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[en] Angiotomography is a method which is particularly suitable for application in the diagnostics of the vertebrobasilar system on account of its ability to increase the selectivity of angiography, the definition of details, and spatial orientation. Available techniques include angioautotomography with and without accessory device, and simultaneous angiotomography and ists variations. Among the indications, those are predominant where disturbing vascular overtshadowing should be eliminated and certain details emphasized. Angiotomography of the vertebrobasilar system visualizes important vascular structures without overshadowing, and hence also facilitates indirectly the assessment of certain neural structures. The visualization of the contours of vascularized tumors is also improved, and visualization of cystic processe becomes possible. The contrast of discrete tumor staining is enhanced, and, last but not least, visualization of the vessels themselves, as well as of important details, is increased. (orig.) 891 MG
[de]Die Angiotomographie ist ein Verfahren, das sich aufgrund seiner Faehigkeit, stoerende Gefaess- und Knochenschatten zu beseitigen, die Selektivitaet der Gefaessdarstellung und die Detailerkennbarkeit zu erhoehen sowie die raeumliche Orientierung zu verbessern, besonders zur Anwendung in der Diagnostik des vertebrobasilaeren Systems eignet. An Techniken stehen zur Verfuegung die Angio-Autotomographie ohne und mit Zusatzgeraet und die Simultan-Angiotomographie in ihren verschiedenen Formen. Unter den Indikationen dominieren diejenigen, bei denen stoerende Gefaessueberlagerungen eliminiert und bestimmte Gefaessdetails hervorgehoben werden sollen. Die Leistung der Vertebralis-Angiotomographie besteht darin, wichtige Gefaessstrukturen ueberlagerungsfrei darzustellen und damit indirekt die Beurteilung auch der neuralen Strukturen zu erleichtern. Weiter wird die Darstellung der Grenzen vaskularisierter Tumoren verbessert und diejenige zystischer Prozesse ermoeglicht. Der Kontrast diskreter Tumoranfaerbungen wird angehoben, und nicht zuletzt wird auch die Erkennbarkeit der Gefaesse selbst samt wichtiger Details erhoeht. (orig.)
[en] A new computerized single cardiac probe system, designed to be useful in the wide field of the nuclear cardiology, is presented. It has high sensitivity enough for first pass study with small amount of the activity. It has unique programs for calculation of the left-to-right cardiac shunt (L-R shunt) ratio from the pulmonary time-activity curves and calculation for the left ventricular ejection fraction (LVEF) from the first pass time-activity curve. It is also useful in ECG gated cardiac pool studies
[en] An acadius is a monster that sometimes develops in single-ovum twin pregnancies as the results of inequalities in the communicating placental circulation. One twin is well developed and normal, whereas the other is imperfectly formed, with either a rudimentary-hemiacardius or an absent heart-holoacardius. The most common variety of the holoacardiac monster is the acephalus, or headless fetus. Authors report a case of acardius acephalus twins associated with hydramnios in a 28 years old, para 1-0-0-1, diagnosed amorphous twins with serial sonograms, terminate in the 23th week pregnancy and the other in 1-25 years old,para 0-0-0-0, diagnosed twins with FDIU in sonogram. We present these two cases with brief review of literatures.
[en] Waveform acquisition and presentation forms the heart of many measurement systems. Particularly, data acquisition and presentation of repeating complex signals like sine sweep and frequency-modulated signals introduces the challenge of waveform time period estimation and live waveform presentation. This paper presents an intelligent technique, for waveform period estimation of both the complex and simple waveforms, based on the normalized auto-correlation method. The proposed technique is demonstrated using LabVIEW based intensive simulations on several simple and complex waveforms. Implementation of the technique is successfully demonstrated using LabVIEW based virtual instrumentation. Sine sweep vibration waveforms are successfully presented and measured for electrodynamic shaker system generated vibrations. The proposed method is also suitable for digital storage oscilloscope (DSO) triggering, for complex signals acquisition and presentation. This intelligence can be embodied into the DSO, making it an intelligent measurement system, catering wide varieties of the waveforms. The proposed technique, simulation results, robustness study and implementation results are presented in this paper.
