Academic literature on the topic 'Conventional Doppler'

Background Timely reexploration and reanastomoses can salvage failing free flaps. The use of the implantable Doppler probe provides direct evidence of vascular impairment of the microvascular anastomoses and allows for postoperative NPWT. The aim of this retrospective study was to compare the Doppler probe to conventional monitoring techniques for free flap monitoring in lower limb reconstruction and to identify risk factors for perfusion disturbance and reexploration. Methods All patients receiving free muscle flap reconstruction for lower limb soft tissue defects at our department from 2000 to 2013 were included, and all adverse events, timely detection of perfusion problems, and outcome of revision surgery were assessed by chart analysis. Results For lower limb reconstruction, 110 free muscle transfers were performed of which 41 muscle flaps were conventionally monitored and 69 flaps were monitored using the implantable Doppler probe. In 18 cases, the free muscle flaps needed revision because of perfusion disturbances. The salvage rate was 80% with monitoring by the implantable Doppler probe compared with 62.5% using conventional monitoring methods resulting in success rates of 95.7 and 92.7%, respectively. Conclusion The use of the implantable Cook–Swartz Doppler probe represents a safe monitoring method for lower limb reconstruction, which allows for the additional use of NPWT. Higher salvage and revision success rates can be attributed to an earlier detection of perfusion impairment. However, a larger patient cohort is necessary to verify superiority over conventional postoperative monitoring.

Purpose: To compare sentinel lymph node biopsy, magnetic resonance imaging (MRI), Doppler ultrasonography, and palpation as staging tools in patients with T1/T2 N0 cancer of the oral cavity. Material and Methods: Forty consecutive patients were enrolled (17 F and 23 M, aged 32–90 years), 24 T1 and 16 T2 cN0 squamous cell carcinoma of the oral cavity. Palpation was carried out by two observers prior to inclusion. MRI, gray-scale and Doppler ultrasonography were performed. Lymphoscintigraphies were done after peritumoral injections of 99mTc labelled rheniumsulphide nanocolloid, followed by sentinel lymph node biopsy guided by a gamma probe and Patent Blue. Palpation, Doppler ultrasonography, MRI, and sentinel lymph node biopsy were compared to a combination of histopathology and follow-up. Diagnostic testing was performed using the x2 test. Results: Histopathological examination revealed metastatic spread to the neck in 14 of 40 patients. One patient had bilateral neck disease. Sentinel lymph node biopsy and ultrasonography were performed in 80 neck sides of 40 patients and MRI in 70 neck sides (5 patients were claustrophobic). SN revealed suspicious lymph nodes in 12 necks, ultrasonography in 23 necks, and MRI in 9 necks. The positive predictive value of sentinel lymph node biopsy was 100%, ultrasonography 57%, and MRI 56%. The respective negative predictive values were 96%, 96%, and 85%. The sensitivity of sentinel lymph node biopsy 80% was comparable to ultrasonography 87%, but the sensitivity of MRI 36% was low. The specificities were 100%, 85%, and 93%, respectively. By combined sentinel lymph node biopsy and ultrasonography the overall sensitivity could have been 100%. Conclusion: Sentinel lymph node biopsy improved staging of patients with small N0 oral cancers. Combined sentinel lymph node biopsy and Doppler ultrasonography may further improve staging. MRI and simple palpation results were poor.

For more than twenty years, conventional altimeters like Topex, Poseidon-2 or Poseidon-3, have been delivering waveforms that are used to estimate many parameters such as the range between the satellite and the observed scene, the wave height and the wind speed. Several waveform models and estimation processing have been developed for the oceanic data in order to improve the quality of the estimated altimetric parameters. Moreover, a great effort has been devoted to process coastal echoes in order to move the altimetric measurements closer to the coast. In this thesis, we are interested in resolving these two problems, i.e., processing coastal waveforms and improving the quality of the estimated oceanic parameters. The first part of the study considers the problem of coastal waveforms and proposes a new altimetric model taking into account the possible presence of peaks affecting altimetric echoes. In a second part of our work, we have been interested in the delay/Doppler altimetry. This new technology aims at reducing the measurement noise and increasing the alongtrack resolution when compared to conventional altimetry. Two altimetric models have been developed in order to estimate the resulting delay/Doppler echoes. These models allow a clear improvement in parameter estimation when compared to conventional altimetry.

