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Multiple regression method for pulmonary apparent diffusion coefficient measurement by hyperpolarized 3 He MRI
Author(s) -
Yu Jiangsheng,
Ishii Masaru,
Kadlecek Stephen,
Lipson David A.,
Emami Kiarash,
Clark Timothy W.,
Rajaei Sheeva,
Rizi Rahim R.
Publication year - 2007
Publication title -
journal of magnetic resonance imaging
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.563
H-Index - 160
eISSN - 1522-2586
pISSN - 1053-1807
DOI - 10.1002/jmri.20901
Subject(s) - imaging phantom , flip angle , effective diffusion coefficient , nuclear magnetic resonance , diffusion , supine position , linear regression , nonlinear regression , nuclear medicine , diffusion mri , linearity , biomedical engineering , materials science , magnetic resonance imaging , physics , mathematics , medicine , regression analysis , radiology , statistics , thermodynamics , quantum mechanics
Purpose To develop and validate a new multiple regression technique for the separation of flip angle effect in pulmonary apparent diffusion coefficient (ADC) measurement. Materials and Methods Hyperpolarized 3 He MRI (HP 3 He MRI) ADC measurements were performed on phantom, pig, and human models. The diffusion‐sensitization sequence is modified from a standard gradient echo (GRE) sequence with a nonlinear progression in the bipolar gradient amplitude with each image. In the self‐diffusion phantom experiment, four images were acquired with base gradient factor b 0 = 0.15 second/cm 2 ; in the pig and human experiment, six images were acquired with base gradient factor b 0 = 1.4 second/cm 2 . Results The self‐diffusion coefficient measured in the phantom experiment was 1.98 ± 0.16 cm 2 /second. The measured uncertainty curve was consistent with the theoretically predicted curve. The measured in vivo ADC values (three coronal slices in the supine direction) were 0.20/0.16/0.13 cm 2 /second and 0.20/0.18/0.16 cm 2 /second for pig and human experiments, respectively. Conclusion With the introduction of a nonlinear progression in the diffusion‐sensitization gradients, the multiple regression technique is capable of separating the flip angle effect in ADC measurement. In addition, this technique can perform a rigorous measurement uncertainty analysis and provide the optimal scan parameters that yield best noise performance. J. Magn. Reson. Imaging 2007;25:982–991. © 2007 Wiley‐Liss, Inc.