title: Impact of nonrigid motion correction technique on pixel-wise pharmacokinetic analysis of free-breathing pulmonary dynamic contrast-enhanced MR imaging.
abstract: OBJECTIVE
  To investigates the impact of nonrigid motion correction on pixel-wise pharmacokinetic analysis of free-breathing DCE-MRI in patients with solitary pulmonary nodules (SPNs). Misalignment of focal lesions due to respiratory motion in free-breathing dynamic contrast-enhanced MRI (DCE-MRI) precludes obtaining reliable time-intensity curves, which are crucial for pharmacokinetic analysis for tissue characterization.
  
  
  METHODS
  Single-slice 2D DCE-MRI was obtained in 15 patients. Misalignments of SPNs were corrected using nonrigid B-spline image registration. Pixel-wise pharmacokinetic parameters K(trans) , v(e) , and k(ep) were estimated from both original and motion-corrected DCE-MRI by fitting the two-compartment pharmacokinetic model to the time-intensity curve obtained in each pixel. The "goodness-of-fit" was tested with χ(2) -test in pixel-by-pixel basis to evaluate the reliability of the parameters. The percentages of reliable pixels within the SPNs were compared between the original and motion-corrected DCE-MRI. In addition, the parameters obtained from benign and malignant SPNs were compared.
  
  
  RESULTS
  The percentage of reliable pixels in the motion-corrected DCE-MRI was significantly larger than the original DCE-MRI (P = 4 × 10(-7) ). Both K(trans) and k(ep) derived from the motion-corrected DCE-MRI showed significant differences between benign and malignant SPNs (P = 0.024, 0.015).
  
  
  CONCLUSIONS
  The study demonstrated the impact of nonrigid motion correction technique on pixel-wise pharmacokinetic analysis of free-breathing DCE-MRI in SPNs.
authors: Harvard Medical School, Boston, MA, USA. tokuda@bwh.harvard.edu
authors: Junichi
authors: J
authors: Tokuda
authors: Hatsuho
authors: H
authors: Mamata
authors: Ritu R
authors: RR
authors: Gill
authors: Nobuhiko
authors: N
authors: Hata
authors: Ron
authors: R
authors: Kikinis
authors: Robert F
authors: RF
authors: Padera
authors: Robert E
authors: RE
authors: Lenkinski
authors: David J
authors: DJ
authors: Sugarbaker
authors: Hiroto
authors: H
authors: Hatabu
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003196:Computer Graphics; D003287:Contrast Media / Q000494:pharmacology; D003952:Diagnostic Imaging / Q000379:methods; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D007700:Kinetics; D008168:Lung / Q000473:pathology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009038:Motion; D015203:Reproducibility of Results; D012119:Respiration; D014584:User-Computer Interface
chemical_list: D003287:Contrast Media