Thesis (M.S. in Electrical Engineering) Naval Postgraduate School, December 1996.
"December 1996." Thesis advisor(s): Gurnam S. Gill. Includes bibliographical references (p. 45). Also available online.

Includes abstract.
Includes bibliographical references (p. 175-218).
Traumatic brain injury (TBI) is a highly complex clinical condition in the most complex organ of the body. The foundation of care of the patient with severe TBI is the prevention of secondary insults to the brain. This relies on conventional monitoring tools to identify patients at risk, but often these may fail to detect important secondary insults. Moreover, the therapies that are used commonly in the critical care environment all have potential adverse effects, many of which may not be evident. TBI treatment in children is further complicated by changing thresholds with age, and the much smaller evidence base compared to their adult counterparts.

Einleitung: Zu den konventionellen αβ T-Zellen zählen die klassischen CD4+ einfach-positiven T-Helfer (Th) bzw. regulatorischen T-Zellen (Treg) sowie CD8αβ+ einfach-positive zytotoxische T-Zellen. Säugetiere besitzen jedoch noch weitere T-Zell-Subpopulationen, die entweder den T-Zell-Rezeptor αβ (TCRαβ) oder γδ (TCRγδ) exprimieren. Bei Hunden wurde bisher nur die hoch aktivierte CD4+CD8α+ doppelt-positive (dp) T-Zellpopulation des peripheren Blutes detailliert charakterisiert. Über ihre Verteilung in lymphatischem und nicht lymphatischem Gewebe ist jedoch wenig bekannt. Darüber hinaus besitzen Hunde αβ T-Zellen, die weder CD4 noch CD8α (CD4-CD8α- doppelt-negative (dn) T-Zellen) exprimieren, sowie γδ T-Zellen, deren Phänotyp bisher noch nicht untersucht wurde. Ziele der Studie: Ziel dieser Studie war es, einen Überblick über das Vorkommen und den Phänotyp von nichtkonventionellen T-Zellen im peripheren Blut und Geweben des Hundes zu bieten. Zu diesem Zweck wurden CD4+CD8α+ dp, TCRαβ+CD4-CD8α- dn und γδ T-Zellen hinsichtlich der Expression von Oberflächenmarkern, wichtigen Transkriptionsfaktoren und Zytokinen charakterisiert. Tiere, Material und Methoden: Canine T-Zellen Zellen aus dem Blut (Stichprobenumfang: n = 10) sowie aus den Peyerschen Platten (PP; n = 10), dem Dünndarmepithel (IEL; n = 6), den mesenterialen Lymphknoten (mLN; n = 10), tracheobronchialen Lymphknoten (tLN; n = 9), der Lunge (n = 10), Milz (n = 10) und dem Thymus (n = 10) wurden mittels Durchflusszytometrie analysiert. Das Studiendesign erforderte, dass die Gewebeproben von einer anderen Gruppe gesunder Beagle-Hunde (n = 12) entnommen wurden als das periphere Blut. CD4+CD8α+ dp T-Zellen wurden auf ihre Gewebeverteilung, die Expression des T-Zell-Rezeptortyps und die Zusammensetzung des CD8-Dimers (d.h. CD8αα Homodimer vs. CD8αβ Heterodimer) sowie die Expression des Aktivierungsmarkers CD25 untersucht. Um Hinweise auf die potenzielle(n) Funktion(en) von CD4+CD8α+ dp T-Zellen in Geweben zu erhalten, wurde die Expression des Transkriptionsfaktors Forkhead Box P3 (FoxP3) und des zytotoxischen Moleküls Granzym B analysiert. Darüber hinaus wurden Gewebe und Blut auf die Verteilung von TCRαβ+CD4-CD8α- dn und γδ T-Zellen untersucht. Eine umfassende Charakterisierung von TCRαβ+CD4-CD8α- dn und γδ T-Zellen des peripheren Blutes erfolgte durch die Untersuchung der folgenden Marker: CD25 und CD5, FoxP3, GATA-3, T-Box-Transkriptionsfaktor TBX21 (T-bet) und Granzym B. Im Rahmen funktioneller Analysen wurde die Zytokinproduktion (Interferon-γ (IFN-γ) und Interleukin-17A, IL-17A) nach Stimulation der Zellen mit Phorbol-Myristat-Acetat (PMA)/Ionomycin durchgeführt. Normalverteilte Datensätze wurden mittels einfaktorieller Varianzanalyse (ANOVA) mit Bonferroni-Post-Hoc-Test (Vergleich mehrerer Gruppen) oder ungepaartem t-Test (zweiseitig; Vergleich zweier Gruppen) analysiert. Bei nichtparametrischen Daten wurde entweder der Kruskal-Wallis H-Test mit Dunn's Post-Test (Ver-gleich mehrerer Gruppen) oder der Mann-Whitney U-Test (zweiseitig; Vergleich zweier Gruppen) angewandt. Ergebnisse: Canine