title: 4D-MRI analysis of lung tumor motion in patients with hemidiaphragmatic paralysis.
abstract: OBJECTIVE
  To investigate the complex breathing patterns in patients with hemidiaphragmatic paralysis due to malignant infiltration using four-dimensional magnetic resonance imaging (4D-MRI).
  
  
  METHODS
  Seven patients with bronchial carcinoma infiltrating the phrenic nerve were examined using 1.5 T MRI. The motion of the tumor and of both hemi-diaphragms were measured on dynamic 2D TrueFISP and 4D FLASH MRI sequences.
  
  
  RESULTS
  For each patient, 3-6 breathing cycles were recorded. The respiratory-induced mean cranio-caudal displacement of the tumor was 6.6 mm (+/-2.8 SD). The mean displacement anterior-posterior was 7.4 mm (+/-2.6), while right-left movement was about 7.4 mm (+/-4.5). The mediastinum moved sidewards during inspiration, realizing a "mediastinal shift". The paralyzed hemidiaphragm and the tumor showed a paradox motion during respiration in five patients. In two patients, the affected hemidiaphragm had a regular, however minimal and asynchronous motion during respiration. Respiratory variability of both tumor and diaphragm motions was about 20% although patients were instructed to breath normally. The findings showed significant differences compared to breathing patterns of patients without diaphragm dysfunction.
  
  
  CONCLUSIONS
  4D-MRI is a promising tool to analyze complex breathing patterns in patients with lung tumors. It should be considered for use in planning of radiotherapy to account for individual tumor motion.
authors.affiliation: Department of Radiology, German Cancer Research Center, Heidelberg, Germany. j.dinkel@dkfz-heidelberg.de
authors.forename: Julien
authors.initials: J
authors.lastname: Dinkel
authors.forename: Christian
authors.initials: C
authors.lastname: Hintze
authors.forename: Ralf
authors.initials: R
authors.lastname: Tetzlaff
authors.forename: Peter E
authors.initials: PE
authors.lastname: Huber
authors.forename: Klaus
authors.initials: K
authors.lastname: Herfarth
authors.forename: Juergen
authors.initials: J
authors.lastname: Debus
authors.forename: Hans U
authors.initials: HU
authors.lastname: Kauczor
authors.forename: Christian
authors.initials: C
authors.lastname: Thieke
mesh_terms: D000328:Adult; D000368:Aged; D001984:Bronchial Neoplasms / Q000503:physiopathology*; D003964:Diaphragm / Q000503:physiopathology*; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007091:Image Processing, Computer-Assisted; D008175:Lung Neoplasms / Q000503:physiopathology*; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D009068:Movement; D010791:Phrenic Nerve / Q000503:physiopathology*; D015656:Respiratory Mechanics