa, Yuichi; Kumamoto, Tsuneo; Fujinawa, Osamu

    2016-01-01

    [Purpose] The intra- and inter-examiner reliabilities of lumbar interspinous process distances measured by ultrasound imaging were examined. [Subjects and Methods] The subjects were 10 males who had no history of orthopedic diseases or dysfunctions. Ten lumbar interspinous images from 360 images captured from 10 subjects were selected. The 10 images were measured by nine examiners. The lumbar interspinous process distance measurements were performed five times by each examiner. In addition, four of the nine examiners measured the distances again after 4 days for test-retest analysis. In statistical analysis, the intraclass correlation coefficient was used to investigate relative reliability, and Bland-Altman analysis was used to investigate absolute reliability. [Results] The intraclass correlation coefficients (1, 1) for intra-examiner reliability ranged from 0.985 to 0.998. For inter-rater reliability, the intraclass correlation coefficient (2, 1) was 0.969. The intraclass correlation coefficients (1, 2) for test-retest reliability ranged from 0.991 to 0.999. The Bland-Altman analysis results indicated no systematic error. [Conclusion] The results indicate that ultrasound measurements of interspinous process distance are highly reliable even when measured only once by a single person. PMID:27630399

  11. Ultrasound-based measurement of molecular marker concentration in large blood vessels: a feasibility study.

    PubMed

    Wang, Shiying; Mauldin, F William; Klibanov, Alexander L; Hossack, John A

    2015-01-01

    Ultrasound molecular imaging has demonstrated efficacy in pre-clinical studies for cancer and cardiovascular inflammation. However, these techniques often require lengthy protocols because of waiting periods or additional control microbubble injections. Moreover, they are not capable of quantifying molecular marker concentration in human tissue environments that exhibit variable attenuation and propagation path lengths. Our group recently investigated a modulated acoustic radiation force-based imaging sequence, which was found to detect targeted adhesion independent of control measurements. In the present study, this sequence was tested against various experimental parameters to determine its feasibility for quantitative measurements of molecular marker concentration. Results indicated that measurements obtained from the sequence (residual-to-saturation ratio, Rresid) were independent of acoustic pressure and attenuation (p > 0.13, n = 10) when acoustic pressures were sufficiently low. The Rresid parameter exhibited a linear relationship with measured molecular marker concentration (R(2) > 0.94). Consequently, feasibility was illustrated in vitro, for quantification of molecular marker concentration in large vessels using a modulated acoustic radiation force-based sequence. Moreover, these measurements were independent of absolute acoustic reflection amplitude and used short imaging protocols (3 min) without control measurements. Copyright © 2015 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

  12. Pulse-echo ultrasound transit time spectroscopy: A comparison of experimental measurement and simulation prediction.

    PubMed

    Wille, Marie-Luise; Almualimi, Majdi A; Langton, Christian M

    2016-01-01

    Considering ultrasound propagation through complex composite media as an array of parallel sonic rays, a comparison of computer-simulated prediction with experimental data has previously been reported for transmission mode (where one transducer serves as transmitter, the other as receiver) in a series of 10 acrylic step-wedge samples, immersed in water, exhibiting varying degrees of transit time inhomogeneity. In this study, the same samples were used but in pulse-echo mode, where the same ultrasound transducer served as both transmitter and receiver, detecting both 'primary' (internal sample interface) and 'secondary' (external sample interface) echoes. A transit time spectrum was derived, describing the proportion of sonic rays with a particular transit time. A computer simulation was performed to predict the transit time and amplitude of various echoes created, and compared with experimental data. Applying an amplitude-tolerance analysis, 91.7% ± 3.7% of the simulated data were within ±1 standard deviation of the experimentally measured amplitude-time data. Correlation of predicted and experimental transit time spectra provided coefficients of determination (R(2)%) ranging from 100.0% to 96.8% for the various samples tested. The results acquired from this study provide good evidence for the concept of parallel sonic rays. Furthermore, deconvolution of experimental input and output signals has been shown to provide an effective method to identify echoes otherwise lost due to phase cancellation. Potential applications of pulse-echo ultrasound transit time spectroscopy include improvement of ultrasound image fidelity by improving spatial resolution and reducing phase interference artefacts.

  13. Ultrasound Elastography: Review of Techniques and Clinical Applications

    PubMed Central

    Sigrist, Rosa M.S.; Liau, Joy; Kaffas, Ahmed El; Chammas, Maria Cristina; Willmann, Juergen K.

    2017-01-01

    Elastography-based imaging techniques have received substantial attention in recent years for non-invasive assessment of tissue mechanical properties. These techniques take advantage of changed soft tissue elasticity in various pathologies to yield qualitative and quantitative information that can be used for diagnostic purposes. Measurements are acquired in specialized imaging modes that can detect tissue stiffness in response to an applied mechanical force (compression or shear wave). Ultrasound-based methods are of particular interest due to its many inherent advantages, such as wide availability including at the bedside and relatively low cost. Several ultrasound elastography techniques using different excitation methods have been developed. In general, these can be classified into strain imaging methods that use internal or external compression stimuli, and shear wave imaging that use ultrasound-generated traveling shear wave stimuli. While ultrasound elastography has shown promising results for non-invasive assessment of liver fibrosis, new applications in breast, thyroid, prostate, kidney and lymph node imaging are emerging. Here, we review the basic principles, foundation physics, and limitations of ultrasound elastography and summarize its current clinical use and ongoing developments in various clinical applications. PMID:28435467

  14. Comparative ultrasound measurement of normal thyroid gland dimensions in school aged children in our local environment.

    PubMed

    Marchie, T T; Oyobere, O; Eze, K C

    2012-01-01

    The objective of this study was to determine the measurement of normal range of ultrasound (US) thyroid gland dimensions in school-aged children (6-16 years) in our environment and compared with what is obtained elsewhere. A prospective ultrasound measurement study done in University of Benin Teaching Hospital Benin, Nigeria. A prospective ultrasound (US) study of thyroid dimensions of 500 school-aged children in our environment consisting of 227 boys and 273 girls was done from 1 December 2006 to July 2007. The subjects were examined by the authors and subjects with palpable abnormal thyroid gland were excluded from the study. The thyroid dimensions (length, height, and diameter) were taken for each lobe by means of ultrasound (US). In addition volume of each thyroid lobe was calculated and the summation of volume of the lobes was taken as thyroid gland volume of each subject. Also height and weight of patients were documented from which the subject's body surface was calculated. Incidental thyroid gland lesion in US was excluded from the study. Using the Statistical program of social science (SPSS) and INSTAT (Graph Pad Inc. USA) the data were analyzed. Informed consent was obtained from all the subjects and the study was done in line with the ethical guidelines of the centers. The US thyroid gland volume in school-aged children in Benin City from this study ranges between 1.17 cm 3 and 7.19 cm 3 , mean volume range of 1.76-4.95 cm 3 , median volume range of 1.73-4.73 cm 3 , and range of standard deviation from 0.39 cm 3 to 1.49 cm 3 . The average mean thyroid volume is 2.32 cm 3 with the following average dimensions; anteroposterior right lobe =1.06 cm, mediolateral right lobe = 1.01 cm and craniocaudal right lobe = 2.34 cm, and anteroposterior left lobe = 1.01 cm, mediolateral left lobe = 1.04 cm and craniocaudal left lobe = 2.41 cm for both boys and girls respectively. These data are significantly lower than data obtained by European based World Health

  15. Non-invasive ultrasound based temperature measurements at reciprocating screw plastication units: Methodology and applications

    NASA Astrophysics Data System (ADS)

    Straka, Klaus; Praher, Bernhard; Steinbichler, Georg

    2015-05-01

    Previous attempts to accurately measure the real polymer melt temperature in the screw chamber as well as in the screw channels have failed on account of the challenging metrological boundary conditions (high pressure, high temperature, rotational and axial screw movement). We developed a novel ultrasound system - based on reflection measurements - for the online determination of these important process parameters. Using available pressure-volume-temperature (pvT) data from a polymer it is possible to estimate the density and adiabatic compressibility of the material and therefore the pressure and temperature depending longitudinal ultrasound velocity. From the measured ultrasonic reflection time from the screw root and barrel wall and the pressure it is possible to calculate the mean temperature in the screw channel or in the chamber in front of the screw (in opposition to flush mounted infrared or thermocouple probes). By means of the above described system we are able to measure axial profiles of the mean temperature in the screw chamber. The data gathered by the measurement system can be used to develop control strategies for the plastication process to reduce temperature gradients within the screw chamber or as input data for injection moulding simulation.

  16. Acoustic characterization of high intensity focused ultrasound fields: A combined measurement and modeling approach

    PubMed Central

    Canney, Michael S.; Bailey, Michael R.; Crum, Lawrence A.; Khokhlova, Vera A.; Sapozhnikov, Oleg A.

    2008-01-01

    Acoustic characterization of high intensity focused ultrasound (HIFU) fields is important both for the accurate prediction of ultrasound induced bioeffects in tissues and for the development of regulatory standards for clinical HIFU devices. In this paper, a method to determine HIFU field parameters at and around the focus is proposed. Nonlinear pressure waveforms were measured and modeled in water and in a tissue-mimicking gel phantom for a 2 MHz transducer with an aperture and focal length of 4.4 cm. Measurements were performed with a fiber optic probe hydrophone at intensity levels up to 24 000 W∕cm2. The inputs to a Khokhlov–Zabolotskaya–Kuznetsov-type numerical model were determined based on experimental low amplitude beam plots. Strongly asymmetric waveforms with peak positive pressures up to 80 MPa and peak negative pressures up to 15 MPa were obtained both numerically and experimentally. Numerical simulations and experimental measurements agreed well; however, when steep shocks were present in the waveform at focal intensity levels higher than 6000 W∕cm2, lower values of the peak positive pressure were observed in the measured waveforms. This underrepresentation was attributed mainly to the limited hydrophone bandwidth of 100 MHz. It is shown that a combination of measurements and modeling is necessary to enable accurate characterization of HIFU fields. PMID:19062878

  17. Acoustic characterization of high intensity focused ultrasound fields: a combined measurement and modeling approach.

    PubMed

    Canney, Michael S; Bailey, Michael R; Crum, Lawrence A; Khokhlova, Vera A; Sapozhnikov, Oleg A

    2008-10-01

    Acoustic characterization of high intensity focused ultrasound (HIFU) fields is important both for the accurate prediction of ultrasound induced bioeffects in tissues and for the development of regulatory standards for clinical HIFU devices. In this paper, a method to determine HIFU field parameters at and around the focus is proposed. Nonlinear pressure waveforms were measured and modeled in water and in a tissue-mimicking gel phantom for a 2 MHz transducer with an aperture and focal length of 4.4 cm. Measurements were performed with a fiber optic probe hydrophone at intensity levels up to 24,000 W/cm(2). The inputs to a Khokhlov-Zabolotskaya-Kuznetsov-type numerical model were determined based on experimental low amplitude beam plots. Strongly asymmetric waveforms with peak positive pressures up to 80 MPa and peak negative pressures up to 15 MPa were obtained both numerically and experimentally. Numerical simulations and experimental measurements agreed well; however, when steep shocks were present in the waveform at focal intensity levels higher than 6000 W/cm(2), lower values of the peak positive pressure were observed in the measured waveforms. This underrepresentation was attributed mainly to the limited hydrophone bandwidth of 100 MHz. It is shown that a combination of measurements and modeling is necessary to enable accurate characterization of HIFU fields.

  18. Automatic segmentation and measurements of gestational sac using static B-mode ultrasound images

    NASA Astrophysics Data System (ADS)

    Ibrahim, Dheyaa Ahmed; Al-Assam, Hisham; Du, Hongbo; Farren, Jessica; Al-karawi, Dhurgham; Bourne, Tom; Jassim, Sabah

    2016-05-01

    Ultrasound imagery has been widely used for medical diagnoses. Ultrasound scanning is safe and non-invasive, and hence used throughout pregnancy for monitoring growth. In the first trimester, an important measurement is that of the Gestation Sac (GS). The task of measuring the GS size from an ultrasound image is done manually by a Gynecologist. This paper presents a new approach to automatically segment a GS from a static B-mode image by exploiting its geometric features for early identification of miscarriage cases. To accurately locate the GS in the image, the proposed solution uses wavelet transform to suppress the speckle noise by eliminating the high-frequency sub-bands and prepare an enhanced image. This is followed by a segmentation step that isolates the GS through the several stages. First, the mean value is used as a threshold to binarise the image, followed by filtering unwanted objects based on their circularity, size and mean of greyscale. The mean value of each object is then used to further select candidate objects. A Region Growing technique is applied as a post-processing to finally identify the GS. We evaluated the effectiveness of the proposed solution by firstly comparing the automatic size measurements of the segmented GS against the manual measurements, and then integrating the proposed segmentation solution into a classification framework for identifying miscarriage cases and pregnancy of unknown viability (PUV). Both test results demonstrate that the proposed method is effective in segmentation the GS and classifying the outcomes with high level accuracy (sensitivity (miscarriage) of 100% and specificity (PUV) of 99.87%).

  19. The use of ultrasound in obstetric anesthesia.

    PubMed

    Weiniger, Carolyn F; Sharoni, Limor

    2017-06-01

    The current review considers an array of recent applications for point-of-care ultrasound in clinical practice including diagnostic and therapeutic procedures that may be relevant for the obstetric anesthesiologist. The rapid advancement of technology and clinical applications for bedside ultrasound in obstetric anesthesiology requires an appraisal of the limitations and uses. The review presents the most recent literature describing ultrasound-guided airway assessments, airway management, cricothyroidotomy, transthoracic echocardiography, gastric volume assessments, point-of-care lung ultrasound diagnoses, intracranial pressure assessments, vascular access, neuraxial blocks, and transversus abdominis plane blocks. Each ultrasound technique is presented along with the most recent advances in knowledge and some limitations to integration of these ultrasound skills in clinical practice. Anesthesiologists have clearly embraced this facile versatile tool for bedside diagnostics and procedures. One limitation to widespread adoption is availability of suitable ultrasound skills and technology. Many of these ultrasound techniques have not yet established clear patient benefit, yet the sheer breadth of ultrasound techniques reported in the past few years demonstrate that our colleagues are becoming more proficient. It is important to follow the development of this emerging field to be aware of limitations to learning these skills and their potential clinical benefit. Proficiency in some of these point-of-care ultrasound techniques may become prerequisite for obstetric anesthesiologists to provide the best care.

  20. Ultrasound annual, 1986

    SciTech Connect

    Sanders, R.C.; Hill, M.C.

    1986-01-01

    This book provides an analyses of developments in the field of diagnostic ultrasound. Endoscopic ultrasound and ultrasound-guided aspiration of ovarian follicles for in vitro fertilization are addressed. The use of Doppler ultrasound to measure blood flow in obstetrics is also examined.

  1. Attenuation measuring ultrasound shearwave elastography and in vivo application in post-transplant liver patients

    NASA Astrophysics Data System (ADS)

    Nenadic, Ivan Z.; Qiang, Bo; Urban, Matthew W.; Zhao, Heng; Sanchez, William; Greenleaf, James F.; Chen, Shigao

    2017-01-01

    Ultrasound and magnetic resonance elastography techniques are used to assess mechanical properties of soft tissues. Tissue stiffness is related to various pathologies such as fibrosis, loss of compliance, and cancer. One way to perform elastography is measuring shear wave velocity of propagating waves in tissue induced by intrinsic motion or an external source of vibration, and relating the shear wave velocity to tissue elasticity. All tissues are inherently viscoelastic and ignoring viscosity biases the velocity-based estimates of elasticity and ignores a potentially important parameter of tissue health. We present attenuation measuring ultrasound shearwave elastography (AMUSE), a technique that independently measures both shear wave velocity and attenuation in tissue and therefore allows characterization of viscoelasticity without using a rheological model. The theoretical basis for AMUSE is first derived and validated in finite element simulations. AMUSE is validated against the traditional methods for assessing shear wave velocity (phase gradient) and attenuation (amplitude decay) in tissue mimicking phantoms and excised tissue. The results agreed within one standard deviation. AMUSE was used to measure shear wave velocity and attenuation in 15 transplanted livers in patients with potential acute rejection, and the results were compared with the biopsy findings in a preliminary study. The comparison showed excellent agreement and suggests that AMUSE can be used to separate transplanted livers with acute rejection from livers with no rejection.

  2. Fetal growth and air pollution - A study on ultrasound and birth measures.

    PubMed

    Malmqvist, Ebba; Liew, Zeyan; Källén, Karin; Rignell-Hydbom, Anna; Rittner, Ralf; Rylander, Lars; Ritz, Beate

    2017-01-01

    Air pollution has been suggested to affect fetal growth, but more data is needed to assess the timing of exposure effects by using ultrasound measures. It is also important to study effects in low exposure areas to assess eventual thresholds of effects. The MAPSS (Maternal Air Pollution in Southern Sweden) cohort consists of linked registry data for around 48,000 pregnancies from an ultrasound database, birth registry and exposure data based on residential addresses. Measures of air pollution exposure were obtained through dispersion modelling with input data from an emissions database (NOx) with high resolution (100-500m grids). Air pollution effects were assessed with linear regressions for the following endpoints; biparietal diameter, femur length, abdominal diameter and estimated fetal weight measured in late pregnancy and birth weight and head circumference measured at birth. We estimated negative effects for NOx; in the adjusted analyses the decrease of abdominal diameter and femur length were -0.10 (-0.17, -0.03) and -0.13 (-0.17, -0.01)mm, respectively, per 10µg/m(3) increment of NOx. We also estimated an effect of NOx-exposures on birth weight by reducing birth weight by 9g per 10µg/m(3) increment of NOx. We estimated small but statistically significant effects of air pollution on late fetal and birth size and reduced fetal growth late in pregnancy in a geographic area with levels below current WHO air quality guidelines.

  3. Attenuation measuring ultrasound shearwave elastography and in vivo application in post-transplant liver patients.

    PubMed

    Nenadic, Ivan Z; Qiang, Bo; Urban, Matthew W; Zhao, Heng; Sanchez, William; Greenleaf, James F; Chen, Shigao

    2017-01-21

    Ultrasound and magnetic resonance elastography techniques are used to assess mechanical properties of soft tissues. Tissue stiffness is related to various pathologies such as fibrosis, loss of compliance, and cancer. One way to perform elastography is measuring shear wave velocity of propagating waves in tissue induced by intrinsic motion or an external source of vibration, and relating the shear wave velocity to tissue elasticity. All tissues are inherently viscoelastic and ignoring viscosity biases the velocity-based estimates of elasticity and ignores a potentially important parameter of tissue health. We present attenuation measuring ultrasound shearwave elastography (AMUSE), a technique that independently measures both shear wave velocity and attenuation in tissue and therefore allows characterization of viscoelasticity without using a rheological model. The theoretical basis for AMUSE is first derived and validated in finite element simulations. AMUSE is validated against the traditional methods for assessing shear wave velocity (phase gradient) and attenuation (amplitude decay) in tissue mimicking phantoms and excised tissue. The results agreed within one standard deviation. AMUSE was used to measure shear wave velocity and attenuation in 15 transplanted livers in patients with potential acute rejection, and the results were compared with the biopsy findings in a preliminary study. The comparison showed excellent agreement and suggests that AMUSE can be used to separate transplanted livers with acute rejection from livers with no rejection.

  4. Automated kidney morphology measurements from ultrasound images using texture and edge analysis

    NASA Astrophysics Data System (ADS)

    Ravishankar, Hariharan; Annangi, Pavan; Washburn, Michael; Lanning, Justin

    2016-04-01

    In a typical ultrasound scan, a sonographer measures Kidney morphology to assess renal abnormalities. Kidney morphology can also help to discriminate between chronic and acute kidney failure. The caliper placements and volume measurements are often time consuming and an automated solution will help to improve accuracy, repeatability and throughput. In this work, we developed an automated Kidney morphology measurement solution from long axis Ultrasound scans. Automated kidney segmentation is challenging due to wide variability in kidney shape, size, weak contrast of the kidney boundaries and presence of strong edges like diaphragm, fat layers. To address the challenges and be able to accurately localize and detect kidney regions, we present a two-step algorithm that makes use of edge and texture information in combination with anatomical cues. First, we use an edge analysis technique to localize kidney region by matching the edge map with predefined templates. To accurately estimate the kidney morphology, we use textural information in a machine learning algorithm framework using Haar features and Gradient boosting classifier. We have tested the algorithm on 45 unseen cases and the performance against ground truth is measured by computing Dice overlap, % error in major and minor axis of kidney. The algorithm shows successful performance on 80% cases.

  5. Pocket-size imaging devices allow for reliable bedside screening for femoral artery access site complications.

    PubMed

    Filipiak-Strzecka, Dominika; Michalski, Błażej; Kasprzak, Jarosław D; Lipiec, Piotr

    2014-12-01

    The aim of this study was to validate pocket-size imaging devices (PSIDs) as a fast screening tool for detecting complications after femoral artery puncture. Forty patients undergoing femoral artery puncture for arterial access related to percutaneous coronary intervention were enrolled. Twenty-four hours after percutaneous coronary intervention, the involved inguinal region was assessed with PSIDs enabling 2-D gray-scale and color Doppler imaging. Subsequently, examination with a stationary high-end ultrasound system was performed to verify the findings of bedside examination in all patients. In 37 patients, PSID imaging had good diagnostic quality. False aneurysms (one asymptomatic) occurred in four patients, and all were recognized during bedside screening with PSID. One case of femoral artery thrombosis was confirmed with PSID and during standard ultrasonographic examination. Physical examination augmented with the quick bedside PSID examination had a sensitivity of 100% and specificity of 91%. PSID facilitated rapid bedside detection of serious access site complications in the vast majority of patients, including asymptomatic cases.

  6. [Shearwave-based ultrasound viscoelasticity measurement system for evaluation of liver fibrosis].

    PubMed

    Wei, Tan; Xiaodong, Han; Gang, Cheng; Hazard, Christopher

    2010-09-01

    This paper describes a liver elasticity and viscosity measurement system based on existing medical ultrasound platforms. This system relies on acoustic radiation force to invoke transient response on soft tissue, and employs displacement estimation algorithms to detect the propagation of shear wave. The research proves that the velocity of the shear wave may serve as a reliable estimation of the Young's modulus and viscosity coefficient of the liver tissue, and existing commercial products may be easily adapted to support this technique without extra hardware cost.

  7. Detection and Measurement of Stones With Ultrasound Strain Elastography: A Phantom Study.

    PubMed

    Li, Qian; Chen, Lei; Halpern, Elkan F; Samir, Anthony E

    2015-12-01

    The sonoelastographic appearances of stones in a phantom were evaluated in this study. Ten stones were embedded into a tissue-mimicking meat phantom. The stone axial (vertical) and transverse (horizontal) dimensions measured by an electronic digital caliper, gray-scale ultrasound, and strain elastography (SE) were compared in 5 groups with stones embedded at different depths. In this study, physically measured axial and transverse stone dimensions were 1.17 to 6.86 and 1.30 to 11.15 mm, respectively. Strain elastography showed a characteristic 3-layer pattern associated with stones, comprising a superficial transition region, a hard region, and a deep transition region. As SE data were available in group 5, only data of groups 1 to 4 were analyzed. Compared with physical measurements, measurement mean errors of SE horizontal and SE vertical dimensions ranged from -0.20 to 0.42 mm and from -1.28 to -0.05 mm, respectively, in the 4 groups. Paired t testing demonstrated a significant horizontal dimension measurement error difference between B mode and SE method in group 4 (0.44 vs -0.20 mm, P < 0.05; F = 1.18, P > 0.05), but not in the other groups. Strain elastography horizontal dimension measurement error was not statistically correlated with stone size in the 4 groups. Strain elastography vertical dimension measurement error significantly correlated with stone size only in group 4 (P < 0.05). Preliminary results indicate that stone horizontal and vertical dimensions can be measured using SE in a soft tissue phantom, including when shadowing precludes measurement of vertical dimension on conventional 2-dimensional ultrasound. These results provide substantial motivation to further investigate SE as a modality to image stones in clinical practice.

  8. Validation of ultrasound as a noninvasive tool to measure subcutaneous fat depth in leatherback sea turtles (Dermochelys coriacea)

    USGS Publications Warehouse

    Harris, Heather S.; Benson, Scott R.; James, Michael C.; Martin, Kelly J.; Stacy, Brian A.; Daoust, Pierre-Yves; Rist, Paul M.; Work, Thierry M.; Balazs, George H.; Seminoff, Jeffrey A.

    2016-01-01

    Leatherback turtles (Dermochelys coriacea) undergo substantial cyclical changes in body condition between foraging and nesting. Ultrasonography has been used to measure subcutaneous fat as an indicator of body condition in many species but has not been applied in sea turtles. To validate this technique in leatherback turtles, ultrasound images were obtained from 36 live-captured and dead-stranded immature and adult turtles from foraging and nesting areas in the Pacific and Atlantic oceans. Ultrasound measurements were compared with direct measurements from surgical biopsy or necropsy. Tissue architecture was confirmed histologically in a subset of turtles. The dorsal shoulder region provided the best site for differentiation of tissues. Maximum fat depth values with the front flipper in a neutral (45–90°) position demonstrated good correlation with direct measurements. Ultrasound-derived fat measurements may be used in the future for quantitative assessment of body condition as an index of health in this critically endangered species.

  9. VALIDATION OF ULTRASOUND AS A NONINVASIVE TOOL TO MEASURE SUBCUTANEOUS FAT DEPTH IN LEATHERBACK SEA TURTLES (DERMOCHELYS CORIACEA).

    PubMed

    Harris, Heather S; Benson, Scott R; James, Michael C; Martin, Kelly J; Stacy, Brian A; Daoust, Pierre-Yves; Rist, Paul M; Work, Thierry M; Balazs, George H; Seminoff, Jeffrey A

    2016-03-01

    Leatherback turtles (Dermochelys coriacea) undergo substantial cyclical changes in body condition between foraging and nesting. Ultrasonography has been used to measure subcutaneous fat as an indicator of body condition in many species but has not been applied in sea turtles. To validate this technique in leatherback turtles, ultrasound images were obtained from 36 live-captured and dead-stranded immature and adult turtles from foraging and nesting areas in the Pacific and Atlantic oceans. Ultrasound measurements were compared with direct measurements from surgical biopsy or necropsy. Tissue architecture was confirmed histologically in a subset of turtles. The dorsal shoulder region provided the best site for differentiation of tissues. Maximum fat depth values with the front flipper in a neutral (45-90°) position demonstrated good correlation with direct measurements. Ultrasound-derived fat measurements may be used in the future for quantitative assessment of body condition as an index of health in this critically endangered species.

  10. Serial measurement of cross-sectional area in peripheral vein grafts using three-dimensional ultrasound.

    PubMed

    Leotta, D F; Primozich, J F; Beach, K W; Bergelin, R O; Strandness, D E

    2001-01-01

    Frequent surveillance of bypass grafts placed in the lower limbs can provide early detection of stenoses. A three-dimensional (3-D) ultrasound (US) imaging system has been used to produce serial surface reconstructions of regions of interest in vein grafts in the lower extremities. Using anatomical reference points, data sets from serial studies are registered in a common 3-D coordinate system. Cross-sectional area measurements are extracted from the surface reconstructions in planes normal to the vessel center axis. These measurements are compared at matched sites over time to track changes in the vessel configuration. The quantitative measurements are paired with surface displays of the vessels for a complete depiction of the changing geometry. Example studies from three patients are shown, for time periods up to 38 weeks. The cross-sectional area measurements highlight regions of remodeling and developing stenoses within the grafts.

  11. A Review on Atherosclerotic Biology, Wall Stiffness, Physics of Elasticity, and Its Ultrasound-Based Measurement.

    PubMed

    Patel, Anoop K; Suri, Harman S; Singh, Jaskaran; Kumar, Dinesh; Shafique, Shoaib; Nicolaides, Andrew; Jain, Sanjay K; Saba, Luca; Gupta, Ajay; Laird, John R; Giannopoulos, Argiris; Suri, Jasjit S

    2016-12-01

    Functional and structural changes in the common carotid artery are biomarkers for cardiovascular risk. Current methods for measuring functional changes include pulse wave velocity, compliance, distensibility, strain, stress, stiffness, and elasticity derived from arterial waveforms. The review is focused on the ultrasound-based carotid artery elasticity and stiffness measurements covering the physics of elasticity and linking it to biological evolution of arterial stiffness. The paper also presents evolution of plaque with a focus on the pathophysiologic cascade leading to arterial hardening. Using the concept of strain, and image-based elasticity, the paper then reviews the lumen diameter and carotid intima-media thickness measurements in combined temporal and spatial domains. Finally, the review presents the factors which influence the understanding of atherosclerotic disease formation and cardiovascular risk including arterial stiffness, tissue morphological characteristics, and image-based elasticity measurement.