CD4+CD8α+ dp T-Zellen der Gewebe sind hauptsächlich TCRαβ+CD4+CD8αα+CD25+ und akkumulieren in den PP (durchschnittlich 1.6 %). Obwohl CD4+CD8α+ dp T-Zellen der LN CD4 und CD8α nicht gleich stark exprimieren und zahlenmäßig gering (durchschnittlich 0,2 %) sind, sind sie teilweise FoxP3+. Dies weist auf ein regulatorisches Potential dieser Untergruppe hin. Einige CD4+CD8α+ dp T-Zellen der IEL exprimieren TCRγδ und/oder Granzym B, was die Einzigartigkeit der intestinalen intraepithelialen Lymphozyten unterstreicht. TCRαβ+CD4-CD8α- dn T-Zellen machen einen wesentlichen Anteil aller αβ T-Zellen in Blut (Median 14,4 %) und Gewebe (Median 15 % (Lunge) - 7,5% (PP)) aus und besitzen ein bemerkenswert hohes Expressionsniveau an CD25. CD25 wird entweder mit FoxP3 (hinweisend auf einen regulatorischen Phänotyp) oder ohne FoxP3 (hinweisend auf einen Effektorphänotyp) exprimiert. Zusätzlich weisen IFN-γ, GATA-3 oder IL-17A-exprimierende Subpopulationen Eigenschaften von konventio-nellen Typ 1 T-Helferzellen (Th1), Th2 bzw. Th17 auf. Interessanterweise wurden auch FoxP3+GATA-3+-Hybridzellen gefunden. Canine γδ T-Zellen hingegen sind entweder CD8α+ einfach-positiv oder CD4 CD8α- dn. Während TCRγδ+CD8α+ einfach-positive T-Zellen ihren zytotoxischen TCRαβ+CD8αβ+ T-Zell-Pendants ähneln (T-bet+, IFN-γ+, Granzym B+), exprimieren TCRγδ+CD4 CD8α- dn T-Zellen GATA-3 und nur geringe Mengen an T-bet und Granzym B. Schlussfolgerungen: Dies ist die erste Studie, die einen umfassenden Überblick über nichtkonventionelle T-Zell-Populationen des Hundes bietet. Hinsichtlich ihrer Gewebeverteilung, ihrer Anzahl und ihres funktionellen Potentials ist es wahrscheinlich, dass diese Zellen an wichtigen Immunreaktionen sowie an der Pathogenese von Erkrankungen des Hundes beteiligt sind. Hierzu werden weitere Studien erforderlich sein. Es ist anzumerken, dass das klassische Schema der CD4+ und CD8αβ+ einfach-positiven T-Zellen als canine Haupteffektor- bzw. regulatorische T-Zellen neu überdacht werden sollte. :1 Introduction 1 1.1 The innate and adaptive immune system of mammals 1 1.2 Conventional αβ T cells 1 1.2.1 Cytotoxic CD8αβ+ T cells 2 1.2.2 CD4+ T cells 3 1.2.2.1 CD4+ T helper cells 3 1.2.2.2 CD4+ regulatory T cells 4 1.3 Non-conventional T cells 5 1.3.1 CD4+CD8α+ double-positive T cells 5 1.3.2 γδ T cells 7 1.3.3 CD4-CD8α- double-negative αβ T cells 8 1.4 Aims of this study 8 2 Results 10 2.1 1st publication 10 2.2 2nd publication 32 3 Discussion 55 3.1 Canine non-conventional CD4+CD8α+ double-positive T cells are a homogeneous population enriched at mucosal sites 55 3.2 Canine non-conventional CD4-CD8α- double-negative T cells are unique in abundance and phenotype 57 3.3 Concluding remarks 60 4 Summary 61 5 Zusammenfassung 63 6 Literature Cited 65
Introduction: Conventional αβ T cells comprise the classical CD4+ single-positive (sp) T helper (Th) resp. T regulatory (Treg) and CD8αβ+ sp cytotoxic T cell subsets. However, further T cell subpopulations either expressing T cell receptor αβ (TCRαβ) or γδ (TCRγδ) occur in mammals. In dogs, only the highly activated CD4+CD8α+ double-positive (dp) T cell population of peripheral blood has been characterized in detail. Yet, little is known about its distribution in lymphoid and non-lymphoid tissues. Furthermore, dogs possess αβ T cells neither expressing CD4 nor CD8α (CD4-CD8α- double-negative (dn) T cells) and γδ T cells, whose phenotype was still undefined. Aims of study: The objective of this study was to provide an overview on the occurrence and phenotype of non-conventional T cells in canine peripheral blood and tissues. To this end, CD4+CD8α+ dp, TCRαβ+CD4-CD8α- dn, and γδ T cells were characterized regarding expression of surface markers, key transcription factors, and cytokines. Animals, material and methods: Canine T lymphocytes from peripheral blood (sample size: n = 10), Peyer’s patches (PP; n = 10), epithelium of the small intestine (IEL; n = 6), mesenteric lymph nodes (mLN; n = 10), tracheobronchial lymph nodes (tLN; n = 9), lung (n = 