Hendrik Zimmermann

Publications (2)5.32 Total impact

• Source

  Available from: Christian Fink

  Article: Influence of different breathing maneuvers on internal and external organ motion: use of fiducial markers in dynamic MRI.

  Christian Plathow, Hendrik Zimmermann, Christian Fink, Reiner Umathum, Max Schöbinger, Peter Huber, Ivan Zuna, Juergen Debus, Wolfgang Schlegel, Hans-Peter Meinzer, Wolfhard Semmler, Hans-Ulrich Kauczor, Michael Bock
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  ABSTRACT: To investigate, with dynamic magnetic resonance imaging (dMRI) and a fiducial marker, the influence of different breathing maneuvers on internal organ and external chest wall motion. Lung and chest wall motion of 16 healthy subjects (13 male, 3 female) were examined with real-time trueFISP (true fast imaging with steady-state precession) dMRI and a small inductively coupled marker coil on either the abdomen or thorax. Three different breathing maneuvers were performed (predominantly "abdominal breathing," "thoracic breathing," and unspecific "normal breathing"). The craniocaudal (CC), anteroposterior (AP), and mediolateral (ML) lung distances were correlated (linear regression coefficient) with marker coil position during forced and quiet breathing. Differences of the CC distance between maximum forced inspiration and expiration were significant between abdominal and thoracic breathing (p < 0.05). The correlation between CC distance and coil position was best for forced abdominal breathing and a marker coil in the abdominal position (r = 0.89 +/- 0.04); for AP and ML distance, forced thoracic breathing and a coil in the thoracic position was best (r = 0.84 +/- 0.03 and 0.82 +/- 0.03, respectively). In quiet breathing, a lower correlation was found. A fiducial marker coil external to the thorax in combination with dMRI is a new technique to yield quantitative information on the correlation of internal organ and external chest wall motion. Correlations are highly dependent on the breathing maneuver.
  International Journal of Radiation OncologyBiologyPhysics 06/2005; 62(1):238-45. · 4.11 Impact Factor
• Article: [Measurements of respiratory motion using fast magnetic resonance imaging and inductively-coupled marker coils].

  Hendrik Zimmermann, Reiner Umathum, Christian Plathow, Wolfhard Semmler, Wolfgang Nitz, Michael Bock
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  ABSTRACT: The respiratory motion of the thoracic wall provides indirect information about the breathing displacement of the inner organs. To analyze the correlation between thoracic wall and lung motion for applications in radiation therapy, the breathing displacement of the lung is visualized with a fast gradient echo pulse sequence (trueFISP) at a rate of 2-3 images/sec. For quantification of the motion, a small inductively-coupled marker coil is attached to the chest wall and detected with a fast projection technique. Since the marker coil generates a flip angle amplification (factor 15) in its interior, very small nominal flip angles of 2 degrees can be used during the projection measurements which do not affect the image quality of the trueFISP images. Volunteer studies with the marker coil showed a good agreement with simultaneously acquired breathing belt data and position information extracted from the MR images. Whereas the breathing belt provided reliable data only within a certain dynamic range, the marker coil could detect also extreme breathing excursions with a precision better than 2 millimeters.
  Zeitschrift für Medizinische Physik 02/2005; 15(1):38-44. · 1.21 Impact Factor