  12. Bone QUS measurement performed under loading condition, a more accuracy ultrasound method for osteoporosis diagnosis.

    PubMed

    Liu, Chengrui; Niu, Haijun; Fan, Yubo; Li, Deyu

    2012-10-01

    Osteoporosis is a worldwide health problem with enormous social and economic impact. Quantitative ultrasound (QUS) method provides comprehensive information on bone mass, microstructure and mechanical properties of the bone. And the cheap, safe and portable ultrasound equipment is more suitable for public health monitoring. QUS measurement was normally performed on bone specimens without mechanical loading. But human bones are subjected to loading during routine daily activities, and physical loading leads to the changes of bone microstructure and mechanical properties. We hypothesized that bone QUS parameters measured under loading condition differ from those measured without loading because the microstructure of bone was changed when loading subjected to bone. Furthermore, when loading was subjected on bone, the loading-lead microstructure change of osteoporosis bone may larger than that of health bone. By considering the high relationship between bone microstructure and QUS parameters, the QUS parameters of osteoporosis bone may changed larger than that of health bone. So osteoporosis may be detected more effectively by the combination of QUS method and mechanical loading.

  13. Measuring the acoustoelectric interaction constant using ultrasound current source density imaging

    NASA Astrophysics Data System (ADS)

    Li, Qian; Olafsson, Ragnar; Ingram, Pier; Wang, Zhaohui; Witte, Russell

    2012-10-01

    Ultrasound current source density imaging (UCSDI) exploits the acoustoelectric (AE) effect, an interaction between ultrasound pressure and electrical resistivity, to map electrical conduction in the heart. The conversion efficiency for UCSDI is determined by the AE interaction constant K, a fundamental property of all materials; K directly affects the magnitude of the detected voltage signal in UCSDI. This paper describes a technique for measuring K in biological tissue, and reports its value for the first time in cadaver hearts. A custom chamber was designed and fabricated to control the geometry for estimating K, which was measured in different ionic salt solutions and seven cadaver rabbit hearts. We found K to be strongly dependent on concentration for the divalent salt CuSO4, but not for the monovalent salt NaCl, consistent with their different chemical properties. In the rabbit heart, K was determined to be 0.041±0.012%/MPa, similar to the measurement of K in physiological saline (0.034±0.003%/MPa). This study provides a baseline estimate of K for modeling and experimental studies that involve UCSDI to map cardiac conduction and reentry currents associated with arrhythmias.

  14. Measuring Myofiber Orientations from High-frequency Ultrasound Images Using Multiscale Decompositions

    PubMed Central

    Qin, Xulei; Fei, Baowei

    2014-01-01

    High-frequency ultrasound (HFU) has the ability to image both skeletal and cardiac muscles. The quantitative assessment of these myofiber orientations has a number of applications in both research and clinical examinations; however, difficulties arise due to the severe speckle noise contained in the HFU images. Thus, for the purpose of automatically measuring myofiber orientations from two-dimensional HFU images, we propose a two-step multiscale image decomposition method. It combines a nonlinear anisotropic diffusion filter (NLADF) and a coherence enhancing diffusion filter (CEDF) to extract myofibers. This method has been verified by ultrasound data from simulated phantoms, excised fiber phantoms, specimens of porcine hearts, and human skeletal muscles in vivo. The quantitative evaluations of both phantoms indicated that the myofiber measurements of our proposed method were more accurate than other methods. The myofiber orientations extracted from different layers of the porcine hearts matched the prediction of an established cardiac mode and demonstrated the feasibility of extracting cardiac myofiber orientations from HFU images ex vivo. Moreover, HFU also demonstrated the ability to measure myofiber orientations in vivo. PMID:24957945

  15. Measuring myofiber orientations from high-frequency ultrasound images using multiscale decompositions

    NASA Astrophysics Data System (ADS)

    Qin, Xulei; Fei, Baowei

    2014-07-01

    High-frequency ultrasound (HFU) has the ability to image both skeletal and cardiac muscles. The quantitative assessment of these myofiber orientations has a number of applications in both research and clinical examinations; however, difficulties arise due to the severe speckle noise contained in the HFU images. Thus, for the purpose of automatically measuring myofiber orientations from two-dimensional HFU images, we propose a two-step multiscale image decomposition method. It combines a nonlinear anisotropic diffusion filter and a coherence enhancing diffusion filter to extract myofibers. This method has been verified by ultrasound data from simulated phantoms, excised fiber phantoms, specimens of porcine hearts, and human skeletal muscles in vivo. The quantitative evaluations of both phantoms indicated that the myofiber measurements of our proposed method were more accurate than other methods. The myofiber orientations extracted from different layers of the porcine hearts matched the prediction of an established cardiac mode and demonstrated the feasibility of extracting cardiac myofiber orientations from HFU images ex vivo. Moreover, HFU also demonstrated the ability to measure myofiber orientations in vivo.

  16. Measuring the acoustoelectric interaction constant using ultrasound current source density imaging

    PubMed Central

    Li, Qian; Olafsson, Ragnar; Ingram, Pier; Wang, Zhaohui; Witte, Russell

    2012-01-01

    Ultrasound Current Source Density Imaging (UCSDI) exploits the acoustoelectric (AE) effect, an interaction between ultrasound pressure and electrical resistivity, to map electrical conduction in the heart. The conversion efficiency for UCSDI is determined by the AE interaction constant K, a fundamental property of all materials; K directly affects the magnitude of the detected voltage signal in UCSDI. This paper describes a technique for measuring K in biological tissue, and reports its value for the first time in cadaver hearts. A custom chamber was designed and fabricated to control the geometry for estimating K, which was measured in different ionic salt solutions and 7 cadaver rabbit hearts. We found K to be strongly dependent on concentration for the divalent salt CuSO4, but not for the monovalent salt NaCl, consistent with their different chemical properties. In the rabbit heart, K was determined to be 0.041±0.012 %/MPa, similar to the measurement of K in physiologic saline (0.034±0.003 %/MPa). This study provides a baseline estimate of K for modeling and experimental studies that involve UCSDI to map cardiac conduction and reentry currents associated with arrhythmias. PMID:22954500

  17. Medical students' perceptions of bedside teaching.

    PubMed

    Gray, David; Cozar, Octavian; Lefroy, Janet

    2017-06-01

    Bedside teaching is recognised as a valuable tool in medical education by both students and faculty members. Bedside teaching is frequently delivered by consultants; however, junior doctors are increasingly engaging in this form of clinical teaching, and their value in this respect is becoming more widely recognised. The aim of this study was to supplement work completed by previous authors who have begun to explore students' satisfaction with bedside teaching, and their perceptions of the relationship with the clinical teachers. Specifically, we aimed to identify how students perceive bedside teaching delivered by junior doctors compared with consultants. We aimed to identify how students perceived bedside teaching delivered by junior doctors compared with consultants METHODS: A questionnaire was distributed to all third-year medical students at Keele University via e-mail. Responses were submitted anonymously. Forty-six students responded (37.4%), 73.3 per cent of whom said that they felt more comfortable having bedside teaching delivered by junior doctors than by consultants. Consultants were perceived as more challenging by 60 per cent of respondents. Students appeared to value feedback on their performance, trust the validity of taught information, and to value the overall educational experience equally, regardless of the clinical grade of the teacher. Student preference does not equate to the value that they place on their bedside teaching. Junior doctors are perceived as being more in touch with students and the curriculum, whereas consultants are perceived as having higher expectations and as being both stricter and more knowledgeable. The clinical teacher's approachable manner and enthusiasm for teaching are more important than clinical grade, as is the ability to deliver well-structured constructive feedback. © 2016 John Wiley & Sons Ltd.

  18. Measurement of Transcranial Distance During Head-Down Tilt Using Ultrasound

    NASA Technical Reports Server (NTRS)

    Torikoshi, Shigeyo; Ballard, R. E.; Watenpaugh, D. E.; Murthy, G.; Bowley, S.; Yost, W. T.; Hargens, Alan R.

    1995-01-01

    Exposure to microgravity probably elevates blood pressure and flow in the head which may increase intracranial volume (ICV) and pressure (ICP). Due to the slightly compliant nature of the cranium, any increase of ICP will increase ICV and transcranial distance. We used a noninvasive ultrasound technique to measure transcranial distance (frontal to occipital) during head-down tilt. Seven subjects (ages 26-53) underwent the following tilt angles: 90 deg. upright, 30 deg., 0 deg., -6 deg., -10 deg., -6 deg., 0 deg., 30 deg., and 90 deg. Each angle was maintained for 1 min. Ultrasound wave frequency was collected continuously and transcranial distance was calculated (Delta(x) = x(Delta)f/f, where x is path length and f is frequency of the wave) for each tilt angle. Frequency decreased from 503.687 kHz (90 deg. upright) to 502.619 kHz (-10 deg.). These frequencies translated to an increased transcranial distance of 0.403 mm. Although our data suggest a significant increase in transcranial distance during head-down tilt, this apparent increase may result, in part, from head-down tilt-induced subcutaneous edema or cutaneous blood volume elevation. In three subjects, when the above protocol was repeated with an ace bandage wrapped around the head to minimize such edema, the increased transcranial distance from 90 deg. to -10 deg. was reduced by 0.174 mm. Further development of the technique to quantify bone-to-bone expansion unconfounded by cutaneous fluid is necessary. Therefore, this ultrasound technique may provide measurements of changes in cranial dimensions during microgravity.

  19. Review article: Use of ultrasound in the developing world

    PubMed Central

    2011-01-01

    As portability and durability improve, bedside, clinician-performed ultrasound is seeing increasing use in rural, underdeveloped parts of the world. Physicians, nurses and medical officers have demonstrated the ability to perform and interpret a large variety of ultrasound exams, and a growing body of literature supports the use of point-of-care ultrasound in developing nations. We review, by region, the existing literature in support of ultrasound use in the developing world and training guidelines currently in use, and highlight indications for emergency ultrasound in the developing world. We suggest future directions for bedside ultrasound use and research to improve diagnostic capacity and patient care in the most remote areas of the globe. PMID:22152055

  20. Comparison of sound speed measurements on two different ultrasound tomography devices.

    PubMed

    Sak, Mark; Duric, Neb; Littrup, Peter; Bey-Knight, Lisa; Sherman, Mark; Gierach, Gretchen; Malyarenko, Antonina

    2014-03-20

    Ultrasound tomography (UST) employs sound waves to produce three-dimensional images of breast tissue and precisely measures the sound speed of breast tissue composition. High breast density is a strong breast cancer risk factor and sound speed is directly proportional to breast density. UST provides a quantitative measure of breast density based on three-dimensional imaging without compression, thereby overcoming the shortcomings of many other imaging modalities. The quantitative nature of the UST breast density measures are tied to an external standard, so sound speed measurement in breast tissue should be independent of specific hardware. The work presented here compares breast sound speed measurement obtained with two different UST devices. The Computerized Ultrasound Risk Evaluation (CURE) system located at the Karmanos Cancer Institute in Detroit, Michigan was recently replaced with the SoftVue ultrasound tomographic device. Ongoing clinical trials have used images generated from both sets of hardware, so maintaining consistency in sound speed measurements is important. During an overlap period when both systems were in the same exam room, a total of 12 patients had one or both of their breasts imaged on both systems on the same day. There were 22 sound speed scans analyzed from each system and the average breast sound speeds were compared. Images were either reconstructed using saved raw data (for both CURE and SoftVue) or were created during the image acquisition (saved in DICOM format for SoftVue scans only). The sound speed measurements from each system were strongly and positively correlated with each other. The average difference in sound speed between the two sets of data was on the order of 1-2 m/s and this result was not statistically significant. The only sets of images that showed a statistical difference were the DICOM images created during the SoftVue scan compared to the SoftVue images reconstructed from the raw data. However, the discrepancy

  1. Comparison of sound speed measurements on two different ultrasound tomography devices

    NASA Astrophysics Data System (ADS)

    Sak, Mark; Duric, Neb; Littrup, Peter; Bey-Knight, Lisa; Sherman, Mark; Gierach, Gretchen; Malyarenko, Antonina

    2014-03-01

    Ultrasound tomography (UST) employs sound waves to produce three-dimensional images of breast tissue and precisely measures the attenuation of sound speed secondary to breast tissue composition. High breast density is a strong breast cancer risk factor and sound speed is directly proportional to breast density. UST provides a quantitative measure of breast density based on three-dimensional imaging without compression, thereby overcoming the shortcomings of many other imaging modalities. The quantitative nature of the UST breast density measures are tied to an external standard, so sound speed measurement in breast tissue should be independent of specific hardware. The work presented here compares breast sound speed measurement obtained with two different UST devices. The Computerized Ultrasound Risk Evaluation (CURE) system located at the Karmanos Cancer Institute in Detroit, Michigan was recently replaced with the SoftVue ultrasound tomographic device. Ongoing clinical trials have used images generated from both sets of hardware, so maintaining consistency in sound speed measurements is important. During an overlap period when both systems were in the same exam room, a total of 12 patients had one or both of their breasts imaged on both systems on the same day. There were 22 sound speed scans analyzed from each system and the average breast sound speeds were compared. Images were either reconstructed using saved raw data (for both CURE and SoftVue) or were created during the image acquisition (saved in DICOM format for SoftVue scans only). The sound speed measurements from each system were strongly and positively correlated with each other. The average difference in sound speed between the two sets of data was on the order of 1-2 m/s and this result was not statistically significant. The only sets of images that showed a statistical difference were the DICOM images created during the SoftVue scan compared to the SoftVue images reconstructed from the raw data

  2. Comparison of sound speed measurements on two different ultrasound tomography devices

    PubMed Central

    Sak, Mark; Duric, Neb; Littrup, Peter; Bey-Knight, Lisa; Sherman, Mark; Gierach, Gretchen; Malyarenko, Antonina

    2014-01-01

    Ultrasound tomography (UST) employs sound waves to produce three-dimensional images of breast tissue and precisely measures the sound speed of breast tissue composition. High breast density is a strong breast cancer risk factor and sound speed is directly proportional to breast density. UST provides a quantitative measure of breast density based on three-dimensional imaging without compression, thereby overcoming the shortcomings of many other imaging modalities. The quantitative nature of the UST breast density measures are tied to an external standard, so sound speed measurement in breast tissue should be independent of specific hardware. The work presented here compares breast sound speed measurement obtained with two different UST devices. The Computerized Ultrasound Risk Evaluation (CURE) system located at the Karmanos Cancer Institute in Detroit, Michigan was recently replaced with the SoftVue ultrasound tomographic device. Ongoing clinical trials have used images generated from both sets of hardware, so maintaining consistency in sound speed measurements is important. During an overlap period when both systems were in the same exam room, a total of 12 patients had one or both of their breasts imaged on both systems on the same day. There were 22 sound speed scans analyzed from each system and the average breast sound speeds were compared. Images were either reconstructed using saved raw data (for both CURE and SoftVue) or were created during the image acquisition (saved in DICOM format for SoftVue scans only). The sound speed measurements from each system were strongly and positively correlated with each other. The average difference in sound speed between the two sets of data was on the order of 1-2 m/s and this result was not statistically significant. The only sets of images that showed a statistical difference were the DICOM images created during the SoftVue scan compared to the SoftVue images reconstructed from the raw data. However, the discrepancy

  3. Application of Digital Ultrasound Speckle Image Velocimetry(DUSIV) for Quantitative Flow Measurements in Aortic Vessel- an In Vitro Study

    NASA Astrophysics Data System (ADS)

    Zarandi, Mehrdad; Dabiri, Dana; Gharib, Morteza

    2001-11-01

    A new method is developed to use speckle signals for obtaining quantitative information about the flow field and its related properties such as wall shear stress. Speckle imaging allows for mapping flows at normal angles to the probe where Doppler technique render little information. Our custom developed method of Digital Ultrasound Speckle Image Velocimetry is used to measure the flow field and wall shear stress in a model of aortic vessel. The method has great potential for other applications such as flow in curved vessels, branching vessels, heart chambers and through valves for quantitative blood flow measurements. It also allows us to correct for the errors in ultrasound measurements caused by the angle of interrogation , or signal attenuation with distance from the ultrasound probe. Speckle velocimetry also allows calibration of the results obtained from the conventional Doppler shift based ultrasound methods and should therefore contribute to more accurate quantitative measurements of blood flow by ultrasound. Providing quantitative information with much higher resolution than Color Doppler measurements and applicability to optically inaccessible flows are the other advantages of this method.

  4. Estimation of multipath transmission parameters for quantitative ultrasound measurements of bone.

    PubMed

    Dencks, Stefanie; Schmitz, Georg

    2013-09-01

    When applying quantitative ultrasound (QUS) measurements to bone for predicting osteoporotic fracture risk, the multipath transmission of sound waves frequently occurs. In the last 10 years, the interest in separating multipath QUS signals for their analysis awoke, and led to the introduction of several approaches. Here, we compare the performances of the two fastest algorithms proposed for QUS measurements of bone: the modified least-squares Prony method (MLSP), and the space alternating generalized expectation maximization algorithm (SAGE) applied in the frequency domain. In both approaches, the parameters of the transfer functions of the sound propagation paths are estimated. To provide an objective measure, we also analytically derive the Cramér-Rao lower bound of variances for any estimator and arbitrary transmit signals. In comparison with results of Monte Carlo simulations, this measure is used to evaluate both approaches regarding their accuracy and precision. Additionally, with simulations using typical QUS measurement settings, we illustrate the limitations of separating two superimposed waves for varying parameters with focus on their temporal separation. It is shown that for good SNRs around 100 dB, MLSP yields better results when two waves are very close. Additionally, the parameters of the smaller wave are more reliably estimated. If the SNR decreases, the parameter estimation with MLSP becomes biased and inefficient. Then, the robustness to noise of the SAGE clearly prevails. Because a clear influence of the interrelation between the wavelength of the ultrasound signals and their temporal separation is observable on the results, these findings can be transferred to QUS measurements at other sites. The choice of the suitable algorithm thus depends on the measurement conditions.

  5. Reliability of measurement of the carpal tunnel and median nerve in asymptomatic subjects with ultrasound.

    PubMed

    Bueno-Gracia, Elena; Malo-Urriés, Miguel; Ruiz-de-Escudero-Zapico, Alazne; Rodríguez-Marco, Sonia; Jiménez-Del-Barrio, Sandra; Shacklock, Michael; Estébanez-de-Miguel, Elena; Tricás-Moreno, José Miguel

    2017-08-05

    Morphology of the carpal tunnel changes with varying wrist postures and compressive forces applied to the wrist. These changes may affect the morphology and pressure on the median nerve and could be used as part of the treatment of the carpal tunnel syndrome patients. Reliability of the ultrasonographic measurements of the median nerve has been widely studied. However, there is a lack of investigation regarding reliability of ultrasonographic measurements of the carpal tunnel. The purpose of this study was to assess intra-tester and inter-tester reliability of measurement of dimensions of the carpal tunnel and median nerve with ultrasound in asymptomatic volunteers. A cross-sectional methodological study. Aspects measured were mediolateral and anteroposterior diameters, flattening ratio, circularity, perimeter and cross-section area of the carpal tunnel and median nerve. Intra-tester reliability was excellent for the carpal tunnel (ICCs from 0.91 to 0.97) and for the median nerve (ICCs from 0.79 to 0.94) measurements. The flattening ratio of the median nerve showed good agreement (ICC = 0.68). Inter-tester reliability was excellent for the carpal tunnel measurements (ICCs from 0.76 to 0.95) and, for the cross sectional area, the perimeter and mediolateral diameter of the median nerve, the ICC values were 0.89, 0.84 and 0.81, respectively. In the context of this study, ultrasound was a reliable instrument for measuring carpal tunnel and median nerve dimensions in asymptomatic subjects. 1b. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. Brachial artery vasomotion and transducer pressure effect on measurements by active contour segmentation on ultrasound

    SciTech Connect

    Cary, Theodore W.; Sultan, Laith R.; Sehgal, Chandra M.; Reamer, Courtney B.; Mohler, Emile R.

    2014-02-15

    Purpose: To use feed-forward active contours (snakes) to track and measure brachial artery vasomotion on ultrasound images recorded in both transverse and longitudinal views; and to compare the algorithm's performance in each view. Methods: Longitudinal and transverse view ultrasound image sequences of 45 brachial arteries were segmented by feed-forward active contour (FFAC). The segmented regions were used to measure vasomotion artery diameter, cross-sectional area, and distention both as peak-to-peak diameter and as area. ECG waveforms were also simultaneously extracted frame-by-frame by thresholding a running finite-difference image between consecutive images. The arterial and ECG waveforms were compared as they traced each phase of the cardiac cycle. Results: FFAC successfully segmented arteries in longitudinal and transverse views in all 45 cases. The automated analysis took significantly less time than manual tracing, but produced superior, well-behaved arterial waveforms. Automated arterial measurements also had lower interobserver variability as measured by correlation, difference in mean values, and coefficient of variation. Although FFAC successfully segmented both the longitudinal and transverse images, transverse measurements were less variable. The cross-sectional area computed from the longitudinal images was 27% lower than the area measured from transverse images, possibly due to the compression of the artery along the image depth by transducer pressure. Conclusions: FFAC is a robust and sensitive vasomotion segmentation algorithm in both transverse and longitudinal views. Transverse imaging may offer advantages over longitudinal imaging: transverse measurements are more consistent, possibly because the method is less sensitive to variations in transducer pressure during imaging.

  7. Investigation of Ultrasound-Measured Flow Rate and Wall Shear Rate in Wrist Arteries Using Flow Phantoms.

    PubMed

    Zhou, Xiaowei; Xia, Chunming; Khan, Faisel; Corner, George A; Huang, Zhihong; Hoskins, Peter R

    2016-03-01

    The aim of this study was to evaluate the errors in measurement of volumetric flow rate and wall shear rate measured in radial and ulnar arteries using a commercial ultrasound scanning system. The Womersley equations were used to estimate the flow rate and wall shear rate waveforms, based on the measured vessel diameter and centerline velocity waveform. In the experiments, each variable (vessel depth, diameter, flow rate, beam-vessel angle and different waveform) in the phantom was investigated in turn, and its value was varied within a normal range while others were fixed at their typical values. The outcomes revealed that flow rate and wall shear rate were overestimated in all cases, from around 13% to nearly 50%. It is concluded that measurements of flow rate and wall shear rate in radial and ulnar arteries with a clinical ultrasound scanner are vulnerable to overestimation. Copyright © 2016 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

  8. Ultrasound in trauma.

    PubMed

    Rippey, James C R; Royse, Alistair G

    2009-09-01

    Point-of-care ultrasound is well suited for use in the emergency setting for assessment of the trauma patient. Currently, portable ultrasound machines with high-resolution imaging capability allow trauma patients to be imaged in the pre-hospital setting, emergency departments and operating theatres. In major trauma, ultrasound is used to diagnose life-threatening conditions and to prioritise and guide appropriate interventions. Assessment of the basic haemodynamic state is a very important part of ultrasound use in trauma, but is discussed in more detail elsewhere. Focussed assessment with sonography for Trauma (FAST) rapidly assesses for haemoperitoneum and haemopericardium, and the Extended FAST examination (EFAST) explores for haemothorax, pneumothorax and intravascular filling status. In regional trauma, ultrasound can be used to detect fractures, many vascular injuries, musculoskeletal injuries, testicular injuries and can assess foetal viability in pregnant trauma patients. Ultrasound can also be used at the bedside to guide procedures in trauma, including nerve blocks and vascular access. Importantly, these examinations are being performed by the treating physician in real time, allowing for immediate changes to management of the patient. Controversy remains in determining the best training to ensure competence in this user-dependent imaging modality.

  9. The use of high frequency ultrasound imaging in skin moisturization measurement.

    PubMed

    Mlosek, Robert K; Malinowska, Sylwia; Sikora, Magdalena; Dębowska, Renata; Stępień, Anna; Czekaj, Karolina; Dąbrowska, Anna

    2013-05-01

    The appropriate skin hydration level enables its normal function and healthy appearance. The purpose of present research was to assess the applicability of high frequency ultrasound (HFU) to the monitoring of skin moisturization treatments. The study sample encompassed 27 women, aged 20-67 y.o. (mean age of 45.48 y.o.) with dry skin. All women applied a strong moisturizing cream on their facial skin for 14 days. The course of treatment was monitored using the HFU. The following parameters were subjected to the ultrasound evaluation: epidermal echo thickness, dermis thickness, and separately the thickness of the superior and inferior layer of dermis. The measurements were taken on the participants' chins and cheeks. In addition, skin hydration and transepidermal water loss (TEWL) were determined. Statistically significant differences were obtained between the echogenicity of the superior layer of the dermis on the chin and cheek. After treatment, the statistically significant values of TEWL decrease and hydration increase were obtained on the cheek skin. No statistically significant differences between the TEWL or hydration levels were found on the chin. No statistically significant differences between the epidermal echo and dermis thickness values for the two measurement points were observed. The HFU is a useful method for the monitoring of skin moisturization treatments. © 2013 John Wiley & Sons A/S. Published by Blackwell Publishing Ltd.

  10. Biofilm thickness measurement using an ultrasound method in a liquid phase.

    PubMed

    Maurício, R; Dias, C J; Jubilado, N; Santana, F

    2013-10-01

    In this report, the development of an online, noninvasive, measurement method of the biofilm thickness in a liquid phase is presented. The method is based in the analysis of the ultrasound wave pulse-echo behavior in a liquid phase reproducing the real reactor conditions. It does not imply the removal of the biomass from the support or any kind of intervention in the support (pipes) to detect and perform the measurements (non-invasiveness). The developed method allows for its sensor to be easily and quickly mounted and unmounted in any location along a pipe or reactor wall. Finally, this method is an important innovation because it allows the thickness measurement of a biofilm, in liquid phase conditions that can be used in monitoring programs, to help in scheduling cleaning actions to remove the unwanted biofilm, in several application areas, namely in potable water supply pipes.

  11. Has bedside teaching had its day?

    PubMed

    Qureshi, Zeshan; Maxwell, Simon

    2012-05-01

    Though a diverse array of teaching methods is now available, bedside teaching is arguably the most favoured. Students like it because it is patient-centred, and it includes a high proportion of relevant skills. It is on the decline, coinciding with declining clinical skills of junior doctors. Several factors might account for this: busier hospitals, broader roles of clinicians, competing teaching modalities, and the limited training of clinicians as medical educators. However, bedside teaching offers unique benefits. Students gain first-hand experience of the doctor patient relationship. They see the process of interacting with patients, investigative yet sensitive, demystified. Certain clinical skills, like the recognition of the tactile sensation of hepatosplenomegaly cannot be simulated elsewhere. We advocate the preservation of bedside learning experience. Teaching guidelines should be written to minimise disruption to ward work, and to ensure the preservation of patient autonomy. Greater emphasis should be placed on bedside skills in the undergraduate curriculum. For teachers, training in teaching methodology should begin at undergraduate level, with subsequent protected teaching time in job plans. This would increase not just the quantity, but also the quality of bedside teaching.

  12. Spectroscopic measurement of adipose tissue thickness and comparison with ultrasound imaging

    NASA Astrophysics Data System (ADS)

    Geraskin, Dmitri; Boeth, Heide; Kohl-Bareis, Matthias

    2007-07-01

    Near-infrared spectroscopy (NIRS) is widely applied for applications monitoring skeletal muscle oxygenation. However, this method is obstructed by the subcutaneous adipose tissue thickness (ATT) which might vary between < 1 mm to more than 12 mm. Though diffuse optical imaging can be applied to measure ATT, the objective here is to get this measure from spectroscopic data of a single source-detector distance. For the measurement of the optical lipid signal we used a broad band spatially resolved system (SRS), which is based on measurements of the wavelength dependence of the attenuation A for source detector distances ρ between 29 mm and 39 mm. Ultrasound images served as an anatomical reference of the lipid layer. The measurements were taken on 5 different muscle groups of 20 healthy volunteers, each for left and right limbs, e.g. vastus medialis, vastus lateralis and gastrocnemius muscle on the leg and ventral forearm muscles and biceps brachii muscle on the arm. Different analysis strategies were tested for the best calculation of ATT. There is a good non-linear correlation between optical lipid signal and ultrasound data, with an overall error in ATT prediction of about 0.5 mm. This finding is supported experimentally by additional MRI measurements as well as a multi-layer Monte Carlo (MC) model. Based on this data of the ATT thickness, a newly developed algorithm which exploits the wavelength dependence of the slope in attenuation with respect to source-detector distance and MC simulation for these parameters as a function of absorption and scattering coefficients delivers a considerably better fit of reflectance spectra when fitting haemoglobin concentrations. Implications for the monitoring of muscle oxygen saturation are discussed.