[en] The development and evaluation of a prototype cardiac gating system for double-shot dual-energy (DE) imaging is described. By acquiring both low- and high-kVp images during the resting phase of the cardiac cycle (diastole), heart misalignment between images can be reduced, thereby decreasing the magnitude of cardiac motion artifacts. For this initial implementation, a fingertip pulse oximeter was employed to measure the peripheral pulse waveform ('plethysmogram'), offering potential logistic, cost and workflow advantages compared to an electrocardiogram. A gating method was developed that accommodates temporal delays due to physiological pulse propagation, oximeter waveform processing and the imaging system (software, filter-wheel, anti-scatter Bucky-grid and flat-panel detector). Modeling the diastolic period allowed the calculation of an implemented delay, timp, required to trigger correctly during diastole at any patient heart rate (HR). The model suggests a triggering scheme characterized by two HR regimes, separated by a threshold, HRthresh. For rates at or below HRthresh, sufficient time exists to expose on the same heartbeat as the plethysmogram pulse [timp(HR) = 0]. Above HRthresh, a characteristic timp(HR) delays exposure to the subsequent heartbeat, accounting for all fixed and variable system delays. Performance was evaluated in terms of accuracy and precision of diastole-trigger coincidence and quantitative evaluation of artifact severity in gated and ungated DE images. Initial implementation indicated 85% accuracy in diastole-trigger coincidence. Through the identification of an improved HR estimation method (modified temporal smoothing of the oximeter waveform), trigger accuracy of 100% could be achieved with improved precision. To quantify the effect of the gating system on DE image quality, human observer tests were conducted to measure the magnitude of cardiac artifact under conditions of successful and unsuccessful diastolic gating. Six observers independently measured the artifact in 111 patient DE images. The data indicate that successful diastolic gating results in a statistically significant reduction (p < 0.001) in the magnitude of cardiac motion artifact, with residual artifact attributed primarily to gross patient motion.
[en] We aimed to develop new equations that predict exercise-induced energy expenditure (EE) more accurately than previous ones during running by including new parameters as fitness level, body composition and/or running intensity in addition to heart rate (HR). Original equations predicting EE were created from data obtained during three running intensities (25%, 50% and 70% of HR reserve) performed by 50 subjects. Five equations were conserved according to their accuracy assessed from error rates, interchangeability and correlations analyses: one containing only basic parameters, two containing VO_2_m_a_x or speed at VO_2_m_a_x and two including running speed with or without HR. Equations accuracy was further tested in an independent sample during a 40 min validation test at 50% of HR reserve. It appeared that: (1) the new basic equation was more accurate than pre-existing equations (R"2 0.809 versus. 0,737 respectively); (2) the prediction of EE was more accurate with the addition of VO_2_m_a_x (R"2 = 0.879); and (3) the equations containing running speed were the most accurate and were considered to have good agreement with indirect calorimetry. In conclusion, EE estimation during running might be significantly improved by including running speed in the predictive models, a parameter readily available with treadmill or GPS. (paper)
[en] A new algorithm which exploits digital image processing and pattern recognition methods for automated definition of left ventricular (LV) contours is presented. Digital image processing and pattern recognition techniques are applied to digitally acquired radiographic images of the heart to extract the LV contours required for quantitative analysis of cardiac function. Knowledge of the image domain is invoked at each step of the algorithm in order to orient the data search and thereby reduce complexity of the solution. A knowledge-based image transformation, directional gradient search, expectations of object versus background location, least-cost path searches by dynamic programming, and a digital representation of possible versus impossible ventricular shape are exploited. The digital representation, composed of a set of characteristic templates, was created using contours obtained by manual tracing
[en] The dissertation deals with a methodological enhancement of a fast MR imaging technique, the snapshot-FLASH (fast low-angle shot) technique. The first and primary goal was to optimize the snapshot-FLASH technique with a view to its application for diagnostic imaging of the heart. This optimization was to achieve a further reduction of measuring time per single shot and an increase in information gained per time unit. Another very important goal was to improve the method towards more exact, faster and as efficient as possible measurement of n.m.r. parameters. With these goals in mind, new two- or three-dimensional versions and a multilayered version of the snapshot-FLASH imaging sequence were developed. The results obtained in practice are explained and discussed. (orig./DG)
[de]Die Arbeit beschaeftigt sich mit der methodischen Weiterbildung eines schnellen Bildgebungsverfahrens mittels kernmagnetischer Resonanz, der ''Snapshot-FLASH (Fast Low Angle Shot)''-Bildgebung. Im Vordergrund stand die Optimierung der ''Snapshot-FLASH''-Technik hinsichtlich einer praktikablen Anwendung zur Herzbildgebung. Damit war eine weitere Reduzierung der Messzeiten pro Einzelbild und eine Erhoehung des Informationsgewinns pro Zeiteinheit verbunden. Aber auch die Weiterbildung dieser Methode zur exakten, schnellen und moeglichst effektiven Messung von NMR-Parametern wurde beruecksichtigt. Ausgehend von diesen Anforderungen wurden neue zwei- bzw. dreidimensionale Versionen und eine Mehrschichtversion der ''Snapshot-FLASH''-Sequenz entwickelt und die damit erzielten Ergebnise in ihrer konkreten Anwendung vorgestellt und diskutiert. (orig./DG)
[en] FK506 is widely used as a potent immunosuppressive agent following organ transplantation. However, the use of FK506 is associated with a wide spectrum of neurotoxicity. FK506-induced cerebral infarctions have rarely been reported. We report here on a case of the acute cerebral infarction caused by vasospasm after FK506 administration in a kidney transplantation recipient. There were areas with increased signal intensity on the diffusion-weighted image. The areas showing increased signal intensity on the diffusion- and T2-weighted images demonstrated decreased signal intensity on the apparent diffusion coefficient mapping. MR angiography showed diffuse stenosis in both the anterior and middle cerebral arteries