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Heuristic linear mapping of physiological parameters in dynamic contrast‐enhanced MRI without T 1 measurement and contrast agent concentration
Author(s) -
Yuan Jing,
Chow Steven K.K.,
King Ann D.,
Yeung David K.W.
Publication year - 2012
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.22885
Subject(s) - contrast (vision) , linearity , heuristic , nonlinear system , dynamic contrast , mathematics , magnetic resonance imaging , linear regression , value (mathematics) , computation , algorithm , computer science , statistics , artificial intelligence , mathematical optimization , physics , medicine , radiology , quantum mechanics
Purpose: To present a novel heuristic linear mapping method to individually estimate physiological parameters for Tofts model without T 1 measurement and contrast agent concentration. Materials and Methods: A linear relationship was used for k ep mapping through a heuristic time intensity curve (TIC) shape factor (TSF). K trans maps were subsequently estimated using k ep maps and another approximate linear model derived from the Tofts model. Twenty‐seven patients with head‐and‐neck squamous cell carcinoma received dynamic contrast‐enhanced magnetic resonance imaging (DCE‐MRI). Physiological parameters maps were obtained using this heuristic linear mapping method and compared to the maps obtained by the normal nonlinear least‐square fitting with T 1 measurement. Results: High linearity (R 2 >0.95) between k ep and TSF was found in all patients for k ep <5/min. This linearity is robust for TSF timepoint selection. The k ep maps generated by this linear fitting were highly consistent with those by the normal nonlinear approach ( P > 0.05). The K trans maps were consistent with the normally derived maps in pattern distribution but the absolute value might be scaled due to the assumption of the reference K trans value. Conclusion: This novel method generates reliable and consistent physiological parameter maps with significantly lower computation complexity than the multiparameter nonlinear fitting. The DCE‐MRI scan time can be greatly shortened without T 1 mapping. J. Magn. Reson. Imaging 2012;35:916–925. © 2011 Wiley Periodicals, Inc.