  13. Ultrasound versus MRI: is there a difference in measurements of the fetal lateral ventricles?

    PubMed

    Behrendt, Nicholas; Zaretsky, Michael V; West, Nancy A; Galan, Henry L; Crombleholme, Timothy M; Meyers, Mariana L

    2017-02-01

    To evaluate whether fetal brain lateral ventricle measurements differ between ultrasound (US) and MRI. We evaluated 115 fetuses with US and MRI performed within 24 h of each other. Ventricular measurements were performed in the axial plane at the level of the atria for both modalities and the right and left ventricles were evaluated separately. We compared mean measurements; mean differences, association with gestational age (GA), association with the presence of a brain anomaly, and agreement between MRI and US. The LV and RV were measured in 65 and 64 cases, respectively. LV and RV size estimates were significantly greater when measured by MRI compared with US (p < 0.001). Therefore, LV and RV were 0.87 mm and 0.89 mm larger in MRI versus US, respectively. Neither GA at measurement or presence/absence of a brain anomaly was significantly associated with differences in measurements. When comparing the agreement between the US and MRI measurements for ventriculomegaly; the kappa level of agreement for the LV and RV was 0.74 for each. MRI measurements of ventricles are significantly larger than the measurements by US by ∼1 mm. There is a good level of agreement when categorizing by normal, mild and severe ventriculomegaly.

  14. Detection and measurement of fetal anatomies from ultrasound images using a constrained probabilistic boosting tree.

    PubMed

    Carneiro, Gustavo; Georgescu, Bogdan; Good, Sara; Comaniciu, Dorin

    2008-09-01

    We propose a novel method for the automatic detection and measurement of fetal anatomical structures in ultrasound images. This problem offers a myriad of challenges, including: difficulty of modeling the appearance variations of the visual object of interest, robustness to speckle noise and signal dropout, and large search space of the detection procedure. Previous solutions typically rely on the explicit encoding of prior knowledge and formulation of the problem as a perceptual grouping task solved through clustering or variational approaches. These methods are constrained by the validity of the underlying assumptions and usually are not enough to capture the complex appearances of fetal anatomies. We propose a novel system for fast automatic detection and measurement of fetal anatomies that directly exploits a large database of expert annotated fetal anatomical structures in ultrasound images. Our method learns automatically to distinguish between the appearance of the object of interest and background by training a constrained probabilistic boosting tree classifier. This system is able to produce the automatic segmentation of several fetal anatomies using the same basic detection algorithm. We show results on fully automatic measurement of biparietal diameter (BPD), head circumference (HC), abdominal circumference (AC), femur length (FL), humerus length (HL), and crown rump length (CRL). Notice that our approach is the first in the literature to deal with the HL and CRL measurements. Extensive experiments (with clinical validation) show that our system is, on average, close to the accuracy of experts in terms of segmentation and obstetric measurements. Finally, this system runs under half second on a standard dual-core PC computer.

  15. Bedside ultrasonography (US), Echoscopy and US point of care as a new kind of stethoscope for Internal Medicine Departments: the training program of the Italian Internal Medicine Society (SIMI).

    PubMed

    Arienti, Vincenzo; Di Giulio, Rosella; Cogliati, Chiara; Accogli, Esterita; Aluigi, Leonardo; Corazza, Gino Roberto

    2014-10-01

    In recent years, thanks to the development of miniaturized ultrasound devices, comparable to personal computers, tablets and even to smart phones, we have seen an increasing use of bedside ultrasound in internal medicine departments as a novel kind of ultrasound stethoscope. The clinical ultrasound-assisted approach has proved to be particularly useful in assessing patients with nodules of the neck, dyspnoea, abdominal pain, and with limb edema. In several cases, it has allowed a simple, rapid and precise diagnosis. Since 2005, the Italian Society of Internal Medicine and its Ultrasound Study Group has been holding a Summer School and training courses in ultrasound for residents in internal medicine. A national network of schools in bedside ultrasound was then organized for internal medicine specialists who want to learn this technique. Because bedside ultrasound is a user-dependent diagnostic method, it is important to define the limits and advantages of different new ultrasound devices, to classify them (i.e. Echoscopy and Point of Care Ultrasound), to establish appropriate different levels of competence and to ensure their specific training. In this review, we describe the point of view of the Italian Internal Medicine Society on these topics.

  16. Effectiveness of the portable ultrasound bladder scanner in the measurement of residual urine volume after total mesorectal extirpation.

    PubMed

    Araki; Ishibashi; Sasatomi; Kanazawa; Ogata; Shirouzu

    2003-09-01

    The measurement of residual urine volume by bladder catheterization causes quite some suffering to the patient and sometimes causes urinary tract infections. To evaluate the postoperative measurement of residual urine volume with a portable ultrasound bladder scanner (Bladder Scan BVI 3000) and the cost-benefit analysis as compared with postoperative catheterization we carried out a study on 30 patients with primary rectal cancer. The data were then compared with actual urine volumes. This was a prospective study dealing with the economical benefit of ultrasound scanning over catheterization during the hospital stay. The ultrasound bladder scanner was found to be a reliable method of estimating residual urine volume since its data correlated with actual volumes with a coefficient of 0.9. The results satisfied both physicians and patients. Ultrasound scanning of the bladder to measure residual urine volume reduced the frequency of catheterization by 38% as compared with the patients on intermittent catheterization, with 17.4 catheters saved for each patient. In conclusion, the ultrasound bladder scanner could protect patients from the discomfort and urethral injury which might have been caused by bladder catheters, thus decreasing medical expenses. This technique will play an important role in determining whether to conduct invasive urethral catheterization for postoperative urinary disturbance in rectal cancer.

  17. Quantitative contrast-enhanced ultrasound measurement of cerebrospinal fluid flow for the diagnosis of ventricular shunt malfunction

    PubMed Central

    Hartman, Robin; Aglyamov, Salavat; Fox, Douglas J.; Emelianov, Stanislav

    2015-01-01

    Object Cerebral shunt malfunction is common but often difficult to effectively diagnose. Current methods are invasive, involve ionizing radiation, and can be costly. This work investigated the feasibility of quantitatively measuring cerebrospinal fluid flow in a shunt catheter using contrast-enhanced ultrasound. Methods A syringe pump was used to push a solution of gas-filled microbubbles at specific flow rates through a shunt catheter while a high-frequency ultrasound imaging system was used to collect ultrasound images for off-line processing. Displacement maps and velocity profiles were generated using a speckle tracking method based on a cross-correlation algorithm. An additional correction factor, to account for a predictable underestimation and to adjust the measured flow rates, was calculated based on the geometry of the ultrasound imaging plane and assuming a simple model of laminar flow. Results The developed method was able to differentiate between physiologically relevant flow rates from 0.0 to 0.09 ml/min with reasonable certainty. The quantitative measurement of flow rates through the catheter using this method was determined to be in good agreement with the expected flow rate. Conclusions This study demonstrated that contrast-enhanced ultrasound has the potential to be used as a minimally invasive and cost-effective alternative method for outpatient shunt malfunction diagnosis. PMID:26090831

  18. Photoacoustic clutter reduction by inversion of a linear scatter model using plane wave ultrasound measurements

    PubMed Central

    Schwab, Hans-Martin; Beckmann, Martin F.; Schmitz, Georg

    2016-01-01

    Photoacoustic imaging aims to visualize light absorption properties of biological tissue by receiving a sound wave that is generated inside the observed object as a result of the photoacoustic effect. In clinical applications, the strong light absorption in human skin is a major problem. When high amplitude photoacoustic waves that originate from skin absorption propagate into the tissue, they are reflected back by acoustical scatterers and the reflections contribute to the received signal. The artifacts associated with these reflected waves are referred to as clutter or skin echo and limit the applicability of photoacoustic imaging for medical applications severely. This study seeks to exploit the acoustic tissue information gained by plane wave ultrasound measurements with a linear array in order to correct for reflections in the photoacoustic image. By deriving a theory for clutter waves in k-space and a matching inversion approach, photoacoustic measurements compensated for clutter are shown to be recovered. PMID:27446669

  19. Photoacoustic clutter reduction by inversion of a linear scatter model using plane wave ultrasound measurements.

    PubMed

    Schwab, Hans-Martin; Beckmann, Martin F; Schmitz, Georg

    2016-04-01

    Photoacoustic imaging aims to visualize light absorption properties of biological tissue by receiving a sound wave that is generated inside the observed object as a result of the photoacoustic effect. In clinical applications, the strong light absorption in human skin is a major problem. When high amplitude photoacoustic waves that originate from skin absorption propagate into the tissue, they are reflected back by acoustical scatterers and the reflections contribute to the received signal. The artifacts associated with these reflected waves are referred to as clutter or skin echo and limit the applicability of photoacoustic imaging for medical applications severely. This study seeks to exploit the acoustic tissue information gained by plane wave ultrasound measurements with a linear array in order to correct for reflections in the photoacoustic image. By deriving a theory for clutter waves in k-space and a matching inversion approach, photoacoustic measurements compensated for clutter are shown to be recovered.

  20. Elastic constants of α Ti-7Al measured using resonant ultrasound spectroscopy

    NASA Astrophysics Data System (ADS)

    Adebisi, R. A.; Sathish, S.; Pilchak, A. L.; Shade, P. A.

    2016-02-01

    The five independent elastic constants of a single-phase (α, HCP crystal structure) titanium alloy, Ti-7Al, have been measured for the first time using resonant ultrasound spectroscopy (RUS). RUS is a nondestructive evaluation method that mea-sures the mechanical resonance of solids and uses the resonance frequencies to extract a complete set of elastic constants of the solid material. The elastic constants of titanium alloys vary substantially depending on manufacturing history and composition. In addition, available data on the elastic constants of titanium alloys is limited. The elastic constants data for Ti-7Al are presented in this paper and the results are compared to the available data for other titanium alloys that are similar in composition.

  1. Measuring the porosity and compressibility of liquid-suspended porous particles using ultrasound.

    PubMed

    Han, Endao; Van Ha, Nigel; Jaeger, Heinrich M

    2017-05-21

    A key parameter describing the behavior of suspensions is the volume fraction ϕ of the solid particles that are dispersed in the liquid. Obtaining accurate values for ϕ becomes difficult for porous particles, because they can absorb some of the liquid. A prime example are the widely used cornstarch suspensions, for which ϕ usually is only estimated from the mass fraction of particles. Here we present a method to measure the effective porosity and compressibility of porous particles with ultrasound. We obtain the speed of sound in dilute cornstarch suspensions at multiple particle concentrations and with different solvent compressibilities. With the measured particle porosity of 0.31 we are able to calculate the volume fraction of the saturated particles reliably.

  2. A Bland-Altman Analysis of the Bias Between Computed Tomography and Ultrasound Prostate Volume Measurements

    SciTech Connect

    Gloi, Aime McCourt, Stephen; Zuge, Corrie; Goettler, AnnDrea; Schlise, Sally; Cooley, Greg

    2008-10-01

    This study assesses the agreement between computed tomography (CT) measurements of prostate volume and those obtained by ultrasound (US), a well-established non-invasive technique. Twenty-six patients aged between 58 and 74 years were evaluated for prostate seed implant therapy using both CT and US measurements. The level of agreement between these 2 methods, which were strongly correlated (R{sup 2} = 0.828; p < 0.0001), was determined through Bland-Altman analysis. The mean prostate volume ({+-} one standard deviation) of the sample was 31.8 {+-} 10.5 cc for the CT method and 27.0 {+-} 8.2 cc for the US method. The prostate volumes obtained by CT were, on average, 17% larger than the corresponding volumes determined by US. The average bias between the 2 imaging methods is 4.80 cc or 15%, which is significantly larger than the clinically acceptable margin of 10%.

  3. Online Condition Measurement of High Power Solid State Laser Cutting Optics using Ultrasound Signals

    NASA Astrophysics Data System (ADS)

    Neumeier, Benedikt; Schmitt-Landsiedel, Doris

    The occurrence of thermally induced focal shifts in high power solid state laser cutting applications has been reported. A fraction of laser light is absorbed in transmissive optical elements and at optical surface contaminations, leading to a temperature rise of the optical elements. The object of this study is experimental identification of temperature changes in laser cutting head optics during processing, and development of a novel method utilizing ultrasound to measure the bulk temperature online for every optical element in the cutting head. A thermal model is provided for each optical element and allows to estimate the absorbed laser power, the condition and focal shift of the optics. The novel method is compared to existing techniques using thermopiles as temperature sensors. Our measurement system facilitates a closed loop focal shift compensation control and enables a fast reacting emergency shutdown when the temperature of an optical element reaches a damage threshold.

  4. Ultrasound Speed of Sound Measurements in Trabecular Bone Using the Echographic Response of a Metallic Pin.

    PubMed

    Guipieri, Séraphin; Nagatani, Yoshiki; Bosc, Romain; Nguyen, Vu-Hieu; Chappard, Christine; Geiger, Didier; Haïat, Guillaume

    2015-11-01

    Bone quality is an important parameter in spine surgery, but its clinical assessment remains difficult. The aim of the work described here was to demonstrate in vitro the feasibility of employing quantitative ultrasound to retrieve bone mechanical properties using an echographic technique taking advantage of the presence of a metallic pin inserted in bone tissue. A metallic pin was inserted in bone tissue perpendicular to the transducer axis. The echographic response of the bone sample was determined, and the echo of the pin inserted in bone tissue and water were compared to determine speed of sound, which was compared with bone volume fraction. A 2-D finite-element model was developed to assess the effect of positioning errors. There was a significant correlation between speed of sound and bone volume fraction (R(2) = 0.6). The numerical results indicate the relative robustness of the measurement method, which could be useful to estimate bone quality intra-operatively. Copyright © 2015 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

  5. Optical measurement of adipose tissue thickness and comparison with ultrasound, magnetic resonance imging, and callipers

    NASA Astrophysics Data System (ADS)

    Geraskin, Dmitri; Boeth, Heide; Kohl-Bareis, Matthias

    2009-07-01

    Near-infrared spectroscopy is used to quantify the subcutaneous adipose tissue thickness (ATT) over five muscle groups (vastus medialis, vastus lateralis, gastrocnemius, ventral forearm and biceps brachii muscle) of healthy volunteers (n=20). The optical lipid signal (OLS) was obtained from the second derivative of broad band attenuation spectra and the lipid absorption peak (λ=930 nm). Ultrasound and MR imaging as well as mechanical calliper readings were taken as reference methods. The data show that the OLS is a good predictor for ATT (<16 mm) with absolute and relative errors of <0.8 mm and <24%, respectively. The optical method compares favourably with calliper reading. The finding of a non-linear relationship of optical signal vs. ultrasound is explained by a theoretical two-layer model based on the diffusion approximation for the transport of photons. The crosstalk between the OLS and tissue hemoglobin concentration changes during an incremental cycling exercise was found to be small, indicating the robustness of OLS. Furthermore, the effect of ATT on spatially-resolved spectroscopy measurements is shown to decrease the calculated muscle hemoglobin concentration and to increase oxygen saturation.

  6. Thermochromic Phantom and Measurement Protocol for Qualitative Analysis of Ultrasound Physiotherapy Systems.

    PubMed

    Costa, Rejane M; Alvarenga, André V; Costa-Felix, Rodrigo P B; Omena, Thaís P; von Krüger, Marco A; Pereira, Wagner C A

    2016-01-01

    Thermochromic test bodies are promising tools for qualitatively evaluating the acoustic output of ultrasound physiotherapy systems. Here, a novel phantom, made of silicone mixed with thermochromic powder material, was developed. Additionally, a procedure was developed to evaluate the stability and homogeneity of the phantom in a metrologic and statistical base. Twelve phantoms were divided into three groups. Each group was insonated by a different transducer. An effective intensity of 1.0 W/cm(2) was applied to each phantom; two operators performed the procedure three times in all phantoms. The heated area was measured after image processing. No statistical difference was observed in the heated areas for different samples or in the results for different operators. The heated areas obtained using each transducer were statistically different, indicating that the thermochromic phantom samples had sufficient sensitivity to represent the heated areas of different ultrasonic transducers. Combined with the evaluation procedure, the phantom provides an approach not previously described in the literature. The proposed approach can be used to quickly assess changes in ultrasonic beam cross-sectional shape during the lifetime of ultrasound physiotherapy systems.

  7. Variability of Liver Shear Wave Measurements Using a New Ultrasound Elastographic Technique.

    PubMed

    Nadebaum, David P; Nicoll, Amanda J; Sood, Siddharth; Gorelik, Alexandra; Gibson, Robert N

    2017-09-29

    A new 2-dimensional (2D) shear wave elastographic (SWE) device has been developed for the noninvasive assessment of liver fibrosis. Guidelines on measurement acquisition parameters are not yet well established for this technique. Our study aimed to assess 2D SWE measurement variability and to determine the number of measurements required per patient to reliably assess liver stiffness. Two-dimensional SWE was assessed in 55 patients with mixed-etiology chronic liver disease on an Aplio 500 ultrasound system (Toshiba Medical Systems Corporation, Tochigi, Japan). Ten measurements were obtained per patient by an operator blinded to all preceding readings. Results were analyzed with clinical information obtained from medical records. The median interquartile range/median ratio for 2D SWE was 0.131 (quartiles 1-3, 0.089-0.174). Five readings provided an approximation within 0.11 m/s, or 4.2% of the median velocity of 10 measurements. Factors associated with increased measurement variability included body mass index (ρ = 0.388; P = .01), increased skin-to-liver capsule distance (ρ = 0.426; P = .002), and measurements taken within 1.5 cm of the liver capsule (P < .001). Measurements with heterogeneous shear wave profiles (indicated by a region of interest [ROI] SD/speed ratio > 0.15) showed greater deviation from the set's median velocity than those with an ROI SD/speed ratio of 0.15 or lower (0.42 versus 0.22 m/s; P = .001). Two-dimensional SWE showed low overall measurement variability, with a minimum of 5 readings providing equivalent precision to the existing method using 10 samples. Obesity, increasing abdominal wall thickness, subcapsular measurements and an ROI SD/speed ratio of greater than 0.15 were all associated with increased measurement variability. The ROI SD/speed ratio warrants further evaluation as a quality assessment metric, to allow objective operator assessment of individual 2D SWE measurement reliability in real

  8. Development of a thermal test object for the measurement of ultrasound intracavity transducer self-heating.

    PubMed

    Killingback, Alban L T; Newey, Valentine R; El-Brawany, Mohamed A; Nassiri, Dariush K

    2008-12-01

    The elevated surface temperature of diagnostic ultrasound transducers imposes an important limitation to their safe use in clinical situations. Moreover, particular care should be taken if transvaginal transducers are to be used during routine scans in the first few weeks of pregnancy as the transducer surface can be very close to embryonic/fetal tissues. Published results have shown that the heating of tissue due to transducer self-heating can equal and often exceed the acoustic heating contribution. In this article, we report the development of a portable self contained thermal test object (TTO) capable of assessing the self-heating of intracavity diagnostic ultrasound transducers. The thermal conductivity and volumetric heat capacity of the tissue mimicking material (TMM) used in the TTO were measured, yielding values of (0.56 +/- 0.01) W m(-1) K(-1) and (3.5 +/- 0.8) MJ m(-3) K(-1). The speed of sound of the TMM was measured as 1540 m s(-1) and the attenuation over a frequency range of 2 to 10 MHz was found to be (0.50 +/- 0.01) dB cm(-1) MHz(-1). These results are in excellent agreement with the International Electrotechnical Commission (IEC 60601-2-37) requirements and the previously published properties of biological soft tissue. The temperature stability and uniformity, and suitability of the TTO for the measurement of transducer self-heating were tested and found to be satisfactory. The TTO reached a stable temperature of 37 degrees C in 3 h and the spatial variation in temperature was less than +/- 0.2 degrees C. Lastly, transducer self-heating measurements from a transvaginal transducer exceeded the IEC temperature limit of 43 degrees C in less than 5 min and the temperature reached after 30 min was 47.3 degrees C.

  9. Reversal time of postprandial changes of the thickness of abdominal muscles employing ultrasound measurements.

    PubMed

    Noormohammadpour, Pardis; Ansari, Majid; Mansournia, Mohammad Ali; Rostami, Mohsen; Nourian, Ruhollah; Kordi, Ramin

    2015-02-01

    Low thickness of Transversus Abdominis, Internal Oblique and External Oblique muscles may play a role in development of low back pain. Ultrasonography is increasingly utilized to measure the thickness of these muscles. Prandial state has recently been proposed as a confounding factor in such measurements. We aimed to compare the reversal time of the postprandial thickness of these muscles with preprandial values. The measurement errors of ultrasonographic values were also assessed in both immediate preprandial and postprandial states. Interventional cross-sectional study. The ultrasonographic thickness of lateral abdominal muscles was measured at rest and during abdominal drawing-in maneuver in 20 healthy participants before and after consumption of a specific meal. Postprandial ultrasound measurements continued every 15 min until their thickness reached 95% of their preprandial values. There was a statistically significant reduction in postprandial thickness of these muscles (all p-values <0.001 on both sides). The reversal times were 1.5, 1.3 and 1.2 h for Transversus Abdominis, Internal Oblique, and External Oblique muscles, respectively. Standard Error of Measurement and Smallest Detectable Change were in the range of 0.007-0.013 mm and 0.020-0.035 mm, respectively. To limit the effects of prandial state on the sonographic thickness of lateral abdominal muscles, we recommend measuring these values at least 1.5-2 h after food consumption. For the future studies, controlling the participants according to their prandial state is recommended. Copyright © 2014 Elsevier Ltd. All rights reserved.

  10. Reliability of ultrasound thickness measurement of the abdominal muscles during clinical isometric endurance tests.

    PubMed

    ShahAli, Shabnam; Arab, Amir Massoud; Talebian, Saeed; Ebrahimi, Esmaeil; Bahmani, Andia; Karimi, Noureddin; Nabavi, Hoda

    2015-07-01

    The study was designed to evaluate the intra-examiner reliability of ultrasound (US) thickness measurement of abdominal muscles activity when supine lying and during two isometric endurance tests in subjects with and without Low back pain (LBP). A total of 19 women (9 with LBP, 10 without LBP) participated in the study. Within-day reliability of the US thickness measurements at supine lying and the two isometric endurance tests were assessed in all subjects. The intra-class correlation coefficient (ICC) was used to assess the relative reliability of thickness measurement. The standard error of measurement (SEM), minimal detectable change (MDC) and the coefficient of variation (CV) were used to evaluate the absolute reliability. Results indicated high ICC scores (0.73-0.99) and also small SEM and MDC scores for within-day reliability assessment. The Bland-Altman plots of agreement in US measurement of the abdominal muscles during the two isometric endurance tests demonstrated that 95% of the observations fall between the limits of agreement for test and retest measurements. Together the results indicate high intra-tester reliability for the US measurement of the thickness of abdominal muscles in all the positions tested. According to the study's findings, US imaging can be used as a reliable method for assessment of abdominal muscles activity in supine lying and the two isometric endurance tests employed, in participants with and without LBP. Copyright © 2014 Elsevier Ltd. All rights reserved.

  11. Volume measurement variability in three-dimensional high-frequency ultrasound images of murine liver metastases.

    PubMed

    Wirtzfeld, L A; Graham, K C; Groom, A C; Macdonald, I C; Chambers, A F; Fenster, A; Lacefield, J C

    2006-05-21

    The identification and quantification of tumour volume measurement variability is imperative for proper study design of longitudinal non-invasive imaging of pre-clinical mouse models of cancer. Measurement variability will dictate the minimum detectable volume change, which in turn influences the scheduling of imaging sessions and the interpretation of observed changes in tumour volume. In this paper, variability is quantified for tumour volume measurements from 3D high-frequency ultrasound images of murine liver metastases. Experimental B16F1 liver metastases were analysed in different size ranges including less than 1 mm3, 1-4 mm3, 4-8 mm3 and 8-70 mm3. The intra- and inter-observer repeatability was high over a large range of tumour volumes, but the coefficients of variation (COV) varied over the volume ranges. The minimum and maximum intra-observer COV were 4% and 14% for the 1-4 mm3 and <1 mm3 tumours, respectively. For tumour volumes measured by segmenting parallel planes, the maximum inter-slice distance that maintained acceptable measurement variability increased from 100 to 600 microm as tumour volume increased. Comparison of free breathing versus ventilated animals demonstrated that respiratory motion did not significantly change the measured volume. These results enable design of more efficient imaging studies by using the measured variability to estimate the time required to observe a significant change in tumour volume.

  12. Perpendicular ultrasound velocity measurement by 2D cross correlation of RF data. Part A: validation in a straight tube

    NASA Astrophysics Data System (ADS)

    Beulen, Bart; Bijnens, Nathalie; Rutten, Marcel; Brands, Peter; van de Vosse, Frans

    2010-11-01

    An ultrasound velocity assessment technique was validated, which allows the estimation of velocity components perpendicular to the ultrasound beam, using a commercially available ultrasound scanner equipped with a linear array probe. This enables the simultaneous measurement of axial blood velocity and vessel wall position, rendering a viable and accurate flow assessment. The validation was performed by comparing axial velocity profiles as measured in an experimental setup to analytical and computational fluid dynamics calculations. Physiologically relevant pulsating flows were considered, employing a blood analog fluid, which mimics both the acoustic and rheological properties of blood. In the core region (| r|/ a < 0.9), an accuracy of 3 cm s-1 was reached. For an accurate estimation of flow, no averaging in time was required, making a beat to beat analysis of pulsating flows possible.

  13. Thoracic ultrasound: Potential new tool for physiotherapists in respiratory management. A narrative review.

    PubMed

    Le Neindre, Aymeric; Mongodi, Silvia; Philippart, François; Bouhemad, Bélaïd

    2016-02-01

    The use of diagnostic ultrasound by physiotherapists is not a new concept; it is frequently performed in musculoskeletal physiotherapy. Physiotherapists currently lack accurate, reliable, sensitive, and valid measurements for the assessment of the indications and effectiveness of chest physiotherapy. Thoracic ultrasound may be a promising tool for the physiotherapist and could be routinely performed at patients' bedsides to provide real-time and accurate information on the status of pleura, lungs, and diaphragm; this would allow for assessment of lung aeration from interstitial syndrome to lung consolidation with much better accuracy than chest x-rays or auscultation. Diaphragm excursion and contractility may also be assessed by ultrasound. This narrative review refers to lung and diaphragm ultrasound semiology and describes how physiotherapists could use this tool in their clinical decision-making processes in various cases of respiratory disorders. The use of thoracic ultrasound semiology alongside typical examinations may allow for the guiding, monitoring, and evaluating of chest physiotherapy treatments. Thoracic ultrasound is a potential new tool for physiotherapists. Copyright © 2015 Elsevier Inc. All rights reserved.

  14. Quantitative ultrasound and DXA measurements in aromatase inhibitor-treated breast cancer women receiving denosumab.

    PubMed

    Catalano, A; Gaudio, A; Morabito, N; Basile, G; Agostino, R M; Xourafa, A; Atteritano, M; Morini, E; Natale, G; Lasco, A

    2017-08-01

    Denosumab has been proven to reduce fracture risk in breast cancer (BC) women under aromatase inhibitors (AIs). Quantitative ultrasound (QUS) provides information on the structure and elastic properties of bone. Our aim was to assess bone health by phalangeal QUS and by dual-energy X-ray absorptiometry (DXA), and to evaluate bone turnover in AIs-treated BC women receiving denosumab. 35 Postmenopausal BC women on AIs were recruited (mean age 61.2 ± 4.5 years) and treated with denosumab 60 mg administered subcutaneously every 6 months. Phalangeal QUS parameters [Amplitude Dependent Speed of Sound (AD-SoS), Ultrasound Bone Profile Index (UBPI), Bone Transmission Time (BTT)] and DXA at lumbar spine and femoral neck were performed. Serum C-telopeptide of type 1 collagen (CTX) and bone-specific alkaline phosphatase (BSAP) were also measured. The main outcomes were compared with a control group not receiving denosumab (n = 39). In patients treated with denosumab, differently from controls, QUS and DXA measurements improved after 24 months, and a reduction of CTX and BSAP was detected at 12 and 24 months in comparison to baseline (P < 0.05). The percent changes (Δ) of QUS measurements were significantly associated with ΔBMD at femoral neck, and ΔCTX and ΔBSAP were associated with ΔBMD at lumbar spine (r = -0.39, P = 0.02; r = -0.49, P = 0.01, respectively). Denosumab preserves bone health as assessed by phalangeal QUS and DXA. Since inexpensive and radiation-free, phalangeal QUS may be considered in the follow-up of AIs-treated BC women receiving denosumab.

