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Your search keyword '"Flentje, Michael"' showing total 25 results
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25 results on '"Flentje, Michael"'

5. Desynchronization of Cartesian k‐space sampling and periodic motion for improved retrospectively self‐gated 3D lung MRI using quasi‐random numbers

Author

Weick, Stefan, primary, Völker, Michael, additional, Hemberger, Kathrin, additional, Meyer, Cord, additional, Ehses, Philipp, additional, Polat, Bülent, additional, Breuer, Felix A., additional, Blaimer, Martin, additional, Fink, Christian, additional, Schad, Lothar R., additional, Sauer, Otto A., additional, Flentje, Michael, additional, and Jakob, Peter M., additional

Published
2016
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9. Late complete remission of supratentorial primitive neuroectodermal tumor (CNS‐PNET) after multiple relapses

Author

von Bueren, André O., primary, Warmuth‐Metz, Monika, additional, Schlegel, Paul G., additional, Soerensen, Niels, additional, Krauss, Juergen, additional, Roggendorf, Wolfgang, additional, Pietsch, Torsten, additional, Feiden, Wolfgang, additional, Graf, Norbert, additional, Pohl, Fabian, additional, Flentje, Michael, additional, Kuehl, Joachim, additional, and Rutkowski, Stefan, additional

Published
2010
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11. Radiotherapy in adrenocortical carcinoma

Author

Polat, Buelent, primary, Fassnacht, Martin, additional, Pfreundner, Leo, additional, Guckenberger, Matthias, additional, Bratengeier, Klaus, additional, Johanssen, Sarah, additional, Kenn, Werner, additional, Hahner, Stefanie, additional, Allolio, Bruno, additional, and Flentje, Michael, additional

Published
2009
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13. Tumor tracking and motion compensation with an adaptive tumor tracking system (ATTS): System description and prototype testing

Author

Wilbert, Jürgen, primary, Meyer, Jürgen, additional, Baier, Kurt, additional, Guckenberger, Matthias, additional, Herrmann, Christian, additional, Heß, Robin, additional, Janka, Christian, additional, Ma, Lei, additional, Mersebach, Torben, additional, Richter, Anne, additional, Roth, Michael, additional, Schilling, Klaus, additional, and Flentje, Michael, additional

Published
2008
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23. Desynchronization of Cartesian k-space sampling and periodic motion for improved retrospectively self-gated 3D lung MRI using quasi-random numbers.

Author

Weick S, Völker M, Hemberger K, Meyer C, Ehses P, Polat B, Breuer FA, Blaimer M, Fink C, Schad LR, Sauer OA, Flentje M, and Jakob PM

Subjects
Adult, Algorithms, Artifacts, Female, Humans, Lung diagnostic imaging, Male, Movement physiology, Imaging, Three-Dimensional methods, Magnetic Resonance Imaging methods, Respiratory-Gated Imaging Techniques methods
Abstract

Purpose: To demonstrate that desynchronization between Cartesian k-space sampling and periodic motion in free-breathing lung MRI improves the robustness and efficiency of retrospective respiratory self-gating., Methods: Desynchronization was accomplished by reordering the phase (k y ) and partition (k z ) encoding of a three-dimensional FLASH sequence according to two-dimensional, quasi-random (QR) numbers. For retrospective respiratory self-gating, the k-space center signal (DC signal) was acquired separately after each encoded k-space line. QR sampling results in a uniform distribution of k-space lines after gating. Missing lines resulting from the gating process were reconstructed using iterative GRAPPA. Volunteer measurements were performed to compare quasi-random with conventional sampling. Patient measurements were performed to demonstrate the feasibility of QR sampling in a clinical setting., Results: The uniformly sampled k-space after retrospective gating allows for a more stable iterative GRAPPA reconstruction and improved ghost artifact reduction compared with conventional sampling. It is shown that this stability can either be used to reduce the total scan time or to reconstruct artifact-free data sets in different respiratory phases, both resulting in an improved efficiency of retrospective respiratory self-gating., Conclusion: QR sampling leads to desynchronization between repeated data acquisition and periodic respiratory motion. This results in an improved motion artifact reduction in shorter scan time. Magn Reson Med 77:787-793, 2017. © 2016 International Society for Magnetic Resonance in Medicine., (© 2016 International Society for Magnetic Resonance in Medicine.)

Published
2017
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24. T-one insensitive steady state imaging: a framework for purely T2-weighted TrueFISP.

Author

Schmitt P, Jakob PM, Kotas M, Flentje M, Haase A, and Griswold MA

Subjects
Humans, Reproducibility of Results, Sensitivity and Specificity, Algorithms, Brain pathology, Brain Neoplasms pathology, Image Enhancement methods, Image Interpretation, Computer-Assisted methods, Magnetic Resonance Imaging methods
Abstract

A new conceptual framework called T-one insensitive steady state imaging is proposed for fast generation of MR images with pure T(2) contrast. This is accomplished by imaging between nonequally spaced inversion pulses, with the magnetization vector alternatively residing in states parallel and antiparallel to B(0) for durations TP(i) and TA(i), respectively. With TP(i) and TA(i) adequately chosen, identical signal time evolution can be obtained for different T(1) values, i.e., T(1) contrast can efficiently be removed from resultant images. As a specific realization of this principle, T-one insensitive steady state imaging sequences are presented which use True free induction steady precession readout blocks between the inversion pulses. While the conventional True free induction steady precession signal time course would be determined by both T(2) and T(1), a pure T(2) dependence is realized with successfully suppressed influence of longitudinal relaxation, and images with essentially T(2) contrast alone are obtained. Analytical expressions are provided for the description of the ideal signal behavior, which help in creating pathways for sequence parameter optimization. The performance of the technique is analyzed with Bloch equation simulations. In vivo results obtained in healthy volunteers and brain tumor patients are presented., (Copyright © 2011 Wiley Periodicals, Inc.)

Published
2012
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25. Inversion recovery TrueFISP: quantification of T(1), T(2), and spin density.

Author

Schmitt P, Griswold MA, Jakob PM, Kotas M, Gulani V, Flentje M, and Haase A

Subjects
Algorithms, Brain anatomy & histology, Computer Simulation, Contrast Media, Electron Spin Resonance Spectroscopy, Humans, Image Processing, Computer-Assisted methods, Models, Theoretical, Phantoms, Imaging, Reproducibility of Results, Image Enhancement methods, Magnetic Resonance Imaging methods
Abstract

A novel procedure is proposed to extract T(1), T(2), and relative spin density from the signal time course sampled with a series of TrueFISP images after spin inversion. Generally, the recovery of the magnetization during continuous TrueFISP imaging can be described in good approximation by a three parameter monoexponential function S(t) = S(stst)(1-INV exp(-t/T(*) (1)). This apparent relaxation time T(*) (1)

Published
2004
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