10), spleen (n = 10), and thymus (n = 10) were analyzed by flow cytometry. Due to the study design tissue samples had to be taken from a different group of healthy Beagle dogs (n = 12) than peripheral blood. CD4+CD8α+ dp T cells were studied for their tissue distribution, expression of T cell receptor type and composition of the CD8 dimer (i.e. CD8αα homodimer vs. CD8αβ heterodimer), as well as expression of the activation marker CD25. To define the potential function(s) of CD4+CD8α+ dp T cells in tissues, expression of the transcription factor forkhead box P3 (FoxP3) and the cytotoxic molecule granzyme B were analyzed. Furthermore, tissues and blood were studied for distribution of TCRαβ+CD4-CD8α- dn and γδ T cells. A comprehensive characterization of blood TCRαβ+CD4-CD8α- dn and γδ T cells was made by investigation of the following markers: CD25 and CD5, FoxP3, GATA-3, T-box transcription factor TBX21 (T-bet), and granzyme B. Functional analyses were performed by examination of cytokine production (interferon γ (IFN-γ) and interleukin 17A, IL-17A) following stimulation of cells with phorbol-myristate-acetate (PMA)/ionomycin. Normally distributed data sets were analyzed using One-way analysis of variance (ANOVA) with Bonferroni post hoc test (multiple groups) or unpaired Student’s t-test (two-tailed; two groups). For nonparametric data, either Kruskal-Wallis H test with Dunn’s post-test (multiple groups) or Mann-Whitney U test (two-tailed; two groups) was applied. Results: Canine CD4+CD8α+ dp T cells of tissues can be mainly described as TCRαβ+CD4+CD8αα+CD25+ accumulating in PP (1.6% on average). Although not homogeneous in expression levels of CD4 and CD8α and low in number (0.2% on average), CD4+CD8α+ dp T cells of LN are partly FoxP3+. This indicates regulatory potential of this subset. Some CD4+CD8α+ dp T cells of IEL express TCRγδ and/or granzyme B, underlining the uniqueness of intestinal intraepithelial lymphocytes. TCRαβ+CD4-CD8α- dn T cells make up a substantial portion of all αβ T cells in blood (median 14.4%) and tissues (median 15% (lung) – 7.5% (PP)) with a remarkably high expression level of CD25. CD25 is either co-expressed with FoxP3 (reminiscent of a regulatory phenotype), or without FoxP3 (reminiscent of an effector phenotype). In addition, subsets expressing IFN-γ, GATA-3, or IL-17A suggest properties of conventional type 1 T helper cells (Th1), Th2, and Th17, respectively. Interestingly, FoxP3+GATA-3+ hybrid cells were found, too. Canine γδ T cells, on the other hand, are either CD8α+ sp or CD4-CD8α- dn. While TCRγδ+CD8α+ sp T cells resemble their TCRαβ+CD8αβ+ cytotoxic T cell counterparts (T-bet+, IFN-γ+, granzyme B+), TCRγδ+CD4-CD8α- dn T cells express GATA-3, and only low levels of T-bet and granzyme B. Conclusions: This is the first study providing a comprehensive overview on canine non-conventional T cell subsets. Regarding tissue distribution, abundance and functions resp. functional potential of these T cells, it is conceivable that they play a major role in health and diseases of dogs. Further studies examining this topic will be needed. Of note, the classical scheme of CD4+ sp Th/Treg and CD8αβ+ cytotoxic T cells as main effector/regulatory T cells in dogs should be reconsidered.:1 Introduction 1 1.1 The innate and adaptive immune system of mammals 1 1.2 Conventional αβ T cells 1 1.2.1 Cytotoxic CD8αβ+ T cells 2 1.2.2 CD4+ T cells 3 1.2.2.1 CD4+ T helper cells 3 1.2.2.2 CD4+ regulatory T cells 4 1.3 Non-conventional T cells 5 1.3.1 CD4+CD8α+ double-positive T cells 5 1.3.2 γδ T cells 7 1.3.3 CD4-CD8α- double-negative αβ T cells 8 1.4 Aims of this study 8 2 Results 10 2.1 1st publication 10 2.2 2nd publication 32 3 Discussion 55 3.1 Canine non-conventional CD4+CD8α+ double-positive T cells are a homogeneous population enriched at mucosal sites 55 3.2 Canine non-conventional CD4-CD8α- double-negative T cells are unique in abundance and phenotype 57 3.3 Concluding remarks 60 4 Summary 61 5 Zusammenfassung 63 6 Literature Cited 65