  15. Predictors of Bone Status by Quantitative Ultrasound Measurements in a Mountain Village in Japan

    PubMed Central

    Tajika, Tsuyoshi; Yamamoto, Atsushi; Ohsawa, Takashi; Oya, Noboru; Iizuka, Haku; Takagishi, Kenji

    2016-01-01

    Background: It seems to be important to recognize predictors of bone health condition in Japanese super-aged society. The purpose of this study was to investigate predictors of the speed of sound (SOS) of calcaneus by quantitative ultrasound measurements of mountain village residents. Materials and Methods: Medical examinations were conducted on 214 participants (69 men, 145 women; average age of 63.6 years). Each had completed a self-administered questionnaire including items such as gender, dominant hand, occupation, and history of smoking and drinking alcohol, experience of falls, and the EuroQol-5-dimensions-3-level Japanese version and a 25-question geriatric locomotive function scale proposed by the Japanese Orthopaedic Association. Bilateral grip and key pinch strength were measured. The SOS of calcaneus was assessed using ultrasound bone densitometry. Body composition was measured using a multi-frequency segmental body composition analyzer. Spearman's rank correlation coefficient was calculated to elucidate the relation between SOS and evaluation items. Stepwise logistic regression was used to identify predictors of SOS using the investigated factors as explanatory variables. P values of < .05 were regarded as statistically significant. Results: Significant positive correlation was found between the SOS and dominant and non-dominant grip and key pinch strength and Euro index and QOL VAS in all participants. In stepwise logistic regression, non-dominant key pinch (β coefficient= 0.27, p= .022) and Euro QOL VAS (β coefficient= 0.24, p= .0001) were predictors of calcaneal SOS for all participants. Conclusion: Key pinch strength and Euro QOL VAS assessment might be useful to predict calcaneal SOS in the general population. PMID:27990194

  16. Concurrent validity of calipers and ultrasound imaging to measure interrecti distance.

    PubMed

    Chiarello, Cynthia M; McAuley, J Adrienne

    2013-01-01

    Clinical measurement, concurrent validity criterion standard. To determine the concurrent validity of digital nylon calipers in comparison to ultrasound imaging (USI) for the measurement of interrecti distance (IRD). Diastasis rectus abdominis is the abnormal increase in the width of the linea alba, measured as IRD. A diastasis rectus abdominis can compromise mechanical trunk function in both genders. IRD has been accurately measured with USI but requires costly equipment and extensive examiner training. Digital nylon calipers are inexpensive and easy to use, but their use to measure IRD has not been validated. A sample of convenience of 56 individuals (11 men, 45 women) was measured. A single examiner was assigned to each tool (calipers or USI), and IRD was measured at 2 locations (above and below the umbilicus) under 2 conditions (abdominal muscles at rest and abdominal muscles contracted). All measurements were made during a single session, and examiners were blinded to measurements with the other tool. Above the umbilicus, the measurements of IRD with calipers were similar to those made with USI, with intraclass correlation coefficients (model 3,2) of 0.79 with abdominal muscles at rest and 0.71 with abdominal muscles contracted. The absolute mean difference between the caliper and USI measurements of IRD above the umbilicus was 0.03 cm larger with the calipers when the abdominal muscles were at rest and 0.03 cm smaller when the abdominal muscles were contracted. The values of IRD obtained with the caliper and USI techniques were not comparable when obtained below the umbilicus. The calipers are a valid tool for measuring IRD above the umbilicus in males and females. Measuring IRD with calipers below the umbilicus should not be considered valid, using USI as the criterion standard. This may reflect anatomical variation of the linea alba or a limitation of the calipers to assess IRD at the same depth as USI.

  17. A Protocol for Improved Measurement of Arterial Flow Rate in Preclinical Ultrasound.

    PubMed

    Kenwright, D A; Thomson, A J W; Hadoke, P W F; Anderson, T; Moran, C M; Gray, G A; Hoskins, P R

    2015-11-01

    To describe a protocol for the measurement of blood flow rate in small animals and to compare flow rate measurements against measurements made using a transit time flowmeter. Measurements were made in rat and mice using a Visualsonics Vevo 770 scanner. The flow rate in carotid and femoral arteries was calculated from the time-average maximum velocity and vessel diameter. A correction factor was applied to correct for the overestimation of velocity arising from geometric spectral broadening. Invasive flow rate measurements were made using a Transonics system. Measurements were achieved in rat carotid and femoral arteries and in mouse carotid arteries. Image quality in the mouse femoral artery was too poor to obtain diameter measurements. The applied correction factor in practice was 0.71-0.77. The diameter varied by 6-18% during the cardiac cycle. There was no overall difference in the flow rate measured using ultrasound and using transit-time flowmeters. The flow rates were comparable with those previously reported in the literature. There was wide variation in flow rates in the same artery in individual animals. Transit-time measurements were associated with changes of a factor of 10 during the typical 40 min measurement period, associated with probe movement, vessel spasm, vessel kinking and other effects. A protocol for the measurement of flow rate in arteries in small animals has been described and successfully used in rat carotid and femoral arteries and in mouse carotid arteries. The availability of a noninvasive procedure for flow rate measurement avoids the problems with changes in flow associated with an invasive procedure.

  18. A Protocol for Improved Measurement of Arterial Flow Rate in Preclinical Ultrasound

    PubMed Central

    Kenwright, D. A.; Thomson, A. J. W.; Hadoke, P. W. F.; Anderson, T.; Moran, C. M.; Gray, G. A.; Hoskins, P. R.

    2015-01-01

    Purpose: To describe a protocol for the measurement of blood flow rate in small animals and to compare flow rate measurements against measurements made using a transit time flowmeter. Materials and Methods: Measurements were made in rat and mice using a Visualsonics Vevo 770 scanner. The flow rate in carotid and femoral arteries was calculated from the time-average maximum velocity and vessel diameter. A correction factor was applied to correct for the overestimation of velocity arising from geometric spectral broadening. Invasive flow rate measurements were made using a Transonics system. Results: Measurements were achieved in rat carotid and femoral arteries and in mouse carotid arteries. Image quality in the mouse femoral artery was too poor to obtain diameter measurements. The applied correction factor in practice was 0.71–0.77. The diameter varied by 6–18% during the cardiac cycle. There was no overall difference in the flow rate measured using ultrasound and using transit-time flowmeters. The flow rates were comparable with those previously reported in the literature. There was wide variation in flow rates in the same artery in individual animals. Transit-time measurements were associated with changes of a factor of 10 during the typical 40 min measurement period, associated with probe movement, vessel spasm, vessel kinking and other effects. Conclusion: A protocol for the measurement of flow rate in arteries in small animals has been described and successfully used in rat carotid and femoral arteries and in mouse carotid arteries. The availability of a noninvasive procedure for flow rate measurement avoids the problems with changes in flow associated with an invasive procedure. PMID:27689153

  19. Feasibility of coded vibration in a vibro-ultrasound system for tissue elasticity measurement.

    PubMed

    Zhao, Jinxin; Wang, Yuanyuan; Yu, Jinhua; Li, Tianjie; Zheng, Yong-Ping

    2016-07-01

    The ability of various methods for elasticity measurement and imaging is hampered by the vibration amplitude on biological tissues. Based on the inference that coded excitation will improve the performance of the cross-correlation function of the tissue displacement waves, the idea of exerting encoded external vibration on tested samples for measuring its elasticity is proposed. It was implemented by integrating a programmable vibration generation function into a customized vibro-ultrasound system to generate Barker coded vibration for elasticity measurement. Experiments were conducted on silicone phantoms and porcine muscles. The results showed that coded excitation of the vibration enhanced the accuracy and robustness of the elasticity measurement especially in low signal-to-noise ratio scenarios. In the phantom study, the measured shear modulus values with coded vibration had an R(2 )= 0.993 linear correlation to that of referenced indentation, while for single-cycle pulse the R(2) decreased to 0.987. In porcine muscle study, the coded vibration also obtained a shear modulus value which is more accurate than the single-cycle pulse by 0.16 kPa and 0.33 kPa at two different depths. These results demonstrated the feasibility and potentiality of the coded vibration for enhancing the quality of elasticity measurement and imaging.

  20. Ultrasound-based measurement of liquid-layer thickness: A novel time-domain approach

    NASA Astrophysics Data System (ADS)

    Praher, Bernhard; Steinbichler, Georg

    2017-01-01

    Measuring the thickness of a thin liquid layer between two solid materials is important when the adequate separation of metallic parts by a lubricant film (e.g., in bearings or mechanical seals) is to be assessed. The challenge in using ultrasound-based systems for such measurements is that the signal from the liquid layer is a superposition of multiple reflections. We have developed an algorithm for reconstructing this superimposed signal in the time domain. By comparing simulated and measured signals, the time-of-flight of the ultrasonic pulse in a layer can be estimated. With the longitudinal sound velocity known, the layer thickness can then be calculated. In laboratory measurements, we validate successfully (maximum relative error 4.9%) our algorithm for layer thicknesses ranging from 30 μm to 200 μm. Furthermore, we tested our method in the high-temperature environment of polymer processing by measuring the clearance between screw and barrel in the plasticisation unit of an injection moulding machine. The results of such measurements can indicate (i) the wear status of the tribo-mechanical screw-barrel system and (ii) unsuitable process conditions.

  1. Ultrasound measurement of the corpus callosum and neural development of premature infants.

    PubMed

    Liu, Fang; Cao, Shikao; Liu, Jiaoran; Du, Zhifang; Guo, Zhimei; Ren, Changjun

    2013-09-15

    Length and thickness of 152 corpus callosa were measured in neonates within 24 hours of birth. Using ultrasonic diagnostic equipment with a neonatal brain-specific probe, corpus callosum length and thickness of the genu, body, and splenium were measured on the standard mid-sagittal plane, and the anteroposterior diameter of the genu was measured in the coronal plane. Results showed that corpus callosum length as well as thickness of the genu and splenium increased with tional age and birth weight, while other measures did not. These three factors on the standard mid-sagittal plane are therefore likely to be suitable for real-time evaluation of corpus callosum velopment in premature infants using cranial ultrasound. Further analysis revealed that thickness of the body and splenium and the anteroposterior diameter of the genu were greater in male infants than in female infants, suggesting that there are sex differences in corpus callosum size during the neonatal period. A second set of measurements were taken from 40 premature infants whose gestational age was 34 weeks or less. Corpus callosum measurements were corrected to a gestational age of 40 weeks, and infants were grouped for analysis depending on the outcome of a neonatal behavioral neurological assessment. Compared with infants with a normal neurological assessment, corpus callosum length and genu and splenium thicknesses were less in those with abnormalities, indicating that corpus callosum growth in premature infants is associated with neurobehavioral development during the early extrauterine stage.

  2. The Reliability of Ultrasound Measurements of the Median Nerve at the Carpal Tunnel Inlet.

    PubMed

    Fowler, John R; Hirsch, David; Kruse, Kevin

    2015-10-01

    To determine the interrater and intra-rater reliability of ultrasound (US) measurement of the cross-sectional area (CSA) of the median nerve at the carpal tunnel inlet. Three examiners of varying levels of experience performed US measurements of the CSA of the median nerve at the carpal tunnel inlet of both wrists of 11 healthy volunteers. Each examiner was blinded to the measurements of the other examiners. The measurements were repeated 2 weeks later in random order to test intra-rater reliability. The Lin concordance correlation coefficient (LCCC) for interrater and intra-rater reliability was calculated. The overall inter-rater LCCC was 0.59 (95% confidence interval [CI], 0.41-0.73). Intra-rater LCCC varied based on examiner experience. The senior author had an intra-rater LCCC of 0.91 (95% CI, 0.80-0.96), the hand fellow had an intra-rater LCCC of 0.45 (95% CI, 0.17-0.66), and the first-year resident had an intra-rater LCCC of 0.78 (95% CI, 0.55-0.90). There is moderate agreement among examiners of varying levels of experience when measuring the CSA of the median nerve at the carpal tunnel inlet. Examiner experience affected intra-rater reliability of measurements; an experienced examiner had nearly perfect agreement compared with moderate agreement for less experienced examiners. Copyright © 2015 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.

  3. Ultrasound measures of supraspinatus tendon thickness and acromiohumeral distance in rotator cuff tendinopathy are reliable.

    PubMed

    McCreesh, Karen M; Anjum, Shakeel; Crotty, James M; Lewis, Jeremy S

    2016-01-01

    Rotator cuff (RC) tendinopathy has been widely ascribed to impingement of the supraspinatus tendon (SsT) in the subacromial space, measured as the acromiohumeral distance (AHD). Ultrasound (US) is suitable for measuring AHD and SsT thickness, but few reliability studies have been carried out in symptomatic populations, and interrater reliability is unconfirmed. This study aimed to examine the intrarater and interrater reliability of US measurements of AHD and SsT thickness in asymptomatic control subjects and patients with RC tendinopathy. Seventy participants were recruited and grouped as healthy controls (n = 25) and RC tendinopathy (n = 45). Repeated US measurements of AHD and SsT thickness were obtained by one rater in both groups and by two raters in the RC tendinopathy group. Intrarater and interrater reliability coefficients were excellent for both measurements (intraclass correlation > 0.92), but the intrarater reliability was superior. The minimal detectable change values in the symptomatic group were 0.7 mm for AHD and 0.6 mm for SsT thickness for a single experienced examiner; the values rose to 1.2 mm and 1.3 mm, respectively, for the pair of examiners. The results support the reliability of US for the measurement of AHD and SsT thickness in patients with symptomatic RC tendinopathy and provide minimal detectable change values for use in future research studies. © 2015 Wiley Periodicals, Inc.

  4. Developing an emergency ultrasound app - a collaborative project between clinicians from different universities.

    PubMed

    Foss, Kim Thestrup; Subhi, Yousif; Aagaard, Rasmus; Bessmann, Ebbe Lahn; Bøtker, Morten Thingemann; Graumann, Ole; Laursen, Christian B; Weile, Jesper; Todsen, Tobias

    2015-06-20

    Focused emergency ultrasound is rapidly evolving as a clinical skill for bedside examination by physicians at all levels of education. Ultrasound is highly operator-dependent and relevant training is essential to ensure appropriate use. When supplementing hands-on focused ultrasound courses, e-learning can increase the learning effect. We developed an emergency ultrasound app to enable onsite e-learning for trainees. In this paper, we share our experiences in the development of this app and present the final product.

  5. Ultrasound Measurement of the Fetal Adrenal Gland as a Predictor of Spontaneous Preterm Birth

    PubMed Central

    Hoffman, Matthew K.; Turan, Ozhan M.; Parker, Corette B.; Wapner, Ronald J.; Wing, Deborah A.; Haas, David M.; Esplin, M. Sean; Parry, Samuel; Grobman, William A.; Simhan, Hyagriv N.; Myers, Stephen; Holder, Tommy E.; Rumney, Pamela; Litton, Christian G.; Silver, Robert M.; Elovitz, Michal A.; Peaceman, Alan M.; Emery, Stephen; Mercer, Brian M.; Koch, Matthew A.; Saade, George R.

    2016-01-01

    Objective To estimate whether ultrasound measurement of the fetal adrenal gland remote from delivery in asymptomatic women can accurately predict spontaneous preterm birth. Methods We conducted a prospective multicenter observational nested cohort study of asymptomatic nulliparous women with a singleton pregnancy to study adverse pregnancy outcomes. Between 22 0/7 and 30 6/7 weeks of gestation, credentialed ultrasonographers measured the width (w), length (l), and when able, depth (d) of the “fetal zone” of the fetal adrenal gland as well as the width (W), length (L) and depth (D) of the total gland. We used the ratios of each measurement (w/W, l/L and d/D) to control for variation in adrenal size by gestational age. The accuracy of each ratio measurement in predicting spontaneous preterm birth <37 0/7 weeks (“SPTB37”) and spontaneous preterm birth <34 0/7 weeks (“SPTB34”) was assessed by receiver operating characteristic (ROC) curves, using area under the curve (AUC). Results Pregnancy outcomes were available for 1,697 women with one or more fetal adrenal gland measurements. SPTB37 and SPTB34 occurred in 82 (4.8%) and 6 women (0.4%), respectively. None of the fetal adrenal gland measurements distinguished spontaneous preterm birth from term birth. The AUCs (95% CIs) for SPTB37 were 0.51 (0.45, 0.58), 0.50 (0.44, 0.56), and 0.52 (0.41, 0.63) for w/W, l/L and d/D ratios, respectively. The AUCs for SPTB34 were 0.52 (0.25, 0.79) and 0.55 (0.31, 0.79) for w/W and l/L ratios. Additionally, none of the means of the gland measurements were statistically different between those delivering at term and spontaneous at preterm (p>0.05). Conclusion Fetal adrenal size, as measured by ultrasound between 22 0/7 and 30 6/7 weeks, is not predictive of spontaneous preterm birth in asymptomatic nulliparous women. PMID:26959201

  6. Ultrasound: An Unexplored Tool for Blood Flow Visualization and Hemodynamic Measurements

    NASA Astrophysics Data System (ADS)

    Shung, K. Kirk; Paeng, Dong-Guk

    2003-05-01

    Ultrasonic scattering by blood has been studied both theoretically and experimentally for a better characterization of the performance of ultrasonic devices. In the course of these investigations it became clear that ultrasonic scattering from blood is critically related to the hematological and hemodynamic properties of blood, including hematocrit, plasma protein concentration, flow rate, and flow cycle duration, to name a few parameters. An unexpected conclusion from this work is that ultrasound appears to be a totally unexplored and ignored tool for blood flow visualization and hemodynamic measurements. Two unique hemodynamic phenomena have been observed: the black hole, a low echogenic zone in the center stream of a blood vessel, and the collapsing ring, an hyperechogenic ring converging from the vessel periphery toward the center, and eventually collapsing during pulsatile flow. They seemed to be resulted from the spatial and temporal variations of the shear rate and acceleration in the vessel.

  7. Review of high-power ultrasound-industrial applications and measurement methods.

    PubMed

    Harvey, Gerald; Gachagan, Anthony; Mutasa, Tapiwa

    2014-03-01

    Applications involving high-power ultrasound are expanding rapidly as ultrasonic intensification opportunities are identified in new fields. This is facilitated through new technological developments and an evolution of current systems to tackle challenging problems. It is therefore important to continually update both the scientific and commercial communities on current system performance and limitations. To achieve this objective, this paper addresses two key aspects of high-power ultrasonic systems. In the first part, the review of high-power applications focuses on industrial applications and documents the developing technology from its early cleaning applications through to the advanced sonochemistry, cutting, and water treatment applications used today. The second part provides a comprehensive overview of measurement techniques used in conjunction with high-power ultrasonic systems. This is an important and evolving field which enables design and process engineers to optimize the behavior and/or operation of key metrics of system performance, such as field distribution or cavitation intensity.

  8. Vascular ultrasound measures before pregnancy and pregnancy complications: A prospective cohort study.

    PubMed

    Harville, Emily W; Juonala, Markus; Viikari, Jorma S A; Kähönen, Mika; Raitakari, Olli T

    2017-02-01

    To examine the relationship between pre-pregnancy indicators of cardiovascular risk and pregnancy complications and outcomes. Data from 359 female participants in the Cardiovascular Risk in Young Finns Study were linked with the national birth registry. Flow-mediated dilatation (FMD; maximum change in the left brachial artery diameter after rest and hyperemia); carotid intima-media thickness (IMT); Young's elastic modulus (YEM); and carotid artery distensibility (Cdist) at the visit prior to the pregnancy were examined as predictors of hypertensive disorders, birthweight, and gestational age using multivariable linear regression with adjustment for confounders (age, BMI, smoking, and socioeconomic status). No relations were seen between FMD, IMT, or the stiffness indices, and hypertensive disorders. Higher pre-pregnancy FMD was associated with lower gestational age, while increased Cdist was associated with reduced birthweight-for-gestational-age. Some cardiovascular ultrasound measures of pre-pregnancy may predict pregnancy complications, but the association is likely to be small.

  9. Transrectal ultrasound and magnetic resonance imaging measurement of extramural tumor spread in rectal cancer

    PubMed Central

    Rafaelsen, Søren R; Vagn-Hansen, Chris; Sørensen, Torben; Pløen, John; Jakobsen, Anders

    2012-01-01

    AIM: To evaluate the agreement between transrectal ultrasound (TRUS) and magnetic resonance imaging (MRI) in classification of ≥ T3 rectal tumors. METHODS: From January 2010 to January 2012, 86 consecutive patients with ≥ T3 tumors were included in this study. The mean age of the patients was 66.4 years (range: 26-91 years). The tumors were all ≥ T3 on TRUS. The sub-classification was defined by the penetration of the rectal wall: a: 0 to 1 mm; b: 1-5 mm; c: 6-15; d: > 15 mm. Early tumors as ab (≤ 5 mm) and advanced tumors as cd (> 5 mm). All patients underwent TRUS using a 6.5 MHz transrectal transducer. The MRI was performed with a 1.5 T Philips unit. The TRUS findings were blinded to the radiologist performing the interpretation of the MRI images and measuring the depth of extramural tumor spread. RESULTS: TRUS found 51 patients to have an early ≥ T3 tumors and 35 to have an advanced tumor, whereas MRI categorized 48 as early ≥ T3 tumors and 38 as advanced tumors. No patients with tumors classified as advanced by TRUS were found to be early on MRI. The kappa value in classifying early versus advanced T3 rectal tumors was 0.93 (95% CI: 0.85-1.00). We found a kappa value of 0.74 (95% CI: 0.63-0.86) for the total sub-classification between the two methods. The mean maximal tumor outgrowth measured by TRUS, 5.5 mm ± 5.63 mm and on MRI, 6.3 mm ± 6.18 mm, P = 0.004. In 19 of the 86 patients the following CT scan or surgery revealed distant metastases; of the 51 patients in the ultrasound ab group three (5.9%) had metastases, whereas 16 (45.7%) of 35 in the cd group harbored distant metastases, P = 0.00002. The odds ratio of having distant metastases in the ultrasound cd group compared to the ab group was 13.5 (95% CI: 3.5-51.6), P = 0.00002. The mean maximal ultrasound measured outgrowth was 4.3 mm (95% CI: 3.2-5.5 mm) in patients without distant metastases, while the mean maximal outgrowth was 9.5 mm (95% CI: 6.2-12.8 mm) in the patients with metastases

  10. Measurement of anastomosis geometry in lower extremity bypass grafts with 3-D ultrasound imaging.

    PubMed

    Leotta, Daniel F; Primozich, Jean F; Lowe, Christopher M; Karr, Leni N; Bergelin, Robert O; Beach, Kirk W; Zierler, R Eugene

    2005-10-01

    The attachment sites of lower extremity bypass grafts are known to exhibit a wide range of geometries. Factors that determine the geometry of a given anastomosis include graft material, graft site, native vessel size, graft size and individual patient anatomy. Therefore, it is difficult to specify a standard anastomosis geometry before surgery and difficult to predict the effect of the geometry on long-term graft patency. We have used 3-D ultrasound imaging to study 46 proximal anastomoses of lower limb bypass grafts. We have developed methods to characterize the 3-D geometry of the anastomosis in terms of component sizes and angles. These detailed geometric measurements describe a range of anastomosis geometries and establish standardized parameters across cases that can be used to relate anastomosis geometry to outcome.

  11. Medical Ultrasound Imaging.

    ERIC Educational Resources Information Center

    Hughes, Stephen

    2001-01-01

    Explains the basic principles of ultrasound using everyday physics. Topics include the generation of ultrasound, basic interactions with material, and the measurement of blood flow using the Doppler effect. (Author/MM)

  12. Medical Ultrasound Imaging.

    ERIC Educational Resources Information Center

    Hughes, Stephen

    2001-01-01

    Explains the basic principles of ultrasound using everyday physics. Topics include the generation of ultrasound, basic interactions with material, and the measurement of blood flow using the Doppler effect. (Author/MM)

  13. 3D thoracoscopic ultrasound volume measurement validation in an ex vivo and in vivo porcine model of lung tumours

    NASA Astrophysics Data System (ADS)

    Hornblower, V. D. M.; Yu, E.; Fenster, A.; Battista, J. J.; Malthaner, R. A.

    2007-01-01

    The purpose of this study was to validate the accuracy and reliability of volume measurements obtained using three-dimensional (3D) thoracoscopic ultrasound (US) imaging. Artificial 'tumours' were created by injecting a liquid agar mixture into spherical moulds of known volume. Once solidified, the 'tumours' were implanted into the lung tissue in both a porcine lung sample ex vivo and a surgical porcine model in vivo. 3D US images were created by mechanically rotating the thoracoscopic ultrasound probe about its long axis while the transducer was maintained in close contact with the tissue. Volume measurements were made by one observer using the ultrasound images and a manual-radial segmentation technique and these were compared with the known volumes of the agar. In vitro measurements had average accuracy and precision of 4.76% and 1.77%, respectively; in vivo measurements had average accuracy and precision of 8.18% and 1.75%, respectively. The 3D thoracoscopic ultrasound can be used to accurately and reproducibly measure 'tumour' volumes both in vivo and ex vivo.

  14. Prenatal Air Pollution Exposure and Ultrasound Measures of Fetal Growth in Los Angeles, California

    PubMed Central

    Ritz, Beate; Qiu, Jiaheng; Lee, Pei-Chen; Lurmann, Fred; Penfold, Bryan; Weiss, Robert Erin; McConnell, Rob; Arora, Chander; Hobel, Calvin; Wilhelm, Michelle

    2014-01-01

    Background Few previous studies examined the impact of prenatal air pollution exposures on fetal development based on ultrasound measures during pregnancy. Methods In a prospective birth cohort of more than 500 women followed during 1993-1996 in Los Angeles, California, we examined how air pollution impacts fetal growth during pregnancy. Exposure to traffic related air pollution was estimated using CALINE4 air dispersion modeling for nitrogen oxides (NOx) and a land use regression (LUR) model for nitrogen monoxide (NO), nitrogen dioxide (NO2) and NOx. Exposures to carbon monoxide (CO), NO2, ozone (O3) and particles <10 μm in aerodynamic diameter (PM10) were estimated using government monitoring data. We employed a linear mixed effects model to estimate changes in fetal size at approximately 19, 29 and 37 weeks gestation based on ultrasound. Results Exposure to traffic-derived air pollution during 29 to 37 weeks was negatively associated with biparietal diameter at 37 weeks gestation. For each interquartile range (IQR) increase in LUR-based estimates of NO, NO2 and NOx, or freeway CALINE4 NOx we estimated a reduction in biparietal diameter of 0.2-0.3 mm. For women residing within 5 km of a monitoring station, we estimated biparietal diameter reductions of 0.9-1.0 mm per IQR increase in CO and NO2. Effect estimates were robust to adjustment for a number of potential confounders. We did not observe consistent patterns for other growth endpoints we examined. Conclusions Prenatal exposure to traffic-derived pollution was negatively associated with fetal head size measured as biparietal diameter in late pregnancy. PMID:24517884

  15. Prenatal air pollution exposure and ultrasound measures of fetal growth in Los Angeles, California.

    PubMed

    Ritz, Beate; Qiu, Jiaheng; Lee, Pei-Chen; Lurmann, Fred; Penfold, Bryan; Erin Weiss, Robert; McConnell, Rob; Arora, Chander; Hobel, Calvin; Wilhelm, Michelle

    2014-04-01

    Few previous studies examined the impact of prenatal air pollution exposures on fetal development based on ultrasound measures during pregnancy. In a prospective birth cohort of more than 500 women followed during 1993-1996 in Los Angeles, California, we examined how air pollution impacts fetal growth during pregnancy. Exposure to traffic related air pollution was estimated using CALINE4 air dispersion modeling for nitrogen oxides (NOx) and a land use regression (LUR) model for nitrogen monoxide (NO), nitrogen dioxide (NO2) and NOx. Exposures to carbon monoxide (CO), NO2, ozone (O3) and particles <10μm in aerodynamic diameter (PM10) were estimated using government monitoring data. We employed a linear mixed effects model to estimate changes in fetal size at approximately 19, 29 and 37 weeks gestation based on ultrasound. Exposure to traffic-derived air pollution during 29 to 37 weeks was negatively associated with biparietal diameter at 37 weeks gestation. For each interquartile range (IQR) increase in LUR-based estimates of NO, NO2 and NOx, or freeway CALINE4 NOx we estimated a reduction in biparietal diameter of 0.2-0.3mm. For women residing within 5km of a monitoring station, we estimated biparietal diameter reductions of 0.9-1.0mm per IQR increase in CO and NO2. Effect estimates were robust to adjustment for a number of potential confounders. We did not observe consistent patterns for other growth endpoints we examined. Prenatal exposure to traffic-derived pollution was negatively associated with fetal head size measured as biparietal diameter in late pregnancy. Copyright © 2014 Elsevier Inc. All rights reserved.

