title: Improvement of multislice oxygen-enhanced MRI of the lung by fully automatic non-rigid image registration.
abstract: OBJECTIVE
  In oxygen-enhanced magnetic resonance imaging of the lung (O2-MRI), motion artifacts related to breathing hamper the quality of the parametric O2-maps. In this study, fully automatic non-rigid image registration was assessed as a post-processing method to improve the quality of O2-MRI.
  
  
  METHODS
  Twenty healthy volunteers were investigated on a 1.5 T MR system. O2-MRI was obtained in four coronal sections using an IR-HASTE sequence with TE/TI of 12/1200 ms. Each section was repeatedly imaged during oxygen and room-air ventilation. Spatial differences among the images were corrected by fully automatic non-rigid registration. Signal variability, relative enhancement ratio between oxygen and room air images, and spatial heterogeneity of lung enhancement were assessed before and after image registration.
  
  
  RESULTS
  Motion artifacts were corrected in 5-10s. Non-rigid registration reduced signal variability of the source images and heterogeneity of the O2-maps by 1.1 ± 0.2% and 11.2 ± 2.9%, respectively (p<0.0001). Registration did not influence O2 relative enhancement ratio (p=0.06).
  
  
  CONCLUSIONS
  Fully automatic non-rigid image registration improves the quality of multislice oxygen-enhanced MRI of the lung.
authors: Department of Bioimaging and Radiological Sciences, Catholic University of Rome, Italy. francescomolinari.dr@gmail.com
authors: Francesco
authors: F
authors: Molinari
authors: Grzegorz
authors: G
authors: Bauman
authors: Guglielmo
authors: G
authors: Paolantonio
authors: Tobias
authors: T
authors: Geisler
authors: Bernhard
authors: B
authors: Geiger
authors: Lorenzo
authors: L
authors: Bonomo
authors: Hans-Ulrich
authors: HU
authors: Kauczor
authors: Michael
authors: M
authors: Puderbach
mesh_terms: D000280:Administration, Inhalation; D000328:Adult; D000465:Algorithms; D003287:Contrast Media / Q000008:administration & dosage; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008168:Lung / Q000033:anatomy & histology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000008:administration & dosage; D010363:Pattern Recognition, Automated / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013382:Subtraction Technique
chemical_list: D003287:Contrast Media; D010100:Oxygen