Sport-related concussion has been referred to as a functional rather than a structural injury with neurometabolic and microstructural alterations reported in several studies. Accordingly, conventional neuroimaging techniques, such as computed tomography (CT) and structural magnetic resonance imaging (MRI), have limited value beyond ruling out structural injury such as a contusion or hemorrhage. This chapter presents a review of three neuroimaging techniques that offer insight into the connectivity and neurometabolic consequences of concussion. A number of studies have now been published using magnetic resonance spectroscopy (MRS), diffusion tensor imaging (DTI)/diffusion-weighted imaging, and transcranial Doppler ultrasound (TCD) with varying findings. The results of these studies will be presented, together with current and possible future application of these techniques within the field of sport-related concussion.

Stress echocardiography has evolved over the last 30 years but image interpretation remains subjective and burdened by the operator’s experience. The objective operator-independent assessment of myocardial ischaemia during stress echocardiography remains a technological challenge. Still, adequate quality of two-dimensional images remains a prerequisite to successful quantitative analysis, even using Doppler and non-Doppler based techniques. No new technology has proved to have a higher diagnostic accuracy than conventional visual wall motion analysis. Tissue Doppler imaging and derivatives may reduce inter-observer variability, but still require a dedicated learning curve and special expertise. The development of contrast media in echocardiography has been slow. In the past decade, transpulmonary contrast agents have become commercially available for clinical use. The approved indication for the use of contrast echocardiography currently lies in improving endocardial border delineation in patients in whom adequate imaging is difficult or suboptimal. Real-time three-dimensional echocardiography is potentially useful but limited by low spatial and temporal resolution. It is possible that these technologies may serve as an adjunct to expert visual assessment of wall motion. At present, these quantitative methods require further validation and simplification of analysis techniques.

Assessment of right ventricular (RV) size, function, and haemodynamics has been challenging because of its unique cavity geometry. Conventional two-dimensional assessment of RV function is often qualitative. Doppler methods involving tricuspid inflow and pulmonary artery flow velocities, which are influenced by changes in pre- and afterload conditions, may not provide robust prognostic information for clinical decision making. Recent advances in echocardiographic assessment of the RV include tissue Doppler imaging, speckle-tracking imaging, and volumetric three-dimensional imaging, but they need specific training, expensive dedicated equipment, and extensive clinical validation. However, assessment of RV function is crucial, especially in patients with signs of right-sided failure and those with congenital or mitral valve diseases. This chapter aims to address the role of the various echocardiographic modalities used to assess RV and pulmonary vascular bed function. Special emphasis has been placed on technical considerations, limitations, and pitfalls of image acquisition and analysis.

Right ventricular (RV) performance plays an important role in the morbidity and mortality of patients with left ventricular dysfunction, congenital heart disease, and pulmonary hypertension. Assessment of RV size, function, and haemodynamics has been challenging because of its complex geometry. Conventional two-dimensional echocardiography is the modality of choice for assessment of RV function in clinical practice. Recent developments in echocardiography have provided several new techniques for assessment of RV dimensions and function, include tissue Doppler imaging, speckle-tracking imaging, and volumetric three-dimensional imaging. However, specific training, expensive dedicated equipment, and extensive clinical validation are still required. Doppler methods interrogating tricuspid inflow and pulmonary artery flow velocities, which are influenced by changes in pre- and afterload conditions, may not provide robust prognostic information for clinical decision-making. This chapter addresses the role of the various echocardiographic modalities used to assess the RV and pulmonary circulation. Special emphasis has been placed on technical considerations, limitations, and pitfalls of image acquisition and analysis.