  16. Practical issues of hemodynamic monitoring at the bedside.

    PubMed

    Polanco, Patricio M; Pinsky, Michael R

    2006-12-01

    The hemodynamic monitoring of a surgical patient acquires a major relevance in high-risk patients and those suffering from surgical diseases associated with hemodynamic instability, such as hemorrhagic or septic shock. This article reviews the fundamental physiologic principles needed to understand hemodynamic monitoring at the bedside. Monitoring defines stability, instability, and response to therapy. The major hemodynamic parameters measured and derived from invasive hemodynamic monitoring, such as arterial, central venous, and pulmonary catheterization, are discussed, as are its clinical indications, benefits, and complications. The current clinical data relevant to hemodynamic monitoring are reviewed and discussed.

  17. Has Bedside Teaching Had Its Day?

    ERIC Educational Resources Information Center

    Qureshi, Zeshan; Maxwell, Simon

    2012-01-01

    Though a diverse array of teaching methods is now available, bedside teaching is arguably the most favoured. Students like it because it is patient-centred, and it includes a high proportion of relevant skills. It is on the decline, coinciding with declining clinical skills of junior doctors. Several factors might account for this: busier…

  18. Adherence to criteria for transvaginal ultrasound imaging and measurement of cervical length.

    PubMed

    Iams, Jay D; Grobman, William A; Lozitska, Albina; Spong, Catherine Y; Saade, George; Mercer, Brian M; Tita, Alan T; Rouse, Dwight J; Sorokin, Yoram; Wapner, Ronald J; Leveno, Kenneth J; Blackwell, Sean C; Esplin, M Sean; Tolosa, Jorge E; Thorp, John M; Caritis, Steve N; Van Dorsten, Peter J

    2013-10-01

    Adherence to published criteria for transvaginal imaging and measurement of cervical length is uncertain. We sought to assess adherence by evaluating images submitted to certify research sonographers for participation in a clinical trial. We reviewed qualifying test results of sonographers seeking certification to image and measure cervical length in a clinical trial. Participating sonographers were required to access training materials and submit 15 images, 3 each from 5 pregnant women not enrolled in the trial. One of 2 sonologists reviewed all qualifying images. We recorded the proportion of images that did not meet standard criteria (excess compression, landmarks not seen, improper image size, or full maternal bladder) and the proportion in which the cervical length was measured incorrectly. Failure for a given patient was defined as >1 unacceptable image, or >2 acceptable images with incorrect caliper placement or erroneous choice of the "shortest best" cervical length. Certification required satisfactory images and cervical length measurement from ≥4 patients. A total of 327 sonographers submitted 4905 images. A total of 271 sonographers (83%) were certified on the first, 41 (13%) on the second, and 2 (0.6%) on the third submission. Thirteen never achieved certification. Of 314 who passed, 196 submitted 15 acceptable images that were appropriately measured for all 5 women. There were 1277 deficient images: 493 were acceptable but incorrectly measured images from sonographers who passed certification because mismeasurement occurred no more than twice. Of 784 deficient images submitted by sonographers who failed the certification, 471 were rejected because of improper measurement (caliper placement and/or failure to identify the shortest best image), and 313 because of failure to obtain a satisfactory image (excessive compression, required landmarks not visible, incorrect image size, brief examination, and/or full maternal bladder). Although 83% of

  19. Improved ultrasound transducer positioning by fetal heart location estimation during Doppler based heart rate measurements.

    PubMed

    Hamelmann, Paul; Vullings, Rik; Schmitt, Lars; Kolen, Alexander Franciscus; Mischi, Massimo; Van Laar, Judith O E H; Bergmans, Jan W M

    2017-09-04

    Doppler Ultrasound (US) is the most commonly applied method to measure the fetal heart rate (fHR). When the fetal heart is not properly located within the ultrasonic beam, fHR measurements often fail. As a consequence, clinical staff needs to reposition the US transducer on the maternal abdomen, which can be a time consuming and tedious task. In this article, a method is presented to aid clinicians with the positioning of the US transducer to produce robust fHR measurements. A maximum likelihood estimation (MLE) algorithm is developed, which provides information on fetal heart location using the power of the Doppler signals received in the individual elements of a standard US transducer for fHR recordings. The performance of the algorithm is evaluated with simulations and in-vitro experiments performed on a beating-heart setup. Both the experiments and the simulations show that the heart location can be accurately determined with an error of less than 7 mm within the measurement volume of the employed US transducer. The results show that the developed algorithm can be used to provide accurate feedback on fetal heart location for improved positioning of the US transducer, which may lead to improved measurements of the fHR. © 2017 Institute of Physics and Engineering in Medicine.

  20. Relationship between flexion-rotation test and ultrasound thickness measurement of the abdominal muscles.

    PubMed

    Rajabzadeh, Fatemeh; Taghipour, Morteza; Pourahmadi, Mohammad Reza; Arab, Amir Massoud

    2016-11-21

    The purpose of this study was to investigate the relationship between flexion-rotation test and ultrasound (US) thickness measurement of the antero-lateral abdominal muscles. Following ethical approval, a convenience sample of 55 subjects between the ages of 20 and 30 years participated in this study. Endurance of the abdominal muscles was measured using the flexion-rotation test in all subjects. US thickness measurement for the transversus abdominis (TrA), internal oblique (IO) and external oblique (EO) muscles was performed on the right side at rest in a supine position. Pearson correlation coefficient between the variables of the study showed no significant relationship between the flexion-rotation test and US thickness measurements of the TrA (r = -0.03, P = 0.80), IO (r = -0.13, P = 0.32), and EO (r = -0.14, P = 0.31) muscles. The significance level of 0.05 was chosen. It seems that there is no significant relationship between the flexion-rotation test and US measurement of abdominal muscles thickness.

  1. Plantar fasciitis (fasciosis) treatment outcome study: plantar fascia thickness measured by ultrasound and correlated with patient self-reported improvement.

    PubMed

    Fabrikant, Jerry M; Park, Tae Soon

    2011-06-01

    Ultrasound, well recognized as an effective diagnostic tool, reveals a thickening of the plantar fascia in patients with plantar fasciitis/fasciosis disease. The authors hypothesized that ultrasound would also reveal a decrease in the plantar fascia thickness for patients undergoing treatment for the disease, a hypothesis that, heretofore, had been only tested on a limited number of subjects. They conducted a more statistically significant study that found that clinical treatment with injection and biomechanical correction does indeed diminish plantar fascia thickness as shown on ultrasound. The study also revealed that patients experience the most heightened plantar fascia tenderness toward the end of the day, and improvement in their symptomatic complaints were associated with a reduction in plantar fascia thickness. As a result, the authors conclude that office-based ultrasound can help diagnose and confirm plantar fasciitis/fasciosis through the measurement of the plantar fascia thickness. Because of the advantages of ultrasound--that it is non-invasive with greater patient acceptance, cost effective and radiation-free--the imaging tool should be considered and implemented early in the diagnosis and treatment of plantar fasciitis/fasciosis.

  2. Implementing bedside handover: strategies for change management.

    PubMed

    McMurray, Anne; Chaboyer, Wendy; Wallis, Marianne; Fetherston, Cathy

    2010-09-01

    To identify factors influencing change in two hospitals that moved from taped and verbal nursing handover to bedside handover. Bedside handover is based on patient-centred care, where patients participate in communicating relevant and timely information for care planning. Patient input reduces care fragmentation, miscommunication-related adverse events, readmissions, duplication of services and enhances satisfaction and continuity of care. Analysing change management was a component of a study aimed at developing a standard operating protocol for bedside handover communication. The research was undertaken in two regional acute care hospitals in two different states of Australia. Data collection included 532 semi-structured observations in six wards in the two hospitals and 34 in-depth interviews conducted with a purposive sample of nursing staff involved in the handovers. Observation and interview data were analysed separately then combined to generate thematic analysis of factors influencing the change process in the transition to bedside handover. Themes included embedding the change as part of the big picture, the need to link the project to standardisation initiatives, providing reassurance on safety and quality, smoothing out logistical difficulties and learning to listen. We conclude that change is more likely to be successful when it is part of a broader initiative such as a quality improvement strategy. Nurses are generally supportive of quality improvement initiatives, particularly those aimed at standardising care. For successful implementation, change managers should be mindful of clinicians' attitudes, motivation and concerns and their need for reassurance when changing their practice. This is particularly important when change is dramatic, as in moving from verbal handover, conducted in the safety of the nursing office, to bedside handover where there is greater transparency and accountability for the accuracy and appropriateness of communication

  3. In-vivo investigation of material quality of bone tissue by measuring apparent phalangeal ultrasound transmission velocity.

    PubMed

    Kann, P; Schulz, U; Klaus, D; Piepkorn, B; Beyer, J

    1995-01-01

    The square of ultrasound transmission velocity in a material is related to the modulus of elasticity, which is known to be an indicator of stability in bone. The aim of our study was to use ultrasound transmission velocity to obtain information about the material properties of bone tissue, keeping other factors possibly influencing ultrasound transmission as constant as possible. Apparent phalangeal ultrasound transmission velocity (APU) measured in 54 isolated, fresh pig phalanges was shown to be independent of bone mineral density (BMD) measured by SPA. Fastest sound transmission led exclusively through cortical bone so that intertrabecular connectivity in spongious bone could not influence the result. In humans APU was measured in the mediolateral direction at the midphalanx of the middle finger. In 53 healthy subjects (15-81 years old; 27 women, 26 men), there was a decrease of APU with age (r = -0.30, p < 0.05). Further, when comparing the results of both hands intraindividually almost identical values indicated constant intraindividual architecture of bone at this location. There was no evidence for a relation of APU to physical load comparing dominant and nondominant hand and relating the results to subjectively estimated physical load. In a second group of 43 perimenopausal women (47-60 years old), APU, which again decreased with age (r = -0.33, p < 0.05), was found not to be correlated to BMD measured by SPA at the distal forearm (cortical bone).(ABSTRACT TRUNCATED AT 250 WORDS)

  4. Fetal Cerebellar Vermis Circumference Measured by 2-Dimensional Ultrasound Scan: Reference Range, Feasibility and Reproducibility

    PubMed Central

    Spinelli, M.; Sica, C.; Meglio, L. D.; Bolla, D.; Raio, L.; Surbek, D.

    2016-01-01

    Purpose: To provide 2-dimensional ultrasonographic (2D-US) normograms of cerebellar vermis biometry, as well as to evaluate the feasibility and the reproducibility of these measurements in clinical practice. Materials and Methods: A prospective cross-sectional study of 328 normal singleton pregnancies between 18 and 33 weeks of gestation. Measurements of the fetal cerebellar vermis circumference (VC) in the mid-sagittal plane were performed by both a senior and a junior operator using 2D-US. VC as a function of gestational age (GA) was expressed by regression equations. In 24 fetuses 3-dimensional (3D) reconstructed planes were obtained in order to allow comparisons with 2D-US measurements. The agreement between 2D and 3D measurements and the interobserver variability were assessed by interclass correlation coefficients (ICC). Results: Satisfactory vermis measurements could be obtained in 89.9% of cases. The VC (constant= − 12.21; slope=2.447; r=0.887, p<0.0001) correlated linearly with GA. A high degree of consistency was observed between 2D and 3D ultrasound measurements (ICC=0.846 95% CI 679–0.930) as well as between measurements obtained by different examiners (ICC=0.890 95% CI 989–0.945). Conclusion: 2-dimensional ultrasonographic measurements of cerebellar vermis throughout gestation in the mid-sagittal view seem to be feasible and reproducible enough to be potentially used in clinical practice. Such measurements may supply a tool for accurate identification of posterior fossa anomalies, providing the basis for proper counseling and management and of these conditions. PMID:27921094

  5. Ultrasound Annual, 1983

    SciTech Connect

    Sanders, R.C.; Hill, M.C.

    1983-01-01

    The 1983 edition of Ultrasound Annual features a state-of-the-art assessment of real-time ultrasound technology and a look at improvements in real-time equipment. Chapters discuss important new obstetric applications of ultrasound in measuring fetal umbilical vein blood flow and monitoring ovarian follicular development in vivo and in vitro fertilization. Other topics covered include transrectal prostate ultrasound using a linear array system; ultrasound of the common bile duct; ultrasound in tropical diseases; prenatal diagnosis of craniospinal anomalies; scrotal ultrasonography; opthalmic ultrasonography; and sonography of the upper abdominal venous system.

  6. Comparison of breast density measurements made using ultrasound tomography and mammography

    NASA Astrophysics Data System (ADS)

    Sak, Mark; Duric, Neb; Littrup, Peter; Bey-Knight, Lisa; Krycia, Mark; Sherman, Mark E.; Boyd, Norman; Gierach, Gretchen L.

    2015-03-01

    Women with elevated mammographic percent density, defined as the ratio of fibroglandular tissue area to total breast area on a mammogram are at an increased risk of developing breast cancer. Ultrasound tomography (UST) is an imaging modality that can create tomographic sound speed images of a patient's breast, which can then be used to measure breast density. These sound speed images are useful because physical tissue density is directly proportional to sound speed. The work presented here updates previous results that compared mammographic breast density measurements with UST breast density measurements within an ongoing study. The current analysis has been expanded to include 158 women with negative digital mammographic screens who then underwent a breast UST scan. Breast density was measured for both imaging modalities and preliminary analysis demonstrated strong and positive correlations (Spearman correlation coefficient rs = 0.703). Additional mammographic and UST related imaging characteristics were also analyzed and used to compare the behavior of both imaging modalities. Results suggest that UST can be used among women with negative mammographic screens as a quantitative marker of breast density that may avert shortcomings of mammography.

  7. An analysis of temperature-induced errors for an ultrasound distance measuring system. M. S. Thesis

    NASA Technical Reports Server (NTRS)

    Wenger, David Paul

    1991-01-01

    The presentation of research is provided in the following five chapters. Chapter 2 presents the necessary background information and definitions for general work with ultrasound and acoustics. It also discusses the basis for errors in the slant range measurements. Chapter 3 presents a method of problem solution and an analysis of the sensitivity of the equations to slant range measurement errors. It also presents various methods by which the error in the slant range measurements can be reduced to improve overall measurement accuracy. Chapter 4 provides a description of a type of experiment used to test the analytical solution and provides a discussion of its results. Chapter 5 discusses the setup of a prototype collision avoidance system, discusses its accuracy, and demonstrates various methods of improving the accuracy along with the improvements' ramifications. Finally, Chapter 6 provides a summary of the work and a discussion of conclusions drawn from it. Additionally, suggestions for further research are made to improve upon what has been presented here.

  8. Prospective multicenter study of ultrasound-based measurements of fetal head station and position throughout labor.

    PubMed

    Vitner, D; Paltieli, Y; Haberman, S; Gonen, R; Ville, Y; Nizard, J

    2015-11-01

    To assess the relationship between fetal head position and head station during labor, as measured using an ultrasound-based system, and the occurrence of occiput posterior (OP) position at delivery. This was an international prospective observational study including women who delivered between January 2009 and September 2013 in four centers: one in Brooklyn, NY, USA; one in Haifa, Israel; and two in Paris, France. We used an ultrasound-based system (LaborPro) to monitor fetal head station and position non-invasively throughout labor. We collected data on demographics, labor parameters and outcome. A total of 595 women were included. In 563 (94.6%) women, fetal head position at delivery was occiput anterior (OA), in 31 (5.2%) it was OP and in one (0.2%) it was occiput transverse. In 89% of pregnancies with intrapartum OP when fetal head station was above -2, the head position turned to OA at delivery; the equivalent figures were 74% and 63% OA at delivery when intrapartum OP was diagnosed at head stations of -2 to < 0, and 0 and below, respectively. Cesarean delivery was performed in 35% of pregnancies with fetal head in OP position at delivery, as opposed to 10% of those with non-OP position at delivery. On retrospective analysis, all deliveries in OP were already in OP at station -2 and below. In this first assessment of fetal head position at delivery according to fetal head position at various station levels, our data show that 100% of OP positions at delivery were already in OP position at station -2 and below. We did not observe rotation from a non-OP to an OP position from station -2 and below. Nearly two-thirds of fetuses in OP at station 0 and below will rotate to an OA position for delivery. Copyright © 2015 ISUOG. Published by John Wiley & Sons Ltd.

  9. Relationship between ultrasound measurements of body fat reserves and body condition score in female donkeys.

    PubMed

    Quaresma, M; Payan-Carreira, R; Silva, S R

    2013-08-01

    Several methods have been developed to monitor body fat reserves of farm animals and body condition scoring (BCS) is generally assumed to be the most practical. Objective methods, such as real time ultrasonography (RTU), are accepted methods for measuring fat reserves in several farm species but there is no published information about the use of RTU to monitor body fat reserves in donkeys. The aim of the present study was to determine the relationship between RTU measurements and BCS in female donkeys (jennies) (n=16) with a BCS of 3-7 on a 9 point scale. Ultrasound images were captured using an Aloka 500-V scanner equipped with a 7.5 MHz probe and subcutaneous fat (SF, range: 1.0-14.0mm) and thoracic wall tissue (TD, range: 5.6-21.4mm) depths measurements were determined. A significant correlation was found between BCS and all RTU measurements (0.65measurements and BCS and between log transformed RTU measurements and log transformed BCS. All equations with variables transformed into a logarithmic scale gave better coefficients of determination (0.42measurements have a logarithmic relationship with BCS and that RTU combined with image analysis permits accurate fat and tissue depths measurements to monitor fat reserves in jennies. Copyright © 2013 Elsevier Ltd. All rights reserved.

  10. Exploratory Analysis of Carbon Dioxide Levels, Ultrasound and Optical Coherence Tomography Measures of the Eye During ISS Missions

    NASA Technical Reports Server (NTRS)

    Schaefer, C.; Young, M.; Mason, S.; Coble, C.; Wear, M. L.; Sargsyan, A.; Garcia, K.; Patel, N.; Gibson, C.; Alexander, D.; hide

    2017-01-01

    Enhanced screening for the Visual Impairment/Intracranial Pressure (VIIP) syndrome has been implemented to better characterize the ocular and vision changes observed in some long-duration crewmembers. This includes implementation of in-flight ultrasound in 2010 and optical coherence tomography (OCT) in 2013. Potential risk factors for VIIP include cardiovascular health, diet, anatomical and genetic factors, and environmental conditions. Carbon dioxide (CO2), a potent vasodilator, is chronically elevated on the International Space Station (ISS) relative to ambient levels on Earth, and is a plausible risk factor for VIIP. In an effort to understand the possible associations between CO2 and VIIP, this study explores the relationship of ambient CO2 levels on ISS compared to inflight ultrasound and OCT measures of the eye obtained from ISS crewmembers. CO2 measurements were aggregated from Operational Data Reduction Complex and Node 3 major constituent analyzers (MCAs) on ISS or from sensors located in the European Columbus module, as available. CO2 levels in the periods between each ultrasound and OCT session are summarized using timeseries metrics, including time-weighted means and variances. Partial least squares regression analyses are used to quantify the complex relationship between specific ultrasound and OCT measures and the CO2 metrics simulataneously. These analyses will enhance our understanding of the possible associations between CO2 levels and structural changes to the eye which will in turn inform future analysis of inflight VIIP data.

  11. A real-time measure of cavitation induced tissue disruption by ultrasound imaging backscatter reduction.

    PubMed

    Hall, Timothy L; Fowlkes, J Brian; Cain, Charles A

    2007-03-01

    A feedback method for obtaining real-time information on the mechanical disruption of tissue through ultrasound cavitation is presented. This method is based on a substantial reduction in ultrasound imaging backscatter from the target volume as the tissue structure is broken down. Ex-vivo samples of porcine liver were exposed to successive high-intensity ultrasound pulses at a low duty cycle to induce mechanical disruption of tissue parenchyma through cavitation (referred to as histotripsy). At the conclusion of treatment, B-scan imaging backscatter was observed to have decreased by 22.4 +/- 2.3 dB in the target location. Treated samples of tissue were found to contain disrupted tissue corresponding to the imaged hypoechoic volume with no remaining discernable structure and a sharp boundary. The observed, substantial backscatter reduction may be an effective feedback mechanism for assessing treatment efficacy in ultrasound surgery using pulsed ultrasound to create cavitation.

  12. Body composition in sport: a comparison of a novel ultrasound imaging technique to measure subcutaneous fat tissue compared with skinfold measurement.

    PubMed

    Müller, Wolfram; Horn, Martin; Fürhapter-Rieger, Alfred; Kainz, Philipp; Kröpfl, Julia M; Maughan, Ronald J; Ahammer, Helmut

    2013-11-01

    Extremely low weight and rapid changes in weight and body composition have become major concerns in many sports, but sufficiently accurate field methods for body composition assessment in athletes are missing. This study aimed to explore the use of ultrasound methods for assessment of body fat content in athletes. 19 female athletes (stature: 1.67(± 0.06) m, weight: 59.6(± 7.6) kg; age: 19.5(± 3.3) years) were investigated by three observers using a novel ultrasound method for thickness measurement of uncompressed subcutaneous adipose tissue and of embedded structures. Two observers also measured skinfold thickness at eight International Society for the Advancement of Kinanthrometry (ISAK) sites; mean skinfold values were compared to mean subcutaneous adipose tissue thicknesses measured by ultrasound. Interobserver reliability of imaging and evaluation obtained by this ultrasound technique: intraclass correlation coefficient ICC=0.968 (95% CI 0.957 to 0.977); evaluation of given images: ICC=0.997 (0.993 to 0.999). Skinfold compared to ultrasound thickness showed that compressibility of subcutaneous adipose tissue depends largely on the site and the person: regression slopes ranged from 0.61 (biceps) to 1.59 (thigh) and CIs were large. Limits of agreement ranged from 2.6 to 8.6 mm. Regression lines did not intercept the skinfold axis at zero because of the skin thickness being included in the skinfold. The four ISAK trunk sites caused ultrasound imaging problems in 13 of 152 sites (8 ISAK sites, 19 athletes). The ultrasound method allows measurement of uncompressed subcutaneous adipose tissue thickness with an accuracy of 0.1-0.5 mm, depending on the probe frequency. Compressibility of the skinfold depends on the anatomical site, and skin thickness varies by a factor of two. This inevitably limits the skinfold methods for body fat estimation. Ultrasound accuracy for subcutaneous adipose tissue measurement is limited by the plasticity of fat and furrowed tissue

  13. Serial Measurements of Splanchnic Vein Diameters in Rats Using High-Frequency Ultrasound

    PubMed Central

    Seitz, Bridget M.; Krieger-Burke, Teresa; Fink, Gregory D.; Watts, Stephanie W.

    2016-01-01

    The purpose of this study was to investigate serial ultrasound imaging in rats as a fully non-invasive method to (1) quantify the diameters of splanchnic veins in real time as an indirect surrogate for the capacitance function of those veins, and (2) assess the effects of drugs on venous dimensions. A 21 MHz probe was used on anesthetized male Sprague–Dawley rats to collect images containing the portal vein (PV), superior mesenteric vein (SMV), abdominal inferior vena cava (IVC), and splenic vein (SpV; used as a landmark in timed studies) and the abdominal aorta (AA). Stable landmarks were established that allowed reproducible quantification of cross-sectional diameters within an animal. The average diameters of vessels measured every 5 min over 45 min remained within 0.75 ± 0.15% (PV), 0.2 ± 0.09% (SMV), 0.5 ± 0.12% (IVC), and 0.38 ± 0.06% (AA) of baseline (PV: 2.0 ± 0.12 mm; SMV: 1.7 ± 0.04 mm; IVC: 3.2 ± 0.1 mm; AA: 2.3 ± 0.14 mm). The maximal effects of the vasodilator sodium nitroprusside (SNP; 2 mg/kg, i.v. bolus) on venous diameters were determined 5 min post SNP bolus; the diameters of all noted veins were significantly increased by SNP, while mean arterial pressure (MAP) decreased 29 ± 4 mmHg. By contrast, administration of the venoconstrictor sarafotoxin (S6c; 5 ng/kg, i.v. bolus) significantly decreased PV and SpV, but not IVC, SMV, or AA, diameters 5 min post S6c bolus; MAP increased by 6 ± 2 mmHg. In order to determine if resting splanchnic vein diameters were stable over much longer periods of time, vessel diameters were measured every 2 weeks for 8 weeks. Measurements were found to be highly reproducible within animals over this time period. Finally, to evaluate the utility of vein imaging in a chronic condition, images were acquired from 4-week deoxycorticosterone acetate salt (DOCA-salt) hypertensive and normotensive (SHAM) control rats. All vessel diameters increased from baseline while MAP increased (67 ± 4 mmHg) in DOCA-salt rats

  14. Prenatal Exposure to NO2 and Ultrasound Measures of Fetal Growth in the Spanish INMA Cohort

    PubMed Central

    Iñiguez, Carmen; Esplugues, Ana; Sunyer, Jordi; Basterrechea, Mikel; Fernández-Somoano, Ana; Costa, Olga; Estarlich, Marisa; Aguilera, Inmaculada; Lertxundi, Aitana; Tardón, Adonina; Guxens, Mònica; Murcia, Mario; Lopez-Espinosa, Maria-Jose; Ballester, Ferran

    2015-01-01

    Background Air pollution exposure during pregnancy has been associated with impaired fetal growth. However, few studies have measured fetal biometry longitudinally, remaining unclear as to whether there are windows of special vulnerability. Objective The aim was to investigate the impact of nitrogen dioxide (NO2) exposure on fetal and neonatal biometry in the Spanish INMA study. Methods Biparietal diameter (BPD), femur length (FL), abdominal circumference (AC), and estimated fetal weight (EFW) were evaluated for up to 2,478 fetuses in each trimester of pregnancy. Size at 12, 20, and 34 weeks of gestation and growth between these points, as well as anthropometry at birth, were assessed by SD scores derived using cohort-specific growth curves. Temporally adjusted land-use regression was used to estimate exposure to NO2 at home addresses for up to 2,415 fetuses. Associations were investigated by linear regression in each cohort and subsequent meta-analysis. Results A 10-μg/m3 increase in average exposure to NO2 during weeks 0–12 was associated with reduced growth at weeks 0–12 in AC (–2.1%; 95% CI: –3.7, –0.6) and EFW (–1.6%; 95% CI: –3.0, –0.3). The same exposure was inversely associated with reduced growth at weeks 20–34 in BPD (–2.6%; 95% CI: –3.9, –1.2), AC (–1.8%; 95% CI: –3.3, –0.2), and EFW (–2.1%; 95% CI: –3.7, –0.2). A less consistent pattern of association was observed for FL. The negative association of this exposure with BPD and EFW was significantly stronger in smoking versus nonsmoking mothers. Conclusions Maternal exposure to NO2 in early pregnancy was associated with reduced fetal growth based on ultrasound measures of growth during pregnancy and measures of size at birth. Citation Iñiguez C, Esplugues A, Sunyer J, Basterrechea M, Fernández-Somoano A, Costa O, Estarlich M, Aguilera I, Lertxundi A, Tardón A, Guxens M, Murcia M, Lopez-Espinosa MJ, Ballester F, on behalf of the INMA Project. 2016. Prenatal exposure

  15. Ultrasound for the diagnosis of infectious diseases: Approach to the patient at point of care and at secondary level.

    PubMed

    Henriquez-Camacho, Cesar; Garcia-Casasola, Gonzalo; Guillén-Astete, Carlos; Losa, Juan

    2015-07-01

    Bedside ultrasound evaluation for infection can be performed promptly at the bedside, using simple equipment and without irradiation. Visualization of the foci often enables prompt antimicrobial therapy and even early ultrasound-guided procedure, facilitating earlier confirmation. These procedures are made safer using the real-time visual control that ultrasound provides. Future challenges for an infectious diseases specialist include gaining experience about the appropriate use of point-of-care ultrasound (POCUS). Ultrasonography training is required to ensure competent use of this technology. Copyright © 2015 The British Infection Association. Published by Elsevier Ltd. All rights reserved.

