PURPOSE: 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. MATERIALS AND 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 chi(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 x 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). CONCLUSION: The study demonstrated the impact of nonrigid motion correction technique on pixel-wise pharmacokinetic analysis of free-breathing DCE-MRI in SPNs.
Tokuda, JunichiMamata, HatsuhoGill, Ritu RHata, NobuhikoKikinis, RonPadera, Robert F JrLenkinski, Robert ESugarbaker, David JHatabu, HirotoP01 CA067165/CA/NCI NIH HHS/United StatesP01 CA067165-12/CA/NCI NIH HHS/United StatesP41 RR013218-13/RR/NCRR NIH HHS/United StatesP41 RR019703-06/RR/NCRR NIH HHS/United StatesP41RR-013218/RR/NCRR NIH HHS/United StatesR21 CA116271/CA/NCI NIH HHS/United StatesR21 CA116271-02/CA/NCI NIH HHS/United StatesU41 RR019703/RR/NCRR NIH HHS/United StatesU54 EB005149/EB/NIBIB NIH HHS/United StatesU54 EB005149-06/EB/NIBIB NIH HHS/United StatesResearch Support, N.I.H., ExtramuralUnited StatesJournal of magnetic resonance imaging : JMRIJ Magn Reson Imaging. 2011 Apr;33(4):968-73. doi: 10.1002/jmri.22490.