An increasing number of two- and three-dimensional echocardiographic, Doppler, and speckle imaging-derived parameters and values can be related to prognosis in heart failure with left ventricular (LV) systolic dysfunction. This chapter discusses both conventional and new indices, including their advantages and potential limitations. There is increasing evidence for the use of new indices, including three-dimensional LV ejection fraction and global longitudinal strain. The follow-up and monitoring of heart failure patients using two-dimensional transthoracic echocardiography is also discussed in this chapter, including how to estimate the LV filling pressures and quantify LV reverse remodelling.

The assessment of left ventricular (LV) systolic function is one of the most important parts of correct diagnosis, selection of treatment strategy or medications, and prediction of prognosis. Although cardiac magnetic resonance imaging is generally accepted as the gold standard in vivo imaging modality for assessing LV systolic function, its practical use is limited due to its limited availability, high cost, and the presence of conditions precluding its performance such as a pacemaker, claustrophobia, and severe arrhythmia. Thus, transthoracic echocardiography is a first-line imaging modality employed in daily practice and has been widely used. Since the first attempts with M-mode approach, remarkable improvements have been made with the advent of two-dimensional echocardiography, and more recently three-dimensional echocardiography, with high accuracy and reproducibility. More sophisticated methodologies such as strain imaging, based on Doppler or speckle tracking techniques, provide a more sensitive and quantitative measurement of myocardial contractility, and are gaining a place in common daily practice. This chapter describes different modalities that have been used for assessment of LV systolic function based on echocardiography, and is grossly composed of two parts: LV global systolic function and LV regional or segmental systolic function. For better application of these conventional and novel methods of assessing LV systolic function, strengths and pitfalls of these techniques should be acknowledged.

The right atrium (RA) is located on the upper right-hand side of the heart and has relatively thin walls. From an anatomical point of view, the RA comprises three basic parts, the appendage, the vestibule of the tricuspid valve, and the venous component (superior and inferior vena cava, and the coronary sinus) receiving the deoxygenated blood. The RA is a dynamic structure dedicated to receive blood and to assist right ventricular (RV) filling. The three components of atrial function are the reservoir function during ventricular systole, the conduit function which consists in passive blood transfer from veins to the RV in diastole, and the booster pump function in relation to atrial contraction in late diastole to complete ventricular filling. Right atrial function depends on cardiac rhythm (sinus or atrial fibrillation), pericardial integrity, RV load and function, and tricuspid function. Right atrial dimension assessment is limited in two-dimensional (2D) echocardiography. Right atrial planimetry in the apical four-chamber view is commonly used with an upper normal value of 18-20 cm2. Minor and major diameters can also be measured. Three-dimensional (3D) echocardiography could overcome the limitation of conventional echocardiography in assessing RA size. Right atrial function has been poorly explored by echocardiography both in physiological and pathological contexts. Although tricuspid inflow and tissue Doppler imaging of tricuspid annulus can be used in the exploration of RA function, 2D speckle tracking and 3D echocardiography appear promising tools to dissect RA function and to overcome the limitations of standard echocardiography.

Echocardiography is an imaging technique that enables accurate assessment of cardiac structures and cardiac function. Conventional echocardiography involves different modalities—especially the M-mode, the 2D, and colour Doppler, as well as the pulsed-wave and continuous wave Doppler. The M-mode illustrates the reflections of a single sound beam plotted against time. 2D echocardiography enables the documentation of views, which represent characteristic sectional planes of the moving heart during one heart cycle. Colour Doppler echocardiography adds the information of blood flow to the 2D cineloop. Pulsed-wave Doppler is the acquisition of a local blood flow spectrum of a defined region represented by the dimension of the sample volume, whereas continuous wave Doppler displays the blood flow spectrum of all measured blood flow velocities along a straight line sound beam from its beginning to the end. The handling of the transducer has to be target-oriented, stable with respect to the imaging targets, and coordinated with respect to angle differences between the defined views to use all these modalities correctly to get optimal image quality of the cineloops and spectra. Thus, the focus of this chapter will be a mainly practically oriented description of scanning technique in transthoracic and transoesophageal echocardiography.