  16. Measuring ultrasound images of abdominal and lumbar multifidus muscles in older adults: A reliability study.

    PubMed

    Wilson, Anitra; Hides, Julie A; Blizzard, Leigh; Callisaya, Michele; Cooper, Andrew; Srikanth, Velandai K; Winzenberg, Tania

    2016-06-01

    Measurement reliability of the L4/5 lumbar multifidus (MF) muscles is high in older adults, but few studies have investigated measurement reliability of the abdominal and upper lumbar MF muscles in this age group. To determine measurement reliability of abdominal and lumbar MF muscles from a single ultrasound (US) image in older adults. Resting thickness of rectus abdominis and obliquus externus, resting and contracted thickness of obliquus internus, transversus abdominis and lumbar MF, and resting cross-sectional area (CSA) of MF levels (L2-5) were obtained from US images of 92 community-dwelling older adults (aged 65-89 years). Measurements of images were undertaken by an experienced rater and repeated 7-10 days later for intra-rater, and by a second expert rater for inter-rater calculations. Intra-rater reliability was estimated for all muscles. Inter-rater reliability was estimated for all abdominal muscles and for L5 multifidus. Reliability was estimated by intraclass correlation coefficients (ICC). Intra-rater ICC(3,1) and inter-rater ICC(2,1) of resting thickness measures of all muscles and CSA of MF were ≥0.86. The ICCs for percentage thickness change were ≥0.76 for the abdominal muscles, and ≥0.42 for MF. Measurement reliability of US imaging for abdominal and MF muscle thickness and MF CSA was high, and consistent with previous findings for younger adults. Reliability of percentage thickness change was lower suggesting caution is needed when using this as an outcome measure or study factor among older adults. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. Towards an Optimal Interest Point Detector for Measurements in Ultrasound Images

    NASA Astrophysics Data System (ADS)

    Zukal, Martin; Beneš, Radek; Číka, Petr; Říha, Kamil

    2013-12-01

    This paper focuses on the comparison of different interest point detectors and their utilization for measurements in ultrasound (US) images. Certain medical examinations are based on speckle tracking which strongly relies on features that can be reliably tracked frame to frame. Only significant features (interest points) resistant to noise and brightness changes within US images are suitable for accurate long-lasting tracking. We compare three interest point detectors - Harris-Laplace, Difference of Gaussian (DoG) and Fast Hessian - and identify the most suitable one for use in US images on the basis of an objective criterion. Repeatability rate is assumed to be an objective quality measure for comparison. We have measured repeatability in images corrupted by different types of noise (speckle noise, Gaussian noise) and for changes in brightness. The Harris-Laplace detector outperformed its competitors and seems to be a sound option when choosing a suitable interest point detector for US images. However, it has to be noted that Fast Hessian and DoG detectors achieved better results in terms of processing speed.

  18. Measurement of viscoelastic properties of in vivo swine myocardium using lamb wave dispersion ultrasound vibrometry (LDUV).

    PubMed

    Urban, Matthew W; Pislaru, Cristina; Nenadic, Ivan Z; Kinnick, Randall R; Greenleaf, James F

    2013-02-01

    Viscoelastic properties of the myocardium are important for normal cardiac function and may be altered by disease. Thus, quantification of these properties may aid with evaluation of the health of the heart. Lamb wave dispersion ultrasound vibrometry (LDUV) is a shear wave-based method that uses wave velocity dispersion to measure the underlying viscoelastic material properties of soft tissue with plate-like geometries. We tested this method in eight pigs in an open-chest preparation. A mechanical actuator was used to create harmonic, propagating mechanical waves in the myocardial wall. The motion was tracked using a high frame rate acquisition sequence, typically 2500 Hz. The velocities of wave propagation were measured over the 50-400 Hz frequency range in 50 Hz increments. Data were acquired over several cardiac cycles. Dispersion curves were fit with a viscoelastic, anti-symmetric Lamb wave model to obtain estimates of the shear elasticity, μ(1), and viscosity, μ(2) as defined by the Kelvin-Voigt rheological model. The sensitivity of the Lamb wave model was also studied using simulated data. We demonstrated that wave velocity measurements and Lamb wave theory allow one to estimate the variation of viscoelastic moduli of the myocardial walls in vivo throughout the course of the cardiac cycle.

  19. Measurement of viscoelastic properties of in vivo swine myocardium using Lamb Wave Dispersion Ultrasound Vibrometry (LDUV)

    PubMed Central

    Urban, Matthew W.; Pislaru, Cristina; Nenadic, Ivan Z.; Kinnick, Randall R.; Greenleaf, James F.

    2012-01-01

    Viscoelastic properties of the myocardium are important for normal cardiac function and may be altered by disease. Thus, quantification of these properties may aid with evaluation of the health of the heart. Lamb Wave Dispersion Ultrasound Vibrometry (LDUV) is a shear wave-based method that uses wave velocity dispersion to measure the underlying viscoelastic material properties of soft tissue with plate-like geometries. We tested this method in eight pigs in an open-chest preparation. A mechanical actuator was used to create harmonic, propagating mechanical waves in the myocardial wall. The motion was tracked using a high frame rate acquisition sequence, typically 2500 Hz. The velocities of wave propagation were measured over the 50–400 Hz frequency range in 50 Hz increments. Data were acquired over several cardiac cycles. Dispersion curves were fit with a viscoelastic, anti-symmetric Lamb wave model to obtain estimates of the shear elasticity, μ1, and viscosity, μ2 as defined by the Kelvin-Voigt rheological model. The sensitivity of the Lamb wave model was also studied using simulated data. We demonstrated that wave velocity measurements and Lamb wave theory allow one to estimate the variation of viscoelastic moduli of the myocardial walls in vivo throughout the course of the cardiac cycle. PMID:23060325

  20. Ultrasound elastography for carpal tunnel pressure measurement: A cadaveric validation study.

    PubMed

    Kubo, Kazutoshi; Zhou, Boran; Cheng, Yu-Shiuan; Yang, Tai-Hua; Qiang, Bo; An, Kai-Nan; Moran, Steven L; Amadio, Peter C; Zhang, Xiaoming; Zhao, Chunfeng

    2017-07-21

    Carpal tunnel pressure is a key factor in the etiology of carpal tunnel syndrome. Numerous approaches have been conducted to measure carpal tunnel pressure. However, most techniques are invasive and take time and effort. We have developed an innovative approach to noninvasively assess the tunnel pressure by using the ultrasound surface wave elastography (USWE) technique. In a previous study it was shown that the shear wave speed in a tendon increased linearly with increasing tunnel pressure enclosed the tendon in a simple tendon model. This study aimed to examine the relationship between the carpal tunnel pressure and the shear wave speeds inside and outside the carpal tunnel in a human cadaveric model. The result showed that the shear wave speed inside the carpal tunnel increased linearly with created carpal tunnel pressure, while the shear wave speed outside the carpal tunnel remained constant. These findings suggest that noninvasive measurement of carpal tunnel pressure is possible by measuring the shear wave speed in the tendon. After fully establishing this technology and being applicable in clinic, it would be useful in the diagnosis of carpal tunnel syndrome. For that reason, further validation with this technique in both healthy controls and patients with carpal tunnel syndrome is required. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

  1. Skin temperature measured by infrared thermography after ultrasound-guided blockade of the sciatic nerve.

    PubMed

    van Haren, F G A M; Kadic, L; Driessen, J J

    2013-10-01

    In the present study, we assessed the relationship between subgluteal sciatic nerve blocking and skin temperature by infrared thermography in the lower extremity. We hypothesized that blocking the sciatic nerve will lead to an increase in temperature, and that this will correlate with existing sensory block tests. We studied 18 healthy individuals undergoing orthopaedic surgery of the foot under ultrasound-guided subgluteal blockade of the sciatic nerve with 30 ml ropivacaine 7.5 mg/ml. Skin temperature was measured on the toes, the dorsal and plantar side of the foot, the malleoli, and the lateral side of the lower leg, just before sciatic nerve blockade and at 10-min intervals thereafter. Baseline skin temperatures showed a significant distal-to-proximal gradient. After sciatic block, temperatures on the blocked side increased significantly in the toes and foot. When comparing pinprick to skin temperature in a receiver operating curve, there was an AUC of 85.9% (95% confidence interval = 83.7-88.2%, P < 0.001). The medial malleolus (not being innervated by the sciatic nerve) showed no significant difference to the lateral. After sciatic nerve block, temperatures of the foot increased significantly. There was a good correlation between pinprick testing and infrared temperature measurement. This makes infrared skin temperature measuring a good test in determining block success when sensory testing is impossible. © 2013 The Acta Anaesthesiologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

  2. Acoustic power measurement of high-intensity focused ultrasound transducer using a pressure sensor.

    PubMed

    Zhou, Yufeng

    2015-03-01

    The acoustic power of high-intensity focused ultrasound (HIFU) is an important parameter that should be measured prior to each treatment to guarantee effective and safe outcomes. A new calibration technique was developed that involves estimating the pressure distribution, calculating the acoustic power using an underwater pressure blast sensor, and compensating the contribution of harmonics to the acoustic power. The output of a clinical extracorporeal HIFU system (center frequency of ~1 MHz, p+ = 2.5-57.2 MPa, p(-) = -1.8 to -13.9 MPa, I(SPPA) = 513-22,940 W/cm(2), -6 dB size of 1.6 × 10 mm: lateral × axial) was measured using this approach and then compared with that obtained using a radiation force balance. Similarities were found between each method at acoustic power ranging from 18.2 W to 912 W with an electrical-to-acoustic conversion efficiency of ~42%. The proposed method has advantages of low weight, smaller size, high sensitivity, quick response, high signal-to-noise ratio (especially at low power output), robust performance, and easy operation of HIFU exposimetry measurement.

  3. Improved accuracy of ultrasound-guided therapies using electromagnetic tracking: in-vivo speed of sound measurements

    NASA Astrophysics Data System (ADS)

    Samboju, Vishal; Adams, Matthew; Salgaonkar, Vasant; Diederich, Chris J.; Cunha, J. Adam M.

    2017-02-01

    The speed of sound (SOS) for ultrasound devices used for imaging soft tissue is often calibrated to water, 1540 m/s1 , despite in-vivo soft tissue SOS varying from 1450 to 1613 m/s2 . Images acquired with 1540 m/s and used in conjunction with stereotactic external coordinate systems can thus result in displacement errors of several millimeters. Ultrasound imaging systems are routinely used to guide interventional thermal ablation and cryoablation devices, or radiation sources for brachytherapy3 . Brachytherapy uses small radioactive pellets, inserted interstitially with needles under ultrasound guidance, to eradicate cancerous tissue4 . Since the radiation dose diminishes with distance from the pellet as 1/r2 , imaging uncertainty of a few millimeters can result in significant erroneous dose delivery5,6. Likewise, modeling of power deposition and thermal dose accumulations from ablative sources are also prone to errors due to placement offsets from SOS errors7 . This work presents a method of mitigating needle placement error due to SOS variances without the need of ionizing radiation2,8. We demonstrate the effects of changes in dosimetry in a prostate brachytherapy environment due to patientspecific SOS variances and the ability to mitigate dose delivery uncertainty. Electromagnetic (EM) sensors embedded in the brachytherapy ultrasound system provide information regarding 3D position and orientation of the ultrasound array. Algorithms using data from these two modalities are used to correct bmode images to account for SOS errors. While ultrasound localization resulted in >3 mm displacements, EM resolution was verified to <1 mm precision using custom-built phantoms with various SOS, showing 1% accuracy in SOS measurement.

  4. Reliability and Validity of Ultrasound Cross Sectional Area Measurements for Long-Duration Spaceflight

    NASA Technical Reports Server (NTRS)

    Scott, Jessica M.; Martin, David S.; Cunningham, David; Matz, Timothy; Caine, Timothy; Hackney, Kyle J.; Arzeno, Natalia; Ploutz-Snyder, Lori

    2010-01-01

    Limb muscle atrophy and the accompanying decline in function can adversely affect the performance of astronauts during mission-related activities and upon re-ambulation in a gravitational environment. Previous characterization of space flight-induced muscle atrophy has been performed using pre and post flight magnetic resonance imaging (MRI). In addition to being costly and time consuming, MRI is an impractical methodology for assessing in-flight changes in muscle size. Given the mobility of ultrasound (US) equipment, it may be more feasible to evaluate changes in muscle size using this technique. PURPOSE: To examine the reliability and validity of using a customized template to acquire panoramic ultrasound (US) images for determining quadriceps and gastrocnemius anatomical cross sectional area (CSA). METHODS: Vastus lateralis (VL), rectus femoris (RF), medial gastrocnemius (MG), and lateral gastrocnemius (LG) CSA were assessed in 10 healthy individuals (36+/-2 yrs) using US and MRI. Panoramic US images were acquired by 2 sonographers using a customized template placed on the thigh and calf and analyzed by the same 2 sonographers (CX50 Philips). MRI images of the leg were acquired while subjects were supine in a 1.5T scanner (Signa Horizon LX, General Electric) and were analyzed by 3 trained investigators. The average of the 2 US and 3 MRI values were used for validity analysis. RESULTS: High inter-experimenter reliability was found for both the US template and MRI analysis as coefficients of variation across muscles ranged from 2.4 to 4.1% and 2.8 to 3.8%, respectively. Significant correlations were found between US and MRI CSA measures (VL, r = 0.85; RF, r = 0.60; MG, r = 0.86; LG, r = 0.73; p < 0.05). Furthermore, the standard error of measurement between US and MRI ranged from 0.91 to 2.09 sq cm with high limits of agreement analyzed by Bland-Altman plots. However, there were significant differences between absolute values of MRI and US for all muscles

  5. Measurement of segmental lumbar spine flexion and extension using ultrasound imaging.

    PubMed

    Chleboun, Gary S; Amway, Matthew J; Hill, Jesse G; Root, Kara J; Murray, Hugh C; Sergeev, Alexander V

    2012-10-01

    Clinical measurement, technical note. To describe a technique to measure interspinous process distance using ultrasound (US) imaging, to assess the reliability of the technique, and to compare the US imaging measurements to magnetic resonance imaging (MRI) measurements in 3 different positions of the lumbar spine. Segmental spinal motion has been assessed using various imaging techniques, as well as surgically inserted pins. However, some imaging techniques are costly (MRI) and some require ionizing radiation (radiographs and fluoroscopy), and surgical procedures have limited use because of the invasive nature of the technique. Therefore, it is important to have an easily accessible and inexpensive technique for measuring lumbar segmental motion to more fully understand spine motion in vivo, to evaluate the changes that occur with various interventions, and to be able to accurately relate the changes in symptoms to changes in motion of individual vertebral segments. Six asymptomatic subjects participated. The distance between spinous processes at each lumbar segment (L1-2, L2-3, L3-4, L4-5) was measured digitally using MRI and US imaging. The interspinous distance was measured with subjects supine and the lumbar spine in 3 different positions (resting, lumbar flexion, and lumbar extension) for both MRI and US imaging. The differences in distance from neutral to extension, neutral to flexion, and extension to flexion were calculated. The measurement methods had excellent reliability for US imaging (intraclass correlation coefficient [ICC3,3] = 0.94; 95% confidence interval: 0.85, 0.97) and MRI (ICC3,3 = 0.98; 95% confidence interval: 0.95, 0.99). The distance measured was similar between US imaging and MRI (P>.05), except at L3-4 flexion-extension (P = .003). On average, the MRI measurements were 1.3 mm greater than the US imaging measurements. This study describes a new method for the measurement of lumbar spine segmental flexion and extension motion using US

  6. In vivo measurement of rotator cuff tendon strain with ultrasound elastography: an investigation using a porcine model.

    PubMed

    Hatta, Taku; Yamamoto, Nobuyuki; Sano, Hirotaka; Itoi, Eiji

    2014-09-01

    To clarify the relationship between the strain ratio measured by ultrasound elastography and the mechanical properties of the tendon measured by a universal testing machine. We also attempted to determine the effect of the type and depth of soft tissue overlying the tendon on the elastographic measurement. Twelve fresh porcine shoulders were prepared. Elastographic measurement was performed on the infraspinatus tendon by manually applying repetitive compressions from an ultrasound probe with an acoustic coupler consisting of an elastomer with definite elasticity as a reference material. The strain ratio, defined as tendon/reference strain, was obtained by 4 different approaches: with the probe placed on the skin, on the subcutaneous fat after removing the skin, on the muscle after removing the subcutaneous fat, and directly on the tendon. The strain ratios measured by these approaches were compared statistically. The relationship between the depth of the tendon measured on elastography and the strain ratio was also investigated. We also attempted to clarify the relationship between the strain ratio of the tendon and its elastic property. The tendon was mounted on a testing machine, and compressive force was applied. Tendon compliance was calculated as the reciprocal of the Young modulus in the range of 5% to 10% strain, which was compared to its strain ratio. The tendon/reference strain ratio significantly correlated with the tendon compliance (r = 0.73; P < .01). The strain ratio was not affected by differences in the measuring approaches (P = .4) or by the depth to the tendon level (P = .8). Our results indicated that the strain ratio of the rotator cuff tendon could be measured with minimal influence by overlying soft tissues if its depth from the skin was less than 22 mm. We believe that ultrasound elastography would be a useful tool for assessment of tendon elasticity in clinical practice. © 2014 by the American Institute of Ultrasound in Medicine.

  7. Quantitative head ultrasound measurements to determine thresholds for preterm neonates requiring interventional therapies following intraventricular hemorrhage

    NASA Astrophysics Data System (ADS)

    Kishimoto, Jessica; Fenster, Aaron; Salehi, Fateme; Romano, Walter; Lee, David S. C.; de Ribaupierre, Sandrine

    2016-04-01

    Dilation of the cerebral ventricles is a common condition in preterm neonates with intraventricular hemorrhage (IVH). This post hemorrhagic ventricle dilation (PHVD) can lead to lifelong neurological impairment through ischemic injury due to increased intracranial pressure and without treatment, can lead to death. Clinically, 2D ultrasound (US) through the fontanelles ('soft spots') of the patients are serially acquired to monitor the progression of the ventricle dilation. These images are used to determine when interventional therapies such as needle aspiration of the built up cerebrospinal fluid (CSF) ('ventricle tap', VT) might be indicated for a patient; however, quantitative measurements of the growth of the ventricles are often not performed. There is no consensus on when a neonate with PHVD should have an intervention and often interventions are performed after the potential for brain damage is quite high. Previously we have developed and validated a 3D US system to monitor the progression of ventricle volumes (VV) in IVH patients. We will describe the potential utility of quantitative 2D and 3D US to monitor and manage PHVD in neonates. Specifically, we will look to determine image-based measurement thresholds for patients who will require VT in comparison to patients with PHVD who resolve without intervention. Additionally, since many patients who have an initial VT will require subsequent interventions, we look at the potential for US to determine which PHVD patients will require additional VT after the initial one has been performed.

  8. Ultrasound safety in early pregnancy: reduced energy setting does not compromise obstetric Doppler measurements.

    PubMed

    Sande, R K; Matre, K; Eide, G E; Kiserud, T

    2012-04-01

    We hypothesized that first-trimester Doppler ultrasonography can be carried out at lower output energies than the currently advocated limits without compromising clinically important information. We recruited 42 pregnant women for an ultrasound examination at 12 weeks' gestation. Twenty-one women were examined with a transvaginal transducer, the rest with a transabdominal transducer. We used pulsed Doppler to measure pulsatility index (PI) and peak systolic velocity (PSV) in five clinically relevant fetal and maternal blood vessels. The energy indicator thermal index for bone (TIb) was set at 1.0, 0.5 and 0.1. Each measurement was repeated three times. A mixed linear regression model accounting for correlation between measurements was used to assess the effect of different TIb levels and transducers. We were able to visualize the vessels by color Doppler and measure PI and PSV in all vessels at all energy levels in all the participants with the exception of the ductus venosus in two participants, yielding 1872 recordings for statistical analysis. A reduction in TIb from 1.0 to 0.5 and 0.1 had no effect on the PI or PSV values, nor was there any trend towards higher parameter variance with decreasing TIb. There was no difference between measured values of PI and PSV between the transducers, but the transabdominal technique was associated with a greater parameter variance. Reliable first-trimester Doppler data can be obtained with output energy reduced to a TIb of 0.5 or 0.1. Copyright © 2012 ISUOG. Published by John Wiley & Sons, Ltd.

  9. Correlation Between Transperineal 3-Dimensional Ultrasound Measurements of Levator Hiatus and Female Sexual Function.

    PubMed

    Aydin, Serdar; Bakar, Rabia Zehra; Arioğlu Aydin, Çağri; Ateş, Seda

    2017-03-09

    The aim of this study is to investigate the association of sexual functions with levator hiatus biometry measurements and levator ani muscle defect. In 62 heterosexual, sexually active premenopausal women without pelvic floor disorders or urinary incontinence, 3-dimensional transperineal ultrasound imaging was used. Two 3-dimensional volumes were recorded, one at rest and one on Valsalva maneuver. Levator biometry measurements and levator defect were evaluated in an axial plane. Sexual function was assessed by a validated questionnaire, Female Sexual Function Index (FSFI). The primary outcome measure was correlation of sexual functions with the levator hiatus area, transverse and anteroposterior diameters, levator ani muscle thickness, vaginal length, and changes in measurements with Valsalva and levator defect. Forty-two women (67.7%) had low total FSFI scores (<26.55). Levator defect rates were similar in female sexual dysfunction (7/42, 16.7%) and women without female sexual dysfunction (5/20, 25%). The FSFI was negatively and weakly correlated with Δhiatal anteroposterior diameter (r = -0.33, P < 0.009) in the study population. There was a weak and inverse correlation between Δhiatal anteroposterior diameter and arousal (r = -0.35, P < 0.002), desire (r = -0.38, P < 0.001), and orgasm (r = -0.33, P < 0.007). Pain and lubrication did not correlate with any measurement. Hiatal area and diameters at rest are not related to sexual functions. Changes in anteroposterior diameter of the levator hiatus during Valsalva, which may be a sign of pelvic floor laxity or levator muscle weakness, are weakly associated with sexual functions, particularly desire, arousal, and orgasm domains.

  10. Newborn adiposity measured by plethysmography is not predicted by late gestation two-dimensional ultrasound measures of fetal growth.

    PubMed

    Moyer-Mileur, Laurie J; Slater, Hillarie; Thomson, J Anne; Mihalopoulos, Nicole; Byrne, Jan; Varner, Michael W

    2009-09-01

    Noninvasive measures of fetal and neonatal body composition may provide early identification of children at risk for obesity. Air displacement plethysmography provides a safe, precise measure of adiposity and has recently been validated in infants. Therefore, we explored relationships between term newborn percent body fat (%BF) measured by air displacement plethysmography to 2-dimensional ultrasound (2-D US) biometric measures of fetal growth and maternal and umbilical cord endocrine activity. A total of 47 mother/infant pairs were studied. Fetal biometrics by 2-D US and maternal blood samples were collected during late gestation (35 wk postmenstrual age); infants were measured within 72 h of birth. Fetal biometrics included biparietal diameter, femur length, head circumference, abdominal circumference (AC), and estimated fetal weight (EFW). Serum insulin, insulin-like growth factor (IGF) 1, IGF binding protein-3, and leptin concentrations were measured in umbilical cord and maternal serum. The mean %BF determined by plethysmography was 10.9 +/- 4.8%. EFW and fetal AC had the largest correlations with newborn %BF (R(2) = 0.14 and 0.10, respectively; P < 0.05); however, stepwise linear regression modeling did not identify any fetal biometric parameters as a significant predictor of newborn %BF. Newborn mid-thigh circumference (MTC; cm) and ponderal index (PI; weight, kg/length, cm(3)) explained 21.8 and 14.4% of the variability in %BF, respectively, and gave the best stepwise linear regression model (%BF = 0.446 MTC + 0.347 PI -29.692; P < 0.001). We conclude that fetal growth biometrics determined by 2-D US do not provide a reliable assessment of %BF in term infants.

  11. ULTRASOUND MEASUREMENTS OF THE DISTANCE BETWEEN LIMBUS AND RETINAL BREAK IN EYES WITH MEDIA OPACITIES.

    PubMed

    Vaiano, Agostino S; Coronado Quitllet, Elisabet; Zinzanella, Gaetano; De Benedetti, Giacomo; Caramello, Guido

    2017-07-01

    To assess the reproducibility and accuracy of ultrasound (US) measurements in determining the distance between corneoscleral limbus and retinal break and its relation with the distance measured by indirect ophthalmoscopy, in patients undergoing a laser retinopexy procedure. Forty-four patients with a single retinal break, scheduled for laser a retinopexy procedure (26 phakic patients and 18 pseudophakic patients), underwent 5 repeated measurements by high-resolution US and 3 measurements (at the time of the laser procedure, 1 and 3 months) by indirect ophthalmoscopy with scleral indentation of the corneoscleral limbus-retinal break distance with a caliper. In the phakic patients group, measurements ranged from 8.75 mm to 14.45 mm (12.56 ± 1.24, mean ± SD) and from 9.5 mm to 15 mm (12.35 ± 1.32) with US and indirect ophthalmoscopy, respectively. In the pseudophakic patients group, measurements ranged from 9.04 mm to 13.95 mm (11.88 ± 1.33) and from 8.5 mm to 13.2 mm (11.93 ± 0.99) with US and indirect ophthalmoscopy, respectively. The correlation coefficient was greater than 0.97. Measurement variability was very small. In phakic eyes, it was 0.13 ± 0.08 mm and 0.13 ± 0.07 mm with US and indirect ophthalmoscopy, respectively. In pseudophakic eyes, it was 0.12 ± 0.05 mm and 0.14 ± 0.05 mm with US and indirect ophthalmoscopy, respectively. US and indirect ophthalmoscopy measurements were not statistically different (Student's t-test, P = 1.71). The analysis of the variance among phakic and pseudophakic patients confirmed that measurements of the two groups do not differ significantly (Fisher's exact test, P = 0.16). The univariate analysis showed no significant difference in both US and indirect ophthalmoscopy measurements (ANOVA, P = 0.09) and between the two types of measurements and patient groups (ANOVA, P = 0.38). This study suggests relevant accuracy and reliability of US readings and provides the possibility of using this technique for localizing tears

  12. Application of the acousto-optic effect to pressure measurements in ultrasound fields in water using a laser vibrometer

    NASA Astrophysics Data System (ADS)

    Buick, J. M.; Cosgrove, J. A.; Douissard, P.-A.; Greated, C. A.; Gilabert, B.

    2004-10-01

    A non-intrusive measuring technique, applied to sensing and measuring acoustic waves at ultrasonic frequencies is considered. The method is optically based and so does not interfere with the ultrasound field. The measurement procedure relies on the acousto-optic effect, that is the change in refractive index which occurs with changing pressure in the ultrasound field. This change in refractive index is detected through the change in the path length of a laser beam propagating through the region of interest. Typically these changes are small corresponding to a physical change of the order of 10-6 m. Fourier analysis is used to separate the component of the signal corresponding to the pressure variation from background noise and vibrations which can be dominant. Application of the technique is illustrated for an underwater ultrasound transducer. Measurements are made using the optical technique and compared to measurements taken with a hydrophone. The effectiveness of the optical measuring technique is discussed. It is shown that the laser vibrometer produces a good estimation of the mean beam pressure provided an estimation of the beam width is available, a restriction which is often satisfied; and the acoustic field can be assumed to be approximately constant across the beam.

  13. New approaches to bedside monitoring in stroke.

    PubMed

    Cyrous, Alma; O'Neal, Brandon; Freeman, W David

    2012-08-01

    Stroke is a common, potentially devastating disease with potential high morbidity and mortality. Recognition at the onset of acute ischemic stroke is pivotal to changing outcomes such as intravenous thrombolysis. Stroke monitoring is a burgeoning field with various methods described and newer devices that aid in detecting acute or worsening ischemia that can lead to improved bedside and intensive care unit management. This article describes various methods of bedside stroke monitoring including newer techniques of intracranial pressure monitoring using the pressure reactivity index and compensatory reserve index to detect changes in autoregulatory states, noninvasive intracranial pressure monitoring, quantitative EEG with alpha-delta ratio, transcranial Doppler, methods of arteriovenous brain oxygen monitoring such as jugular venous oxygen and near-infrared spectroscopy, invasive brain oxygen probes such as Licox™ (brain tissue O₂), cerebral blood flow probe (CBF Hemedex™) and cerebral microdialysis.

  14. Comparison of grey scale median (GSM) measurement in ultrasound images of human carotid plaques using two different softwares.

