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  • 1
    Keywords: evaluation ; Germany ; imaging ; QUANTIFICATION ; SYSTEM ; SYSTEMS ; VOLUME ; NEW-YORK ; ACCURACY ; SURGERY ; validation ; FLOW ; magnetic resonance ; MAGNETIC-RESONANCE ; magnetic resonance imaging ; VECTORS ; VECTOR ; SURFACE ; RECONSTRUCTION ; COLOR DOPPLER ; LACKING ; VOLUMES ; AORTIC REGURGITATION ; CARDIOVASCULAR-SYSTEM ; CONTROL-VOLUME METHOD ; INTEGRATION ; MITRAL REGURGITATION ; QUANTITATIVE ASSESSMENT ; resonance imaging ; respiratory system ; STANDARD ; VALVULAR REGURGITATION ; VELOCITY
    Abstract: Background. Three-dimensional assessment of regurgitant jet volume is the prerequisite for stratifying valve insufficiency. However, systematic comparison of three-dimensional methods is lacking. Therefore, we evaluated magnetic resonance imaging and three-dimensional echocardiography experimentally. Methods. An insufficiency chamber (22 x 18.5 x 27 cm; ostia 10, 16, and 20 mm; regurgitant volumes 2.3 to 25 mL) within experimental circulation (BioMedicus pump, tubes, pulsatile flow 0.2 to 1.9 L/min) was used for three-dimensional echocardiography (HP Sonos 2500) and magnetic resonance imaging (Siemens Magnetom Vision). Doppler flowmeter served as a gold standard. Segmentation used thresholding and surface integration of velocity vectors. jet volume was evaluated qualitatively by polynom fitting. Results. jet volume calculated by magnetic resonance (r = 0.99, p 〈 0.0001) and by echocardiography (r = 0.99, p 〈 0.0001) correlated identically to the gold standard. jet volume derived from imaging correlated with each other by r = 0.98 (p 〈 0.0001). Polynom fits indicated a more paraboloid shape of magnetic resonance jet volume. Conclusions. Experimentally, three-dimensional echocardiography and magnetic resonance imaging possess identical accuracy for determining regurgitant jet volume. Magnetic resonance imaging seems to provide qualitatively better image data for three-dimensional reconstruction. (C) 2004 by The Society of Thoracic Surgeons
    Type of Publication: Journal article published
    PubMed ID: 15223411
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  • 2
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    German Medical Science GMS Publishing House; Düsseldorf
    In:  Deutscher Kongress für Orthopädie und Unfallchirurgie (DKOU 2012); 20121023-20121026; Berlin; DOCGR15-1463 /20121002/
    Publication Date: 2012-10-03
    Keywords: Osteochondraler Defekt ; Knochen ; Tricalciumphosphat ; Osteoinduktiv ; Wachstumsfaktor ; BMP ; Minipig ; Grosstier ; ddc: 610
    Language: German
    Type: conferenceObject
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  • 3
    Publication Date: 2018-06-30
    Description: Measurements on a quantum particle unavoidably affect its state, since the otherwise unitary evolution of the system is interrupted by a nonunitary projection operation. To probe measurement-induced effects in the state dynamics using a quantum simulator, the challenge is to implement controlled measurements on a small subspace of the system and continue the evolution from the complementary subspace. A powerful platform for versatile quantum evolution is represented by photonic quantum walks because of their high control over all relevant parameters. However, measurement-induced dynamics in such a platform have not yet been realized. We implement controlled measurements in a discrete-time quantum walk based on time-multiplexing. This is achieved by adding a deterministic outcoupling of the optical signal to include measurements constrained to specific positions resulting in the projection of the walker’s state on the remaining ones. With this platform and coherent input light, we experimentally simulate measurement-induced single-particle quantum dynamics. We demonstrate the difference between dynamics with only a single measurement at the final step and those including measurements during the evolution. To this aim, we study recurrence as a figure of merit, that is, the return probability to the walker’s starting position, which is measured in the two cases. We track the development of the return probability over 36 time steps and observe the onset of both recurrent and transient evolution as an effect of the different measurement schemes, a signature which only emerges for quantum systems. Our simulation of the observed one-particle conditional quantum dynamics does not require a genuine quantum particle but is demonstrated with coherent light.
    Electronic ISSN: 2375-2548
    Topics: Natural Sciences in General
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