The transthoracic and transooesophageal documentation is the base of understanding and interpretation of sonographic findings. Practical and technical skills and a standardized acquisition of an echocardiographic image dataset make it possible to compare examinations due to better reproducibility. Standardization is also necessary to make diagnoses correctly and to objectify changes of the cardiovascular state. Despite the wide range of textbooks in the literature, there are limited user-oriented instructions for echocardiography. Thus, the present chapter starts by describing the practical aspects of transducer holding and its handling in transthoracic, as well as transooesophageal, echocardiography. Then, the reader is familiarized with the standard documentation of grey-scale 2D imaging, colour-coded imaging, and spectral Doppler imaging according to the actual international guidelines and recommendations. Illustrations of all important sectional planes are given. In addition, schemata for understanding special views, as well as for incorrect documentation, are given. At the end, a table of standard values and a table of cineloops and spectra belonging to a standardized investigation in echocardiography are given.

Unlike traditional phased-array radars that need successive scans to cover the entire field of view, MIMO radar transmits orthogonal waveforms from each antenna element simultaneously, allowing the illumination of all targets at once. Also, better detection performance and a high spatial resolution can be obtained using all the components extracted by the matched filters. MIMO radar systems can detect the range, angle, and doppler of the targets, using traditional techniques such as the fast fourier transform (FFT), the multiple signal classifier (MUSIC), and the minimum variance distortionless response (MVDR). On the other hand, deep learning (DL) techniques have been proposed for MIMO radar systems as an alternative to traditional techniques that are computationally expensive and very sensitive to clutters and interferences. This chapter presents the performance of MIMO radar systems in a cluttered environment using both conventional and DL techniques.

Traumatic cerebral vascular injury (TCVI) is a frequent, if not universal, feature after traumatic brain injury (TBI). Because multiple pharmacologic and nonpharmacologic therapies promote vascular health, TCVI is an attractive target for therapeutic intervention after TBI. The cerebral microvasculature is a component of the neurovascular unit (NVU) coupling neuronal metabolism with local cerebral blood flow. The NVU participates in the pathogenesis of TBI, either directly from physical trauma or as part of the cascade of secondary injury that occurs after TBI. Pathologically, there is extensive microvascular injury in humans and experimental animals, identified with either conventional light microscopy or ultrastructural examination. Noninvasive, physiologic measures of cerebral microvascular function show dysfunction after TBI in humans and experimental animal models of TBI. These include imaging sequences, transcranial Doppler, and near infrared spectroscopy. Understanding the pathophysiology of TCVI, a relatively understudied component of TBI, has promise for the development of novel therapies for TBI.

The recent developments in the remote sensing technologies have resulted in large amounts of data transmitted from spaceborne sensors. To keep up with the volume, speed, and variety of these data, new data acquisition and visualization systems need to be developed. This chapter focuses on some design and development considerations for a real-time data acquisition and visualization of X-band in a frequency-modulated continuous wave (FMCW) radar. Relevant issues such as high-speed network, parallel data processing system, and large-scale storage system are discussed. Ideally, the acquisition system should be capable of concurrent processing at low cost and visualization technique should be in the same time scale with other conventional 2D visualization of X-band weather radars. Benefits of this type of radar are that it is not just safe and inexpensive, but also serves as a means in filling in gaps of higher-powered pulse-doppler radars when used in conjunction with them.

Abstract Evidence of involvement of sacroiliac joints (sacroiliitis) is one of the hallmarks of AS, usually detected on obtaining the conventional anterior–posterior (AP) or angled (Ferguson’s) view of the pelvis, especially in patients with long-standing disease. However, such pelvic X-ray examinations can sometimes be normal or are difficult to interpret due to various reasons. This is particularly the case in patients being seen in very early stages of their disease. In this situation, a magnetic resonance imaging (MRI) scan appears to be the method of choice for the early detection of sacroiliitis, and is radiation-free, although much more costly and unavailable in some parts of the world. Low dose computed tomography (CT) with minimal radiation has now been increasingly available that can better detect structural bone damage. Ultrasound examination with high-frequency color and power Doppler can be helpful for evaluating peripheral arthritis, tendinitis, and enthesitis. Ultrasonography can also be helpful in placing the needle to aspirate joint fluid or for joint injection.