    PubMed

    Östling, Gerd; Persson, Margaretha; Hedblad, Bo; Gonçalves, Isabel

    2013-11-01

    Grey scale median (GSM) measured on ultrasound images of carotid plaques has been used for several years now in research to find the vulnerable plaque. Centres have used different software and also different methods for GSM measurement. This has resulted in a wide range of GSM values and cut-off values for the detection of the vulnerable plaque. The aim of this study was to compare the values obtained with two different softwares, using different standardization methods, for the measurement of GSM on ultrasound images of carotid human plaques. GSM was measured with Adobe Photoshop(®) and with Artery Measurement System (AMS) on duplex ultrasound images of 100 consecutive medium- to large-sized carotid plaques of the Beta-blocker Cholesterol-lowering Asymptomatic Plaque Study (BCAPS). The mean values of GSM were 35·2 ± 19·3 and 55·8 ± 22·5 for Adobe Photoshop(®) and AMS, respectively. Mean difference was 20·45 (95% CI: 19·17-21·73). Although the absolute values of GSM differed, the agreement between the two measurements was good, correlation coefficient 0·95. A chi-square test revealed a kappa value of 0·68 when studying quartiles of GSM. The intra-observer variability was 1·9% for AMS and 2·5% for Adobe Photoshop. The difference between softwares and standardization methods must be taken into consideration when comparing studies. To avoid these problems, researcher should come to a consensus regarding software and standardization method for GSM measurement on ultrasound images of plaque in the arteries.

  15. Manual planimetric measurement of carotid plaque volume using three-dimensional ultrasound imaging

    SciTech Connect

    Landry, Anthony; Ainsworth, Craig; Blake, Chris; Spence, J. David; Fenster, Aaron

    2007-04-15

    We investigated the utility of three manual planimetric methods to quantify carotid plaque volume. A single observer measured 15 individual plaques from 15 three-dimensional (3D) ultrasound (3D US) images of patients ten times each using three different planimetric approaches. Individual plaque volumes were measured (range: 32.6-597.1 mm{sup 3}) using a standard planimetric approach (M1) whereby a plaque end was identified and sequential contours were measured. The same plaques were measured using a second approach (M2), whereby plaque ends were first identified and the 3D US image of the plaque was then subdivided into equal intervals. A third method (M3) was used to measure total plaque burden (range: 165.1-1080.0 mm{sup 3}) in a region ({+-}1.5 cm) relative to the carotid bifurcation. M1 systematically underestimated individual plaque volume compared to M2 (V{sub 2}=V{sub 1}+14.0 mm{sup 3}, r=0.99, p=0.006) due to a difference in the mean plaque length measured. Coefficients of variance (CV) for M1 and M2 decrease with increasing plaque volume, with M2 results less than M1. Root mean square difference between experimental and theoretical CV for M2 was 3.2%. The standard deviation in the identification of the transverse location of the carotid bifurcation was 0.56 mm. CVs for plaque burden measured using M3 ranged from 1.2% to 7.6% and were less than CVs determined for individual plaque volumes of the same volume. The utility of M3 was demonstrated by measuring carotid plaque burden and volume change over a period of 3 months in three patients. In conclusion, M2 was determined to be a more superior measurement technique than M1 to measure individual plaque volume. Furthermore, we demonstrated the utility of M3 to quantify regional plaque burden and to quantify change in plaque volume.

  16. Elective bedside surgery in critically injured patients is safe and cost-effective.

    PubMed Central

    Van Natta, T L; Morris, J A; Eddy, V A; Nunn, C R; Rutherford, E J; Neuzil, D; Jenkins, J M; Bass, J G

    1998-01-01

    OBJECTIVE: The success of elective minimally invasive surgery suggested that this concept could be adapted to the intensive care unit. We hypothesized that minimally invasive surgery could be done safely and cost-effectively at the bedside in critically injured patients. SUMMARY BACKGROUND DATA: This case series, conducted between October 1991 and June 1997 at a Level I trauma center, examined bedside dilatational tracheostomy (BDT), percutaneous endoscopic gastrostomy (PEG), and inferior vena cava (IVC) filter placement. All procedures had been performed in the operating room (OR) before initiation of this study. METHODS: All BDTs and PEGs were performed with intravenous general anesthesia (fentanyl, diazepam, and pancuronium) administered by the surgical team. IVC filters were placed using local anesthesia and conscious sedation. BDTs were done using a Ciaglia set, PEGs were done using a 20 Fr Flexiflow Inverta-PEG kit, and IVC filters were placed percutaneously under ultrasound guidance. Cost difference (delta cost) was defined as the difference in hospital cost and physician charges incurred in the OR as compared to the bedside. RESULTS: Of 16,417 trauma admissions, 379 patients (2%) underwent 472 minimally invasive procedures (272 BDTs, 129 PEGs, 71 IVC filters). There were four major complications (0.8%). Two patients had loss of airway requiring reintubation. Two patients had an intraperitoneal leak from the gastrostomy requiring operative repair. No patient had a major complication after IVC filter placement. Total delta cost was $611,994. When examined independently, the cost was $324,224 for BDT, $164,088 for PEG, and $123,682 for IVC filter. OR use was reduced by 506 hours. CONCLUSIONS: These bedside procedures have minimal complications, eliminate the risk associated with patient transport, reduce cost, improve OR utilization, and should be considered for routine use in the general surgery population. PMID:9605653

  17. Exploratory Analysis of Carbon Dioxide Levels, Ultrasound and Optical Coherence Tomography Measures of the Eye During ISS Missions

    NASA Technical Reports Server (NTRS)

    Schaefer, C.; Coble, C.; Mason, S.; Young, M.; Wear, M. L.; Sargsyan, A.; Garcia, K.; Patel, N.; Gibson, C.; Alexander, D.; hide

    2017-01-01

    Carbon dioxide (CO2) levels on board the International Space Station (ISS) have typically averaged 2.3 to 5.3 mmHg, with large fluctuations occurring over periods of hours and days. CO2 has effects on cerebral vascular tone, resulting in vasodilation and alteration of cerebral blood flow (CBF). Increased CBF leads to elevated intracranial pressure (ICP), a factor leading to visual disturbances, headaches, and other central nervous system symptoms. Ultrasound of the optic nerve and optical coherence tomography (OCT) provide surrogate measurements of ICP; in-flight measurements of both were implemented as enhanced screening tools for the Visual Impairment/Intracranial Pressure (VIIP) syndrome. This analysis examines the relationships between ambient CO2 levels on ISS, ultrasound and OCT measures of the eye in an effort to understand how CO2 may possibly be associated with VIIP and to inform future analysis of in-flight VIIP data.

  18. Automated measurement of fetal myocardial performance index in ultrasound Doppler waveforms

    NASA Astrophysics Data System (ADS)

    Yoon, Heechul; Lee, Hyuntaek; Jeon, Kang-Won; Jung, Haekyung; Lee, Mi-Young; Won, Hye-Sung; Jeon, Eun-Jin; Yang, Eun-Ho; Choi, Jin-Young; Hong, Soon-Jae

    2014-03-01

    We introduce an automated method for myocardial performance index (MPI), also known as Tei index, which is one of the most substantial indicators in the early screening of heart defects. Since assessing fetal cardiac functions using MPI has become a routine and significant process, there have been explicit requirements to automate MPI measurements. Due to small heart sizes of fetuses, we focus on the automation of modified MPI (Mod-MPI) which uses a single Doppler gate. The proposed method detects four valve click signals in Doppler waveforms using four image features which are extracted by vertical projection of Doppler waveforms after several transformations. To evaluate performance, 88 of fetal examinations were collected from a commercial ultrasound machine, and two clinical experts measured the Mod-MPI both manually and automatically. Quantitative comparisons based on intra-class correlation coefficients (ICC) yield that intra-observer reproducibility is higher when performing the proposed method (ICC=0.951 and 0.932 for observer 1 and 2) comparing to those of manual measurements (ICC=0.868 and 0.857 for observer 1 and observer 2). Thus, our method (ICC=0.962) reveals superior inter-observer reproducibility than that of manual method (ICC=0.597). Although mean difference from observer 2 (-0.062) is over three times larger than that of observer 1 (-0.018) due to different experiences, both of mean differences are acceptable. In conclusion, the proposed MPI measurement method can improve intra- and inter-reproducibility while providing reliable results.

  19. Abdominal Ultrasound

    MedlinePlus

    ... Ultrasound - Abdomen Ultrasound imaging of the abdomen uses sound waves to produce pictures of the structures within ... pictures of the inside of the body using sound waves. Ultrasound imaging, also called ultrasound scanning or ...

  20. Hip Ultrasound

    MedlinePlus

    ... Index A-Z Hip Ultrasound Hip ultrasound uses sound waves to produce pictures of muscles, tendons, ligaments, ... pictures of the inside of the body using sound waves. Ultrasound imaging, also called ultrasound scanning or ...

  1. Ultrasound - Breast

    MedlinePlus

    ... Ultrasound - Breast Ultrasound imaging of the breast uses sound waves to produce pictures of the internal structures ... pictures of the inside of the body using sound waves. Ultrasound imaging, also called ultrasound scanning or ...

  2. Obstetrical Ultrasound

    MedlinePlus

    ... Index A-Z Obstetric Ultrasound Obstetric ultrasound uses sound waves to produce pictures of a baby (embryo ... pictures of the inside of the body using sound waves. Ultrasound imaging, also called ultrasound scanning or ...

  3. Peer-assisted bedside teaching rounds.

    PubMed

    Doumouras, Aristithes; Rush, Raphael; Campbell, Anthony; Taylor, David

    2015-06-01

    Although postgraduate trainees play a well-accepted role in medical education, little consideration has traditionally been given to senior undergraduate trainees as teachers. Recently, research has shown senior medical students (SMS) can play an effective teaching role for junior medical students (JMS) in non-clinical medical settings. The purpose of our study was to understand the perceptions of SMSs as teachers in a clinical environment for JMS. All students who participated in our peer-led bedside teaching programme from September 2010 to May 2012 were invited to complete a questionnaire following their teaching session. Fifty-six of 70 JMS (80%) and 15 of 15 SMS (100%) participated. Survey questions addressed learning, bedside experiences, teacher effectiveness and the overall usefulness of these sessions. The data collected were analysed for significance of the perceptions reported. We found students reported positive and statistically significant results in all domains examined. JMS reported that sessions were highly valuable learning, improved confidence and comfort at the bedside, had excellent teaching and were a valuable addition to their clinical skills training. SMS reported getting highly valuable learning through preparation and developing improved comfort in a teaching role. Little consideration has traditionally been given to senior undergraduate trainees as teachers Our findings demonstrate that peer-directed learning in undergraduate medical education can be effectively implemented in the clinical arena. © 2015 John Wiley & Sons Ltd.

  4. Noninvasive measurement of acoustic field inside mother's uterus generated by ultrasound scanning

    NASA Astrophysics Data System (ADS)

    Antonets, V. A.; Kazakov, V. V.

    2015-07-01

    Sounds in the audible range arising in mother's uterus during conventional ultrasound scanning were recorded noninvasively for the first time. It was found that their level is comparable with the level of spoken language.

  5. Measurement of cervical range of motion pattern during cyclic neck movement by an ultrasound-based motion system.

    PubMed

    Wang, Shwu-Fen; Teng, Chin-Chih; Lin, Kwan-Hwa

    2005-02-01

    Goniometers and radiographic imaging have been used to measure active or passive cervical range of motion (ROM) in asymptomatic adults. However, the ultrasound-based coordinate measuring system (CMS) can measure continuous neck motion in three dimensions. The aims of this investigation are to evaluate the reliability and validity of ultrasound-based CMS (Zebris, CMS 70P), and to compare the cervical ROM patterns of asymptomatic young and middle-aged adults during continuous neck motions in the three cardinal planes. The ROM reciprocal ratio was defined as the ratio of the ROM from neutral position in one direction versus that in the opposite direction at the same cardinal plane. This study demonstrated the high test-retest reliability and validity of CMS during cervical motion in Chinese participants. Middle-aged adults exhibit reduced ROM ratios in the sagittal and frontal planes. The advantages and limitations of the CMS measurement tool and the potential future applications are documented. The measurement of neck motion pattern by ultrasound-based CMS may provide information on the management of neck dysfunction during functional movements.

  6. Detection and measurement of fetal abdominal contour in ultrasound images via local phase information and iterative randomized Hough transform.

    PubMed

    Wang, Weiming; Qin, Jing; Zhu, Lei; Ni, Dong; Chui, Yim-Pan; Heng, Pheng-Ann

    2014-01-01

    Due to the characteristic artifacts of ultrasound images, e.g., speckle noise, shadows and intensity inhomogeneity, traditional intensity-based methods usually have limited success on the segmentation of fetal abdominal contour. This paper presents a novel approach to detect and measure the abdominal contour from fetal ultrasound images in two steps. First, a local phase-based measure called multiscale feature asymmetry (MSFA) is de ned from the monogenic signal to detect the boundaries of fetal abdomen. The MSFA measure is intensity invariant and provides an absolute measurement for the signi cance of features in the image. Second, in order to detect the ellipse that ts to the abdominal contour, the iterative randomized Hough transform is employed to exclude the interferences of the inner boundaries, after which the detected ellipse gradually converges to the outer boundaries of the abdomen. Experimental results in clinical ultrasound images demonstrate the high agreement between our approach and manual approach on the measurement of abdominal circumference (mean sign difference is 0.42% and correlation coef cient is 0.9973), which indicates that the proposed approach can be used as a reliable and accurate tool for obstetrical care and diagnosis.

  7. Ultrasound measurement of the size of the anterior tibial muscle group: the effect of exercise and leg dominance.

    PubMed

    McCreesh, Karen; Egan, Sinead

    2011-09-13

    Knowledge of normal muscle characteristics is crucial in planning rehabilitation programmes for injured athletes. There is a high incidence of ankle and anterior tibial symptoms in football players, however little is known about the effect of limb dominance on the anterior tibial muscle group (ATMG). The purpose of this study was to assess the effect of limb dominance and sports-specific activity on ATMG thickness in Gaelic footballers and non-football playing controls using ultrasound measurements, and to compare results from transverse and longitudinal scans. Bilateral ultrasound scans were taken to assess the ATMG size in 10 Gaelic footballers and 10 sedentary controls (age range 18-25 yrs), using a previously published protocol. Both transverse and longitudinal images were taken. Muscle thickness measurements were carried out blind to group and side of dominance, using the Image-J programme. Muscle thickness on the dominant leg was significantly greater than the non-dominant leg in the footballers with a mean difference of 7.3%, while there was no significant dominance effect in the controls (p < 0.05). There was no significant difference between the measurements from transverse or longitudinal scans. A significant dominance effect exists in ATMG size in this group of Gaelic footballers, likely attributable to the kicking action involved in the sport. This should be taken into account when rehabilitating footballers with anterior tibial pathology. Ultrasound is a reliable tool to measure ATMG thickness, and measurement may be taken in transverse or longitudinal section.

  8. Computerized Tomography-Guided Paracentesis: An Effective Alternative to Bedside Paracentesis?

    PubMed Central

    Gaduputi, Vinaya; Tariq, Hassan; Chandrala, Chaitanya; Sakam, Sailaja; Abbas, Naeem; Chilimuri, Sridhar

    2017-01-01

    Background Ascites remains the most common cause of hospitalization among patients with decompensated cirrhosis. Paracentesis is a relatively safe procedure with low complication rates. Computerized tomography (CT)-guided therapeutic paracentesis could be a safe and effective alternative to unaided or aided (ultrasonogram-guided) bedside paracentesis. In this retrospective study, we aimed to compare the efficacy, safety, and cost-effectiveness of CT-guided paracentesis with bedside paracentesis. Methods The period of study was from 2002 to 2012. All patients with cirrhosis who underwent therapeutic paracentesis were included in the study. These patients were divided into two groups. Group I consisted of patients who underwent CT-guided pigtail catheter insertion with ascitic fluid drainage. Group II consisted of patients who underwent beside therapeutic paracentesis after localization of fluid either by physical examination or sonographic localization. We measured the efficacy of CT-guided paracentesis and bedside paracentesis in terms of volume of fluid removed, length of stay, discharge doses of diuretics (spironolactone and furosemide) and number of days to readmission for symptomatic ascites. We also computed the cost-effectiveness of CT-guided therapeutic paracentesis when compared to a bedside procedure. Fischer exact test was used to analyze the distribution of categorical data and unpaired t-test was used for comparison of means. Results There were a total of 546 unique patients with diagnosed cirrhosis who were admitted to the hospital with symptomatic ascites and underwent therapeutic paracentesis. Two hundred and forty-seven patients underwent CT-guided paracentesis, while 272 patients underwent bedside paracentesis. There was significant inverse correlation between the amount of ascitic fluid removed and total length of stay in the hospital. We found that the volume of fluid removed via a CT-guided pigtail insertion and drainage (2.72 ± 2.02 L) is

  9. SOLO: An Interactive Microcomputer-Based Bedside Monitor

    PubMed Central

    Comerchero, Harry; Vernia, Michael; Tivig, Gerhard; Kalinsky, David; Miller, Avram; Rackow, Eric C.; Welch, Jim

    1979-01-01

    An interactive, microcomputer-based bedside monitor is described which facilitates continuous on-line monitoring of a given patient's hemodynamic parameters. Used primarily in shock/trauma and intensive care units, the user has easy access to the patient data via a special interactive keypad and video display integrally a part of the bedside monitor. Phasic waveforms are analyzed in order to derive heart rate, arterial pressure, pulmonary artery pressure, central venous pressure, temperature and respiration rate. Special procedure functions are available to facilitate on-line, interactive measurement of Cardiac Output, Pulmonary Wedge Pressure, and Fluid Input/Output. All continuously monitored parameters, as well as specially acquired parameters, can be graphically trended over the last 72 hours. Medication administration and special event markers can be displayed together with trends to correlate such actions with changes in the patient status. The SOLO MONITOR is currently implemented on a Digital Equipment Corporation LSI-11 with 28K words of memory and is commercially available through Mennen Medical Inc. ImagesFig. 1Fig. 11

  10. Correlation of preoperative MRI and intraoperative 3D ultrasound to measure brain tissue shift

    NASA Astrophysics Data System (ADS)

    Gobbi, David G.; Lee, Belinda K. H.; Peters, Terence M.

    2001-05-01

    B-Mode ultrasound is often used during neurosurgery to provide intra-operative images of the brain though a craniotomy, but the use of 3D ultrasound during surgery is still in its infancy. We have developed a system that provides real-time freehand 3D ultrasound reconstruction at a reduced resolution. The reconstruction proceeds incrementally and the 3D image is overlayed, via a computer, on a pre-operative 3D MRI scan. This provides the operator with the necessary feedback to maintain a constant freehand sweep-rate, and also ensures that the sweep covers the desired anatomical volume. All of the ultrasound video frames are buffered, and a full-resolution, compounded reconstruction proceeds once the manual sweep is complete. We have also developed tools for manual tagging of homologous landmarks in the 3D MRI and 3D ultrasound volumes that use a piecewise cubic approximation of thin-plate spline interpolation to achieve interactive nonlinear registration and warping of the MRI volume to the ultrasound volume: Each time a homologous point-pair is identified by the use, the image of the warped MRI is updated on the computer screen after less than 0.5 s.

  11. Stable and Unstable Chromosome Aberrations Measured after Occupational Exposure to Ionizing Radiation and Ultrasound

    PubMed Central

    Fučić, Aleksandra; Želježić, Davor; Kašuba, Vilena; Kopjar, Nevenka; Rozgaj, Ružica; Lasan, Ružica; Mijić, August; Hitrec, Vlasta; Lucas, Joe Nathan

    2007-01-01

    Aim To evaluate chromosome aberration and fluorescent in situ hybridization (FISH) assays as a method to estimate of health risk, we monitored 9 male subjects occupationally exposed to low doses of both ionizing radiation and ultrasound during a period of over 3 years. Methods Sampling was performed at 6-month intervals during a three-year period. First we used conventional chromosomal aberrations analysis. When the aberration frequency for a particular subject reached the background, we measured translocations in the final sample, using fluorescence in situ hybridization. Chromosome painting probes for chromosomes 1, 2, and 4 were used simultaneously. Results Dicentric and ring chromosomes were eliminated within a year. Translocations persisted and deviated from control values in all examinees. Translocations were detected long after unstable aberrations decreased to the background level. Conclusion Fluorescence in situ hybridization-based translocation detection was a reliable method for monitoring chronic occupational clastogen exposure. Chromosome aberration assay correlated with translocation frequency. Stable chromosomal aberrations reflected cumulative genome damage during job exposure. PMID:17589981

  12. The effect of patellar taping on patellar position measured using ultrasound scanning.

    PubMed

    Herrington, Lee

    2010-03-01

    Previous research into the effect of patellar taping has found conflicting results and when studies have found positive findings these effects appear to be negated by exercise. The purpose of this study was to re-examine the effect of patellar taping on patellar position using ultrasound scanning. Twelve asymptomatic subjects (six males and six females (age 20.4+/-1.2 years)) had their patellar position examined, prior to and following the application of tape, and also following exercise (25 step ups). Mean patellar position (distance border patella to edge lateral femoral condyle) prior to application of tape was 6.2+/-1.3 mm following the application of tape mean patellar position was 7.9+/-1.7 mm, this was a statistically significant change in position (p=0.003). Following exercise mean patellar position was 7.6+/-1.7 mm this was a significant reduction compared to the taped position prior to exercise (p=0.001). This value was though still significantly greater than prior to the application of tape (p=0.006). This study found that patellar position was significantly changed following the application of tape. Furthermore, the study found that though low intensity exercise resulted in a significant change in the patellar position compared to the taped position prior to exercise, that change was most likely to have occurred due to random chance or measurement error. Copyright 2009 Elsevier B.V. All rights reserved.

  13. Transcranial measurements of the acoustic field produced by a low frequency focused ultrasound system

    NASA Astrophysics Data System (ADS)

    Voie, Arne; Fisher, David; Ahadi, Golnaz; Hölscher, Thilo

    2012-11-01

    The purpose of this study was to ascertain the effects of the skull on the location, shape and power of the acoustic field produced by a 150 mm radius hemispherical array operating at 220 kHz. We wanted to determine whether phase aberrations were significant at this frequency, the amount of attenuation, and whether CT data could be predictive of the trans-skull field. The effects of five calvaria were evaluated. Acoustic field data and CT scans for each skull specimen were imported into MATLAB® for measurements and visualization in two and three dimensions. We examined the effects of skull density, porosity, thickness, and sonication incident angles, and estimated the relative contributions of longitudinal and shear transmission to the total transmitted power. Power transmission through the skulls varied between 4% and 23% (mean: 12%). The range of focal position shifts was from 0.50 mm to 4.32 mm (mean: 1.95 mm). The 3 dB dimensions of the focused ultrasound (FUS) intensity focal volume increased on average by 39% (low: 4%, high: 122%). The 6 dB pressure focal volume increased by an average of 130 ± 75%. In general, the main effects of the skulls were power reduction, field dispersion and slight shift of focal peak location.

  14. Spectral energy measurements of simulated microemboli of various sizes using a diffraction grating ultrasound probe

    NASA Astrophysics Data System (ADS)

    Weiss, William J.; Ballakur, Sowmya G.; Tran, Hoang; Hazard, Sprague W.; Blebea, John

    2003-05-01

    This study characterizes the Doppler signal from simulated microemboli of various sizes in blood mimicking fluid using spectral energy parameters. The goal of this research is to detect microemboli as a non-invasive diagnostic tool, or intra-operatively as a surgical aid. A dual beam diffraction-grating ultrasound probe operating at 10 MHz (Model Echoflow BVM-1, EchoCath, Inc., Princeton, NJ) was used with a flow phantom. Microemboli were polystyrene microspheres in 200 to 1000 micron diameters, in concentrations of 0.1, 0.5, and 1.0 per ml. Average flow velocities were 25, 50, 75, and 100 cm/sec. The distribution of peak values of the power spectrum at 2.5 msec windows was plotted over 15 seconds. The means of the distributions corresponding to the microspheres and background fluid were averaged for the four velocity conditions. Embolic peak spectral power ranged from approximately 12 to 25 dB relative to the background. A detection method based on these measurements is currently being developed.

  15. Reliability of ultrasound texture measures of Biceps Brachialis and Gastrocnemius Lateralis muscles' images.

    PubMed

    da Silva Pereira Júnior, Newton; da Matta, Thiago Torres; Alvarenga, André Victor; de Albuquerque Pereira, Wagner Coelho; de Oliveira, Liliam Fernandes

    2017-01-01

    Ultrasound (US) is an important tool for diagnosing of many musculoskeletal tissue conditions. Image texture analysis can be used to characterize this tissue. The complexity curve (CC) is a technique commonly used to characterize the number of grey-level transitions in an image. Variability and reliability of US texture measures in the muscle tissue are unavailable in the literature. The aim of this study was to determine the variability and reliability of five CC texture parameters from US images of healthy Biceps Brachialis and Gastrocnemius Lateralis (GL) muscles, with longitudinal and transversal orientations of the probe. Eight images per subject were obtained for 30 men in 2 days. Mean, standard deviation, coefficient of variation and intraclass correlation coefficient for the five parameters were calculated for regions of interest. Results showed that the variability was similar for both muscles and most of the parameters showed satisfactory reliability (r > 0·7) for the Biceps Brachialis with the transverse scan and for the GL with the longitudinal scan. © 2015 Scandinavian Society of Clinical Physiology and Nuclear Medicine. Published by John Wiley & Sons Ltd.

  16. Doppler ultrasound measurement of resistance index in the diagnosis of prostate cancer.

    PubMed

    Huang, Wei; Cen, Son; Kang, Xin-Li; Wang, Wei Fu; Wang, Yang; Chen, Xiang

    2015-01-01

    Prostate cancer (PCa) remains the second leading cause of cancer diagnosis worldwide. Early diagnosis and treatment of PCa is critical since the long-term prognosis is excellent in patients with tumors confined to the prostate gland. The current meta-analysis investigates the diagnostic value of resistive index (RI) measurement using color Doppler ultrasound in patients with PCa. Electronic literature databases were exhaustively searched for relevant studies published prior to May 31, 2014. Nine studies met our predetermined inclusion criteria for the present meta-analysis. The methodologic quality of the selected studies was independently assessed by 2 reviewers based on Quality Assessment of Diagnostic Accuracy Studies tool. Our meta-analysis results showed that RI values were significantly higher in malignant prostate tissues compared to normal prostate tissues (standardized mean difference [SMD] 0.42, 95% confidence interval [CI] 0.12~0.73, p = 0.007) and benign prostate tissues (SMD 0.41, 95% CI 0.26~0.56, p<0.001). Subgroup analysis based on the diagnostic instruments used revealed that RI values were accurate in diagnosis of PCa when compared between malignant tissue vs normal tissue and malignant tissue vs benign tissue (all p<0.05). Taken together, our findings support the potential clinical applications of RI values in diagnosis of PCa.

  17. Use of ultrasound measurement of the inferior vena cava diameter as an objective tool in the assessment of children with clinical dehydration.

    PubMed

    Chen, Lei; Kim, Yunie; Santucci, Karen A

    2007-10-01

    Bedside ultrasonography (US) measurement of the inferior vena cava (IVC) and aorta (Ao) may be useful in objectively assessing children with dehydration. The objectives of this study were 1) to compare the IVC and Ao diameters (IVC/Ao) ratio of dehydrated children with controls and 2) to compare the IVC/Ao ratio before and after intravenous (i.v.) rehydration in children with dehydration. This prospective observational study was performed in an urban pediatric emergency department. Children between 6 months and 16 years of age with clinical evidence of dehydration were enrolled. Bedside US measurements of the IVC and Ao were taken before and immediately after i.v. fluids were administered. An age-, gender-, and weight-matched control without dehydration was enrolled for each subject. The IVC/Ao ratios of subjects and controls were compared using Wilcoxon signed rank test, as were the ratios before and after i.v. hydration for each subject. Thirty-six pairs of subjects and matched controls were enrolled. The IVC/Ao ratios in the subjects were lower as compared with controls (mean of 0.75 vs. 1.01), with a mean difference of 0.26 (95% confidence interval = 0.18 to 0.35). In subjects, the IVC/Ao ratios were significantly lower before i.v. hydration (mean of 0.75 vs. 1.09), with a mean difference of 0.34 (95% confidence interval = 0.29 to 0.39). As measured by bedside US measurement, the IVC/Ao ratio is lower in children clinically assessed to be dehydrated. Furthermore, it increases with administration of i.v. fluid boluses.