This chapter discusses the subset of ischemic neuropathy which is due primarily to peripheral arterial disease. Peripheral arterial disease affects 5% of men and 2.5% of women and results in ischemic pain and claudication. Disease progression occurs in a small minority of patients to a stage of critical ischemia with rest pain and threatens limb survival. Ischemic neuropathy encompasses pain due to several stages of progression of tissue ischemia. Patients may have multiple comorbid conditions due to the same pathological process that affects coronary, cerebral, and other circulations. Diabetes mellitus is commonly associated with vascular ischemia and results in arterial occlusive diseases. Pathological changes involve demyelination, axonal loss, and disorderly remyelination. In addition to simple palpation of a pulse, Doppler flow estimation and angiography are used to determine the location and extent of the disease process. Ankle-brachial index, toe-brachial index, and digital flow estimations are more sensitive methods used for early identification. In addition to controlling risk factors and the management of comorbid conditions, medication and procedures to restore blood flow play a prominent role in management of ischemic neuropathy. Sympatholysis and spinal cord stimulation are effective methods to help manage chronic pain in advanced cases that are refractory to conventional treatment measures.

Both the autodyne coherent lidars and conventional coherent lidars using the cw CO2-lasers have a restricted operational range while the use of the pulsed laser increases the range significantly. We try to combine high sensitivity inherent in the autodyne lidar techniques with the capabilities of the pulsed lidar. To this end the hybrid version of cw-pulsed autodyne lidar is suggested. Here both the cw-laser and the pulsed one are placed in the same resonator. The pulsed CO2-laser generates the sounding signals while the cw-laser is used here as a a high sensitive detector. Such an approach makes it possible to determine the time delay between a pulse and its echo, the Doppler frequency shift and to increase the cw autodyne lidar operational range. The description of the experimental setup and the experimental results will be reported as well.

As originally conceived, resonance ionization mass spectrometry (RIMS) combined the elemental selectivity of resonance ionization (1) with the isotopic selectivity of mass spectrometry to improve the accuracy and sensitivity of conventional mass spectrometry (2). For many applications, especially quantitation by isotope dilution (3) , it is important that no isotopic selectivity accompany the resonance ionization process. This condition is easily met for all but a few elements of the periodic table (4), since the great majority of optical isotope shifts are small with respect to typical dye laser bandwidths and Doppler-broadened linewidths in common atom reservoirs. However, another class of problem exists for which it is desirable to achieve isotopically selective resonance ionization. These applications involve the detection of extremely, rare stable or radioactive isotopes in the presence of the major isotopic species of an element. Miller et al. (5) have explored the optical isotopic selectivity of the isotopes of Lu using a RIMS spectrometer equipped with a high-resolution (single-mode) continuous-wave (cw) laser. Cannon et al. (6) have measured an optical selectivity (defined below) of 800 for isotopes of Ba, using a RIMS spectrometer with two cw lasers. We have proposed the use of pulsed, two-photon, Doppler-free resonance ionization to extend the capability of conventional mass spectrometers to measure isotope ratios in excess of 1012 (7). Initial experimental results using this approach, for the isotopes 9Be and 10Be, are reported here.

Single element ultrasonic Doppler velocimeter flow measurement instruments are available (Metflow) that allow velocity measurement along the main lobe of the transducer through gated processing of Doppler shift from echoes from targets in the flow. Correlation of target migration through the time gates has been used to supplement the Doppler data, and to measure void wave speeds when the targets are bubbles in the liquid flow. These methods are developed using helium bubbles in water flow with optical verification, and then used with helium bubbles in mercury. A second method for bubble rise velocity is presented using conventional 2-D medical ultrasound imaging equipment by Terason, with a 12L5V transducer, to develop an ultrasonic imaging analogue to conventional Particle Image Velocimetry. This system is also first tested in the water with helium bubbles using optical verification, and then in the mercury with helium bubbles.

Undersampling is an effective way to simplify the wideband CO2 Doppler lidar hardware as shown in [1,2] offering several times lower sampling frequency. Its application assumes precise analysis for the optimal choice of the sampling frequency and filtering parameters because of the possible aliasing causing a decrease of the SNR. In this work, on the base of simulation and processing of the identical signals, two proposed by us undersampling schemes of wideband detection are compared with the conventional quadrature detection and with sampling at Nyquist frequency directly after the photomixer. Using as a model output the Doppler frequency estimate characteristics, we obtain by the undersampling the same accuracy as with the known methods. The proposed schemes use filters with constant frequency characteristics and do not require a knowledge of reference frequency before the laser shot.