  18. In vivo ultrasound measurement of posterior femoral glide during hip joint mobilization in healthy college students.

    PubMed

    Loubert, Peter V; Zipple, J Tim; Klobucher, Michael J; Marquardt, Eric D; Opolka, Matthew J

    2013-08-01

    Descriptive study. To measure femoral translational glide in vivo during posterior hip joint mobilization and to interpret data in the context of the normal arthrokinematic glide necessary for hip flexion. Joint play, or translational glide available at a joint, is largely influenced by the geometry of the articular surfaces. The high degree of congruence between the articular surfaces at the hip and the substantial arc of concavity of the acetabulum suggests that the amount of translational glide available at the hip should be very small. Twenty subjects received manual posteriorly directed hip mobilization at a force equal to 50% of their body weight, while concurrent ultrasound imaging of the joint was performed. Images were captured before and during application of the target mobilization force. Femoroacetabular distance for each image was measured, and the average of the 3 greatest differences between corresponding before/during mobilization values represented the translational glide produced. The amplitude of arthrokinematic glide (tangential glide) was calculated using the measured femoral head radius and hip flexion passive range of motion for each subject. The average posterior femoral translational glide was 2.0 mm (range, 0.8-4.2 mm). The average calculated tangential glide required for hip flexion passive range of motion was 53.8 mm (range, 43.2-64.8 mm). The average translational glide as a percentage of tangential glide was 3.8% (range, 1.5%-7.9%). Translational glides at the hip are small, particularly in the context of the amplitude of glide necessary for normal hip flexion range of motion.

  19. Breast density measurements using ultrasound tomography for patients undergoing tamoxifen treatment

    PubMed Central

    Sak, Mark; Duric, Neb; Littrup, Peter; Li, Cuiping; Bey-Knight, Lisa; Sherman, Mark; Boyd, Norman; Gierach, Gretchen

    2014-01-01

    Women with high breast density have an increased risk of developing breast cancer. Women treated with the selective estrogen receptor modulator tamoxifen for estrogen receptor positive breast cancer experience a 50% reduction in risk of contralateral breast cancer and overall reduction of similar magnitude has been identified among high-risk women receiving the drug for prevention. Tamoxifen has been shown to reduce mammographic density, and in the IBIS-1 chemoprevention trial, risk reduction and decline in density were significantly associated. Ultrasound tomography (UST) is an imaging modality that can create tomographic sound speed images of the breast. These sound speed images are useful because breast density is proportional to sound speed. The aim of this work is to examine the relationship between UST-measured breast density and the use of tamoxifen. So far, preliminary results for a small number of patients have been observed and are promising. Correlations between the UST-measured density and mammographic density are strong and positive, while relationships between UST density with some patient specific risk factors behave as expected. Initial results of UST examinations of tamoxifen treated patients show that approximately 45% of the patients have a decrease in density in the contralateral breast after only several months of treatment. The true effect of tamoxifen on UST-measured density cannot yet be fully determined until more data are collected. However, these promising results suggest that UST can be used to reliably assess quantitative changes in breast density over short intervals and therefore suggest that UST may enable rapid assessment of density changes associated with therapeutic and preventative interventions. PMID:25426270

  20. Measuring mechanical properties of the vastus lateralis tendon-aponeurosis complex in vivo by ultrasound imaging.

    PubMed

    Bojsen-Møller, J; Hansen, P; Aagaard, P; Kjaer, M; Magnusson, S P

    2003-08-01

    The mechanical properties of the human vastus lateralis (VL) tendon-aponeurosis complex were investigated in eight male subjects. Knee extensor force, knee joint angle, and corresponding longitudinal VL aponeurosis displacement were monitored synchronously during graded (10-s) maximal isometric knee extension contractions. Displacement observed during isometric conditions may be regarded as an expression of deformation in the tissues distal to the measurement site. Furthermore, aponeurosis displacement was measured during passive knee extension (90-75 degrees degrees ), and used to correct displacement values obtained during active contraction for joint angular motion. The passive trial yielded a highly linear relationship between aponeurosis displacement and joint angular motion (r2 = 0.998 +/- 0.002) with a mean correction factor of 0.41 +/- 0.10 mm/degree. Maximal knee extensor force was 5834 +/- 1341 N with a corresponding VL aponeurosis displacement of 12.7 +/- 2.5 mm, while correcting for joint angular motion reduced maximal displacement approximately 9% (to 11.6 +/- 2.5 mm, P < 0.005) (data presented as means +/- SD). Two separate graded contraction trials were performed, and no between-trial differences were observed in either maximal force or maximal displacement. Between trial coefficient of determination and CV for maximal force and maximal displacement were r2 = 0.97, CV = 2.9% and r2 = 0.92, CV = 4.6%, respectively, indicating intra-day reproducibility of measurements. These data demonstrate that when applying the newly established ultrasound-based method of investigating quadriceps connective tissue mechanical properties, maximal isometric contraction is inevitably associated with some joint angular motion that significantly influences the calculations.

  1. [Ultrasound and regional anaesthesia].

    PubMed

    Delaunay, L; Plantet, F; Jochum, D

    2009-02-01

    The use of ultrasound is the latest major evolution in regional anaesthesia. Review of available literature shows significant changes in clinical practice. Ultrasound guidance allows the visualization of anatomical variations or unsuspected intraneural injections, reduces the volume of local anaesthetic injections and confirms correct local anaesthetic distribution or catheter placement. No study has found a statistical difference in success rates and safety because all studies were underpowered. However, the ability to visualize an invasive procedure that has been performed blindly in the past is an undeniable progress in terms of safety. The necessity to be familiar with the machine and the learning curve can be repulsive. The aim of this article is to demystify ultrasound guidance by explaining the fundamentals of the clinical use of ultrasound. With the help of different chapters, the authors explain the different adjustments and possible artefacts and give easy solutions for the use of bedside ultrasound. Training is essential and can be performed on manikins or training phantom. For each region the main anatomical landmarks are explained. One must be familiar with several imaging techniques: short axis (transverse) or long axis (longitudinal) nerve imaging, in-plane or out-of-plane imaging and hydrolocalization. Viewing the needle's tip position during its progression remains the main safety endpoint. Therefore, electrical nerve stimulation and ultrasound guidance should be combined, especially for beginners, to confirm proximity to neural structures and to help in case of difficulty. Optimizing safety and clinical results must remain a key priority in regional anaesthesia. Finally, specific regulations concerning the transducers are described. Paediatric specificities are also mentioned.

  2. Investigation of Ultrasound-Measured Flow Velocity, Flow Rate and Wall Shear Rate in Radial and Ulnar Arteries Using Simulation.

    PubMed

    Zhou, Xiaowei; Xia, Chunming; Stephen, Gandy; Khan, Faisel; Corner, George A; Hoskins, Peter R; Huang, Zhihong

    2017-05-01

    Parameters of blood flow measured by ultrasound in radial and ulnar arteries, such as flow velocity, flow rate and wall shear rate, are widely used in clinical practice and clinical research. Investigation of these measurements is useful for evaluating accuracy and providing knowledge of error sources. A method for simulating the spectral Doppler ultrasound measurement process was developed with computational fluid dynamics providing flow-field data. Specific scanning factors were adjusted to investigate their influence on estimation of the maximum velocity waveform, and flow rate and wall shear rate were derived using the Womersley equation. The overestimation in maximum velocity increases greatly (peak systolic from about 10% to 30%, time-averaged from about 30% to 50%) when the beam-vessel angle is changed from 30° to 70°. The Womersley equation was able to estimate flow rate in both arteries with less than 3% error, but performed better in the radial artery (2.3% overestimation) than the ulnar artery (15.4% underestimation) in estimating wall shear rate. It is concluded that measurements of flow parameters in the radial and ulnar arteries with clinical ultrasound scanners are prone to clinically significant errors. Copyright © 2017. Published by Elsevier Inc.

  3. A hybrid FDTD-Rayleigh integral computational method for the simulation of the ultrasound measurement of proximal femur.

    PubMed

    Cassereau, Didier; Nauleau, Pierre; Bendjoudi, Aniss; Minonzio, Jean-Gabriel; Laugier, Pascal; Bossy, Emmanuel; Grimal, Quentin

    2014-07-01

    The development of novel quantitative ultrasound (QUS) techniques to measure the hip is critically dependent on the possibility to simulate the ultrasound propagation. One specificity of hip QUS is that ultrasounds propagate through a large thickness of soft tissue, which can be modeled by a homogeneous fluid in a first approach. Finite difference time domain (FDTD) algorithms have been widely used to simulate QUS measurements but they are not adapted to simulate ultrasonic propagation over long distances in homogeneous media. In this paper, an hybrid numerical method is presented to simulate hip QUS measurements. A two-dimensional FDTD simulation in the vicinity of the bone is coupled to the semi-analytic calculation of the Rayleigh integral to compute the wave propagation between the probe and the bone. The method is used to simulate a setup dedicated to the measurement of circumferential guided waves in the cortical compartment of the femoral neck. The proposed approach is validated by comparison with a full FDTD simulation and with an experiment on a bone phantom. For a realistic QUS configuration, the computation time is estimated to be sixty times less with the hybrid method than with a full FDTD approach.

  4. Reliability of the ultrasound measurements of abdominal muscles activity when activated with and without pelvic floor muscles contraction.

    PubMed

    Tahan, Nahid; Rasouli, Omid; Arab, Amir Massoud; Khademi, Khosro; Samani, Elham Neisani

    2014-01-01

    Synergistic co-activation of the abdominal and pelvic floor muscles (PFM) has been shown in literature. Some studies have assessed the reliability of ultrasound measures of the abdominal muscles. The aim of this study was to determine the reliability of ultrasound measurements of transverses abdominis (TrA) and obliquus internus (OI) muscles during different conditions (PFM contraction, abdominal hollowing manoeuvre (AHM) with and without PFM contraction) in participants with and without chronic low back pain (LBP). 21 participants (9 with LBP, 12 healthy) participated in the study. The reliability of thickness measurements at rest and during each condition and thickness changes and percentage of this changes at different conditions were assessed. The results showed high reliability of the thickness measurement at rest and during each condition of TrA and OI muscles, moderate to substantial reliability for the thickness change and percentage of thickness change of TrA, and fair to moderate reliability of the thickness change and percentage of thickness change of OI in both groups. Ultrasound imaging can be used as a reliable method for assessment of abdominal muscle activity with and without PFM contraction.

  5. Comparison of central corneal thickness measured by hand-held and desk-mounted ultrasound pachymeters in glaucoma patients.

    PubMed

    Salim, Sarwat; Du, Haiming; Wan, Jim

    2015-07-01

    The purpose of this study was to compare the accuracy and reproducibility of central corneal thickness measured by hand-held and desk-mounted ultrasound pachymeter in glaucoma patients under treatment. Prospective study of 65 glaucoma patients. Central corneal thickness was measured by two ultrasound pachymeters: the hand-held, portable PachPen (Accutome, Lynwood, WA), and the desk-mounted PacScan 300 (Sonomed, Lake Success, NY). The mean ± SD central corneal thickness was 526.5 ± 44.8 µm and 530.0 ± 44.7 µm for the hand-held and desk-mounted pachymeters, respectively (p = 0.15). Linear regression analysis revealed a slope of 0.97 with Pearson correlation coefficient of 0.96. Bland-Altman analysis showed a mean difference of measurements by both pachymeters of 3.22 µm with two standard deviations = 9.51. Both instruments showed high intraobserver correlation: 0.972 for the hand-held pachymeter and 0.993 for the desk-mounted pachymeter. Central corneal thickness measurements were comparable with the use of hand-held and desk-mounted ultrasound units in glaucoma patients with good intraobserver reproducibility.

  6. Inter-rater, intra-rater, and inter-machine reliability of quantitative ultrasound measurements of the patellar tendon.

    PubMed

    Gellhorn, Alfred C; Carlson, M Jake

    2013-05-01

    The use of ultrasound (US) to perform quantitative measurements of musculoskeletal tissues requires accurate and reliable measurements between investigators and ultrasound machines. The objective of this study was to evaluate inter-rater and intra-rater reliability of patellar tendon measurements between providers with different levels of US experience and inter-machine reliability of US machines. Sixteen subjects without a history of knee pain were evaluated with US examinations of the patellar tendon. Each tendon was scanned independently by two investigators using two different ultrasound machines. Tendon length and cross-sectional area (CSA) were obtained, and examiners were blinded to each other's results. Tendon length was measured using a validated system involving surface markers and calipers, and CSA was measured using each machine's measuring software. Intra-class correlation coefficients (ICCs) were used to determine reliability of measurements between observers, where ICC > 0.75 was considered good and ICC > 0.9 was considered excellent. Inter-rater reliability between sonographers was excellent and revealed an ICC of 0.90 to 0.92 for patellar tendon CSA and an ICC of 0.96 for tendon length. ICC for intra-rater reliability of tendon CSA was also generally excellent, with ICC between 0.87 and 0.96. Inter-machine reliability was excellent, with ICC of 0.91-0.98 for tendon CSA and 0.96-0.98 for tendon length. Bland-Altman plots were constructed to measure validity and demonstrated a mean difference between sonographers of 0.03 mm(2) for CSA measurements and 0.2 mm for tendon length. Using well-defined scanning protocols, a novice and an experienced musculoskeletal sonographer attained high levels of inter-rater agreement, with similarly excellent results for intra-rater and inter-machine reliability. To our knowledge, this study is the first to report inter-machine reliability in the setting of quantitative musculoskeletal ultrasound. Copyright © 2013

  7. Validation of ultrasound techniques applied to body fat measurement. A comparison between ultrasound techniques, air displacement plethysmography and bioelectrical impedance vs. dual-energy X-ray absorptiometry.

    PubMed

    Pineau, Jean-Claude; Guihard-Costa, Anne-Marie; Bocquet, Michel

    2007-01-01

    To evaluate the accuracy of body fat percentage (BF%) estimates from a portable, non-traumatizing ultrasound device with high accuracy and reliability compared to dual-energy X-ray absorptiometry (DEXA), the reference technique. Cross-validation between ultrasound technique (UT), DEXA, air displacement plethysmography (ADP) and bioelectrical impedance (BIA) was developed in the study. A total of 89 healthy subjects (41 women, 48 men), aged 48.4 +/- 17.7 (mean +/- SD), with Body mass index (28.5 +/- 7.7 kg/m(2)) and body fat DEXA (29.6 +/- 10.8 kg) participated. BF% was measured using an UT associated with anthropometric parameters and simultaneously, with the DEXA reference technique, BIA and ADP. UT estimates of BF% were better correlated with those of DEXA in both males and females (r = 0.98, SEE = 2.0) than with ADP (r = 0.94, SEE = 3.7) or BIA (r = 0.92, SEE = 4.4). The UT in both genders was better (TE = 1.0) than BIA (TE = 2.6) and ADP (TE = 3.0). The 95% limits of agreement were also better for the UT (-2%; 2%) than with BIA (-5.1%; 4.9%) and ADP (-6.3%; 5.3%). The limits of agreement with BIA and ADP are unacceptably high compared to a DEXA measure criterion. The use of a new portable device based on a UT produced a very accurate BF% estimate in relation to the DEXA reference technique. (c) 2007 S. Karger AG, Basel.

  8. Ultrasound in the management of pleural disease.

    PubMed

    Mercer, Rachel M; Psallidas, Ioannis; Rahman, Najib M

    2017-04-01

    Pleural disease encompasses a large range of conditions, is a common presentation to the acute medical take and often requires comprehensive investigation and treatment. Ultrasound is well recognised as a useful investigative tool in pleural disease especially in the field of pleural effusion, pleural thickening and interventional procedures. Thoracic ultrasound (TUS) has gained widespread use by physicians as evidence has shown a reduced rate of complications when performing pleural procedures with ultrasound guidance. Areas covered: This article will review studies assessing the role of TUS in the management of pleural disease and examine ongoing research into how TUS could advance our knowledge and understanding over the next decade. Expert commentary: Physician lead thoracic ultrasound has become commonplace over the last decade, and now represents a minimum standard of safety in conducting the majority of 'bedside' pleural procedures. The current evidence points to important diagnostic and procedural roles of the use of bedside thoracic ultrasound. In the future, research developments are likely to lead to the use of thoracic ultrasound in prognostication, targeted treatment and understanding pathogenesis in pleural disease.

  9. In-situ Attenuation Corrections for Radiation Force Measurements of High Frequency Ultrasound With a Conical Target

    PubMed Central

    Fick, Steven E.; Ruggles, Dorea

    2006-01-01

    Radiation force balance (RFB) measurements of time-averaged, spatially-integrated ultrasound power transmitted into a reflectionless water load are based on measurements of the power received by the RFB target. When conical targets are used to intercept the output of collimated, circularly symmetric ultrasound sources operating at frequencies above a few megahertz, the correction for in-situ attenuation is significant, and differs significantly from predictions for idealized circumstances. Empirical attenuation correction factors for a 45° (half-angle) absorptive conical RFB target have been determined for 24 frequencies covering the 5 MHz to 30 MHz range. They agree well with previously unpublished attenuation calibration factors determined in 1994 for a similar target. PMID:27274946

  10. In-situ Attenuation Corrections for Radiation Force Measurements of High Frequency Ultrasound With a Conical Target.

    PubMed

    Fick, Steven E; Ruggles, Dorea

    2006-01-01

    Radiation force balance (RFB) measurements of time-averaged, spatially-integrated ultrasound power transmitted into a reflectionless water load are based on measurements of the power received by the RFB target. When conical targets are used to intercept the output of collimated, circularly symmetric ultrasound sources operating at frequencies above a few megahertz, the correction for in-situ attenuation is significant, and differs significantly from predictions for idealized circumstances. Empirical attenuation correction factors for a 45° (half-angle) absorptive conical RFB target have been determined for 24 frequencies covering the 5 MHz to 30 MHz range. They agree well with previously unpublished attenuation calibration factors determined in 1994 for a similar target.

  11. Comparison of Central Corneal Thickness Measurements Obtained by RTVue OCT, Lenstar, Sirius Topography, and Ultrasound Pachymetry in Healthy Subjects.

    PubMed

    Şimşek, Ali; Bilak, Şemsettin; Güler, Mete; Çapkin, Musa; Bilgin, Burak; Reyhan, Ali Hakim

    2016-01-01

    To compare central corneal thickness (CCT) measurement results obtained by RTVue OCT, Lenstar, Sirius topography, and ultrasound pachymetry (UP) (OcuScan RxP Ophthalmic Ultrasound System, Alcon Laboratories) in healthy subjects. 256 eyes of 128 healthy subjects were included in the study. CCT measurements were obtained from the eyes for each subject using the UP, Lenstar, Sirius topography, and RTVue OCT instruments. Ultrasound pachymetry measurements were performed after the eyes were anesthetized with one drop of 0.5% proparacaine hydrochloride and were performed at the same day after 15 minutes after previous measurements. Of 128 participants, 84 were male and 44 were female with a mean age of 33.15 ± 12.95 years (ranging from 18 to 75 years). The mean CCTs for UP, Lenstar, Sirius topography, and RTVue OCT were 535.60 ± 35.15 (440,00-668,00); 532.63 ± 34.44 (449,00-650,00); 526.05 ± 36.45 (314,00-640,00); 525.89 ± 33.21 (437,00-646,00) µm, respectively. The mean CCT measurements were statistically different among the three groups (p = 0.002). CCT measurements obtained using RTVue-OCT were significantly thinner than those obtained using UP (p = 0.009). Sirius CCT measurements were also thinner than UP (p = 0.011). Mean CCT measurements between UP and Lenstar were similar (p = 0.769). Measurements with Lenstar (r = 0.849), Sirius topography (r = 0.883), and RTVue OCT (0.949) were highly correlated with UP measurements. RTVue OCT and Sirius topography significantly underestimated the CCT compared with UP. Although highly correlated, the measurement values with these devices are not directly interchangeable in clinical practice.

  12. Joseph F. Keithley Award For Advances in Measurement Science: Resonant Ultrasound Spectroscopy: An Odyssey in Measurement Science

    NASA Astrophysics Data System (ADS)

    Migliori, Albert

    Perhaps the speeds of sound, or, equivalently, the elastic moduli are some of the most fundamental attributes of a solid, connecting to fundamental physics, metallurgy, non-destructive testing, and more. Unlike most of the quantities used to characterize condensed matter, the elastic moduli are fourth-rank tensors containing a wealth of detail, directional information, and consistency constraints that provide some of the most revealing probes of solids. We describe here the current state of the art in one method, Resonant Ultrasound Spectroscopy, where the mechanical resonances of a specimen of regular shape (easy to measure) are analyzed (difficult computational problem) to obtain the full elastic tensor. With modern advances in electronics and analysis, fractions of a part per million changes in elastic moduli are detectable providing new and important insight into grand challenges in condensed matter physics. This work was supported as part of the Materials Science of Actinides, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Basic Energy Sciences under Award # DE-SC0001089.

  13. [Value of lung ultrasound in emergency and intensive care medicine].

    PubMed

    Michels, G; Breitkreutz, R; Pfister, R

    2014-11-01

    Lung ultrasound has traditionally been limited to evaluation of pleural effusion and as guidance for thoracocentesis. However, in recent years, thoracic ultrasound became an increasingly valuable diagnostic tool in emergency and intensive care medicine. The relative easy use of bedside examination made chest ultrasonography diagnostic valuable additional tool to be used in any clinical acute context. Various pulmonary diseases like pleural effusion, pulmonary-venous congestion und edema, pneumonia and pneumothorax can be detected very fast under emergency conditions.

  14. Is ultrasound of bone relevant for corticosteroid-treated patients? A comparative study with bone densitometry measured by DEXA.

    PubMed

    Oliveri, Beatriz; Di Gregorio, Silvana; Parisi, Muriel Solange; Solís, Fabiana; Mautalen, Carlos

    2003-02-01

    Corticosteroid treatment diminishes bone mass and alters bone quality. The objective was to evaluate bone in corticosteroid-treated patients and controls and in fractured and non-fractured patients treated with corticosteroids using both X-ray densitometry (DEXA) and ultrasound. We evaluated 34 women aged 58 +/- 14 years (X +/- SD), who had been on long-term low dose prednisone therapy for at least 6 months, and who had never received specific treatment for osteoporosis. Bone mineral density of total skeleton (TS), lumbar spine (LS), femoral neck (FN), and vertebral morphometry (MXA) were measured by DEXA. Speed of sound (SOS), broadband ultrasound attenuation (BUA) and stiffness were measured using an Achilles Plus system. Forty-two healthy women served as controls. Both densitometric and ultrasound parameters in the patients were significantly diminished compared with controls: TS: P < 0.002, LS: P < 0.025, FS: P < 0.005, Stiffness: P < 0.001, BUA: P < 0.002 and SOS: P < 0.002. The percentage of patients with a Z score below -2 was higher in Stiffness and BUA: 38% and 47%, respectively, compared with a range of 16-24% in the other parameters (P < 0.05 BUA vs. DEXA measurements). Eleven patients with previous bone fracture had values lower than the non-fractured patients, both according to DEXA and ultrasound measurements, but the difference was only significant for BUA (P < 0.02). BUA of the calcaneus was more effective in detecting the specific skeletal alterations and fracture risk of the group of patients receiving chronic corticosteroid treatment.

  15. A step towards measuring the fetal head circumference with the use of obstetric ultrasound in a low resource setting

    NASA Astrophysics Data System (ADS)

    van den Heuvel, Thomas L. A.; Petros, Hezkiel; Santini, Stefano; de Korte, Chris L.; van Ginneken, Bram

    2017-03-01

    Worldwide, 99% of all maternal deaths occur in low-resource countries. Ultrasound imaging can be used to detect maternal risk factors, but requires a well-trained sonographer to obtain the biometric parameters of the fetus. One of the most important biometric parameters is the fetal Head Circumference (HC). The HC can be used to estimate the Gestational Age (GA) and assess the growth of the fetus. In this paper we propose a method to estimate the fetal HC with the use of the Obstetric Sweep Protocol (OSP). With the OSP the abdomen of pregnant women is imaged with the use of sweeps. These sweeps can be taught to somebody without any prior knowledge of ultrasound within a day. Both the OSP and the standard two-dimensional ultrasound image for HC assessment were acquired by an experienced gynecologist from fifty pregnant women in St. Luke's Hospital in Wolisso, Ethiopia. The reference HC from the standard two-dimensional ultrasound image was compared to both the manually measured HC and the automatically measured HC from the OSP data. The median difference between the estimated GA from the manual measured HC using the OSP and the reference standard was -1.1 days (Median Absolute Deviation (MAD) 7.7 days). The median difference between the estimated GA from the automatically measured HC using the OSP and the reference standard was -6.2 days (MAD 8.6 days). Therefore, it can be concluded that it is possible to estimate the fetal GA with simple obstetric sweeps with a deviation of only one week.

  16. Transversus abdominis and obliquus internus activity during pilates exercises: measurement with ultrasound scanning.

    PubMed

    Endleman, Irit; Critchley, Duncan J

    2008-11-01

    To assess activity of transversus abdominis (TrA) and obliquus internus abdominis (OI) muscles during classical Pilates exercises performed correctly and incorrectly, and with or without equipment. Repeated-measures descriptive study. Pilates studio. A volunteer sample of women (n=18) and men (n=8), mean age +/- SD (43+/-14y), with more than 6 months classical Pilates training and no back pain or other condition likely to influence abdominal muscle activity. Participants performed Pilates imprint, hundreds A and B, roll-up, and leg-circle exercises on a mat. The hundreds exercise was also performed on a reformer (sliding platform). Mat imprint and hundreds exercises were instructed to be performed correctly (with abdominal drawing-in) or incorrectly (without drawing-in). Thickness of TrA and OI middle fibers measured with ultrasound imaging. TrA thickness increased during the mat imprint, hundreds A, hundreds B, leg-circle, and roll-up exercises (all P=.001) compared with resting. OI thickness increased during the mat imprint, hundreds A, hundreds B, leg-circle (all P=.001), and roll-up exercises (P=.002) compared with resting. TrA thickness during reformer hundreds B was greater than during mat hundreds B (P=.011); OI thicknesses were not different for this comparison. During incorrect imprint, neither TrA or OI thicknesses were different to resting. TrA and OI muscle thicknesses were moderately correlated (R=.410; P=.001). This study provides the first evidence that a selection of classic Pilates exercises activates TrA and OI. Use of the reformer exercise machine can result in greater TrA activation in some exercises. TrA and OI did not function independently during these exercises. Research into the training effects of Pilates or in patient populations can be undertaken using ultrasonography in submaximal exercises.

  17. Model-based correction of velocity measurements in navigated 3-D ultrasound imaging during neurosurgical interventions.

    PubMed

    Iversen, Daniel Hoyer; Lindseth, Frank; Unsgaard, Geirmund; Torp, Hans; Lovstakken, Lasse

    2013-09-01

    In neurosurgery, information of blood flow is important to identify and avoid damage to important vessels. Three-dimensional intraoperative ultrasound color-Doppler imaging has proven useful in this respect. However, due to Doppler angle-dependencies and the complexity of the vascular architecture, clinical valuable 3-D information of flow direction and velocity is currently not available. In this work, we aim to correct for angle-dependencies in 3-D flow images based on a geometric model of the neurovascular tree generated on-the-fly from free-hand 2-D imaging and an accurate position sensor system. The 3-D vessel model acts as a priori information of vessel orientation used to angle-correct the Doppler measurements, as well as provide an estimate of the average flow direction. Based on the flow direction we were also able to do aliasing correction to approximately double the measurable velocity range. In vitro experiments revealed a high accuracy and robustness for estimating the mean direction of flow. Accurate angle-correction of axial velocities were possible given a sufficient beam-to-flow angle for at least parts of a vessel segment . In vitro experiments showed an absolute relative bias of 9.5% for a challenging low-flow scenario. The method also showed promising results in vivo, improving the depiction of flow in the distal branches of intracranial aneurysms and the feeding arteries of an arteriovenous malformation. Careful inspection by an experienced surgeon confirmed the correct flow direction for all in vivo examples.

  18. Breast density measurements using ultrasound tomography for patients undergoing tamoxifen treatment

    NASA Astrophysics Data System (ADS)

    Sak, Mark; Duric, Neb; Littrup, Peter; Li, Cuiping; Bey-Knight, Lisa; Sherman, Mark; Boyd, Norman; Gierach, Gretchen

    2013-03-01

    Women with high breast density have an increased risk of developing breast cancer. Women treated with the selective estrogen receptor modulator tamoxifen for estrogen receptor positive breast cancer experience a 50% reduction in risk of contralateral breast cancer and overall reduction of similar magnitude has been identified among high-risk women receiving the drug for prevention. Tamoxifen has been shown to reduce mammographic density, and in the IBIS-1 chemoprevention trial, risk reduction and decline in density were significantly associated. Ultrasound tomography (UST) is an imaging modality that can create tomographic sound speed images of the breast. These sound speed images are useful because breast density is proportional to sound speed. The aim of this work is to examine the relationship between USTmeasured breast density and the use of tamoxifen. So far, preliminary results for a small number of patients have been observed and are promising. Correlations between the UST-measured density and mammographic density are strong and positive, while relationships between UST density with some patient specific risk factors behave as expected. Initial results of UST examinations of tamoxifen treated p